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Biomedical subjects

A Stiehl

Publications and source records attributed to A Stiehl.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effect of tauroursodeoxycholic acid on bile-acid-induced apoptosis and cytolysis in rat hepatocytes.

BACKGROUND/AIMS: In cholestatic liver disease, bile acids may initiate or aggravate hepatocellular damage. Cellular necrosis and cell death may be due to detergent effects of bile acids, but apoptosis may also play a role. In cholestasis, the conditions determining either apoptotic or cytolytic cell death are still unclear. Primary rat hepatocytes in culture represent a suitable model to study bile-acid-induced liver damage. METHODS: Glycochenodeoxycholic acid, a hydrophobic bile acid, was used to induce cell damage. Tauroursodeoxycholic acid, a hydrophilic bile acid, served as substrate to study possible protective effects of such compounds. To study the time and concentration dependency of bile-acid-induced cytolysis and apoptosis, morphologic alterations, hepatocellular enzyme release and nucleosomal DNA fragmentation were evaluated. RESULTS: Bile-acid-induced cytolysis, as indicated by hepatocellular enzyme release and by morphologic signs of membrane destruction, increased with concentration and time. Addition of tauroursodeoxycholic acid to the incubation medium reduced cytolysis significantly, indicating a direct hepatoprotective effect of this bile acid against the detergent action of hydrophobic bile acids. In contrast to cytolysis, apoptosis with DNA fragmentation was induced by low concentrations of glycochenodeoxycholic acid a few hours after incubation. Coincubation with tauroursodeoxycholic acid in equimolar concentrations significantly reduced apoptosis, indicating another direct hepatoprotective effect of tauroursodeoxycholic acid. CONCLUSIONS: It seems likely that in severe cholestasis, bile-acid-induced injury of hepatocytes is due mainly to cytolysis, whereas in moderately severe cholestasis apoptosis represents the predominant mechanism of bile acid toxicity. Tauroursodeoxycholic acid may reduce both bile-acid-induced apoptosis and cytolysis.

Animals↗
PubMed1998

Effect of S-adenosylmethionine versus tauroursodeoxycholic acid on bile acid-induced apoptosis and cytolysis in rat hepatocytes.

BACKGROUND: S-adenosylmethionine (SAMe) increases survival in alcoholic liver cirrhosis and may have a beneficial effect in cholestatic liver disease. SAMe repletes glutathione stores and protects tissue from oxygen free radicals. The effect of SAMe on bile acid-induced apoptosis is unknown. In the present study the possible hepatoprotective effect of SAMe was evaluated and compared with that of tauroursodeoxycholic acid (TUDCA). METHODS: Primary rat hepatocytes treated with glycochenodeoxycholic acid (GCDCA) were used as a model for cholestasis-induced hepatocellular damage, which served to study the effects of SAMe and TUDCA on bile acid-induced apoptosis and cytolysis. RESULTS: SAMe reduced bile acid-induced apoptosis but did not prevent bile acid-induced cytolysis. Compared with SAMe, TUDCA was more efficient in reducing apoptosis due to toxic bile acids. The combination of SAMe and TUDCA had additive effects in reducing apoptosis. CONCLUSION: The reduction in bile acid-induced apoptosis by SAMe may represent one of the factors responsible for its beneficial effects in the treatment of liver diseases.

Animals↗
PubMed1998

Adjuvant treatment with ursodeoxycholic acid may reduce the incidence of acute cardiac allograft rejection.

BACKGROUND: The nontoxic bile acid, ursodeoxycholic acid (UDCA), is an effective drug for the treatment of different cholestatic conditions. Furthermore, an immunomodulatory capacity of UDCA has been reported in vitro, as well as in vivo, in different immune-mediated liver diseases and after liver transplantation. METHODS: In this retrospective study, the influence of UDCA on heart transplant rejection was investigated in 21 cardiac allograft recipients receiving UDCA for cyclosporine-induced cholestasis (500 mg administered twice daily, start of therapy within the first postoperative month, duration >8 weeks). Thirty-one patients not receiving UDCA served as control subjects. All patients received triple-maintenance immunosuppression (cyclosporine, azathioprine, prednisolone). For quantitative comparison of rejection severity, the following score was applied: 0, no specific therapy; 1, temporary increase in oral steroids; 2, intravenous steroids; 3, ATG or OKT3 therapy. RESULTS: During the first 6 postoperative months, the number of acute rejection episodes requiring specific anti-rejection therapy was significantly lower in the UDCA group as compared with control subjects (1.38 +/- 1.36 vs 2.74 +/- 1.83 rejection episodes per patient, p = 0.005). The cumulative score was significantly lower in the UDCA group as compared with control subjects (2.38 +/- 2.29 vs 5.06 +/- 3.61, p = 0.004). CONCLUSIONS: These initial data indicate a beneficial effect of adjuvant UDCA treatment in the early phase after heart transplantation probably related to immunomodulating properties of UDCA, which may be used therapeutically after organ transplantation.

Acute Disease↗
PubMed1997

MRI findings in chronic hepatic encephalopathy depend on portosystemic shunt: results of a controlled prospective clinical investigation.

BACKGROUND/AIMS: Deterioration of hepatic encephalopathy is a major concern with the transjugular intrahepatic portosystemic shunt procedure. Symmetric hyperintense globus pallidus on T1-weighted cranial magnetic resonance imaging in patients with liver cirrhosis anticipates hepatocerebral disease. It is hypothesized that hepatic encephalopathy and basal ganglia signal intensity progress in patients with cirrhosis of the liver undergoing transjugular intrahepatic portosystemic shunt. METHODS: Twenty-four patients were randomized to undergo either transjugular intrahepatic portosystemic shunt or elective sclerotherapy. At study entry and 6 months after randomization, neurologic assessment, psychometric tests, standard EEG, and magnetic resonance imaging were performed. The severity of liver failure was graded using Child-Pugh's classification. The signal intensity of the globus pallidus was determined on sagittal T1-weighted magnetic resonance imaging. RESULTS: The T1-weighted signal intensity of the globus pallidus on magnetic resonance imaging significantly increased after transjugular intrahepatic portosystemic shunt placement (p<0.01), but not with elective sclerotherapy. At follow-up, neurological symptoms indicating decline of mental status and motor performance were somewhat more prevalent in transjugular intrahepatic portosystemic shunt patients. Significant deterioration of EEG abnormalities occurred in patients treated with transjugular intrahepatic portosystemic shunt as opposed to elective sclerotherapy (p<0.01). CONCLUSIONS: Transjugular intrahepatic portosystemic shunt procedure increases hyperresonant globus pallidus on magnetic resonance imaging. Neuropsychiatric evaluation shows advancing hepatic encephalopathy, in particular with transjugular intrahepatic portosystemic shunt; however, it does not parallel the augmentation of pallidal signal intensity on magnetic resonance imaging.

Adult↗
PubMed1997

Efficacy of ursodeoxycholic acid treatment and endoscopic dilation of major duct stenoses in primary sclerosing cholangitis. An 8-year prospective study.

BACKGROUND/AIMS: Primary sclerosing cholangitis is characterized by progressive fibrotic inflammation and obliteration of intra- and extrahepatic bile ducts. Ursodeoxycholic acid treatment leads to improvement of biochemical parameters of cholestasis and in part also of liver histology. During treatment, obstruction of major ducts may lead to deterioration of liver function, which may be prevented by endoscopic dilation of the stenoses. Controlled trials for evaluation of the beneficial effects of ursodeoxycholic acid treatment and of endoscopic measures in patients with major duct stenoses have become clinically difficult. Estimation of survival probabilities without treatment allows comparison of actuarial survival with the estimated survival probabilities. METHODS/RESULTS: We studied survival in 65 patients with PSC treated with ursodeoxycholic acid (750 mg/day) and by endoscopic measures whenever necessary. Patients with decompensated cirrhosis in whom transplantation was foreseen were excluded. The study was started in May 1987 and the mean follow-up period was 45.0+/-3.5 (mean+/-SEM) months. Liver histology was performed in each of the patients before entry into the study and revealed that 21% were in stage 1, 37% in stage 2, 21% in stage 3 and 20% in stage 4. Of 65 patients, 12 had major duct stenosis at entry and another 11 developed major duct stenosis during ursodeoxycholic acid treatment, which was successfully treated by repeated endoscopic balloon dilations. The actuarial Kaplan-Meier survival probabilities without liver transplantation after treatment with ursodeoxycholic acid and dilation of major duct stenoses were significantly improved compared to the predicted survival rates with p=0.001. CONCLUSIONS: Ursodeoxycholic acid does not prevent major bile duct occlusion. When ursodeoxycholic acid treatment and endoscopic opening of duct stenoses are combined, survival may be significantly improved.

Adolescent↗
PubMed1997

Transjugular intrahepatic portosystemic stent shunt versus sclerotherapy plus propranolol for variceal rebleeding.

BACKGROUND & AIMS: In patients with cirrhosis of the liver, after the first variceal bleeding episode, transjugular intrahepatic portosystemic stent shunting (TIPS) and endoscopic sclerotherapy plus propranolol (ES) were compared regarding prevention of variceal rebleeding and mortality. METHODS: Eighty-three patients with cirrhosis of the liver were randomized to undergo TIPS (n = 42) or ES (n = 41). RESULTS: Median observation time was in 1.6 years in the TIPS group and 1.45 years in the ES group. Cumulative rates of rebleeding were 23% in the TIPS group and 57% in the ES group (P = 0.0001). Hepatic encephalopathy was observed in 29% of the patients in the TIPS group and in 13% of those in the ES group (P = 0.041). Cumulative rates of survival were 69% in the TIPS group and 67% in the ES group (P = 0.62). Mortality rates in both groups were positively correlated with a higher Child's classification. CONCLUSIONS: Although TIPS significantly reduced the rate of rebleeding, survival rates were not improved. Because TIPS is associated with an increased risk of encephalopathy and high rates of shunt dysfunction, which requires reintervention, the procedure cannot be recommended for elective treatment after the first variceal bleeding episode, but it is an effective therapy in patients in whom endoscopic sclerotherapy fails to control bleeding.

Adult↗
PubMed1996

Phenprocoumon for prevention of shunt occlusion after transjugular intrahepatic portosystemic stent shunt: a randomized trial.

Development of stenosis or occlusion of the transjugular intrahepatic portosystemic stent shunt (TIPSS) is one of the major limiting factors in the long-term viability of this procedure. The efficacy of anticoagulation with heparin which is used in different centers is still unclear. In the present study, we evaluated the effect of phenprocoumon on shunt patency after TIPSS placement using Palmaz stents; 49 patients with Child's A and B cirrhosis, who underwent successful TIPSS placement were randomized into the treatment group (n = 24) who received phenprocoumon and a control group (n = 25). After 11 to 13 weeks, all patients were admitted and had a reevaluation that included control angiography by transjugular approach. Phenprocoumon treatment was stopped after the first reevaluation and both groups were followed for 1 year after randomization. During the 3-month treatment period 11 of 22 patients of the treatment group and 12 of 23 patients of the control group required reintervention because of an increased portosystemic gradient. Five of the 12 patients in the control group showed complete occlusion of the shunt, whereas no occlusion in the treatment group was observed (P < .05). During the mean follow-up of 8 months after the treatment was stopped, in both groups stenosis occurred in 50% of patients, but no further occlusion of the stent was observed. These data indicate that occlusion of the stent is related to thrombosis, whereas stenosis does not appear to be dependent on blood coagulation. In patients with preserved liver function occlusion of the shunt may be prevented by phenprocoumon treatment in the first 3 months after TIPSS placement. Thereafter shunt occlusion was not observed and further phenprocoumon treatment seemed unnecessary.

Anticoagulants↗
PubMed1996

Kinetics of primary bile acids in patients after orthotopic liver transplantation.

Administration of cyclosporin A (CsA) may induce cholestasis, and this effect has been attributed to impaired hepatocellular uptake, transport, secretion and intestinal absorption of bile acids. Disturbances of the enterohepatic circulation may affect metabolism of bile acids. To test whether liver transplantation and treatment with CsA alters pool sizes or synthesis and turnover rates, we determined kinetics of primary bile acids in patients after orthotopic liver transplantation on CsA. Two male and four female patients were studied 6-20 months after transplantation. They had no overt signs of cholestasis, graft dysfunction or rejection. Kinetics of cholic acid (CA) and chenodeoxycholic acid (CDCA) were simultaneously determined after oral administration of [24-13C]-CA and [24-13C]-CDCA on the basis of isotope dilution in a single pool of bile acids. Ten healthy volunteers served as controls. After orthotopic liver transplantation, pool sizes, fractional turnover rates and synthesis rates of both primary bile acids, CA and CDCA were not significantly different from control subjects. In spite of the known interference of CsA with the enterohepatic circulation of bile acids, in the majority of patients after orthotopic liver transplantation without cholestasis, graft dysfunction of rejection, treatment with CsA does not disturb kinetics of primary bile acids.

Adult↗
PubMed1996

Low prevalence of alterations in the pancreatic duct system in patients with primary sclerosing cholangitis.

BACKGROUND AND STUDY AIMS: Primary sclerosing cholangitis (PSC) is a rare disease of unknown origin that involves the intrahepatic or extrahepatic biliary system, or both. To obtain more precise information on concomitant involvement of the pancreatic duct system, a comparatively large group of 44 patients was studied. PATIENTS AND METHODS: Between 1989 and 1995, 44 patients took part in a study of the therapeutic effect of ursodeoxycholic acid, and their data were analyzed. In 42 of the 44 patients, both the pancreatic and biliary system were visualized by endoscopic retrograde cholangiopancreatography (ERCP). RESULTS: Pancreas divisum was detected in four patients (9.5%) with an otherwise normal major pancreatic duct. Three (7.1%) patients had pancreatic duct changes of the type seen in chronic pancreatitis. When risk factors such as alcohol abuse were excluded, there was only one patient with PSC and pancreatic duct alterations. CONCLUSION: In PSC patients, the prevalence of chronic pancreatitis is low.

Adult↗
PubMed1996

[Changes in fecal bile acid excretion after proctocolectomy].

To study the effect of total colectomy for fecal bile acid excretion we examined groups of patients with ulcerative colitis and familial adenomatous polyposis coli 4,8 +/- 2.9 years after surgery. Patients after total colectomy showed a significant higher fecal bile acid excretion compared to healthy persons (mean +/- SD: 190.8 +/- 195.2 mumol/d). The highest fecal output occurred in patients with permanent ileostomies (mean +/- SD: 7595.0 +/- 5651.4 mumol/d), it was significantly higher compared to patients with ileoanal pouch anastomosis (mean +/- SD: 2212.8 +/- 2132.8 mumol/d). The daily fecal output of patients with ileorectal anastomosis (mean +/- SD: 4331.8 +/- 6314.7 mumol/d) is between the results of both other groups without any significance. After total colectomy only primary bile acids were found in each group whereas healthy people had almost identically rates of primary and secondary bile acids in their stools.

Adenomatous Polyposis Coli↗
PubMed1996

Ursodeoxycholic acid in the treatment of primary sclerosing cholangitis.

Ursodeoxycholic acid treatment used in the management of primary sclerosing cholangitis leads to a rapid improvement in liver enzymes and is well tolerated in most patients. Fatigue and pruritus also showed an improvement, even if not significant compared with placebo, in some 50% of cases. Results of the investigations also showed that liver transplantation may be postponed in primary sclerosing cholangitis treated with ursodeoxycholic acid.

Cholagogues and Choleretics↗
PubMed1995

In patients with orthotopic liver transplantation, serum markers of cholestasis are unreliable indicators of biliary secretion.

BACKGROUND/AIMS: In patients after orthotopic liver transplantation, treatment with the novel immunosuppressant FK 506 may lead to elevated levels of alkaline phosphatase, gamma glutamyl transferase and bilirubin. Up to now it was unclear whether the excretory capacity of the liver in such patients is impaired. METHODS: We measured quantitatively the secretion of bile acids, phospholipids and cholesterol using the duodenal perfusion method, which allows assessment of biliary secretion without interruption of the enterohepatic circulation. Six healthy volunteers served as controls. RESULTS: All patients studied after orthotopic liver transplantation had elevated concentrations of serum alkaline phosphatase and gamma glutamyl transferase, whereas only half of them had slightly abnormal serum bilirubin levels. On average, the FK 506-treated patients excreted 1.23 +/- 0.27 mmol/h bile acids, 0.23 +/- 0.04 mmol/h phospholipids and 0.11 +/- 0.02 mmol/h cholesterol, which was not significantly different from the healthy controls. CONCLUSIONS: The normal secretion rates of biliary bile acids and lipids in FK 506-treated patients with elevated serum alkaline phosphatase and gamma glutamyl transferase indicate that the excretory capacity of the transplanted liver has completely recovered 2-3 months after surgery. In addition, in the majority of these patients elevated serum levels of alkaline phosphatase, gamma glutamyl transferase and bilirubin do not reflect impaired biliary secretion.

Adult↗
PubMed1995

Inhibition of ileal bile acid transport by cyclosporin A in rat.

Chronic administration of cyclosporin A may induce cholestasis and this effect has been attributed to impaired hepatic bile salt synthesis, metabolism and transport. We investigated the effect of cyclosporin A on intestinal absorption of bile acids in the ileum of rat. Ileal bile acid absorption was measured by in vivo intestinal perfusion with cyclosporin A and the solvent Cremophor EL. During ileal perfusion with 25 microM glycocholic acid, the concentration of 2.8 mM cyclosporin A inhibited intestinal bile acid absorption on average by 34%. Additional experiments were performed with everted gut sacs of the distal ileum to evaluate active absorption. A dose and time dependent inhibition of the active intestinal absorption of bile acids was found, with a 50% transport inhibition at an average cyclosporin A concentration of 2.69 mmol L-1. Thus, cyclosporin A inhibits the active intestinal absorption of bile acids which may influence bile acid synthesis, turnover and secretion and may contribute to cyclosporin A induced cholestasis.

Animals↗
PubMed1995

[Bile acids in liver diseases--current indications].

Ursodeoxycholic acid (UDCA) has beneficial effects in cholestatic diseases such as primary biliary cirrhosis, primary sclerosing cholangitis and cholestasis of pregnancy. In chronic hepatitis and alcoholic hepatitis, an effect of UDCA is uncertain. After organ transplantation (liver, bone, heart), favorable effects of UDCA which await confirmation were observed. UDCA very likely has a beneficial effect in children with Byler's and Alagille's syndrome, extrahepatic biliary atresia after the Kasai procedure and in cholestasis of cystic fibrosis. Unclear is the effect of UDCA in benign intermittent cholestasis (Summerskill-Tygstrup syndrome). Children with cholestasis and inborn errors of bile acid synthesis need additional administration of a primary bile acid (cholic acid, chenodeoxycholic acid). UDCA treatment in general does not lead to definitive cure of the disease but to improvement of laboratory parameters and possibly of symptoms and liver histology, and liver transplantation may be postponed to a later time point.

Bile Acids and Salts↗
PubMed1995

Biliary excretion of mezlocillin in patients with hepatic disease.

In three patients with liver disease (2 patients with alcoholic liver cirrhosis and 1 patient with chronic cholangitis) total, renal, biliary and metabolic clearance of the acylureidopenicillin mezlocillin was examined under steady state conditions. Mezlocillin was infused for 6 hours at a constant infusion rate of 10 mg/min. Renal clearance was calculated based on urinary excretion rates. Duodenal perfusion and marker dilution technique was applied to determine biliary excretion rates of the drug. Clearances were estimated by dividing the excretion rate by the respective plasma concentration. Total clearance was calculated by dividing the infusion rate by the plasma concentration. Biliary clearance was markedly reduced in the patients compared to the data of 8 healthy controls (0.65 +/- 0.33 ml/min vs 98.6 +/- 42.5 ml/min). Total and renal clearance were diminished (total clearance: 121.4 +/- 21.6 ml/min vs 286.5 +/- 54.6 ml/min, renal clearance, 65.4 +/- 1.0 ml/min vs 137.6 +/- 32.6 ml/min). In contrast, metabolic clearance was not changed (53.3 23.1 ml/min vs 50.3 +/ 24.2 ml/min). As mezlocillin is well tolerated and has a wide margin of safety we do not recommend reduced dosage. On the contrary, it might even be necessary to increase the dose when treating biliary tract infections in patients with cholestasis in order to assure effective drug concentrations in the bile.

Adult↗
PubMed1995

Intestinal absorption of bile acids: effect of ursodeoxycholic acid treatment.

Absorption of bile acids by diffusion occurs in all parts of the intestine whereas the active transport is only located in the terminal ileum. Absorption of ursodeoxycholic acid (UDCA) in the small intestine is slow and incomplete due to the poor solubility of this bile acid. After oral administration, UDCA competitively inhibits the absorption of endogenous bile acids in the ileum. This effect leads to changes in bile acid metabolism which may be related to its beneficial effect in cholestatic diseases.

Administration, Oral↗