Papers by Rocío García Macías
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2005
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Pediatric Research, 1995
Bile acids and bilirubin are synthesized by the fetal liver very early on during intrauterine lif... more Bile acids and bilirubin are synthesized by the fetal liver very early on during intrauterine life. The main fate of these compounds is to be transferred to the mother. This excretory role of the placenta is primarily determined by the ability of the trophoblast to transport them, which is believed to occur mainly by carrier-mediated processes. The aim of this study was to investigate the role of the cholephilic organic anion exchanger located in the fetal-facing plasma membrane of the human trophoblast in placental "biliary-like" function. No relationship between the magnitude of transplacental gradients for total bile acids and bilirubin was found. However, transport studies, which were carried out by using purified plasma membrane vesicles derived from the fetal-facing pole of the human trophoblast, revealed that [14C]taurocholate transport was affected by both another bile acid (taurochenodeoxycholic acid) and a non-bile acid cholephilic organic anion (bromosulfophthalein). On plotting the ability of different major bile acid species to inhibit radiolabeled taurocholate uptake by these vesicles versus their concentrations in fetal serum or the magnitude of their transplacental gradients, inverse relationships were found. Lower fetal serum concentrations and transplacental gradients were found for bile acid species with higher abilities to affect this transport and presumably to interact with the carrier. By contrast, the magnitude of the transplacental gradient for bile acid species was not correlated with their hydrophobic/hydrophilic balance, as would be expected if diffusion across the lipidic structures of the placental barrier would be the major pathway for the flux of bile acid across this organ.(ABSTRACT TRUNCATED AT 250 WORDS)
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International Journal of Cancer, 1998
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Journal of Hepatology, 1998
Bile acids have previously been used as shuttles for directing organic drugs to the liver. The ai... more Bile acids have previously been used as shuttles for directing organic drugs to the liver. The aim of this study was to investigate liver transport and biotransformation of a new cytostatic bioinorganic complex (Bamet-H2), that was obtained by binding platinum(II) to two cholylglycinate moieties. Using rat hepatocytes in primary culture, the kinetics of cholylglycinate, cisplatin and Bamet-H2 uptake were studied. Sodium-dependency of Bamet-H2 uptake was investigated by replacement of 116 mM NaCl by 116 mM choline chloride. Liver biotransformation was investigated by HPLC analysis of bile samples collected from anesthetized rats following intravenous Bamet-H2 administration. Using isolated rat liver preparations, which were perfused with erythrocyte- and albumin-free Krebs-Henseleit solutions for 40 min, measurement of cholylglycinate, cisplatin and Bamet-H2 uptake and bile output was carried out. Interaction between Bamet-H2 and cholylglycinate for liver transport was studied by co-administration of 1 microM Bamet-H2 plus 500 microM cholylglycinate and 1 microM [14C]-cholylglycinate plus 500 microM Bamet-H2. Both cholylglycinate and Bamet-H2 uptake by rat hepatocytes followed saturation kinetics. Comparison between the two compounds indicated that the Vmax (22.2 versus 8.5 nmol.5 min(-1).mg protein(-1)), and Kt (365 versus 171 microM) were higher for Bamet-H2 uptake. The efficiency of Bamet-H2 uptake (Vmax/Kt) was significantly reduced (-35%) in the absence of sodium. Cisplatin uptake by rat hepatocytes was approximately 10-fold lower than that for Bamet-H2 at any dose used. Moreover, this was not saturable up to 400 microM cisplatin. Bamet-H2 was not biotransformed during its intrahepatic residence in anesthetized rats. Bamet-H2 uptake and secretion into bile by isolated rat livers exceeded cisplatin but were less than cholylglycinate. Differences between Bamet-H2 and cholylglycinate were more marked for bile output than for liver uptake. Thus, higher drug liver content was found after perfusion with Bamet-H2 than with cholylglycinate or cisplatin. Co-administration of Bamet-H2 and cholylglycinate revealed the existence of partial cross-inhibition in both liver uptake and bile output. Bamet-H2 induced a more profound alteration on cholylglycinate uptake and bile secretion than cholylglycinate on both process for Bamet-H2. These results suggest that in the transfer of Bamet-H2 from the sinusoids to the canaliculi both bile acid and non-bile acid transport systems are involved.
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Biochemical Pharmacology, 2007
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Liver International, 2008
Potentially toxic endogenous compounds, such as bile acids (BAs) and biliary pigments, as well as... more Potentially toxic endogenous compounds, such as bile acids (BAs) and biliary pigments, as well as many xenobiotics, such as drugs and food components, are biotransformed and eliminated by the hepatobiliary system with the collaboration of the kidney. However, the situation is very different during pregnancy because the fetal liver produces biliary compounds despite the fact that this organ, owing to its immaturity, is not able to eliminate them into bile. Moreover, the excretory ability of the fetal kidneys is also very limited. Thus, during the intra-uterine life, the major route to eliminate fetal BAs and biliary pigments is their transfer to the mother across the placenta. The maternal liver and, to a lesser extent, the maternal kidney, are then in charge of their biotransformation and elimination into faeces and urine respectively. This review describes current knowledge of the machinery responsible for the detoxification and excretion of cholephilic compounds through the pathway formed by the fetal liver–placenta–maternal liver trio.
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Journal of Lipid Research, 2007
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International Journal of Cancer, 2000
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Placenta, 2007
Using cytokeratin-7-positive trophoblast cells (hTr) isolated from human term placentas and the c... more Using cytokeratin-7-positive trophoblast cells (hTr) isolated from human term placentas and the choriocarcinoma cell lines (hCC) BeWo, Jeg-3 and JAr, the expression of genes involved in the hepatobiliary excretion of cholephilic compounds was investigated by RT-PCR/sequencing followed by measurement of the absolute abundance of mRNA by real-time RT-PCR. Although mRNA of BSEP was detectable and its expression confirmed by Western blotting, its very low expression (higher in hTr than in whole placenta and hCC) did not permit its detection by immunohistochemistry. In hTr, the expression was high for OATP-B/2B1, OATP-8/1B3, MRP1, MRP3, BCRP, FIC1, RARalpha, FXR and SHP, low for OSTalpha, MRP2, MRP4, MRP8, MDR1, CAR and SXR, very low for OATP-A/1A2 and MDR3, and not detectable for OATP-C/1B1, HNF1alpha and HNF4. Expression patterns in hCC mimicked those in hTr, although some important cell line-specific differences were found. The functionality of transporters expressed in hCC was confirmed by their ability to take up and export estradiol 17beta-d-glucuronide in a self-inhibitable and temperature-sensitive manner. In conclusion, several transporters, export pumps, and nuclear receptors involved in the liver excretory function may play a similar role in the placenta, whose specific aspects can be studied by selectively using BeWo, Jeg-3 or JAr cells.
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Antiviral Research, 2005
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Placenta, 2006
We have investigated whether maternal obstructive cholestasis during pregnancy (OCP) causes oxida... more We have investigated whether maternal obstructive cholestasis during pregnancy (OCP) causes oxidative stress and apoptosis in rat placenta and whether treatment with ursodeoxycholic acid (UDCA, i.g., 60 microg/100 g b.wt./day, following complete biliary obstruction on day 14 of pregnancy) has protective effects on this organ. In rats with OCP, increased (15-fold) serum bile acid concentrations (BAs) together with signs of placental oxidative stress (lipid peroxidation and protein carbonylation) were found. The latter were partly prevented by UDCA, even though hypercholanemia was not corrected. Some elements of the antioxidant system (total glutathione content, GSH/GSSG ratio and catalase, glutathione peroxidase, and glutathione-S-transferase--but not glutathione reductase--activities) were impaired in placentas from the OCP group. UDCA treatment partly prevented changes in the antioxidant system. OCP induced an increase in Bax-alpha/Bcl-2 mRNA ratio, as determined by real-time quantitative PCR, suggesting enhanced susceptibility to apoptosis activation through the mitochondria-mediated pathway. Accordingly, the activity of caspase-3, but not caspase-8, was increased in OCP placentas, in which DNA-ladder analysis and TUNEL confirmed the existence of apoptosis. UDCA prevented changes in the Bax-alpha/Bcl-2 mRNA ratio and caspase-3 activity. In conclusion, OCP causes oxidative stress and apoptosis in rat placenta, which can be prevented by treatment with UDCA.
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Biometals, 1999
With a view to using bile acids as shuttles for delivering platinum-related cytostatic drugs to l... more With a view to using bile acids as shuttles for delivering platinum-related cytostatic drugs to liver tumors, a chenodeoxycholylglycinato(CDCG)-derivative of platinum(II) has been synthesized. The complex - named Bamet-M2- was chemically characterized by elemental analysis, FT-IR, NMR, FAB-MS, and UV spectroscopy. The results indicate the following composition: C26H42N2O5Cl2NaPt(II), the metal Pt(II) being bound to two Cl− and one bidentate CDCG moiety, i.e., Na[Pt CDCG(N,O) Cl2]. The compound is highly soluble (up to 20 mM) in water and (up to 35 mM) in ethanol, methanol and DMSO. Hydrolysis was investigated because this is assumed to be an important step in intracellular activation and interaction with DNA of this type of compounds. The reaction kinetics of this complex in aqueous solution show unusual behaviour; the substitution process with the displacement of two Cl− was almost instantaneous, and the resulting species were found to be very stable. Kinetic studies carried out in the presence of different NaCl concentrations (up to 500 mM) revealed similar fast and nonreversible aquations of Bamet-M2. This contrasts with the slow aquation of cisplatin in extracellular-line solutions (i.e., at high NaCl concentrations) as compared with fast hydrolysis in cells. This difference may partly account for the low cytostatic activity observed here for Bamet-M2 against several tumor cell-lines.
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Journal of Hepatology, 2005
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Cell and Tissue Research, 2007
Sinusoidal and apical transporters are responsible for the uptake and biliary elimination of many... more Sinusoidal and apical transporters are responsible for the uptake and biliary elimination of many compounds by hepatocytes. Few in vitro models are however available for analyzing such functions. The expression and bile-acid inducibility of 13 transporters and two nuclear receptors were investigated in the new rat polarized lines, Can 3−1 and Can 10, and in their unpolarized parent, Fao. The relative abundance of mRNA, the protein level, and their localization were examined by real-time quantitative PCR, Western blotting, immunofluorescence, and confocal microscopy. Compared with rat liver, mRNA levels of Fao cells were: negligible for Bsep/Abcb11; lower for the uptake transporters Ntcp and Oatps; similar for SHP, FXR, and Bcrp/Abcg2; and higher (four–fold to 160-fold) for the efflux pumps Mdr1b/Abcb1b, Mdr2/Abcb4, Mrp1/Abcc1, Mrp2/Abcc2, Mrp3/Abcc3, Abcg5, and Abcg8. This profile was mostly maintained (and improved for Bsep) in Can 10. Some transporters were less well expressed in Can 3−1. In both lines, sinusoidal (Ntcp, Mrp3) and canalicular transporters (Mdr-P-glycoproteins detected with C219 antibody, Mrp2) were localized at their correct poles. Bile-acid effects on polarity and mRNA levels of transporters were analyzed after a 6-day treatment with 50 μM taurocholic, chenodeoxycholic (CDCA), or ursodeoxycholic acid (UDCA). No polarization of Fao cells was induced; Can 10 and Can 3−1 polarity was maintained. CDCA and UDCA induced marked enhancement of the volume of Can 10 bile canaliculi. CDCA upregulated Bsep, Mdr2, SHP, Mdr1b, and Oatp2/1a4 in Can 10 (two- to seven-fold) and in Fao cells. Thus, Can 10 constitutes an attractive polarized model for studying vectorial hepatobiliary transport of endogenous and xenobiotic cholephilic compounds.
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Hepatology, 2000
Cholestasis of pregnancy induces alterations in bile acid transport by human trophoblast plasma m... more Cholestasis of pregnancy induces alterations in bile acid transport by human trophoblast plasma membrane (TPM) vesicles. We investigated whether maternal cholestasis affects the overall ability of the rat placenta to carry out vectorial bile acid transfer from the fetus to the mother. Complete obstructive cholestasis (OCP) was maintained during the last week of pregnancy and released at term (day 21), before experiments were performed. In situ single-pass perfusion of one placenta per rat with 250 nmol [14C]glycocholic acid (GC) revealed an impaired uptake in OCP rats (2.28 vs. 5.53 nmol in control rats). Approximately 100% of GC taken up by control placentas was secreted in maternal bile over 120 minutes (5.38 nmol), whereas this was only 61% (1.40 nmol) of the GC taken up by OCP placentas. When 5 nmol GC was administered through the jugular vein no significant difference between both groups in total GC bile output was found. The efficiency (Vmax /KM ) of adenosine triphosphate (ATP)-dependent GC transport by vesicles from the maternal side of TPM was decreased (−41%) in OCP. Moreover, histological examination of the placentas suggested a reduction in the amount of functional trophoblast in the OCP group. This was consistent with a lower antipyrine diffusion across the placenta in these animals. In sum, our results indicate that maternal cholestasis affects the ability of the placenta to efficiently carry out bile acid transfer from fetal to maternal blood. Changes in both the structure and the functionality of the chorionic tissue may account for this impairment.
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Journal of Hepatology, 2004
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Journal of Hepatology, 2008
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Journal of Biological Chemistry, 2006
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Placenta, 2003
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Papers by Rocío García Macías