Publications (11)19.78 Total impact
-
Article: Strong predictors for alcohol recidivism after liver transplantation: non-acceptance of the alcohol problem and abstinence of <3 months.
[show abstract] [hide abstract]
ABSTRACT: Alcohol-toxic liver cirrhosis (ALC) is one of the main indications for liver transplantation (LT). The aim of the study is to define predictors for alcohol recidivism and to identify the outcome and quality of life of such patients. From March 2003 to July 2009, 226 patients underwent LT in our centre. In 53% liver cirrhosis was caused by alcohol abuse (sole/cofactor). Outcome and alcohol recidivism were assessed using patients' records, laboratory tests and interviews (patient, family members and family doctor). Furthermore, patients received an SF-36 quality of life and a self-designed questionnaire anonymously. Mean follow-up after LT was 31 + 23 months. The 5-year survival rate after LT in patients with ALC was significantly better compared to patients with other indications (78 vs. 64%; p = 0.016). Quality of life of both patient groups was comparable. After LT, alcohol recidivism rate was 16%. Patients with an alcohol abstinence of <3 months before LT had a significantly higher (p = 0.012) rate of alcohol recidivism in comparison to those with an abstinence of >3 months. Another predictor for alcohol recidivism was the patients' non-acceptance of having an alcohol problem before LT (p = 0.001). ALC is a good indication for LT. An alcohol abstinence of <3 months before LT and a non-acceptance of having an alcohol problem are strong predictors for alcohol recidivism after LT.Scandinavian journal of gastroenterology 08/2011; 46(10):1257-66. · 2.08 Impact Factor -
Article: A therapeutic exploratory study to determine the efficacy and safety of calcineurin-inhibitor-free de-novo immunosuppression after liver transplantation: CILT.
[show abstract] [hide abstract]
ABSTRACT: Immunosuppression with calcineurin inhibitors (CNI) increases the risk of renal dysfunction after orthotopic liver transplantation (OLT). Controlled trials have shown improvement of renal function in patients that received delayed and/or reduced-dose CNI after OLT. Delaying immunosuppression with CNI in combination with induction therapy does not increase the risk of acute rejection but reduces the incidence of acute renal dysfunction. Based on this clinical data this study protocol was designed to assess the efficacy and safety of calcineurin-inhibitor-free de-novo immunosuppression after liver transplantation. A prospective therapeutic exploratory, non-placebo controlled, two stage monocenter trial in a total of 29 liver transplant patients was designed to assess the safety and efficacy of de-novo CNI-free immunosuppression with basiliximab, mycophenolate sodium, prednisolone and everolimus. The primary endpoint is the rate of steroid resistant rejections. Secondary endpoints are the incidence of acute rejection, kidney function (assessed by incidence and duration of renal replacement therapy, incidence of chronic renal failure, and measurement glomerular filtration rate), liver allograft function (assessed by measurement of AST, ALT, total bilirubin, AP, GGT), treatment failure, (i. e., re-introduction of CNI), incidence of adverse events, and mortality up to one year after OLT. This prospective, two-stage, single-group pilot study represents an intermediate element of the research chain. If the data of the phase II study corroborates safety of de-novo CNI-free immunosuppressive regimen this should be confirmed in a randomized, prospective, controlled double-blinded clinical trial. The exploratory data from this trial may then also facilitate the design (e. g. sample size calculation) of this phase III trial. NCT00890253 (clinicaltrials.gov).BMC Surgery 04/2010; 10:15. · 1.33 Impact Factor -
Article: Serum galectin-3 is elevated in obesity and negatively correlates with glycosylated hemoglobin in type 2 diabetes.
[show abstract] [hide abstract]
ABSTRACT: Context: Adipocytes synthesize galectin-3 whose deficiency protects from inflammation associated with metabolic diseases. We aimed to study circulating galectin-3 in obesity and type 2 diabetes (T2D). Study Design: Galectin-3 was measured by ELISA in the serum of male normal-weight and overweight controls and T2D patients and in T2D patients of both sexes. Because visceral fat contributes to systemic inflammation, galectin-3 was analyzed in paired samples of human and rodent sc and visceral adipose tissue. Visceral adipose tissue adipokines are released to the portal vein, and galectin-3 was analyzed in portal, hepatic, and systemic venous serum (PVS, HVS, and SVS, respectively) of patients with liver cirrhosis and in patients who underwent surgery for nonhepatic diseases. The effect of metformin on adipocyte galectin-3 was analyzed by immunoblot. Results: Circulating galectin-3 was similarly elevated in T2D and obesity compared with normal-weight individuals and revealed a body mass index-dependent positive correlation with leptin, resistin, IL-6, and age. In T2D patients, galectin-3 was increased in serum of patients with elevated C-reactive protein and negatively correlated with glycated hemoglobin. Metformin treatment was associated with lower systemic galectin-3. Reduced galectin-3 in metformin-incubated human adipocytes indicated that low galectin-3 may be a direct effect of this drug. Galectin-3 was higher in PVS compared with HVS and SVS, suggesting that the splanchnic region is a major site of galectin-3 synthesis. Low galectin-3 in HVS compared with PVS demonstrated hepatic removal. Conclusions: Systemic galectin-3 is elevated in obesity and negatively correlates with glycated hemoglobin in T2D patients, pointing to a modifying function of galectin-3 in human metabolic diseases.The Journal of clinical endocrinology and metabolism 03/2010; 95(3):1404-11. · 6.50 Impact Factor -
Article: A prospective randomised, open-labeled, trial comparing sirolimus-containing versus mTOR-inhibitor-free immunosuppression in patients undergoing liver transplantation for hepatocellular carcinoma
[show abstract] [hide abstract]
ABSTRACT: Abstract Background The potential anti-cancer effects of mammalian target of rapamycin (mTOR) inhibitors are being intensively studied. To date, however, few randomised clinical trials (RCT) have been performed to demonstrate anti-neoplastic effects in the pure oncology setting, and at present, no oncology endpoint-directed RCT has been reported in the high-malignancy risk population of immunosuppressed transplant recipients. Interestingly, since mTOR inhibitors have both immunosuppressive and anti-cancer effects, they have the potential to simultaneously protect against immunologic graft loss and tumour development. Therefore, we designed a prospective RCT to determine if the mTOR inhibitor sirolimus can improve hepatocellular carcinoma (HCC)-free patient survival in liver transplant (LT) recipients with a pre-transplant diagnosis of HCC. Methods/Design The study is an open-labelled, randomised, RCT comparing sirolimus-containing versus mTOR-inhibitor-free immunosuppression in patients undergoing LT for HCC. Patients with a histologically confirmed HCC diagnosis are randomised into 2 groups within 4-6 weeks after LT; one arm is maintained on a centre-specific mTOR-inhibitor-free immunosuppressive protocol and the second arm is maintained on a centre-specific mTOR-inhibitor-free immunosuppressive protocol for the first 4-6 weeks, at which time sirolimus is initiated. A 2<sup>1/2</sup> -year recruitment phase is planned with a 5-year follow-up, testing HCC-free survival as the primary endpoint. Our hypothesis is that sirolimus use in the second arm of the study will improve HCC-free survival. The study is a non-commercial investigator-initiated trial (IIT) sponsored by the University Hospital Regensburg and is endorsed by the European Liver and Intestine Transplant Association; 13 countries within Europe, Canada and Australia are participating. Discussion If our hypothesis is correct that mTOR inhibition can reduce HCC tumour growth while simultaneously providing immunosuppression to protect the liver allograft from rejection, patients should experience less post-transplant problems with HCC recurrence, and therefore could expect a longer and better quality of life. A positive outcome will likely change the standard of posttransplant immunosuppressive care for LT patients with HCC. Trial Register Trial registered at http://www.clinicaltrials.gov : NCT00355862 (EudraCT Number: 2005-005362-36)BMC Cancer. 01/2010; -
Article: Adult Living Donor Liver Transplantation with ABO-Incompatible Grafts: A German Single Center Experience.
[show abstract] [hide abstract]
ABSTRACT: Adult living donor liver transplantations (ALDLTs) across the ABO blood group barrier have been reported in Asia, North Americas, and Europe, but not yet in Germany. Several strategies have been established to overcome the detrimental effects that are attached with such a disparity between donor and host, but no gold standard has yet emerged. Here, we present the first experiences with three ABO-incompatible adult living donor liver transplantations in Germany applying different immunosuppressive strategies. Four patient-donor couples were considered for ABO-incompatible ALDLT. In these patients, resident ABO blood group antibodies (isoagglutinins) were depleted by plasmapheresis or immunoadsorption and replenishment was inhibited by splenectomy and/or B-cell-targeted immunosuppression. Despite different treatments ALDLT could safely be performed in three patients and all patients had good initial graft function without signs for antibody-mediated rejection (AMR). Two patients had long-term graft survival with stable graft function. We thus propose the feasibility of ABO-incompatible ALDLT with these protocols and advocate further expansion of ABO incompatible ALDLT in multicenter trials to improve efficacy and safety.Journal of Transplantation 01/2009; 2009:759581. -
Article: Adult living donor liver transplantation: body mass index and MELD score of recipients are independent risk factors for hospital mortality.
[show abstract] [hide abstract]
ABSTRACT: Adult living donor liver transplantation (LDLT) has been established as elective procedure or urgent procedure to save the life of patients with terminal liver diseases. The outcome of LDLT varies between transplant centers. Here, we aim to evaluate the outcome of LDLT in our center and to identify the risk factors that are associated with hospital mortality of recipients. A cohort study with 32 consecutive cases of adult living donor liver transplantation was conducted in two cooperated medical centers. Perioperative data, incidence of postoperative complications, and hospital mortality were analyzed. No major surgical complications and no hospital mortality were observed in all 32 donors. All donors were discharged with normal liver function with median intensive care unit (ICU) stay of 1 day and median hospital stay of 10 days. All recipients had normal liver function in early posttransplant period. Eighty-one percent of the recipient survived with normal liver function for more than 1 year. The pretransplant ICU stay, renal failure, international normalized ratio (>1.8), and Model for End-stage Liver Disease (MELD) score (>20) were independent risk factors for hospital mortality of recipients. Adult living donor liver transplantation should be reserved to less "sick" patients in the era of organ allocation based on MELD score.Langenbeck s Archives of Surgery 05/2008; 394(2):235-41. · 1.81 Impact Factor -
Article: Current concepts and perspectives of immunosuppression in organ transplantation.
[show abstract] [hide abstract]
ABSTRACT: BACKGROUND: While early surgical success made organ transplantation possible in the 1950s and 1960s, the breakthrough in clinical organ transplantation was achieved through the discovery and invention of modern immunosuppressive agents in the early/mid-1980s. Especially during the 1990 s, a large array of immunosuppressants has expanded the armamentarium used to prevent and treat allograft rejection, resulting in an excellent short-term and an acceptable long-term outcome. However, these drugs have potent but still non-specific immunosuppressive properties and frequently show severe acute and chronic side effects, sometimes questioning the overall success. CONCEPTS/TRENDS: As the "Holy-Grail" of the transplant community, the induction of "true donor-specific tolerance" has not been achieved yet; current immunosuppressive strategies, in particular in Europe, include "individually tailored immunosuppressive" protocols, mostly based on specific immunologic and non-immunologic risk factors. These protocols allow for optimal immunosuppressive protocols for each patient group according to their needs by choosing the most suitable, well-tolerated combination of agents and the most effective doses to avoid acute rejection episodes (incidence and severity) and minimise drug-related toxicity to reduce long-term drug-related morbidity and mortality. Nevertheless, transplant recipient are still being forced to take a life-long course of chemical immunosuppressive agents to keep their graft, knowing about the possible life-threatening side effects. SUMMARY: We review current trends of immunosuppressive protocols in liver and kidney transplantation, focusing on calcineurin-inhibitor-sparing protocols, mammalian-target-of-rapamycin (mTOR) inhibitor based-protocols and corticosteroid-avoidance protocols, being aware of the fact, that most of these strategies could be applicable for other transplanted organs, too. Finally, we describe future trends and new developments that are rising on the horizon.Langenbeck s Archives of Surgery 10/2007; 392(5):511-23. · 1.81 Impact Factor -
Article: Binding analysis of 1alpha- and 17alpha-dihydrotestosterone derivatives to homodimeric sex hormone-binding globulin.
[show abstract] [hide abstract]
ABSTRACT: Binding studies of the interaction of immobilized 1alpha- and 17alpha-aminoalkyl derivatives of 5alpha-dihydrotestosterone (DHT) with purified N-deglycosylated homodimeric human sex hormone-binding globulin (SHBG) were performed using a surface plasmon resonance biosensor. These 1alpha- and 17alpha-derivatives with spacers of appropriate lengths between the amine function and the steroid ring skeleton enabled privileged, sterically undisturbed, interactions of either the 17- or 3-characteristic functional groups of DHT with SHBG. The association constants (K(a)1) for the binding of these immobilized DHT derivatives to the first binding site of SHBG, determined by SPR measurements, were 0.16 x 10(7) M(-1) for 17alpha-aminopropyl-17beta-hydroxy-5alpha-androstan-3-one (1), 1.64 x 10(7) M(-1) for 17alpha-aminocaproyl-17beta-hydroxy-5alpha-androstan-3-one (2), and 1.2 x 10(8) M(-1) for 1alpha-aminohexyl-17beta-hydroxy-5alpha-androstan-3-one (3). These values were compared with global K(a) data for the corresponding nonimmobilized DHT derivatives from equilibrium measurements using competitions with a tritiated testosterone tracer: the K(a) values were 1.25 x 10(7) M(-1) for 1, 1.50 x 10(7) M(-1) for 2, and 140 x 10(7) M(-1) for 3, confirming a remarkably high binding affinity of this latter compound for SHBG. A global fitting analysis of the biosensor data revealed that the interaction of the three immobilized steroids with SHBG was best described by a kinetic model assuming two structurally independent binding sites. This hypothesis of a bivalent binding model was also directly suggested by a dual fluorescent signal observed by the flow cytometry analysis of SHBG immobilized as a hybrid complex binding simultaneously two 1alpha-aminohexyl DHT ligands, one formed by 3, covalently coupled to phycoerythrin-labeled latex microspheres, and the other by the same DHT derivative, coupled to a fluorescein derivative (4).Biochemistry 12/2003; 42(46):13735-45. · 3.42 Impact Factor -
Article: Binding Analysis of 1α- and 17α-Dihydrotestosterone Derivatives to Homodimeric Sex Hormone-Binding Globulin
[show abstract] [hide abstract]
ABSTRACT: Binding studies of the interaction of immobilized 1α- and 17α-aminoalkyl derivatives of 5α-dihydrotestosterone (DHT) with purified N-deglycosylated homodimeric human sex hormone-binding globulin (SHBG) were performed using a surface plasmon resonance biosensor. These 1α- and 17α-derivatives with spacers of appropriate lengths between the amine function and the steroid ring skeleton enabled privileged, sterically undisturbed, interactions of either the 17- or 3-characteristic functional groups of DHT with SHBG. The association constants (Ka1) for the binding of these immobilized DHT derivatives to the first binding site of SHBG, determined by SPR measurements, were 0.16 × 107 M-1 for 17α-aminopropyl-17β-hydroxy-5α-androstan-3-one (1), 1.64 × 107 M-1 for 17α-aminocaproyl-17β-hydroxy-5α-androstan-3-one (2), and 1.2 × 108 M-1 for 1α-aminohexyl-17β-hydroxy-5α-androstan-3-one (3). These values were compared with global Ka data for the corresponding nonimmobilized DHT derivatives from equilibrium measurements using competitions with a tritiated testosterone tracer: the Ka values were 1.25 × 107 M-1 for 1, 1.50 × 107 M-1 for 2, and 140 × 107 M-1 for 3, confirming a remarkably high binding affinity of this latter compound for SHBG. A global fitting analysis of the biosensor data revealed that the interaction of the three immobilized steroids with SHBG was best described by a kinetic model assuming two structurally independent binding sites. This hypothesis of a bivalent binding model was also directly suggested by a dual fluorescent signal observed by the flow cytometry analysis of SHBG immobilized as a hybrid complex binding simultaneously two 1α-aminohexyl DHT ligands, one formed by 3, covalently coupled to phycoerythrin-labeled latex microspheres, and the other by the same DHT derivative, coupled to a fluorescein derivative (4).10/2003; -
Article: Syntheses and ligand-binding studies of 1 alpha- and 17 alpha-aminoalkyl dihydrotestosterone derivatives to human sex hormone-binding globulin.
[show abstract] [hide abstract]
ABSTRACT: We report on the syntheses of 1 alpha- and 17 alpha-aminoalkyl dihydrotestosterone (DHT) derivatives and the particularly high binding affinity of the 1 alpha-aminohexyl ligand for human sex hormone-binding globulin (SHBG). The two 17 alpha-aminopropyl-17 beta-hydroxy-5 alpha-androstan-3-one (1) and 17 alpha-aminocaproylamidoethyl-17 beta-hydroxy-5 alpha-androstan-3-one (2) derivatives were synthesized via a 17beta-spirooxirane intermediate in high yields. The 1 alpha-aminohexyl-17 beta-hydroxy-5 alpha-androstan-3-one compound (3) was obtained in a seven step synthesis using a copper-catalyzed conjugate addition of a omega-silyloxyhexyl Grignard reagent to 17 beta-benzoyloxy-5 alpha-androst-1-en-3-one. All structures were elucidated based on 1H NMR spectroscopy and mass spectral analyses. The three aminosteroid derivatives were tested as ligands for SHBG by competition experiments with tritiated testosterone as tracer under equilibrium conditions. The association constants of the two 17 alpha-DHT derivatives were approximately 1 x 10(7) M(-1), whereas the 1 alpha-DHT derivative showed a remarkably high binding affinity to SHBG with an association constant of 1.40 x 10(9) M(-1). These aminoalkyl derivatives, substituted either at the D-ring or the A-ring of the steroid skeleton, can be easily coupled onto a carboxymethylated solid state surface of a biosensor. Such a device lends itself to kinetic and thermodynamic studies aimed to provide a better understanding of the biospecific interaction of steroids with SHBG.Steroids 10/2003; 68(7-8):629-39. · 2.83 Impact Factor -
Article: Syntheses and ligand-binding studies of 1α- and 17α-aminoalkyl dihydrotestosterone derivatives to human sex hormone-binding globulin
[show abstract] [hide abstract]
ABSTRACT: We report on the syntheses of 1α- and 17α-aminoalkyl dihydrotestosterone (DHT) derivatives and the particularly high binding affinity of the 1α-aminohexyl ligand for human sex hormone-binding globulin (SHBG). The two 17α-aminopropyl-17β-hydroxy-5α-androstan-3-one (1) and 17α-aminocaproylamidoethyl-17β-hydroxy-5α-androstan-3-one (2) derivatives were synthesized via a 17β-spirooxirane intermediate in high yields. The 1α-aminohexyl-17β-hydroxy-5α-androstan-3-one compound (3) was obtained in a seven step synthesis using a copper-catalyzed conjugate addition of a ω-silyloxyhexyl Grignard reagent to 17β-benzoyloxy-5α-androst-1-en-3-one. All structures were elucidated based on NMR spectroscopy and mass spectral analyses. The three aminosteroid derivatives were tested as ligands for SHBG by competition experiments with tritiated testosterone as tracer under equilibrium conditions. The association constants of the two 17α-DHT derivatives were approximately 1×107 M−1, whereas the 1α-DHT derivative showed a remarkably high binding affinity to SHBG with an association constant of 1.40×109 M−1.These aminoalkyl derivatives, substituted either at the D-ring or the A-ring of the steroid skeleton, can be easily coupled onto a carboxymethylated solid state surface of a biosensor. Such a device lends itself to kinetic and thermodynamic studies aimed to provide a better understanding of the biospecific interaction of steroids with SHBG.Steroids.
Top co-authors
Top Journals
Institutions
-
2009
-
Universitätsklinikum Regensburg
Regensburg, Bavaria, Germany
-
-
2003
-
Universität Regensburg
- Institut für Organische Chemie
Regensburg, Bavaria, Germany -
Deutsches Herzzentrum München
München, Bavaria, Germany
-
