Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0008370 (cholestasis)
 9,378 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We compared the diagnostic utility of DU-PAN-2 and CAR-3 with that of CA 19-9 in differentiating pancreatic cancer (23 patients) from chronic pancreatitis (16 patients) and various extra-pancreatic diseases (28 patients) mainly of the upper gastrointestinal and biliary tract. The influence of some pathophysiologic variables on the three markers was also assessed. The sensitivities of the three markers in detecting pancreatic cancer were: CA 19-9, 83%; DU-PAN-2, 56%; and CAR-3, 39%. In patients with chronic pancreatitis and extra-pancreatic diseases, CA 19-9 gave the highest number of false positives. Receiver-operating characteristic curves showed that the ability of CAR-3 to discriminate between pancreatic cancer and other diseases was similar to that of CA 19-9, whereas DU-PAN-2 was a less reliable discriminator. Correlations were found between the behavior of all three markers and that of the cholestasis indices (ALP and GGT). Our findings indicate that DU-PAN-2 and CAR-3 serum determinations do not provide any more information than does CA 19-9 alone. The latter remains the marker of choice in the differential diagnosis of pancreatic cancer, even though it cannot be considered a definitive aid. Serum levels of all three markers increase in the presence of extra-hepatic cholestasis, possibly due to interference with the hepatic clearance of glycoproteins and destruction of ductal biliary epithelium.
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PMID:Comparison of two newly identified tumor markers (CAR-3 and DU-PAN-2) with CA 19-9 in patients with pancreatic cancer. 167 69

The aim of this study was to compare the utility of two recently identified tumour markers of pancreatic cancer, CA 19-9 and CAR-3, and to ascertain the roles of some factors influencing both antigens. CA 19-9 and CAR-3 were measured in sera of 18 control subjects, 27 patients with pancreatic cancer, 25 with chronic pancreatitis, and 29 with extra-pancreatic diseases. CA 19-9 and CAR-3 were, respectively, found to be increased in 85 per cent and 44 per cent of patients with pancreatic cancer, 28 per cent and 0 per cent with chronic pancreatitis and 72 per cent and 28 per cent with extra-pancreatic diseases. The ROC curves showed that, for any serum value considered, CA 19-9 is more effective than CAR-3 in discriminating between pancreatic cancer and control subjects and chronic pancreatitis. With the combined use of both antigens the results were no better than those given by CA 19-9 alone. Correlations were found between liver function tests and CA 19-9 levels and between cholestasis indices only and CAR-3 values. Our findings show that CAR-3 is not a sufficiently reliable marker of pancreatic cancer, due to its low sensitivity. Nor does it offer any more information than CA 19-9. Both assays are influenced, at least in part, by the extent of the neoplasia. Cholestasis which can greatly influence a serum glycoproteic marker such as CA 19-9, was found also to affect, to a lesser extent, CAR-3, an epitope on the same mucin molecule.
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PMID:CAR-3 and CA 19-9 serum levels in pancreatic cancer: any differences between two epitopes of the same mucin-like glycoprotein? 170 17

A new tumour marker, CAR-3, was isolated using the monoclonal antibody technique and measured in the sera of 27 patients with pancreatic cancer, 25 chronic pancreatitis, 30 extra-pancreatic diseases and in that of 18 healthy controls in order (1) to evaluate the diagnostic role of CAR-3 in patients with pancreatic cancer and (2) to ascertain whether liver dysfunction influences CAR-3 serum levels. The increased levels were found in 12/27 patients with pancreatic cancer (sensitivity 44.4%). No increase was found in patients with chronic pancreatitis, whereas abnormal levels were found in patients with other gastrointestinal diseases, especially those of the liver and biliary tract. Correlations were found between serum CAR-3 and (1) total bilirubin and (2) alkaline phosphatase. In conclusion, CAR-3, an antigen structurally related to CA 19-9, does not appear to be accurate enough to be considered a tumour marker. Cholestasis seems to increase CAR-3 levels as well as those of other glycoproteic tumour markers, probably by interfering with the hepatic clearance of these substances.
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PMID:Does serum CAR-3 play a role in pancreatic cancer diagnosis? 198 95

The ABC transporter, Mrp4, transports the sulfated steroid DHEA-s, and sulfated bile acids interact with Mrp4 with high affinity. Hepatic Mrp4 levels are low, but increase under cholestatic conditions. We therefore inferred that up-regulation of Mrp4 during cholestasis is a compensatory mechanism to protect the liver from accumulation of hydrophobic bile acids. We determined that the nuclear receptor CAR is required to coordinately up-regulate hepatic expression of Mrp4 and an enzyme known to sulfate hydroxy-bile acids and steroids, Sult2a1. CAR activators increased Mrp4 and Sult2a1 expression in primary human hepatocytes and HepG2, a human liver cell line. Sult2a1 was down-regulated in Mrp4-null mice, further indicating an inter-relation between Mrp4 and Sult2a1 gene expression. Based on the hydrophilic nature of sulfated bile acids and the Mrp4 capability to transport sulfated steroids, our findings suggest that Mrp4 and Sult2a1 participate in an integrated pathway mediating elimination of sulfated steroid and bile acid metabolites from the liver.
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PMID:Interactions between hepatic Mrp4 and Sult2a as revealed by the constitutive androstane receptor and Mrp4 knockout mice. 1500 17

BALB/c Fech(m1Pas) mice have a mutated ferrochelatase gene resulting in protoporphyria that models the hepatic injury occurring sporadically in human erythropoietic protoporphyria. We used this mouse model to study the development of the injury and to compare the dysfunction of heme synthesis with hepatic gene expression of liver metabolism, oxidative stress, and cellular injury/inflammation. From an early age expression of total cytochrome P450 and many of its isoforms was significantly lower than in wild-type mice. However, despite massive accumulation of protoporphyrin in the liver, expression of the main genes controlling heme synthesis and catabolism (Alas1 and Hmox1, respectively) were only modestly affected even in the presence of the cytochrome P450-inducing CAR agonist 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene. In contrast, in BALB/c mice exhibiting griseofulvin-induced hepatic protoporphyria with induction and destruction of cytochrome P450, both Alas1 and Hmox1 genes were markedly up-regulated. Other expression profiles in BALB/c Fech(m1Pas) mice identified roles for oxidative mechanisms in liver injury while modulated gene expression of hepatocyte transport proteins and cholesterol and bile acid synthesis illustrated the development of cholestasis. Subsequent inflammation and cirrhosis were also shown by the up-regulation of cytokine, cell cycling, and procollagen genes. Thus, gene expression profiles studied in Fech(m1Pas) mice may provide candidates for human polymorphisms that explain the sporadic hepatic consequences of erythropoietic protoporphyria.
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PMID:Hepatic gene expression in protoporphyic Fech mice is associated with cholestatic injury but not a marked depletion of the heme regulatory pool. 1579 85

The detoxification and elimination of potentially toxic foreign and endogenous compounds depends on the concerted action of xenobiotic metabolizing enzymes. Nuclear hormone receptors (NHRs) have emerged as key regulators of the expression of these enzymes and his review focuses on the xenosenor CAR (Constitutive Androstane Receptor, NR1I3). CAR is highly expressed in the liver and the small intestine, two key tissues expressing xenobiotic metabolizing enzymes, and mediates the induction of their expression by the widely used antiepileptic drug, phenobarbital (PB) and the potent synthetic inducer 1, 4-bis-(2-(3, 5, -dichloropyridyloxy)) benzene (TCPOBOP). TCPOBOP is an agonist ligand for CAR. PB induces its nuclear translocation, which results in increased expression of CAR target genes since, unlike the classical, ligand-dependent nuclear receptors, CAR is an apparently constitutive transactivator. This constitutive activity is inhibited by the inverse agonist ligands androstanol and androstenol. The CAR mediated induction of the expression of xenobiotic metabolizing enzymes is generally protective, but can be deleterious if toxic metabolites are produced. CAR also has a protective role in the stress response elicited by hyperbilirubinemia, as well as lithocholic acid induced cholestasis. In addition, recent studies show that CAR activation disrupts thyroid hormone homeostasis. Finally, CAR activation promotes hepatocyte proliferation and blocks apoptosis, and is essential for the tumorigenesis induced by its activators PB and TCPOBOP. The role of CAR in endobiotic and xenobiotics metabolism has clinical implications in disease prevention, drug-drug interactions, and the development of better drug treatments.
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PMID:CAR, the continuously advancing receptor, in drug metabolism and disease. 1610 72

Hepatic uptake and biliary excretion of organic anions (e.g., bile acids and bilirubin) is mediated by hepatobiliary transport systems. Defects in transporter expression and function can cause or maintain cholestasis and jaundice. Recruitment of alternative export transporters in coordination with phase I and II detoxifying pathways provides alternative pathways to counteract accumulation of potentially toxic biliary constituents in cholestasis. The genes encoding for organic anion uptake (NTCP, OATPs), canalicular export (BSEP, MRP2) and alternative basolateral export (MRP3, MRP4) in liver are regulated by a complex interacting network of hepatocyte nuclear factors (HNF1, 3, 4) and nuclear (orphan) receptors (e.g., FXR, PXR, CAR, RAR, LRH-1, SHP, GR). Bile acids, proinflammatory cytokines, hormones and drugs mediate causative and adaptive transporter changes at a transcriptional level by interacting with these nuclear factors and receptors. Unraveling the underlying regulatory mechanisms may therefore not only allow a better understanding of the molecular pathophysiology of cholestatic liver diseases but should also identify potential pharmacological strategies targeting these regulatory networks. This review is focused on general principles of transcriptional basolateral and canalicular transporter regulation in inflammation-induced cholestasis, ethinylestradiol- and pregnancy-associated cholestasis, obstructive cholestasis and liver regeneration. Moreover, the potential therapeutic role of nuclear receptor agonists for the management of liver diseases is highlighted.
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PMID:Principles of hepatic organic anion transporter regulation during cholestasis, inflammation and liver regeneration. 1729 2

To investigate how the liver adapts to chronic obstructive cholestasis, liver samples from infants with early- and late-stage cholestasis were analyzed for changes in the levels of hepatocyte transporters and nuclear receptors. At early-stage cholestasis, most canalicular transporters and sinusoidal uptake transporters were downregulated, including bile salt export pump (BSEP, ABCB11), multidrug resistant protein 3 (MDR3, ABCB4), multidrug-resistant associated protein 2 (MRP2, ABCC2), sodium-dependent taurocholate cotransporting polypeptide (NTCP, SLC10A1), organic anion transporter (OATP, SLCO1A2), and nuclear receptor farnesoid X receptor (FXR, NR1H4). At late-stage cholestasis, FXR-BSEP levels returned to normal, MDR3 and MDR1 (ABCB1) were upregulated, and MRP-2 was downregulated. In addition, alternative sinusoidal efflux transporters, organic solute transporter alpha/beta (OSTalpha/beta) and MRP4 were upregulated, and pregnane X receptor (PXR, NR1I2) levels decreased. Cytochrome enzyme P450 7A1 was markedly downregulated at both early and late-stage cholestasis. An analysis of the long-term prognosis of 18 patients revealed lower PXR and constitutive androstane receptor (CAR, NR1I3) levels in the poor prognosis group. In conclusion, at long-term cholestasis, hepatocyte bile efflux was through sinusoidal and canalicular transporters, with FXR-BSEP levels maintained and PXR downregulated. Low PXR and CAR levels were associated with poor prognosis.
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PMID:Expression of hepatocyte transporters and nuclear receptors in children with early and late-stage biliary atresia. 1832 54

Decreased drug metabolism, hyperbilirubinemia and intrahepatic cholestasis are frequently observed during inflammation. Additionally, it has long been appreciated that exposure to drug metabolism-inducing xenobiotics can impair immune function. The nuclear receptor CAR (constitutive androstane receptor or NR1I3) and PXR (pregnane X receptor, NR1I2) control phase I (cytochrome P450 2B and 3A), phase II (GSTA, UGT1A1), and transporter (MDR1, SLC21A6, MRP2) genes involved in drugs metabolism, bile acids and bilirubin clearance in response to xenobiotics. It is well known that inflammation, through the activation of NF-kappaB pathway, leads to a decrease of CAR, PXR and RXRalpha expression and the expression of their target genes. In addition, a new study reveals the mutual repression between PXR and NF-kappaB signaling pathways, providing a molecular mechanism linking xenobiotic metabolism and inflammation.
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PMID:[[Inflammation and drug metabolism: NF-kappB and the CAR and PXR xeno-receptors]. 1833 80

We previously reported that mice deficient in stearoyl-CoA desaturase-1 (Scd1) and maintained on a very low-fat (VLF) diet for 10 days developed severe loss of body weight, hypoglycemia, hypercholesterolemia, and many cholestasis-like phenotypes. To better understand the metabolic changes associated with these phenotypes, we performed microarray analysis of hepatic gene expression in chow- and VLF-fed female Scd1+/+ and Scd1-/- mice. We identified an extraordinary number of differentially expressed genes (>4,000 probe sets) in the VLF Scd1-/- relative to both VLF Scd1+/+ and chow Scd1-/- mice. Transcript levels were reduced for genes involved in detoxification and several facets of fatty acid metabolism including biosynthesis, elongation, desaturation, oxidation, transport, and ketogenesis. This pattern is attributable to the decreased mRNA abundance of several genes encoding key transcription factors, including LXRalpha, RXRalpha, FXR, PPARalpha, PGC-1beta, SREBP1c, ChREBP, CAR, DBP, TEF, and HLF. A robust induction of endoplasmic reticulum (ER) stress is indicated by enhanced splicing of XBP1, increased expression of the stress-induced transcription factors CHOP and ATF3, and elevated expression of several genes involved in the integrated stress and unfolded protein response pathways. The gene expression profile is also consistent with induction of an acute inflammatory response and macrophage recruitment. These results highlight the importance of monounsaturated fatty acid synthesis for maintaining metabolic homeostasis in the absence of sufficient dietary unsaturated fat and point to a novel cellular nutrient-sensing mechanism linking fatty acid availability and/or composition to the ER stress response.
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PMID:Liver gene expression analysis reveals endoplasmic reticulum stress and metabolic dysfunction in SCD1-deficient mice fed a very low-fat diet. 1838 40


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