[show abstract][hide abstract] ABSTRACT: We present nine patients with progressive sclerosing cholangitis after septic shock.
All nine patients had previously required long term treatment in an intensive care unit for septic shock: two patients with polytrauma, five with burn injury, and two with extensive surgery. They were admitted to our hospital because of cholangitis. Endoscopic retrograde cholangiography revealed severe intrahepatic stenoses in all patients and liver biopsies showed typical signs of sclerosing cholangitis. No patient had pre-existing liver disease.
Mean follow up time was 35 months. In patients with major bile duct stenoses (3/9), 12 endoscopic dilations were performed in total. In one patient, concrements were extracted and intermittent stenting was necessary. To date, 4/9 patients have rapidly developed liver cirrhosis. During follow up, 5/9 patients died: two after fulminant cholangitis, one after liver failure, one due to liver transplantation associated problems, and one after cerebral ischaemia. One patient has been registered for transplantation and the remaining three patients show no acute signs of liver failure.
Patients with sclerosing cholangitis, following septic shock, represent a new variant of vanishing bile duct disorders. In such patients liver disease rapidly progresses to cirrhosis. Endoscopic treatment may only transiently improve the course of the disease. Orthotopic liver transplantation is indicated in end stage disease.
[show abstract][hide abstract] ABSTRACT: Bacterial infections are life-threatening complications in cirrhosis and early diagnosis is mandatory. Procalcitonin, a 116 amino acid propeptide of calcitonin, is an early marker of infection. The aim was to evaluate prospectively procalcitonin in the diagnosis of bacterial infection in cirrhosis. 127 patients with liver cirrhosis were analysed and stratified into three groups according bacteriological and morphological findings; decompensated patients with (group I = 36) and without (group II = 64) infection, and 27 non-decompensated and non-infected (group III).
Diagnosis of infection was made using standard criteria. Serum procalcitonin, tumour necrosis factor alpha, interleukin-6 and C-reactive protein were measured using commercially available methods.
PCT serum levels were significantly different between group I (2.8 ng/ml [0.4 - 20.4]), group II (0.6 ng/ml [0.1 - 5.9]) and group III (0.4 ng/ml [0.1 - 1.2]), respectively. Levels above 0.58 ng/ml had a sensitivity of 92 % and specificity of 78 % for the diagnosis of infection and were associated with a 50 % mortality in the first two months. Interleukin-6, tumour necrosis factor alpha and C-reactive protein were less sensitive and specific for the diagnosis of infection.
In decompensated cirrhosis procalcitonin serum levels provided the most sensitive and specific tool for the initial diagnosis of bacterial infection.
Zeitschrift für Gastroenterologie 03/2003; 41(2):165-70. · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: Chronic inflammatory bowel disease is diagnosed and monitored by the combination of colonoscopy and small bowel enteroklysis. Magnetic resonance imaging has become the gold standard for the imaging of perirectal and pelvic fistulas. With the advent of ultrafast MRI small and large bowel imaging has become highly attractive and is being advocated more and more in the diagnostic work up of inflammatory bowel disease. Imaging protocols include fast T1-weighted gradient echo and T2-weighted TSE sequences and oral or rectal bowel distension. Furthermore, dedicated imaging protocols are based on breath-hold imaging under pharmacological bowel paralysis and gastrointestinal MR contrast agents (Hydro-MRI). High diagnostic accuracy can be achieved in Crohn's disease with special reference to the pattern of disease, depth of inflammation, mesenteric reaction, sinus tract depiction and formation of abscess. In ulcerative colitis, the mucosa-related inflammation causes significantly less bowel wall thickening compared to Crohn's disease. Therefore with MRI, the extent of inflammatory changes is always underestimated compared to colonoscopy. According to our experience in more than 200 patients as well as the results in other centers, Hydro-MRI possesses the potential to replace enteroklysis in the diagnosis of chronic inflammatory bowel disease and most of the follow-up colonoscopies in Crohn's disease. Further technical improvements in 3D imaging will allow interactive postprocessing of the MR data.
RöFo - Fortschritte auf dem Gebiet der R 02/2001; 173(1):4-11. · 2.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Endothelin-1 (ET-1) has been proposed to contribute to atherogenesis and plaque rupture in coronary heart disease through activation of mitogen-activated protein kinases (MAPKs) in smooth muscle cells (SMCs). Reactive oxygen species (ROS) have been shown to be important signal transduction molecules in SMCs. Thus, the present study aimed to assess the role of ROS in ET-1-mediated activation of c-Jun amino-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) 1/2. Rat SMCs were exposed to ET-1 over time at concentrations from 10(-6) to 10(-10) mol/L, and MAPK activity was quantified. Activation of JNK and ERK was observed with a maximum stimulation at 10(-7) mol/L ET-1. JNK and ERK were activated by ET-1 binding to a single receptor (ET-1A) but differed in their downstream mechanisms: only JNK activation was sensitive to the radical scavenger N-acetylcysteine and diphenylene iodonium, an inhibitor of NADPH oxidase, indicating a role for ROS. The downstream MAPK effector and proinflammatory transcription factor, the activator protein-1 complex, was maximally activated 2 hours after the addition of ET-1. It was mainly composed of the JNK substrate c-Jun, and activation was also dependent on ROS formation. We suggest that plaque activation by ET-1 can be mediated through ROS. It can be hypothesized that the clinical benefit of antioxidants in the treatment of atherogenesis may partially depend on neutralization of ET-1-mediated ROS production.
[show abstract][hide abstract] ABSTRACT: The atherogenic effect of the renin-angiotensin system can be explained, in part, by the influence of its effector, angiotensin II (Ang II), on vascular smooth muscle cell (VSMC) growth. There is evidence that reactive oxygen species (ROS) play a role in the atherogenesis and activation of mitogen-activating protein (MAP) kinases, which are involved in proliferation and differentiation. The study was performed to further characterize the role of ROS in Ang II-mediated MAP kinase activation and the regulation of the transcription factor activator protein-1 (AP-1). Rat VSMCs were stimulated with Ang II. The activities of MAP kinases were assessed by Western blot analysis or by immunocomplex kinase assay. AP-1 binding was determined by using an electrophoretic mobility shift assay. Rat VSMCs were treated with Ang II-activated MAP kinases, extracellular signal-regulated kinase (ERK), c-Jun amino terminal kinase (JNK), p38 MAP kinase (p38 MAPK), and their downstream effector, AP-1. Interestingly, only the activation of ERK1/2, but not JNK or p38 MAPK, was tyrosine kinase, protein kinase C, and MEK1/2 dependent. Ang II also induced the rapid formation of ROS, which could be inhibited by a specific antibody as well as by antisense against the p22phox subunit of the NAD(P)H oxidase. JNK and p38 MAPK, but not ERK, activation was inhibited by an inhibitor of NAD(P)H oxidase. Antisense against p22phox also solely inhibited p38 MAPK but did not affect ERK. The results indicate that in VSMCs, Ang II activates MAP kinases and AP-1 through different pathways; the results further suggest that ROS, generated by p22phox, mediate Ang II-induced JNK and p38 MAPK activation, which may contribute to the pathogenesis of atherosclerosis.
[show abstract][hide abstract] ABSTRACT: Biliary epithelial cells (BECs) express different Na(+), H(+) exchange (NHE) isoforms. In this study, the potential role of NHE in ductular bile secretion is assessed. Experiments were performed in guinea pig perfused livers and isolated BECs. Inhibition of NHE was achieved by hypotonic stress and by using the unspecific NHE inhibitor, amiloride, or the specific NHE 1 inhibitor, cariporide (HOE 642). Hypotonic stress inhibited basal bile flow by 46% and prevented secretin stimulation of bile flow by reducing biliary bicarbonate output by 50%. Secretin increased bile flow from 3.7 +/- 0.8 microL/min/g to 4.78 microL/min/g (P <.01); subsequent exposure to hypotonic stress decreased secretin-stimulated bile flow by 35% and biliary bicarbonate secretion by approximately 50%. Inhibition of NHE by amiloride or cariporide resulted in a similar reduction of secretin-stimulated bile flow and bicarbonate secretion. Basal bile flow was unaffected by the NHE inhibitors. In isolated guinea pig BECs, regulatory volume decrease and inhibition of NHE was demonstrated after hypotonic stress under basal and secretin-stimulated conditions. In contrast, hypotonic exposure inhibited Cl(-), HCO(3)(-) exchange activity in isolated BECs only during basal conditions but incompletely after secretin stimulation. Our study shows that hypotonic stress inhibits basal bile flow in the guinea pig by inhibition of Cl(-), HCO(3)(-) exchange. NHE1 is not involved in basal bile formation. Increased choleresis after ductular stimulation by secretin depends on intact NHE1 activity. These data indicate that BEC volume changes have profound effects on biliary secretory function.
[show abstract][hide abstract] ABSTRACT: A sodium dependent bile acid carrier has recently been cloned and characterized in rat ileum. The present study demonstrates the presence of a mRNA species specific for the rat ileal bile acid carrier (r-IBAT) in rat biliary epithelial cells. Moreover, immunohistochemistry with a peptide specific antibody demonstrates protein expression in biliary epithelial cells from normal and bile duct ligated rat livers. Besides a cytoplasmic staining a predominant staining of the apical membrane could be observed. These observations indicate that biliary epithelial cells are involved in bile acid transport across the biliary tree. In addition the carrier could also play a role in the signal transduction of bile acid induced ductular secretion.
European journal of medical research 05/1999; 4(4):165-8. · 1.10 Impact Factor
[show abstract][hide abstract] ABSTRACT: Sensitivity of cellular fatty acids uptake to the membrane potential difference is still a matter of controversy. For direct evaluation of potential sensitivity the effect of changing membrane potential on uptake of a fluorescent long chain fatty acid derivative, 12-NBD-stearate, in isolated rat hepatocytes, was examined. Changes in membrane potential were achieved by patch clamp procedures. Fatty acid influx was simultaneously determined by recording of cell fluorescence. Hyperpolarization from -30 to -70 mV accelerated fatty acid influx whereas depolarization to +50 mV reduced uptake. After obtaining equilibrium hyperpolarization increased cell fluorescence, whereas depolarization pushed NBD-stearate out of cells. Potential sensitivity of uptake was dependent on the fatty acid concentrations in the medium with most prominent effects at low unbound concentrations. These data show that, at low fatty acid concentrations, uptake is, in part, driven by an intracellular negative electric membrane potential.
European journal of medical research 09/1998; 3(8):393-6. · 1.10 Impact Factor
[show abstract][hide abstract] ABSTRACT: Studies of regulation of free fatty acid (FFA) utilization by skeletal muscles have focused on plasma FFA delivery and on intracellular factors affecting FFA metabolism. The present study was conducted to directly analyse the uptake process of fatty acids into single myocytes. Cells were isolated from the rat flexor digitorum brevis muscle. Confocal laser scanning microscopy was utilized to analyse the uptake of the fluorescent fatty acid derivative 12-NBD-stearate, which is not metabolized by muscle tissue. Uptake represented a saturable function of the unbound fatty acid concentration in the medium (K(m) 366 +/- 118 nM, Vmax 2.1 +/- 0.3 AU/s) and depended on the medium sodium concentration. Reduced buffer pH increased initial uptake rates, whereas lactate (10 mM) had no effect. Membrane hyper- and depolarization decreased uptake rates. This study demonstrates for the first time kinetic data from isolated myocytes with evidence for a carrier-mediated transport mechanism for long-chain fatty acids.
Cellular and Molecular Life Sciences CMLS 08/1998; 54(7):744-50. · 5.62 Impact Factor
[show abstract][hide abstract] ABSTRACT: The aim was to explore whether biliary epithelial cells show muscarinic acetylcholine receptors and to investigate their role in ductular bile formation. In both, isolated rat biliary epithelial cells and Mz-Cha-1 cells, a biliary epithelial cell line, binding of [3H]N-methyl-scopolamine occurred with 0.718 +/- 0.08 and 0.482 +/- 0.05 fmol per 10(6) cells, respectively. To characterize the involved second messenger, intracellular Ca2+ levels were monitored by confocal microscopy. Stimulation of biliary epithelial cells with carbachol produced an increase in free cytosolic Ca2+ levels that declined to baseline values describing a sinusoidal oscillation curve. Increasing concentrations of the agonist decreased latency of the response and increased oscillation frequency. Similar results were obtained in Mz-Cha-1 cells. The intracellular Ca2+ originated from IP3 sensitive intracellular stores and from the extracellular medium. The Ca2+ response could partially be blocked by atropine and completely by pirenzepine, a specific muscarinic receptor-type M1 antagonist. The presence of M1 receptor messenger RNA (mRNA) in biliary epithelial cells was confirmed by reverse transcriptase polymerase chain reaction. In the isolated perfused guinea pig liver, a model with high ductular bile flow, carbachol induced a dose dependent decrease of bile flow by 79.6% +/- 9.8% at 50 mumol/L carbachol (P < .001), without affecting perfusion pressure or biliary electrolyte concentrations. It is concluded that biliary epithelial cells express muscarinic acetylcholine receptors. Stimulation of this receptor leads to cholestasis. This could be because of changes in peribiliary permeability and/or inhibition of biliary epithelial cell secretory function.
[show abstract][hide abstract] ABSTRACT: Fatty acids enter hepatocytes, at least in part, by a carrier-mediated uptake mechanism. The importance of driving forces for fatty acid uptake is still controversial. To evaluate possible driving mechanisms for fatty acid transport across plasma membranes, we examined the role of transmembrane proton gradients on fatty acid influx in primary cultured rat hepatocytes. After hepatocytes were loaded with SNARF-1 acetoxymethyl ester, changes in intracellular pH (pHi) under different experimental conditions were measured and recorded by confocal laser scanning microscopy. Fatty acid transport was increased by 45% during cellular alkalosis, achieved by adding 20 mM NH4Cl to the medium, and a concomitant paracellular acidification was observed. Fatty acid uptake was decreased by 30% during cellular acidosis after withdrawal of NH4Cl from the medium. Cellular acidosis activates the Na+/H+ antiporter to export excessive protons to the outer cell surface. Inhibition of Na+/H+ antiporter activity by amiloride diminishes pHi recovery and thereby accumulation of protons at the outer surface of the plasma membrane. Under these conditions, fatty acid uptake was further inhibited by 57% of control conditions. This suggests stimulation of fatty acid influx by an inwardly directed proton gradient. The accelerating effect of protons at the outer surface of the plasma membrane was confirmed by studies in which pH of the medium was varied at constant pHi. Significantly higher fatty acid influx rates were observed at low buffer pH. Recorded differences in fatty acid uptake appeared to be independent of changes in membrane potential, because BaCl2 did not influence initial uptake velocity during cellular alkalosis and paracellular acidosis. Moreover, addition of oleate-albumin mixtures to the NH4Cl incubation buffer did not change the observed intracellular alkalinization. In contrast, after cells were acid loaded, addition of oleate-albumin solutions to the recovery buffer increased pHi recovery rates from 0.21 +/- 0.02 to 0.36 +/- 0.05 pH units/min (P < 0.05), indicating that fatty acids further stimulate Na+/H+ antiporter activity during pHi recovery from an acid load. It is concluded that carrier-mediated uptake of fatty acids in hepatocytes follows an inwardly directed transmembrane proton gradient and is stimulated by the presence of H+ at the outer surface of the plasma membrane.
The American journal of physiology 01/1997; 271(6 Pt 1):G1067-73.
[show abstract][hide abstract] ABSTRACT: Extracellular nucleotides are secretagogues and influence ion permeability. The aim of this study was to investigate whether secretagogues activate transmembrane acid-base carriers, e.g., sodium, hydrogen antiporter in cholangiocytes.
Cells were loaded with pH and Ca(2+)-sensitive dyes. Intracellular changes in ion concentrations were monitored by confocal laser scanning microscopy. Adenosine 3', 5'-cyclic monophosphate was determined by standard methods.
Baseline intracellular pH (pH1) averaged 7.28 +/- 0.17 pH units. Adenosine triphosphate (ATP; 10 mumol/L) increased baseline pH1 by 0.28 +/- 0.06 pH units/10 min (P < 0.01). Ten and 100 mumol/L ATP increased Na+, H+ antiporter-mediated proton flux from 9.4 +/- 4.9 mmol. L-1 min-1 to 17.2 +/- 11.8 and 16.7 +/- 10.3 mmol. L(-1)-min(-1) (P < 0.001), respectively. Under control and ATP-stimulated conditions, 1 mmol/L amiloride blocked pH1 recovery, indicating true activation of Na+, H+ antiporter by extracellular ATP. Inhibition of basolateral Na+, H+ antiporter isoform inhibited stimulation by ATP. Na+, H+ antiporter-mediated proton flux was stimulated by adenosine, uridine triphosphate, adenosine-5'-0-(3-thiotriphosphate), alpha, beta-methylene-ATP, and 2-methylthio-ATP but not prevented by adenosine receptor blocking. Activation by ATP was not influenced by the Ca2+/protein kinase C/calmodulin system but could be mimicked by addition of N6,2'-O-dibutyryladenosine-3',5'-cyclic monophosphate and was inhibited by pertussis toxin.
Extracellular nucleotides may modulate secretory and absorptive function of cholangiocytes by activating Na+/H+ exchange mechanisms.
[show abstract][hide abstract] ABSTRACT: Apoptosis by loss of adherence is a recently described phenomenon termed "anoikis." beta 1, integrins are heterodimeric surface molecules mediating adhesion to the extracellular matrix. The aim of this study was to address whether anoikis accounts for the elimination of senescent enterocytes and, if so, whether beta 1 integrins are involved.
Whole crypts were isolated from normal human colonic mucosa and examined in vitro.
The vast majority of cells in resuspended crypts rapidly underwent apoptosis within 4 hours. Apoptosis was partially inhibited when cells had contact with collagen I-coated membranes or when whole crypts were embedded in a collagen gel. Preincubation of crypts with an inhibiting anti-beta 1 antibody before readhesion caused a much higher apoptotic rate. Confocal microscopy of embedded crypts revealed two critical zones of high sensitivity to temporary loss of adherence: the base of the crypts where stem cells are supposed to reside and the crypt mouth including the surface epithelium.
Survival of colonic epithelia crucially depends on matrix adhesion and is likely to be guaranteed by beta 1-integrin/ matrix interaction. The data strongly suggest that anoikis is the way senescent colon cells die.
[show abstract][hide abstract] ABSTRACT: Long-chain free fatty acids (FA) were shown to exert a regulatory function in the nucleus. However, the route of their entry remains uncertain. The aim of the present study was to examine whether the extracellular FA enter the hepatocellular nuclei. The experiments were carried out in vivo and in vitro. Intravenous administration of albumin-bound [14C]-palmitic and [14C]-linoleic acid resulted in rapid accumulation of the labels in the nuclear lipids. Unesterified [14C]-palmitic acid represented 22.4 +/- 1.7 and [14C]-linoleic acid 17.6 +/- 1.3 percent of the total lipid radioactivity. In vitro, confocal laser scanning microscopy was used to examine 12-NBD-stearate (a fluorescent derivative of stearate) translocation into the nuclei of isolated hepatocytes. It was found that 12-NBD stearate enters the nucleus and that this uptake depends on the extracellular and/or cytoplasmic concentration. It is concluded that factors (e.g. dietary) leading to alterations in the plasma FA composition and content can result in rapid changes of the nuclear FA pool and thus regulate certain nuclear processes.
Life Sciences 02/1996; 59(25-26):2209-15. · 2.56 Impact Factor
[show abstract][hide abstract] ABSTRACT: Biliary epithelial cells line the intra- and extrahepatic biliary tree. They are involved in bile formation and are of importance in different cholestatic conditions (vanishing bile duct syndrome). In recent years, progress has been made to elucidate more precisely the physiological role of biliary epithelial cells. Biliary epithelial cells are involved in the cholehepatic shunting of bile acids, they reabsorb sugar and glutamate from bile. Secretin-induced electrolyte secretion is regulated by intracellular cAMP levels in these cells. Intracellular Ca2+ levels, which are increased by different agonists, e.g. carbachol, regulate transmembrane ion channels. ATP acts as secretagogue in these cells by activating ion channels and Na+, H+ antiporter. Further studies have to investigate in which parts of the biliary tree absorptive or secretory mechanisms are predominant.