Christina Schleicher

EP300--a miRNA-regulated metastasis suppressor gene in ductal adenocarcinomas of the pancreas.

Genetic and epigenetic alterations during development of pancreatic ductal adenocarcinomas (PDACs) are well known. This study investigates genetic and epigenetic data together with tumor biology to find specific alterations responsible for metastasis formation. Using 16 human PDAC cell lines in a murine orthotopic PDAC model, local infiltration and metastatic spread were assessed by standardized dissemination scores. The cell lines were further classified into 3 hierarchical groups according to their metastatic potential. Their mRNA and microRNA (miRNA) expression was profiled via mRNA‐microarray as well as Taqman Low Density Array, and validated by single quantitative RT‐PCR and Western blotting. In the highly metastatic group, a significant induction of EP300 targeting miRNAs miR‐194 (fold change: 26.88), miR‐200b (fold change: 61.65), miR‐200c (fold change: 19.44) and miR‐429 (fold change: 21.67) (p < 0.05) was detected. Corresponding to this, decreased expression of EP300 mRNA (p < 0.0001) and protein (p < 0.05) were detected in the highly metastatic PDAC cell lines with liver metastases compared to the nonmetastatic or marginally metastatic cell lines, while no correlation with local tumor growth was found. In conclusion, epigenetic alterations with upregulated EP300 targeting miRNAs miR‐194, miR‐200b, miR‐200c and miR‐429 are related to reduced EP300 mRNA and protein in PDAC. These results demonstrate that miRNAs might be able to modulate the expression of metastasis‐specific suppressor genes and metastatic behavior in PDAC, suggesting diagnostic and therapeutic opportunities for EP300 and its targeting miRNAs in PDAC.

Impact of failed allograft nephrectomy on initial function and graft survival after kidney retransplantation

The management of an asymptomatic failed renal graft remains controversial. The aim of our study was to explore the effect of failed allograft nephrectomy on kidney retransplantation by comparing the outcome of recipients who underwent graft nephrectomy prior to retransplantation with those who did not. Retrospective comparison of patients undergoing kidney retransplantation with (group A, n = 121) and without (group B, n = 45) preliminary nephrectomy was performed, including subgroup analysis with reference to patients with multiple (≥2) retransplantations and patients of the European Senior Program (ESP). Nephrectomy leads to increased panel reactive antibody (PRA) levels prior to retransplantation and is associated with significantly increased rates of primary nonfunction (PNF; P = 0.05) and acute rejection (P = 0.04). Overall graft survival after retransplantation was significantly worse in group A compared with group B (P = 0.03). Among the subgroups especially ESP patients showed a shorter graft survival after previous allograft nephrectomy. On the multivariate analysis, pretransplant graft nephrectomy and PRA >70% were independent and significant risk factors associated with graft loss after kidney retransplantation. Nephrectomy of the failed allograft was not beneficial for retransplant outcome in our series. Patients with failed graft nephrectomy tended to have a higher risk of PNF and acute rejection after retransplantation. The possibility that the graft nephrectomy has a negative impact on graft function and survival after retransplantation is worth studying further.

Timing of Conversion to Mammalian Target of Rapamycin Inhibitors Is Crucial in Liver Transplant Recipients With Impaired Renal Function at Transplantation

BACKGROUND Renal dysfunction, primarily related to long-term use of calcineurin inhibitor-based immunosuppression, is the most common complication after liver transplantation. OBJECTIVE To evaluate whether liver transplant recipients with impaired kidney function at transplantation can benefit from early conversion to mammalian target of rapamycin inhibitor therapy (mTORi) compared with patients with late induction of mTORi-based therapy. MATERIALS AND METHODS Between 2003 and 2008, therapy was changed to an mTORi-based regimen in 57 patients. Patients were divided into 4 groups: group 1, early conversion (≤3 months after orthotopic liver transplantation) to mTORi therapy, and with impaired perioperative renal function; group 2, early conversion to mTORi therapy, and with normal perioperative renal function; group 3, late conversion to mTORi therapy, and with impaired perioperative renal function; and group 4, late conversion to mTORi therapy, and with normal perioperative renal function. RESULTS One month after conversion, the mean (SD) increase in calculated glomerular filtration rate in groups 1 (early conversion) and 3 (late conversion) was comparable: 8 (9) mL/min vs 7 (10) mL/min. At month 3, the increase in calculated glomerular filtration rate between groups 1 and 3 was significant (15 [11] mL/min vs 9 [15] mL/min; P = .04), an effect that persisted at month 6 (16 [12] mL/min vs 10 [12] mL/min; P = .05) and month 12 (22 [14] mL/min vs 12 [15] mL/min; P = .04). CONCLUSION In liver transplant recipients with perioperatively impaired renal function, early conversion to mTORi therapy should be performed because this approach seems to be more effective in improving long-term renal function.

Which imaging modalities should be used for biliary strictures of unknown aetiology

Why is it so difficult to determine the nature of isolated biliary strictures? In patients with no history of biliary surgery, most bile duct strictures have to be considered malignant until proven otherwise. This usually leads to extensive usage of diagnostic imaging—in many cases even to explorative laparotomy. Furthermore, we usually have a “luxury problem”: doctors have to choose the appropriate imaging technique out of the wide range of endoscopic and radiological modalities. For this purpose, doctors should have information about each technique. In a multimodal approach, we prospectively analysed sensitivity and specificity for differentiation between malignant and benign strictures, penetration into surrounding tissues, vascular invasiveness and staging of lymph node. We included patients with jaundice of unknown aetiology and suspected biliary stricture. According to the study protocol, patients underwent diagnostic laparotomy; alternatively, a long follow-up of more than 12 months …

Endosonographic and Histopathological Staging of Extrahepatic Bile Duct Cancer: Time to Leave the Present TNM-Classification?

OBJECTIVES:The discrepancy between high rates of sensitivity, specificity, and accuracy for intraductal ultrasonography (IDUS) in extrahepatic bile duct carcinoma and the failure to depict different wall layers as defined by the TNM classification have not yet been elucidated sufficiently.METHODS:In a prospective study, endosonographic images were correlated with histomorphology including immunohistochemistry. Using IDUS, we examined fresh resection specimens of patients who had undergone pancreato-duodenectomy. For histological analysis, the formalin-fixed and paraffin-embedded specimens were stained by hematoxylin-eosin, elastica-van-Gieson, and immunohistochemically by smooth muscle-actin. To confirm our hypothesis, further cases from the archives were analyzed histopathologically and immunohistochemically.RESULTS:The various wall layers of the extrahepatic bile duct as described by the International Union Against Cancer are neither histomorphologically nor immunohistochemically consistently demonstrable. Especially, a clear differentiation between tumor invasion beyond the wall of the bile duct (T2) and invasion of the pancreas (T3) by histopathological means is often not possible. Endosonographic images using high-resolution miniprobes similarly confirm the difficulty in imaging various layers in the bile duct wall.CONCLUSIONS:Most adaptations made by the sixth edition of the TNM classification accommodate to the endosonographic and most of the histopathological findings as demonstrated in our study. In contrast to the new edition, however, our findings suggest to combine T2- and T3-staged tumors into one single class leading to clarification, and improved reproducibility of histopathological staging.

Reticuloendothelial System Blockade Promotes Progression from Mild to Severe Acute Pancreatitis in the Opossum

ObjectiveTo examine the relation between hepatic reticuloendothelial system (RES) dysfunction and the development of acute biliary pancreatitis. In an opossum model, the authors tested the hypothesis that RES blockade can turn the mild pancreatitis seen after pancreatic duct obstruction (PDO) into the severe form. Summary Background DataBiliary obstruction is considered the decisive event in gallstone pancreatitis. Suppression of the RES occurs during biliary obstruction. MethodsEighteen opossums were placed into three groups of six animals each: group A, RES blockade with &lgr;-carrageenan; group B, PDO; and group C, PDO and RES blockade with carrageenan. The severity of pancreatitis was evaluated by enzyme serum levels and percentage of pancreatic tissue necrosis. RES capacity was measured by dynamic liver scintigraphy, and hepatic blood flow was documented using the hydrogen clearance technique. ResultsNo changes in hepatic blood flow occurred in groups A to C. RES capacity was suppressed in groups A and C; in group B, RES function remained unchanged. In group A, amylase and lipase levels remained normal, 3 ± 1.9% of pancreatic tissue were necrotic. The animals in group B developed mild edematous pancreatitis with an increase in amylase and lipase levels and 15 ± 10% of pancreatic necrosis. In group C, amylase and lipase increased significantly and histology revealed severe necrotizing pancreatitis, with 72 ± 11% of necrotic areas. ConclusionsArtificial RES blockade can promote the progression from mild pancreatitis as observed after PDO to the severe necrotizing form of the disease. Thus, RES dysfunction resulting from biliary obstruction might be an important cofactor in the pathogenesis of bile-induced pancreatitis.

Role of Tumor Microenvironment on Gene Expression in Pancreatic Cancer Tumor Models

OBJECTIVES The microenvironment is known to be a relevant factor of influence on tumor growth and metastasis in pancreatic ductal adenocarcinoma (PDAC). To determine the influence of the microenvironment on changes in gene expression, we analyzed gene expression in different PDAC tissues. METHODS Four human PDAC cell lines were introduced into a murine PDAC model with two insertion techniques: injection and implantation. Gene expression profiles of the cell lines growing in vitro and in vivo (ectopically and orthotopically) were established by microarray and validated by RT-PCR. RESULTS Significant differences were found in the gene expression profiles of the in vitro versus in vivo tissues (P < 0.05), while no differences were found between the in vivo tissues. Analyzing the orthotopic tumors derived from the injection and implantation methods, similar gene expression patterns with 0%-18% significantly differentially expressed genes between tumors of the two different methods were observed (analysis of variance [ANOVA]; P < 0.0001). CONCLUSIONS Gene expression from cell lines growing in vitro differed from the expression patterns of the same cells growing in vivo, while the localization of the growing tumor cells did not significantly alter gene expression. These data demonstrate that the implantation and injection techniques used in this study yield similar results and may be compared with each other.

Renal graft outcome in combined heart-kidney transplantation compared to kidney transplantation alone: a single-center, matched-control study.

BACKGROUND Renal allograft outcome in heart-kidney transplantation (HKTx) might be affected by hemodynamic instability and high levels of calcineurin inhibitor-dependent immunosuppression. METHODS From November 1999 to March 2008, 13 patients who received HKTx were compared with a matched control group of 13 kidney transplantation (KTx) recipients with similar cardiovascular risk factors. Graft function, rejection periods, and patient survival were analyzed. RESULTS Renal allograft rejection was noted in three patients (23%) after HKTx and in four patients (31%) after KTx. Serum creatinine levels were comparable at 1 week, 1 month, 1, 2, and 3 years after transplantation. Patient survival rates at 1, 2, and 3 years were 100% for HKTx recipients and 100, 92, and 92% for isolated KTx patients. Graft survival was 92% at 1, 2, and 3 years after HKTx and 100% at 1 year and 92% at 2 and 3 years after isolated KTx. CONCLUSIONS Our results with excellent long-term graft function and survival after combined HKTx indicate that this procedure is a valuable option for a growing number of patients suffering from coexistent cardiac and renal failure.

Poor organ quality and donor-recipient age mismatch rather than poor donation rates account for the decrease in deceased kidney transplantation rates in a Germany Transplant Center.

Kidney transplantation is limited not by technical or immunological challenges but by lack of donor organs. Whereas the number of patients on waiting list increased, the transplantation rate decreased. We analyzed the development of decline rates and reasons as well as the fate of declined organs. In total, 1403 organs offered to 1950 patients between 2001 and 2010 were included. Of 440 organs offered between 2009 and 2011 that were declined, we investigated whether these organs were transplanted elsewhere and requested delayed graft function, creatinine, graft and patient survival. Data were compared to results of transplantations at the same time at our center. Decline rate increased from 47% to 87%. Main reasons were poor organ quality and donor–recipient age or size mismatch. Of the rejected organs, 55% were transplanted at other centers with function, graft and patient survival equivalent to patients transplanted at our center during that period. The number of decline has increased over time mainly due to a growing number of marginal donors accounting for poor organ quality or a mismatch of donor and recipient. If proper donor–recipient selection is performed, many organs that would otherwise be discarded can be transplanted successfully.

Aorto-hepatic bypass in liver transplantation in the MELD-era: outcomes after supraceliac and infrarenal bypasses

PurposePoor arterial inflow during orthotopic liver transplantation (OLT) may necessitate arterial revascularisation using aorto-hepatic bypasses with supraceliac (SC) or infrarenal (IR) allografts. This study compared both techniques focusing on the patients’ preoperative conditions, postoperative graft/organ function, complications and survival.MethodsFifteen out of 114 OLT patients underwent revascularisation (7 IR/8 SC) between 2005 and 2008 and were included in the study. The patients’ records were reviewed retrospectively.ResultsIR patients presented with a higher BMI, received more male donor organs and their reperfusion sequence was predominately portal venous (SC: primary arterial). SC patients presented a significantly worse preoperative creatinine clearance and a trend towards a higher MELD score. The postoperative graft/organ function, morbidity and mortality did not differ between the groups despite a trend towards a worse survival in the SC group. A deteriorated preoperative creatinine clearance and higher MELD score negatively impacted the survival. Postoperative bleeding episodes and major re-interventions also affected the outcome.ConclusionsWe found no evidence for superiority of either bypass technique in our OLT patients. The trend toward a worse survival in SC patients was most likely caused by the worse preoperative conditions of these patients and highlights the importance of the impact of the MELD score on the outcome after OLT.