J Pácha

Charles University in Prague, Praha, Praha, Czech Republic

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Publications (48)158.92 Total impact


  • No preview · Article · Jul 2014 · European Journal of Cancer
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    ABSTRACT: Multiple lines of evidence suggest the participation of the hippocampus in the feedback inhibition of the hypothalamus-pituitary-adrenal axis during stress response. This inhibition is mediated by glucocorticoid feedback due to the sensitivity of the hippocampus to these hormones. The sensitivity is determined by the expression of glucocorticoid (GR) and mineralocorticoid (MR) receptors and 11beta-hydroxysteroid dehydrogenase type 1 (11HSD1), an enzyme that regulates the conversion of glucocorticoids from inactive to active form. The goal of our study was to assess the effect of stress on the expression of 11HSD1, GR and MR in the ventral and dorsal region of the CA1 hippocampus in three different rat strains with diverse responses to stress: Fisher 344, Lewis and Wistar. Stress stimulated 11HSD1 in the ventral but not dorsal CA1 hippocampus of Fisher 344 but not Lewis or Wistar rats. In contrast, GR expression following stress was decreased in the dorsal but not ventral CA1 hippocampus of all three strains. MR expression was not changed in either the dorsal or ventral CA1 region. These results indicate that (1) depending on the strain, stress stimulates 11HSD1 in the ventral hippocampus, which is known to be involved in stress and emotion reactions whereas (2) independent of strain, stress inhibits GR in the dorsal hippocampus, which is predominantly involved in cognitive functions.
    No preview · Article · Jan 2014 · Physiological research / Academia Scientiarum Bohemoslovaca
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    M Hock · M Soták · M Kment · J Pácha
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    ABSTRACT: Increased colonic Cl(-) secretion was supposed to be a causative factor of diarrhea in inflammatory bowel diseases. Surprisingly, hyporesponsiveness to Cl(-) secretagogues was later described in inflamed colon. Our aim was to evaluate changes in secretory responses to cholinergic agonist carbachol in distal and proximal colon during colitis development, regarding secretory activity of enteric nervous system (ENS) and prostaglandins. Increased responsiveness to carbachol was observed in both distal and proximal colon after 3 days of 2 % dextran sodium sulfate (DSS) administration. It was measured in the presence of mucosal Ba(2+) to emphasize Cl(-) secretion. The described increase was abolished by combined inhibitory effect of tetrodotoxin (TTX) and indomethacin. Indomethacin also significantly reduced TTX-sensitive current. On the 7th day of colitis development responsiveness to carbachol decreased in distal colon (compared to untreated mice), but did not change in proximal colon. TTX-sensitive current did not change during colitis development, but indomethacin-sensitive current was significantly increased the 7th day. Decreased and deformed current responses to serosal Ba(2+) were observed during colitis induction, but only in proximal colon. We conclude that besides inhibitory effect of DSS on distal colon responsiveness, there is an early stimulatory effect that manifests in both distal and proximal colon.
    Full-text · Article · Dec 2011 · Physiological research / Academia Scientiarum Bohemoslovaca
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    ABSTRACT: The intestinal transport of nutrients exhibits distinct diurnal rhythmicity, and the enterocytes harbor a circadian clock. However, temporal regulation of the genes involved in colonic ion transport, i.e., ion transporters and channels operating in absorption and secretion, remains poorly understood. To address this issue, we assessed the 24-h profiles of expression of genes encoding the sodium pump (subunits Atp1a1 and Atp1b1), channels (α-, β-, and γ-subunits of Enac and Cftr), transporters (Dra, Ae1, Nkcc1, Kcc1, and Nhe3), and the Na(+)/H(+) exchanger (NHE) regulatory factor (Nherf1) in rat colonic mucosa. Furthermore, we investigated temporal changes in the spatial localization of the clock genes Per1, Per2, and Bmal1 and the genes encoding ion transporters and channels along the crypt axis. In rats fed ad libitum, the expression of Atp1a1, γEnac, Dra, Ae1, Nhe3, and Nherf1 showed circadian variation with maximal expression at circadian time 12, i.e., at the beginning of the subjective night. The peak γEnac expression coincided with the rise in plasma aldosterone. Restricted feeding phase advanced the expression of Dra, Ae1, Nherf, and γEnac and decreased expression of Atp1a1. The genes Atp1b1, Cftr, αEnac, βEnac, Nkcc1, and Kcc1 did not show any diurnal variations in mRNA levels. A low-salt diet upregulated the expression of βEnac and γEnac during the subjective night but did not affect expression of αEnac. Similarly, colonic electrogenic Na(+) transport was much higher during the subjective night than the subjective day. These findings indicate that the transporters and channels operating in NaCl absorption undergo diurnal regulation and suggest a role of an intestinal clock in the coordination of colonic NaCl absorption.
    Preview · Article · Sep 2011 · AJP Gastrointestinal and Liver Physiology
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    ABSTRACT: Introduction: The tumorigenesis is associated with deregulation of Wnt signaling pathway which is mostly involved in regulation of cell proliferation and differentiation. Mutation or deregulations of expression of the Wnt pathway components are able to inducel diseases including development of carcinoma. In case of the development of neoplastic changes in colon β-catenin is stabilized and accumulated in cytosol without Wnt signaling due to a decreased rate of its degradation. It is translocated to the cell nucleus where it forms a transcriptionally complex and initiates inappropriate transcription of several genes including protooncogenes. The question is, what is the cause of β-catenin accumulation (mutation or deregulation of expression of certain components of Wnt pathway) and whether the deregulation of canonic Wnt/β-catenin signaling is accompanied with changes of noncanonical Wnt signaling pathways could also be involved in tumorigenesis. The aim of the study: The aim of the study was to compare the expression of selected components of Wnt signaling in specimens of neoplastic tissue and surrounding healthy tissue of patients with colorectal cancer. Material and methods: Transcript levels of selected genes of Wnt pathway were measured by quantitative PCT in specimens of tissue from patients operated for colorectal cancer. Results: Neoplastic tissue showed increased upregulation of transcript genes for Axin 2, DKK1 a NKD1 and down-regulation for sFRP1 transcript. Other selected genes (Axin 1, LRP5, βTrCP, DKK2, DKK3 a β-katenin) showed no significant changes between neoplastic and normal tissue. Conclusion: We demonstrated that neoplastic tissue of patients with colorectal cancer, that is commonly associated with canonical Wnt/β-catenin pathway, had increased mRNA expression of 4 components of Wnt signaling which are known to cause inactivation of Wnt/β-catenin pathway. The finding of NKD1 mRNA up-regulation and simultaneous sFRP1 mRNA down-regulation suggests the shift of Wnt response to the noncanonical pathway which might play a role in tumorigenesis. Our data suggest the possibility of using NKD1 mRNA and sFRP1 mRNA as markers of colorectal carcinogenesis.
    No preview · Article · Jan 2009 · Ceska a Slovenska Gastroenterologie a Hepatologie
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    ABSTRACT: The objective of this study was to investigate the role of 11beta-hydroxysteroid dehydrogenases (11HSD1 and 11HSD2) in determining the fetal concentration of glucocorticoids. The expression patterns for mRNA abundance, protein level, and enzyme activities of placental and fetal 11HSD1 and 11HSD2 were assessed from embryonic day 13 (E13) to day 21 (E21; term E22). The transplacental passage of maternal corticosterone and its contribution to fetal glucocorticoids was also studied. Placental 11HSD1 mRNA decreased between days E13 and E14 and then remained at much lower values up to E21. Similarly, NADP+-dependent 11beta-oxidation and 11-reduction were lower in late gestation. In contrast, placental 11HSD2 mRNA and protein decreased between E13 and E21. Dithiothreitol increased the activity of 11HSD2 and the output of 11-dehydrocorticosterone into fetal circulation.The fetal activity of 11HSD1 increased and 11HSD2 decreased between E16 and E21. The final third of gestation is accompanied by reciprocal changes in placental and fetal metabolism of corticosterone due to changes in 11HSD1 and 11HSD2 not only at the level of transcription but also at a posttranslational level.
    Full-text · Article · Oct 2008 · Reproductive sciences (Thousand Oaks, Calif.)
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    ABSTRACT: Recent in vitro studies have shown the involvement of pro-inflammatory cytokines in the regulation of the local metabolism of glucocorticoids via 11beta-hydroxysteroid dehydrogenase type 1 and type 2 (11HSD1 and 11HSD2). However, direct in vivo evidence for a relationship among the local metabolism of glucocorticoids, inflammation and steroid enzymes is still lacking. We have therefore examined the changes in the local metabolism of glucocorticoids during colonic inflammation induced by TNBS and the consequences of corticosterone metabolism inhibition by carbenoxolone on 11HSD1, 11HSD2, cyclooxygenase 2 (COX-2), mucin 2 (MUC-2), tumor necrosis factor alpha (TNF-alpha), and interleukin 1beta (IL-1beta). The metabolism of glucocorticoids was measured in tissue slices in vitro and their 11HSD1, 11HSD2, COX-2, MUC-2, TNF-alpha, and IL-1beta mRNA abundances by quantitative reverse transcription-polymerase chain reaction. Colitis produced an up-regulation of colonic 11HSD1 and down-regulation of 11HSD2 in a dose-dependent manner, and these changes resulted in a decreased capacity of the inflamed tissue to inactivate tissue corticosterone. Similarly, 11HSD1 transcript was increased in colonic intraepithelial lymphocytes of TNBS-treated rats. Topical intracolonic application of carbenoxolone stimulated 11HSD1 mRNA and partially inhibited 11HSD2 mRNA and tissue corticosterone inactivation and these changes were blocked by RU-486. The administration of budesonide mimicked the effect of carbenoxolone. In contrast to the local metabolism of glucocorticoids, carbenoxolone neither potentiates nor diminishes gene expression for COX-2, TNF-alpha, and IL-1beta, despite the fact that budesonide down-regulated all of them. These data indicate that inflammation is associated with the down-regulation of tissue glucocorticoid catabolism. However, these changes in the local metabolism of glucocorticoids do not modulate the expression of COX-2, TNF-alpha, and IL-1beta in inflamed tissue.
    Full-text · Article · Sep 2008 · Digestive Diseases and Sciences
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    ABSTRACT: Introduction: Long-standing ulcerative colitis (UC) has an increased risk of evolving into colorectal cancer (CRC). The overexpression of some proproliferative and antiapoptotic genes such as survivin, telomerase catalytic subunit (hTERT), integrin-linked kinase (ILK) and transcription factors c-MYB and Tcf-4 have been implicated in the development and progression of several human malignancies including CRC. The aims of the study: In this study, we analyzed changes in the expression of these markers and proinflammatory enzymes cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) in samples obtained from pacients with ulcerative colitis-associated neoplastic epithelial changes and in samples of sporadic colon cancer. Material and methods: The levels of mRNA were analyzed by quantitative real-time polymerase chain reaction in 19 biopsy samples obtained from patients with chronic ulcerative colitis and in 12 samples from patients operated on for colon carcinoma. Results: Compared to mucosa of UC patients without dysplasia the UC-associated neoplasia expressed significantly elevated transcripts of survivin, c-MYB, Tcf-4, COX-2 and iNOS, whereas hTERT and ILK expression was not significantly elevated. In contrast, the specimens of CRC showed upregulated expression of not only survivin, c-MYB, Tcf-4, COX-2 and iNOS but also hTERT. Conclusion: These results suggest that telomerase and ILK upregulation might occur during later stages of cancer progression, whereas survivin, c-MYB and Tcf-4 are upregulated during early stages of neoplasia development and thus they might serve as an early indicator for ulcerative colitis-associated colorectal carcinogenesis.
    No preview · Article · Jan 2008 · Ceska a Slovenska Gastroenterologie a Hepatologie
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    ABSTRACT: The ligand specificity and activation of steroid receptors depend considerably on the enzymatic activities involved in local pre-receptor synthesis and the metabolism of the steroids. Several enzymes in particular, steroid dehydrogenases have been shown to participate in this process. Here we report the isolation of 20-hydroxysteroid dehydrogenase (ch20HSD) cDNA from chicken intestine and the distribution of ch20HSD mRNA and 20-reductase activity in various avian tissues. Using a reverse transcription PCR and comparison with the known sequences of mammalian 20betaHSDs, we have isolated a new ch20HSD cDNA. This cDNA predicted 276 amino acid residues that shared about 75% homology with mammalian 20betaHSD. Sequences specific to the short-chain dehydrogenase/reductase superfamily (SDR) were found, the Gly-X-X-X-Gly-X-Gly cofactor-binding motif (residues 11-17) and the catalytic activity motif Tyr-X-X-X-Lys (residues 193-197). The cDNA coding for ch20HSD was expressed in Escherichia coli by placing it under isopropylthiogalactoside (IPTG) inducible control. Both the IPTG cells of E. coli and the isolated recombinant protein reduced progesterone to 20-dihydroprogesterone, corticosterone to 20-dihydrocorticosterone and 5alpha-dihydrotestosterone to its 3-ol derivative. The 20-reductase and 3-reductase activities of ch20HSD catalyzed both 3alpha/beta- and 20alpha/20beta-epimers. The mRNA transcripts of ch20HSD were found in the kidney, colon, and testes; weaker expression was also found in the heart, ovaries, oviduct, brain, liver, and ileum. 20-Reductase activity has been proven in tissue slices of kidney, colon, ileum, liver, oviduct, testis, and ovary; whereas the activity was nearly absent in the heart and brain. A similar distribution of 20-reductase activity was found in tissue homogenates measured under V(max) conditions. These results suggest that chicken 20HSD is the latest member of the SDR superfamily to be found, is expressed in many avian tissues and whose precise role remains to be determined.
    No preview · Article · Jan 2007 · Journal of Molecular Endocrinology
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    ABSTRACT: The effect of glucocorticoids is controlled at the pre-receptor level by the activity of 11beta-hydroxysteroid dehydrogenase (11HSD). The isoform 11HSD1 is an NADP+ -dependent oxidoreductase, usually reductase, that amplifies the action of glucocorticoids due to reduction of the biologically inactive 11-oxo derivatives cortisone and 11-dehydrocorticosterone to cortisol and corticosterone. The NAD+ -dependent isoform (11HSD2) is an oxidase that restrains the effect of hormones due to 11beta-oxidation of cortisol and corticosterone to their 11-oxo derivatives. Although the immunosuppressive and anti-inflammatory effects of glucocorticoids are well known, the relationship between inflammation and local metabolism of glucocorticoids is not well understood. In this study, we demonstrated that colitis induced by dextran sulfate sodium modulates colonic 11HSD1. Experimentally induced intestinal inflammation stimulated colonic NADP+ -dependent but not NAD+ -dependent 11HSD activity. Colonic 11HSD1 mRNA was increased, whereas 11HSD2 mRNA was not changed. Additional parallel studies revealed a similar pattern of 11HSD1 mRNA induction in mesenteric lymph nodes and intestinal intraepithelial lymphocytes, but not in spleen and peritoneal macrophages. These data suggest that inflammation modulates local metabolism of glucocorticoid and support the notion that pre-receptor regulation of endogenous corticosteroids might play a role in inflammatory processes.
    Full-text · Article · Dec 2006 · Journal of Endocrinology
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    ABSTRACT: Glucocorticoids influence the function of numerous tissues. Although there are a very large number of studies that have investigated the local metabolism of glucocorticoids in mammals, the knowledge of this metabolism in birds is limited. The local concentration of corticosterone is critical for both glucocorticoid- and mineralocorticoid-dependent activity, and we have therefore carried out studies of corticosterone metabolism in various chicken organs. It was found that corticosterone was metabolized to 20-dihydrocorticosterone, and in some tissues also to 11-dehydrocorticosterone and 11-dehydro-20-dihydrocorticosterone. The activity of 20-hydroxysteroid dehydrogenase (20HSD), responsible for the transformation of corticosterone to 20-hydroxy derivatives, was abundant in the kidney and intestine, with lower levels in the liver and testis. Low levels of 20HSD were detected in the brain and ovaries. In contrast, 11-hydroxysteroid dehydrogenase (11HSD) activity was only found in the kidney and intestine. No activity was observed in the brain, testis, or ovaries. The treatment of chickens with estrogens stimulated 20HSD activity in the kidney, intestine, and oviduct and 11HSD activity in the liver and oviduct. Kinetic studies for corticosterone yielded an apparent Km for 11HSD in the nanomolar (Km = 21 +/- 5 nmol.l(-1)) and for 20HSD in the micromolar range (Km = 3.7 +/- 0.3 micromol.l(-1)). When progesterone or 5alpha-dihydrotestosterone were used instead of corticosterone, the tissues reduced the former to 20beta-dihydroprogesterone and the latter to both 5alpha,3alpha- and 5alpha,3beta-dihydrotestosterone. The data presents the first evidence for corticosterone metabolism via 11beta-, 3alpha/3beta-, and 20beta-hydroxysteroid dehydrogenases in various chicken organs and provide support for the theory of prereceptor modulation of glucocorticoid signals in avian tissues.
    Full-text · Article · Aug 2006 · General and Comparative Endocrinology
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    ABSTRACT: Although rat is the most widely used model of glucocorticoid programming of the fetus, the role of rat placental 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) in the transplacental pharmacokinetics of the naturally occurring glucocorticoid, corticosterone, has not yet been fully elucidated. In this study, expression of 11beta-HSD2 in the rat placenta on two different gestation days (16 and 22) was examined using quantitative RT-PCR and Western blotting, and dually perfused rat term placenta was employed to evaluate its functional capacity to transfer and metabolize corticosterone. Marked decrease in placental expression of 11beta-HSD2 toward term was observed on both mRNA and protein levels. In perfusion studies, increasing maternal corticosterone concentration from 3 to 200 nM resulted in the fall of 11beta-HSD2 conversion capacity from 64.3 to 16.3%, respectively. Enzyme saturation occurred at about 50 nM substrate concentration. When delivering corticosterone (3 or 100 nM) from the fetal side, a similar decline of 11beta-HSD2 conversion capacity was observed (66.5% and 48.5%, respectively). Addition of carbenoxolone (10 or 100 microM), a non-specific 11beta-HSD inhibitor, to maternal perfusate decreased conversion capacity from 66.7 to 12.6 or 8.1%, respectively. Similarly potent inhibitory effect was observed in feto-maternal studies. Neither saturation nor inhibition of 11beta-HSD2 was associated with transformation of corticosterone in metabolites other than 11-dehydrocorticosterone. These data suggest that 11beta-HSD2 is the principal enzyme controlling transplacental passage of corticosterone in rats and is able to eliminate corticosterone in both maternal and fetal circulations.
    Full-text · Article · Feb 2006 · Placenta
  • J Bryndová · S Zbánková · M Kment · J Pácha
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    ABSTRACT: Pro-inflammatory processes are counteracted by anti-inflammatory factors such as glucocorticoids. The response of target cells to glucocorticoids depends on several factors including prereceptor modulation of glucocorticoid signals via local glucocorticoid metabolism. This is determined by two isoforms of 11beta-hydroxysteroid dehydrogenase (11betaHSD); 11betaHSD1 operates in vivo as a reductase converting inactive 11-oxo glucocorticoids to active glucocorticoids cortisol or corticosterone, whereas 11betaHSD2 catalyses oxidation of active glucocorticoids to their inactive 11-oxo derivatives. The aim of this study was to investigate the changes in local metabolism of glucocorticoids and in the expression of 11betaHSD1 and 11betaHSD2 mRNA during colonic inflammation. Acute colitis was induced by intracolonic administration of 2,4,6-trinitrobenzenesulphonic acid (TNBS) or by drinking a dextran sodium sulphate (DSS) solution. Metabolism of glucocorticoids was measured in tissue fragments in vitro and 11betaHSD1 and 11betaHSD2 mRNA abundance was quantified using real-time RT-PCR one week after administration of TNBS and 10 days after drinking the DSS solution. In both models of inflammatory bowel disease we observed down-regulation of corticosterone oxidation to 11-dehydrocorticosterone by 64% (TNBS) and 53% (DSS) and reciprocal stimulation of reduction of 11-dehydrocorticosterone to corticosterone by 83% and 54%, respectively. A similar pattern was observed at the level of mRNA; 11betaHSD1 mRNA was significantly higher (TNBS: increase by 660%; DSS: increase by 760%) and 11betaHSD2 mRNA lower (TNBS: decrease by 85%; DSS: decrease by 60%) during inflammation. Colitis induces local glucocorticoid activation from 11-oxo steroids and decreases glucocorticoid inactivation; i.e. inflammation increases local tissue ratio of active and inactive glucocorticoids. The results indicate that the changes in local metabolism of glucocorticoids could contribute to the control of an overshoot of inflammation processes in the colon.
    No preview · Article · Jul 2004 · Scandinavian Journal of Gastroenterology
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    ABSTRACT: Many mammalian species including human are immature at birth and undergo major developmental changes during suckling and weaning period. This problem is also conspicuous for the gastrointestinal tract that undergoes abrupt transitions coinciding with birth and weaning. This review deals with the maturation of ion transport functions in colon, the intestinal segment that plays an important role in sodium and potassium absorption and secretion. The purpose of the present review is to summarize the mechanism of sodium and potassium transport pathways and show how these transport processes change postnatally and how hormones, particularly corticosteroids, modify the pattern of development. Finally we describe some of the ways, how to analyze corticosteroid metabolism in target tissue.
    Full-text · Article · Feb 2004 · Physiological research / Academia Scientiarum Bohemoslovaca
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    ABSTRACT: Previous studies from our laboratory have indicated that secondary hyperaldosteronism affects phospholipids of rat colonic enterocytes. To assess whether this represents a direct effect of mineralocorticoids on enterocytes, the role of aldosterone and dexamethasone in the regulation of lipid metabolism was examined in Caco-2 cells during development of their enterocyte phenotype. Differentiation of Caco-2 cells was associated with increased levels of triglycerides (TG) and cholesteryl esters (CE), a decreased content of cholesterol and phospholipids and changes in individual phospholipid classes. The phospholipids of differentiated cells had a higher content of n-6 polyunsaturated fatty acids (PUFA) and lower amounts of monounsaturated (MUFA) and saturated fatty acids than subconfluent undifferentiated cells. Differentiated cells exhibited a higher ability to incorporate [3H]arachidonic acid (AA) into cellular phospholipids and a lower ability for incorporation into TG and CE. Incubation of subconfluent undifferentiated cells with aldosterone or dexamethasone was without effect on the content of lipids, their fatty acids and [3H]AA incorporation. In contrast, aldosterone treatment of differentiated cells diminished the content of TG, increased the content of phospholipids and modulated their fatty acid composition. The percentage of n-6 and n-3 PUFA in phospholipids was increased and that of MUFA decreased, whereas no changes in TG were observed. The incorporation of [3H]AA into phospholipids was increased and into TG decreased and these changes were blocked by spironolactone. Treatment of differentiated cells with dexamethasone increased their CE content but no effect was identified upon other lipids, their fatty acid composition and on the incorporation of [3H]AA. As expected for the involvement of corticosteroid hormones the mineralocorticoid and glucocorticoid receptors were identified in Caco-2 cells by RT-PCR. The results suggest that aldosterone had a profound influence on lipid metabolism in enterocytes and that its effect depends on the stage of differentiation. The aldosterone-dependent changes occurring in phospholipids and their fatty acid composition may reflect a physiologically important phenomenon with long-term consequences for membrane structure and function.
    No preview · Article · Dec 2003 · The Journal of Steroid Biochemistry and Molecular Biology
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    Jiřı́ Pácha · Věra Lisá · Ivan Mikšı́k
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    ABSTRACT: 11β-Hydroxysteroid dehydrogenase (11βHSD) converts endogenous glucocorticoids to their biologically inactive 11-dehydro derivatives and is therefore able to determine, at least in part, the biological action of glucocorticoids. Type 1 11βHSD has both oxidase and reductase activities interconverting corticosterone and 11-dehydrocorticosterone, whereas type 2 11βHSD has only oxidase activity converting corticosterone to 11-dehydrocorticosterone. Since 11βHSD expression is regulated during development and by hormones in a tissue-specific manner and since glucocorticoids play an important role in postnatal intestinal maturation, we investigated the role of corticosteroids and cytodifferentiation in the regulation of intestinal 11βHSD. Using rat intestinal organ cultures and epithelial cell lines derived from rat small intestine (IEC-6, IEC-18) and from human colon adenocarcinoma (Caco-2, HT-29), we analyzed the effect of corticosteroids and cytodifferentiation on 11βHSD. Screening of the clonal cell lines showed that Caco-2 cells expressed by far the greatest 11βHSD2 oxidase activity, lower activity was observed in HT-29 cells, and lowest activity was seen in IEC cells. Treatment with dexamethasone (50 nM) increased the activity of 11βHSD2 in IEC-6 cells (+59%) and HT-29 cells (+31%), whereas aldosterone (50 nM) stimulated 11βHSD2 in IEC-6 cells only (+31%). Caco-2 cells and IEC-18 cells did not respond to corticosteroids. Growth of IEC-6 cells on Matrigel, treatment of HT-29 cells with butyrate, and postconfluency of Caco-2 cells increased not only the markers of cytodifferentiation, such as alkaline phosphatase and sucrase, but also the activity of 11βHSD2 in all of these cell lines (IEC-6, +96%; HT-29, +139%; Caco-2, +95%). Addition of corticosteroids to these more differentiated cell cultures did not enhance 11βHSD2 activity. In intestinal organ cultures of suckling rat small intestine, dexamethasone and aldosterone stimulated 11βHSD by more than 300%. We conclude that corticosteroids markedly and differentially regulate intestinal 11βHSD2 and that cytodifferentiation of intestinal epithelial cells is associated with upregulation of 11βHSD2 activity that is independent of corticosteroids.
    Preview · Article · Feb 2002 · Steroids
  • Š. Žbánková · M. Kment · J. Pácha
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    ABSTRACT: Inflammatory bowel diseases are chronic, non-infectious intestinal inflammation of unknown origin that afflicts individuals of both sexes throughout life. The disease is clinically characterized by two overlapping phenotypes-ulcerative colitis and Crohn's disease. Ulcerative colitis and Crohn's disease predominantly affect colon Crohn's disease the distal small intestine (terminal ileum). Histologically like as a superficial (UC) or transmural (CD) inflammation. Clinical and laboratory studies in human with IBD have long suggested that genetic and environmental factors play an important role in the pathogenesis of these disorders. Experimental animal models allow study of possible etiologic agens, interactions among different components and identification of immunologic processes and genetic susceptibility in ways that are not possible in humans. There is no right or wrong model of IBD, the purpose of this review is to define what the different models have told us and where they seem to be most useful for the study of IBD.
    No preview · Article · Jan 2002 · Ceska a Slovenska Gastroenterologie a Hepatologie
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    ABSTRACT: The regulation of intracellular pH (pHi) in colonocytes of the rat proximal colon has been investigated using the pH-sensitive dye BCECF and compared with the regulation of pHi in the colonocytes of the distal colon. The proximal colonocytes in a HEPES-buffered solution had pHi=7.24±0.04 and removal of extracellular Na+ lowered pHi by 0.24 pH units. Acid-loaded colonocytes by an NH3/NH+4 prepulse exhibited a spontaneous recovery that was partially Na+-dependent and could be inhibited by ethylisopropylamiloride (EIPA). The Na+-dependent recovery rate was enhanced by increasing the extracellular Na+ concentration and was further stimulated by aldosterone. In an Na+- and K+-free HEPES-buffered solution, the recovery rate from the acid load was significantly stimulated by addition of K+ and this K+-dependent recovery was partially blocked by ouabain. The intrinsic buffer capacity of proximal colonocytes at physiological pHi exhibited a nearly 2-fold higher value than in distal colonocytes. Butyrate induced immediate colonocyte acidification that was smaller in proximal than in distal colonocytes. This acidification was followed by a recovery phase that was both EIPA-sensitive and -insensitive and was similar in both groups of colonocytes. In a HCO−3/CO2-containing solution, pHi of the proximal colonocytes was 7.20±0.04. Removal of external Cl− caused alkalinization that was inhibited by DIDS. The recovery from an alkaline load induced by removal of HCO−3/CO2 from the medium was Cl−-dependent, Na+-independent and blocked by DIDS. Recovery from an acid load in EIPA-containing Na+-free HCO−3/CO2-containing solution was accelerated by addition of Na+. Removal of Cl− inhibited the effect of Na+. In summary, the freshly isolated proximal colonocytes of rats express Na+/H+ exchanger, H+/K+ exchanger ((H+-K+)-ATPase) and Na+-dependent Cl−/HCO−3 exchanger that contribute to acid extrusion and Na+-independent Cl−/HCO−3 exchanger contributing to alkali extrusion. All of these are likely involved in the regulation of pHi in vivo. Proximal colonocytes are able to maintain a more stable pHi than distal cells, which seems to be facilitated by their higher intrinsic buffer capacity.
    Full-text · Article · Jun 2001 · Biochimica et Biophysica Acta
  • J Pácha
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    ABSTRACT: Considerable progress has been made over the last decade in the understanding of mechanisms responsible for the ontogenetic changes of mammalian intestine. This review presents the current knowledge about the development of intestinal transport function in the context of intestinal mucosa ontogeny. The review predominantly focuses on signals that trigger and/or modulate the developmental changes of intestinal transport. After an overview of the proliferation and differentiation of intestinal mucosa, data about the bidirectional traffic (absorption and secretion) across the developing intestinal epithelium are presented. The largest part of the review is devoted to the description of developmental patterns concerning the absorption of nutrients, ions, water, vitamins, trace elements, and milk-borne biologically active substances. Furthermore, the review examines the development of intestinal secretion that has a variety of functions including maintenance of the fluidity of the intestinal content, lubrication of mucosal surface, and mucosal protection. The age-dependent shifts of absorption and secretion are the subject of integrated regulatory mechanisms, and hence, the input of hormonal, nervous, immune, and dietary signals is reviewed. Finally, the utilization of energy for transport processes in the developing intestine is highlighted, and the interactions between various sources of energy are discussed. The review ends with suggestions concerning possible directions of future research.
    No preview · Article · Nov 2000 · Physiological Reviews
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    I Pohlová · I Miksík · J Kunes · J Pácha
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    ABSTRACT: The role of the enzyme 11beta-hydroxysteroid dehydrogenase (11betaHSD) in hypertension remains unknown even if it appears that the inappropriately decreased 11betaHSD activity might be involved in a process that leads to high blood pressure. The possible changes of 11betaHSD were therefore investigated in rats with spontaneous or salt-induced hypertension. The adult male rats of the following genotypes were used: spontaneously hypertensive rats (SHR), normotensive Wistar-Kyoto rats (WKY), Dahl salt-sensitive rats fed either a high-salt diet containing 8% NaCl (DS-HS) or low-salt diet containing 0.2% NaCl (DS-LS), and Dahl salt-resistant rats fed the same diets (DR-HS, DR-LS). 11betaHSD was investigated in colon, aorta, renal cortex, and renal medulla and was assessed as percentage conversion of [3H]corticosterone to [3H]11-dehydrocorticosterone in the presence of NAD or NADP. The results demonstrated that genotype exerts a significant effect on 11betaHSD. 11betaHSD activity was significantly increased in colon and renal medulla of SHR compared with WKY rats. No significant differences were observed in renal cortex and aorta. In Dahl rats kept on a low-salt diet, 11betaHSD activity was significantly higher in colon, renal medulla, and cortex of DS-LS than in DR-LS rats but no difference was observed in aorta. The differences disappeared in age-matched DS and DR rats fed the high-salt diet. Increased dietary sodium intake stimulated the activity of 11betaHSD in renal cortex and medulla of DR rats and decreased the activity in colon of DS rats. We conclude that the development of spontaneous and salt-induced hypertension is not associated with decreased activity of 11betaHSD. However, the results showed that salt intake is able to modulate the activity of 11betaHSD and that 11betaHSD in DS and DR rats responds to high dietary salt intake in a different manner.
    Full-text · Article · Sep 2000 · American Journal of Hypertension

Publication Stats

673 Citations
158.92 Total Impact Points

Institutions

  • 2006-2014
    • Charles University in Prague
      • • Faculty of Science
      • • Department of Physiology (PF)
      • • Faculty of Pharmacy in Hradec Králové
      Praha, Praha, Czech Republic
  • 1993-2014
    • Academy of Sciences of the Czech Republic
      • Institute of Physiology
      Praha, Praha, Czech Republic
  • 1995-2000
    • The Police Academy of the Czech Republic in Prague
      Praha, Praha, Czech Republic