Publications (22)128.32 Total impact
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Article: Prognostic indicators of survival in patients with compensated and decompensated cirrhosis.
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ABSTRACT: Patients with cirrhosis are classified in a compensated and a decompensated stage. Portal hypertension is responsible for most of the complications of cirrhosis that mark the transition from compensated to decompensated cirrhosis. The objectives of this study were (a) to analyse survival of the different stages and substages of cirrhosis and (b) to examine the prognostic value of the hepatic venous pressure gradient (HVPG) at each of the stages. A total of 729 patients with suspected cirrhosis underwent routine measurement of portal pressure and systemic haemodynamics between 11/1995 and 12/2004. The primary end-point of the study was death, collected until November 30th, 2006. Multivariable analysis was performed using two models to determine predictors of death at each stage. A total of 443 patients were included in the study. The 1-year mortality was 5.4% in compensated and 20.2% in decompensated patients. Compensated patients in stage 1 (no varices) had a longer survival than stage 2 patients (varices present) (P = 0.015). In decompensated patients, survival was not different between stage 3 (ascites, with or without varices) and stage 4 (variceal haemorrhage, with or without ascites). Age and HVPG (cut-off 10 mmHg) were independent predictors of death in compensated patients, whereas MELD was in decompensated patients. Survival rates and predictors of death are different between patients with compensated and decompensated cirrhosis. Unlike the Italian cohort staging system, ascites is a better stratifying clinical event than variceal haemorrhage in patients with decompensated cirrhosis. The presence of clinically significant portal hypertension has prognostic value in compensated cirrhosis.Liver international: official journal of the International Association for the Study of the Liver 06/2012; 32(9):1407-14. · 3.82 Impact Factor -
Article: Incorporating indocyanin green clearance into the Model for End Stage Liver Disease (MELD-ICG) improves prognostic accuracy in intermediate to advanced cirrhosis.
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ABSTRACT: The Model for End Stage Liver Disease (MELD) predicts mortality in end stage liver disease. Incorporation of serum sodium into the MELD may improve diagnostic accuracy in decompensated patients with ascites. However, other complications of cirrhosis are not reflected. This study investigates whether quantitative liver function tests predict survival and increase prognostic accuracy of the MELD. 604 patients with suspected cirrhosis were staged clinically and haemodynamically. Galactose-elimination-capacity, sorbitol clearance, lidocaine metabolism and indocyanin green (ICG) half life were determined. Survival was the primary end point of the study. Prognostic effects of individual parameters were calculated using Cox regression models and ROC curves. 321 patients on standard pharmacological and endoscopic treatment (PET) and 74 patients undergoing transjugular portosystemic shunting (TIPS) were studied. Of all quantitative liver function tests, ICG half life was the most accurate in predicting survival. Upon incorporation into the MELD, it modified the score in patients with PET up to 35 points. Clinically relevant changes to the score, however, occurred in patients with a MELD score between 10 and 30, allowing an objective prognostic discrimination of individual survival based on laboratory liver function and blood flow. The MELD-ICG was validated in the second cohort of patients undergoing TIPS implantation. ICG had the highest predictive value of the examined tests. Its incorporation into the MELD adds an estimation of liver blood flow and renders the new score MELD-ICG more accurate in predicting survival in intermediate to advanced cirrhosis than the MELD and MELD-Na.Gut 07/2010; 59(7):963-8. · 10.11 Impact Factor -
Article: Propranolol impairs liver regeneration after partial hepatectomy in C57Bl/6-mice by transient attenuation of hepatic lipid accumulation and increased apoptosis.
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ABSTRACT: Acute hepatic fat accumulation appears to be crucial for liver regeneration after partial hepatectomy. Since fatty acids in the liver are provided by catecholamine-induced lipolysis in the adipose tissue, we investigated whether beta-adrenergic blockade of lipolysis might affect liver regeneration. Mice were treated with propranolol prior to partial hepatectomy. Subsequently, liver regeneration was evaluated histologically, by determination of the relative liver weight and the mitotic index at different time points after surgery. Liver mass restoration was delayed by propranolol, which was associated with a lower hepatic triglyceride content. Ki-67 labelling indicated that liver regeneration was attenuated by propranolol through inhibition of mitosis. Hepatocytes were arrested in the G1 phase of the cell cycle, as shown by the expression of G1-related proteins such as proliferating cell nuclear antigen, cyclin D1 and cyclin-dependent kinase-2, and underwent apoptosis as indicated by detection of poly(adenosine diphosphate-ribose) polymerase fragments. beta-adrenergic blockade of the host animal did not provide transplanted hepatocytes with a growth advantage over host cells. Impairment of liver regeneration by propranolol is related to the inhibition of acute hepatic fat accumulation and to a predisposition of hepatocytes to apoptosis.Scandinavian journal of gastroenterology 04/2010; 45(4):468-76. · 2.08 Impact Factor -
Article: Thymostimulin versus placebo for palliative treatment of locally advanced or metastasised hepatocellular carcinoma: a phase III clinical trial.
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ABSTRACT: Thymostimulin is a thymic peptide fraction with immune-mediated cytotoxicity against hepatocellular carcinoma (HCC) in vitro and palliative efficacy in advanced HCC in two independent phase II trials. The aim of this study was to assess the efficacy of thymostimulin in a phase III trial. The study was designed as a prospective randomised, placebo-controlled, double-blind, multicenter clinical phase III trial. Between 10/2002 and 03/2005, 135 patients with locally advanced or metastasised HCC (Karnofsky >or=60%/Child-Pugh <or= 12) were randomised to receive thymostimulin 75 mg s.c. 5x/week or placebo stratified according to liver function. Primary endpoint was twelve-month survival, secondary endpoints overall survival (OS), time to progression (TTP), tumor response, safety and quality of life. A subgroup analysis according to liver function, KPS and tumor stage (Okuda, CLIP and BCLC) formed part of the protocol. Twelve-month survival was 28% [95%CI 17-41; treatment] and 32% [95%CI 19-44; control] with no significant differences in median OS (5.0 [95% CI 3.7-6.3] vs. 5.2 [95% CI 3.5-6.9] months; p = 0.87, HR = 1.04 [95% CI 0.7-1.6]) or TTP (5.3 [95%CI 2.0-8.6] vs. 2.9 [95%CI 2.6-3.1] months; p = 0.60, HR = 1.13 [95% CI 0.7-1.8]). Adjustment for liver function, Karnofsky status or tumor stage did not affect results. While quality of life was similar in both groups, fewer patients on thymostimulin suffered from accumulating ascites and renal failure. In our phase III trial, we found no evidence of any benefit to thymostimulin in the treatment of advanced HCC and there is therefore no justification for its use as single-agent treatment. The effect of thymostimulin on hepato-renal function requires further confirmation. Current Controlled Trials ISRCTN64487365.BMC Cancer 01/2010; 10:457. · 3.01 Impact Factor -
Article: Chemotherapy for advanced gastric cancer.
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ABSTRACT: Gastric cancer currently ranks second in global cancer mortality. Most patients are either diagnosed at an advanced stage, or develop a relapse after surgery with curative intent. Apart from supportive care and palliative radiation to localized (e.g. bone) metastasis, systemic chemotherapy is the only treatment option available in this situation. To assess the efficacy of chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapy regimens in advanced gastric cancer. We searched the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE up to March 2009, reference lists of studies, and contacted pharmaceutical companies and national and international experts. Randomised controlled trials on systemic intravenous chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapies in advanced gastric cancer. Two authors independently extracted data. A third investigator was consulted in case of disagreements. We contacted study authors to obtain missing information. Thirty five trials, with a total of 5726 patients, have been included in the meta-analysis of overall survival. The comparison of chemotherapy versus best supportive care consistently demonstrated a significant benefit in overall survival in favour of the group receiving chemotherapy (hazard ratios (HR) 0.37; 95% confidence intervals (CI) 0.24 to 0.55, 184 participants). The comparison of combination versus single-agent chemotherapy provides evidence for a survival benefit in favour of combination chemotherapy (HR 0.82; 95% CI 0.74 to 0.90, 1914 participants). The price of this benefit is increased toxicity as a result of combination chemotherapy. When comparing 5-FU/cisplatin-containing combination therapy regimens with versus without anthracyclines (HR 0.77; 95% CI 0.62 to 0.95, 501 participants) and 5-FU/anthracycline-containing combinations with versus without cisplatin (HR 0.82; 95% CI 0.73 to 0.92, 1147 participants) there was a significant survival benefit for regimens including 5-FU, anthracyclines and cisplatin. Both the comparison of irinotecan versus non-irinotecan (HR 0.86; 95% CI 0.73 to 1.02, 639 participants) and docetaxel versus non-docetaxel containing regimens (HR 0.93; 95% CI 0.75 to 1.15, 805 participants) show non-significant overall survival benefits in favour of the irinotecan and docetaxel-containing regimens. Chemotherapy significantly improves survival in comparison to best supportive care. In addition, combination chemotherapy improves survival compared to single-agent 5-FU. All patients should be tested for their HER-2 status and trastuzumab should be added to a standard fluoropyrimidine/cisplatin regimen in patients with HER-2 positive tumours. Two and three-drug regimens including 5-FU, cisplatin, with or without an anthracycline, as well as irinotecan or docetaxel-containing regimens are reasonable treatment options for HER-2 negative patients.Cochrane database of systematic reviews (Online) 01/2010; · 5.72 Impact Factor -
Article: Percutaneous ethanol injection or percutaneous acetic acid injection for early hepatocellular carcinoma.
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ABSTRACT: Hepatocellular carcinoma (HCC) is the fifth most common global cancer. When HCC is detected early, interventions such as percutaneous ethanol injection (PEI), percutaneous acetic acid injection (PAI), and radiofrequency thermal ablation (RFTA) have curative potential and represent low invasive alternatives to surgery. The role of PEI or PAI has not been addressed in a systematic review. To evaluate the beneficial and harmful effects of PEI or PAI in adults with early HCC. A systematic search was performed in The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and ISI Web of Science in May 2009. Meeting abstracts of six oncological and hepatological societies (ASCO, ESMO, ECCO, AASLD, EASL, APASL) and references of articles were handsearched. Researchers in the field were contacted. Randomised trials comparing PEI or PAI with no intervention, sham intervention, other percutaneous interventions or surgery for the treatment of early HCC were considered regardless of blinding, publication status, or language. Studies comparing RFTA or combination treatments were excluded. Two authors independently selected trials for inclusion, and extracted and analysed data. The hazard ratios for median overall survival and recurrence-free survival were calculated using the Cox regression model with Parmar's method. Type and number of adverse events were reported descriptively. Three randomised trials with a total of 261 patients were eligible for inclusion. The risk of bias was high in all trials. Two of the trials compared PEI with PAI. Overall survival (HR 1.47; 95% confidence interval (CI) 0.68 to 3.19) and recurrence-free survival (HR 1.42; 95% CI 0.68 to 2.94) were not significantly different. Data on the duration of hospital stay were inconclusive. Data on quality of life were not available. There were only mild adverse events in both treatment modalities.The other trial compared PEI with surgery. There was no significant difference in overall survival (HR 1.57; 95% CI 0.53 to 4.61) and recurrence-free survival (HR 1.35; 95% CI 0.69 to 2.63). No serious adverse events were reported in the PEI group. Three postoperative deaths occurred in the surgery group. PEI and PAI does not differ significantly regarding benefits and harms in patients with early HCC, but only a limited number of patients have been examined and the bias risk was high in all trials. There is also insufficient evidence to determine whether PEI or segmental liver resection is more effective, although PEI may seem safer.Cochrane database of systematic reviews (Online) 02/2009; · 5.72 Impact Factor -
Article: Rapid development of a hepatocellular carcinoma in isolated thrombosis of hepatic veins (classic Budd-Chiari syndrome): case report and review of literature.
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ABSTRACT: Budd-Chiari syndrome and membranous obstruction of the inferior vena cava frequently result in the development of mostly benign hepatic lesions. In cases of membranous obstruction of the inferior vena cava, which is prevalent mostly in the East, these lesions often progress to hepatocellular carcinoma. In contrast, malignant transformation has not yet been recognised in patients with isolated hepatic vein thrombosis. We report the case of a 37-year-old male Caucasian who presented with acute Budd-Chiari syndrome without involvement of the inferior vena cava. Despite porto-caval shunting, a hepatocellular carcinoma developed within several months. Three hepatic lesions were treated by radiofrequency thermal ablation until liver transplantation was performed. This report emphasises the possibility of malignant transformation of regenerative nodules in patients with disturbed hepatic perfusion in general. Physicians must be aware of this when assessing regenerative nodules, especially as no unambiguous predictors for the development of hepatocellular carcinoma have been identified so far.Case Reports 01/2009; 2009. -
Article: Hepatocyte differentiation of mesenchymal stem cells from human adipose tissue in vitro promotes hepatic integration in vivo.
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ABSTRACT: The hepatic integration of human adipose tissue derived mesenchymal stem cells (hAT-MSCs) in vivo with or without prior differentiation to hepatocyte-like cells in vitro was investigated. Cells, isolated either from peritoneal or subcutaneous adipose tissue, expressed mesenchymal stem cell surface markers and featured multiple lineage differentiation. Under conditions favouring hepatocyte differentiation, hAT-MSCs gained hepatocytic functions in vitro including urea formation, glycogen synthesis, cytochrome P450 enzyme activity, and expression of hepatocyte-specific transcripts of carbamoylphosphate synthetase, albumin and cytochrome P450 type 3A4 (CYP3A4). Transgenic expression of green fluorescent protein emerged upon hepatocyte differentiation when driven by the hepatocyte-specific promoter of the cytosolic phosphoenolpyruvate carboxykinase gene but was constitutive from the ubiquitin gene promoter. Human AT-MSCs were transplanted into livers of immunodeficient Pfp/Rag2-/- mice with or without prior hepatocyte differentiation in vitro. Donor-derived human cells engrafted in the mouse host liver predominantly in the periportal region of the liver lobule. They expressed HepPar1 and albumin, typical features of differentiated human hepatocytes, in the otherwise negative mouse liver background. Engraftment was significantly more efficient using hAT-MSCs pre-differentiated to hepatocyte-like cells in vitro as compared with undifferentiated cells. Pre-differentiation of human MSCs from adipose tissue into hepatocyte-like cells in vitro facilitates long term functional hepatic integration in vivo.Gut 12/2008; 58(4):570-81. · 10.11 Impact Factor -
Article: Thymostimulin in advanced hepatocellular carcinoma: a phase II trial.
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ABSTRACT: Thymostimulin is a thymic peptide fraction with immune-mediated cytotoxicity against hepatocellular carcinoma in vitro. In a phase II trial, we investigated safety and efficacy including selection criteria for best response in advanced or metastasised hepatocellular carcinoma. 44 patients (84 % male, median age 69 years) not suitable or refractory to conventional therapy received thymostimulin 75 mg subcutaneously five times per week for a median of 8.2 months until progression or complete response. 3/44 patients were secondarily accessible to local ablation or chemoembolisation. Primary endpoint was overall survival, secondary endpoint tumor response or progression-free survival. A multivariate Cox's regression model was used to identify variables affecting survival. Median survival was 11.5 months (95% CI 7.9-15.0) with a 1-, 2- and 3-year survival of 50%, 23% and 9%. In the univariate analysis, a low Child-Pugh-score (p = 0.01), a low score in the Okuda- and CLIP-classification (p < 0.001) or a low AFP-level (p < 0.001) were associated with better survival, but not therapy modalities other than thymostimulin (p = 0.1) or signs of an invasive HCC phenotype such as vascular invasion (p = 0.3) and metastases (p = 0.1). The only variables independently related to survival in the Cox's regression model were Okuda stage and presence of liver cirrhosis (p < 0.01) as well as response to thymostimulin (p < 0.05). Of 39/44 patients evaluable for response, two obtained complete responses (one after concomitant radiofrequency ablation), five partial responses (objective response 18%), twenty-four stable disease (tumor control rate 79%) and eight progressed. Median progression-free survival was 6.4 months (95% CI 0.8-12). Grade 1 local reactions following injection were the only side effects. Outcome in our study rather depended on liver function and intrahepatic tumor growth (presence of liver cirrhosis and Okuda stage) in addition to response to thymostimulin, while an invasive HCC phenotype had no influence in the multivariate analysis. Thymostimulin could therefore be considered a safe and promising candidate for palliative treatment in a selected target population with advanced hepatocellular carcinoma, in particular as component of a multimodal therapy concept. Current Controlled Trials ISRCTN29319366.BMC Cancer 01/2008; 8:72. · 3.01 Impact Factor -
Article: Hepatocyte differentiation of mesenchymal stem cells from rat peritoneal adipose tissue in vitro and in vivo.
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ABSTRACT: Mesenchymal tissues harbour stromal cells capable of multilineage differentiation. Here, we demonstrate the isolation of mesenchymal stem cells (MSC) from rat peritoneal adipose tissue capable of osteogenic and adipogenic differentiation. Under in vitro conditions favouring hepatocyte differentiation, these MSC gained characteristic functions of hepatocytes such as the capacity to synthesize urea or store glycogen. Hepatocyte-specific transcripts of dipeptidylpeptidase type IV (CD26), albumin, cytochrome P450 type 1A1 (CYP1A1) and connexin CX32 (CX32) were detected only in differentiated but not undifferentiated cells. Transient transgenic expression of luciferase could be stimulated by cAMP when driven by the hepatocyte-specific promoter of the cytosolic phosphoenolpyruvate carboxykinase (PCK1) gene. Finally, stem cell-derived hepatocytes from wild type (CD26+/+) rats were transplanted into the livers of CD26-deficient animals after lentiviral transduction with the GFP gene under the control of the ubiquitin promoter. GFP-positive cells engrafted in the host liver predominantly in the periportal region of the liver lobule. They continued to express CD26, a prominent feature of differentiated hepatocytes, indicating their topologically and functionally proper integration into the host liver parenchyma. Thus, MSCs from rat peritoneal adipose tissue exhibit the potential to differentiate into hepatocyte-like cells in vitro and in vivo.Experimental Cell Research 09/2007; 313(13):2875-86. · 3.58 Impact Factor -
Article: Functional integration of hepatocytes derived from human mesenchymal stem cells into mouse livers.
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ABSTRACT: At present, clinical success of hepatocyte transplantation as an alternative to whole liver transplantation is hampered by the limited availability of suitable donor organs for the isolation of transplantable hepatocytes. Hence, novel cell sources are required to deliver hepatocytes of adequate quality for clinical use. Mesenchymal stem cells (MSCs) from human bone marrow may have the potential to differentiate into hepatocytes in vitro and in vivo. Isolated MSCs were selected by density gradient centrifugation and plastic adherence, differentiated in the presence of human hepatocyte growth medium and transplanted in immunodeficient Pfp/Rag2 mice. Here, we demonstrate that human MSCs gain in vitro the characteristic morphology and function of hepatocytes in response to specified growth factors. Specifically, preconditioned MSCs store glycogen, synthesise urea and feature the active hepatocyte-specific gene promoter of phosphoenolpyruvate carboxykinase (PCK1). After transplantation into livers of immunodeficient mice, preconditioned MSCs engraft predominantly in the periportal portion of the liver lobule. In situ, the cells continue to store glycogen and express PCK1, connexin32, albumin and the human hepatocyte-specific antigen HepPar1, indicating that the transplanted cells retain prominent qualities of hepatocytes after their regional integration. MSCs derived from human bone marrow may serve as a novel source for the propagation of hepatocyte-like cells suitable for cell therapy in liver diseases.Gut 04/2007; 56(3):405-15. · 10.11 Impact Factor -
Article: Chemotherapy in advanced gastric cancer: a systematic review and meta-analysis based on aggregate data.
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ABSTRACT: This systematic review and meta-analysis were performed to assess the efficacy and tolerability of chemotherapy in patients with advanced gastric cancer. Randomized phase II and III clinical trials on first-line chemotherapy in advanced gastric cancer were identified by electronic searches of Medline, Embase, the Cochrane Controlled Trials Register, and Cancerlit; hand searches of relevant abstract books and reference lists; and contact to experts. Meta-analysis was performed using the fixed-effect model. Overall survival, reported as hazard ratio (HR) with 95% CI, was the primary outcome measure. Analysis of chemotherapy versus best supportive care (HR = 0.39; 95% CI, 0.28 to 0.52) and combination versus single agent, mainly fluorouracil (FU) -based chemotherapy (HR = 0.83; 95% CI = 0.74 to 0.93) showed significant overall survival benefits in favor of chemotherapy and combination chemotherapy, respectively. In addition, comparisons of FU/cisplatin-containing regimens with versus without anthracyclines (HR = 0.77; 95% CI, 0.62 to 0.95) and FU/anthracycline-containing combinations with versus without cisplatin (HR = 0.83; 95% CI, 0.76 to 0.91) both demonstrated a significant survival benefit for the three-drug combination. Comparing irinotecan-containing versus nonirinotecan-containing combinations (mainly FU/cisplatin) resulted in a nonsignificant survival benefit in favor of the irinotecan-containing regimens (HR = 0.88; 95% CI, 0.73 to 1.06), but they have never been compared against a three-drug combination. Best survival results are achieved with three-drug regimens containing FU, an anthracycline, and cisplatin. Among these, regimens including FU as bolus exhibit a higher rate of toxic deaths than regimens using a continuous infusion of FU, such as epirubicin, cisplatin, and continuous-infusion FU.Journal of Clinical Oncology 07/2006; 24(18):2903-9. · 18.37 Impact Factor -
Article: The role of chemotherapy in patients with established gastric cancer.
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ABSTRACT: Chemotherapy significantly improves survival in comparison to best supportive care in patients with metastasised gastric cancer. In patients for whom a three-drug-combination is considered as the treatment of choice, ECF (epirubicin, cisplatin and 5-FU as a continuous infusion) should be regarded as standard of care. However, results for ECF have been challenged by the recently presented REAL-2-trial, which demonstrated a significant survival benefit for EOX (epirubicin, oxaliplatin, capecitabine) over ECF. Adjuvant 5-FU-based chemoradiation should be discussed in patients with inadequate lymphadenectomy, but is not internationally accepted as standard of care: whether patients with adequate lymhphadenectomy benefit from adjuvant chemoradiotherapy is currently unclear. According to the results of the UK MAGIC trial, perioperative treatment with ECF (3 cycles prior to and post surgery) results in a significantly reduced risk of death for patients with resectable gastric cancer as compared to surgery alone. Neo-adjuvant chemotherapy has the ability to downsize gastric tumours and appears to improve R0-resection rates, but its potential to improve overall survival is still unclear.Baillière' s Best Practice and Research in Clinical Gastroenterology 02/2006; 20(4):789-99. · 2.46 Impact Factor -
Article: Impact of capsule endoscopy on outcome in obscure intestinal bleeding: A multi-center cohort study in 285 patients
Gastroenterology 01/2006; 130(4):A475. · 11.68 Impact Factor -
Article: [Hepatocyte transplantation].
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ABSTRACT: Transplantation of hepatocytes is considered a promising technology for the cell therapy of liver diseases. Cells are isolated from donor livers, which are not allocated for organ transplantation and transplanted into the liver of a suitable recipient. Ideally, the transplanted cells functionally replace the hepatocytes of the diseased organ and restore its metabolic capacity either permanently or for a period of bridging to organ transplantation. Although about 50 cases of clinical hepatocyte transplantation have been documented, therapeutic benefit is doubtful, and the reasons for this are largely unknown. Minor quality of the transplanted cells isolated from marginal donor livers may be a major cause. Therefore, animal models have been established, which enable scientists to develop novel procedures of hepatocyte transplantation and to specifically study the mechanisms of hepatocyte integration in the host liver. Hopefully, results generated in animal models will set the basis for the design of novel procedures of hepatocyte transplantation individualized to the underlying disease in order to provide a growth advantage for donor over host cells. The plasticity of stem cells and their proliferative potential is the basis for current efforts to generate stem cell-derived hepatocytes of transplantation quality for the treatment of liver diseases.Medizinische Klinik 11/2005; 100(10):650-5. · 0.34 Impact Factor -
Article: Hepatozytentransplantation*
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ABSTRACT: Hintergrund:Die Transplantation von Hepatozyten stellt heute eine aussichtsreiche experimentelle Methode zur Zelltherapie bei Lebererkrankungen dar. Dabei werden die Zellen aus Organen, die nicht für die Lebertransplantation freigegeben werden, isoliert und einem geeigneten Empfänger in die Leber implantiert. Im Idealfall übernehmen die transplantierten Zellen die Funktion des erkrankten Organs und stellen somit die Organleistungen entweder dauerhaft oder für die Zeit der Überbrückung bis zur Lebertransplantation wieder her. Methodik und Ergebnisse:Obwohl weltweit bisher ca. 50 Fälle der klinischen Anwendung der Hepatozytentransplantation dokumentiert sind, ist der therapeutische Erfolg bis heute zweifelhaft. Die Ursachen dafür sind weitgehend unbekannt, liegen aber möglicherweise in der unzureichenden Qualität der aus marginalen Lebern gewonnenen transplantierten Zellen. Deshalb werden zurzeit im Tiermodell neue Verfahren zur Transplantation erprobt, die u. a. auch Aufschluss über den Mechanismus der Integration der transplantierten Zellen in der Empfängerleber geben sollen. Diese Kenntnis wird es ermöglichen, in Abhängigkeit von der Grunderkrankung der Leber individualisierte Methoden zu entwickeln, die den transplantierten Zellen einen Wachstumsvorteil verschaffen und so die effiziente Besiedlung der Empfängerleber ermöglichen. Perspektiven:Stammzellen scheinen aufgrund ihrer Plastizität und ihrer Proliferationsfähigkeit zur Herstellung von Hepatozyten besonders gut geeignet zu sein. Deshalb wird auch die Möglichkeit untersucht, aus Stammzellen unterschiedlicher Herkunft Hepatozyten zu generieren, die künftig in der Zelltherapie bei Lebererkrankungen Verwendung finden könnten. Background:Transplantation of hepatocytes is considered a promising technology for the cell therapy of liver diseases. Cells are isolated from donor livers, which are not allocated for organ transplantation and transplanted into the liver of a suitable recipient. Ideally, the transplanted cells functionally replace the hepatocytes of the diseased organ and restore its metabolic capacity either permanently or for a period of bridging to organ transplantation. Methods and Results:Although about 50 cases of clinical hepatocyte transplantation have been documented, therapeutic benefit is doubtful, and the reasons for this are largely unknown. Minor quality of the transplanted cells isolated from marginal donor livers may be a major cause. Therefore, animal models have been established, which enable scientists to develop novel procedures of hepatocyte transplantation and to specifically study the mechanisms of hepatocyte integration in the host liver. Hopefully, results generated in animal models will set the basis for the design of novel procedures of hepatocyte transplantation individualized to the underlying disease in order to provide a growth advantage for donor over host cells. Perspectives:The plasticity of stem cells and their proliferative potential is the basis for current efforts to generate stem cell-derived hepatocytes of transplantation quality for the treatment of liver diseases.09/2005; 100(10):650-655. -
Article: Functional characterization of serum-free cultured rat hepatocytes for downstream transplantation applications.
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ABSTRACT: Although ex vivo culture of hepatocytes is known to impair functionality, it may still be considered as desirable to propagate or manipulate them in culture prior to transplantation into the host liver. The aim of this study was to clarify whether rat hepatocytes cultured over different periods of time proliferate and retain their hepatocyte-specific functions following transplantation into the recipient liver. Rat hepatocytes were cultured under serum-free conditions in the presence of hepatocyte and epidermal growth factors. Cells derived from wild-type donor livers were transplanted into the livers of CD26-deficient rats. Cell proliferation and the expression of hepatocyte-specific markers were determined before and after transplantation. Cell number increased threefold over a culture period of 10 days. The expression of connexin 32 and phosphoenolpyruvate carboxykinase declined over time, indicating the loss of hepatocyte-specific functions. Hepatocytes cultured over 4 or 7 days and then transplanted proliferated in the host parenchyma. The transplanted cells expressed connexin 32, cytokeratin 18, and phosphoenolpyruvate carboxykinase, indicating the differentiated phenotype. The loss of hepatocyte-specific functions during culture may be restored after transplantation, suggesting that the proper physiological environment is required to maintain the differentiated phenotype.Cell Transplantation 02/2005; 14(7):497-506. · 5.13 Impact Factor -
Article: Ligation versus propranolol for the primary prophylaxis of variceal bleeding in cirrhosis.
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ABSTRACT: In this randomized controlled multicenter trial, we compared endoscopic variceal banding ligation (VBL) with propranolol (PPL) for primary prophylaxis of variceal bleeding. One hundred fifty-two cirrhotic patients with 2 or more esophageal varices (diameter >5 mm) without prior bleeding were randomized to VBL (n = 75) or PPL (n = 77). The groups were well matched with respect to baseline characteristics (age 56 +/- 10 years, alcoholic etiology 51%, Child-Pugh score 7.2 +/- 1.8). The mean follow-up was 34 +/- 19 months. Data were analyzed on an intention-to-treat basis. Neither bleeding incidence nor mortality differed significantly between the 2 groups. Variceal bleeding occurred in 25% of the VBL group and in 29% of the PPL group. The actuarial risks of bleeding after 2 years were 20% (VBL) and 18% (PPL). Fatal bleeding was observed in 12% (VBL) and 10% (PPL). It was associated with the ligation procedure in 2 patients (2.6%). Overall mortality was 45% (VBL) and 43% (PPL) with the 2-year actuarial risks being 28% (VBL) and 22% (PPL). 25% of patients withdrew from PPL treatment, 16% due to side effects. In conclusion, VBL and PPL were similarly effective for primary prophylaxis of variceal bleeding. VBL should be offered to patients who are not candidates for long-term PPL treatment.Hepatology 08/2004; 40(1):65-72. · 11.66 Impact Factor -
Article: Serum-free cryopreservation of porcine hepatocytes.
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ABSTRACT: The use of porcine hepatocytes in xenotransplantation, bioartificial liver support or pharmacological approaches demands serum-free cryopreservation protocols yielding high quality, viable, functional hepatocytes. Here, primary porcine hepatocytes were frozen without serum in liquid nitrogen by the use of a computer-assisted freezing device. After thawing, more than 90% of the initial hepatocytes were lost, in part because of damage to genomic DNA. When cryoprotectants were used, the loss was lowered to 70% of the initial cell number; 90% of the remaining cells excluded trypan blue indicating a high degree of viability. Cells were seeded serum-free onto collagen-coated plastic dishes to determine proliferation and retainment of specific functions representing prominent features of hepatocytes in vivo. Whereas no cells adhered to the substratum effectively in conventional culture medium, the addition of conditioned medium derived from hepatic non-parenchymal cells improved attachment. Cells proliferated, retained hepatocyte-specific functions, such as urea production and cytochrome P450 activity, and expressed liver-specific genes to levels observed in non-cryopreserved hepatocytes. Thus, serum-free cryopreserved primary porcine hepatocytes may serve as a valid source of cells for downstream applications. The cells seem to function adequately when an appropriate environment is chosen for recovery after cryopreservation, an ultimate demand for the clinical application of human hepatocytes.Cell and Tissue Research 08/2004; 317(1):45-56. · 3.11 Impact Factor -
Article: Simethicone for small bowel preparation for capsule endoscopy: a systematic, single-blinded, controlled study.
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ABSTRACT: Capsule endoscopy is a new imaging method for visualization of the entire small bowel. However, no standardized protocol for bowel preparation for capsule endoscopy has been evaluated. Capsule endoscopy was performed in 36 consecutive patients, all of whom fasted for 12 hours before ingestion of the capsule. Before capsule endoscopy, 18 patients received 80 mg simethicone and 18 had no supplemental medication for bowel preparation. Two observers, both experienced endoscopists, independently reviewed the examinations in a single-blinded and randomly assigned fashion. Mucosal visibility and intraluminal gas bubbles were assessed and graded by both observers. Bowel preparation with simethicone resulted in significantly better visibility because of fewer intraluminal bubbles (p<0.01). Interobserver agreement was excellent (r>/=0.8; k 0.78: 95% CI[0.57, 0.98] ). No adverse effect of simethicone was observed. Simethicone may be added to the routine preparation for capsule endoscopy to improve the visibility of small bowel mucosa.Gastrointestinal Endoscopy 05/2004; 59(4):487-91. · 4.88 Impact Factor
Top co-authors
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Institutions
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2004–2012
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Martin-Luther-Universität Halle-Wittenberg
- • Poliklinik für Innere Medizin I (Gastroenterologie, Pneumologie)
- • Institut für Rechtsmedizin
Halle, Saxony-Anhalt, Germany
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2010
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University Hospital of Lausanne
- Fondation du Centre pluridisciplinaire d'oncologie
Lausanne, VD, Switzerland
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2009
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University of Leipzig
Leipzig, Saxony, Germany
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