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Background: Matrix metalloproteinases (MMPs) play a crucial role in tumour initiation, progression, and metastasis, including peritoneal carcinosis (PC) formation. MMPs serve as biomarkers for tumour progression in colorectal cancer (CRC), and MMP overexpression is associated with advanced-stage metastasis and poor survival. However, the molecular mechanisms of PC from CRC remain largely unclear. Methods: We investigated the role of MMPs during peritoneal colonisation by CRC cell lines in a human ex vivo peritoneum model and in patient-derived CRC and corresponding PC samples. MMP2 and MMP9 were inhibited using the small-molecule inhibitors batimastat and the specific MMP2/9 inhibitor III. Results: MMP2 and MMP9 were strongly upregulated in patient-derived samples and following peritoneal colonisation by CRC cells in the ex vivo model. MMP inhibition with batimastat reduced colonisation of HT29 and Colo205 cells by 36% and 68%, respectively (p = 0.0073 and p = 0.0002), while MMP2/9 inhibitor III reduced colonisation by 50% and 41%, respectively (p = 0.0003 and p = 0.0051). Fibronectin cleavage was enhanced in patient-derived samples of PC and during peritoneal colonisation in the ex vivo model, and this was inhibited by MMP2/9 inhibition. Conclusion: MMPs were upregulated in patient-derived samples and during peritoneal attachment of CRC cell lines in our ex vivo model. MMP2/9 inhibition prevented fibronectin cleavage and peritoneal colonisation by CRC cells. MMP inhibitors might thus offer a potential treatment strategy for patients with PC.

We consider discrete‐time dynamic principal–agent problems with continuous choice sets and potentially multiple agents. We prove the existence of a unique solution for the principal's value function only assuming continuity of the functions and compactness of the choice sets. We do this by a contraction mapping theorem and so also obtain a convergence result for the value function iteration. To numerically compute a solution for the problem, we have to solve a collection of static principal–agent problems at each iteration. As a result, in the discrete‐time setting solving the static problem is the difficult step. If the agent's expected utility is a rational function of his action, then we can transform the bi‐level optimization problem into a standard nonlinear program. The final results of our solution method are numerical approximations of the policy and value functions for the dynamic principal–agent model. We illustrate our solution method by solving variations of two prominent social planning models from the economics literature. Optimal unemployment tax principal–agent model repeated moral hazard C63 D80 D82

Background To compare the frequency of adverse events of thermal microwave (MWA) and radiofrequency ablation (RFA) with non-thermal irreversible electroporation (IRE) in percutaneous ablation of hepatocellular carcinoma (HCC). Patients and methods We retrospectively analyzed 117 MWA/RFA and 47 IRE procedures (one tumor treated per procedure; 144 men and 20 women; median age, 66 years) regarding adverse events, duration of hospital and intensive care unit (ICU) stays and occurrence of a post-ablation syndrome. Complications were classified according to the Clavien & Dindo classification system. Results 70.1% of the RFA/MWA and 63.8% of the IRE procedures were performed without complications. Grade I and II complications (any deviation from the normal postinterventional course, e.g., analgesics) occurred in 26.5% (31/117) of MWA/RFA and 34.0% (16/47) of IRE procedures. Grade III and IV (major) complications occurred in 2.6% (3/117) of MWA/RFA and 2.1% (1/47) of IRE procedures. There was no significant difference in the frequency of complications (p = 0.864), duration of hospital and ICU stay and the occurrence of a post-ablation syndrome between the two groups. Conclusions Our results suggest that thermal (MWA and RFA) and non-thermal IRE ablation of malignant liver tumors have comparable complication rates despite the higher number of punctures and the lack of track cauterization in IRE.

Although 2D cell cultures are commonly used to predict therapy response, it has become clear that 3D cultures may better mimic the in vivo situation and offer the possibility of tailoring translational clinical approaches. Here, we compared the response of 2D and 3D colorectal cancer (CRC) cell lines to irradiation and chemotherapy. Classic 2D cultures and 3D spheroids of CRC cell lines (CaCo2, Colo205, HCT116, SW480) were thoroughly established, then irradiated with doses of 1, 4, or 10 Gy, using a clinical-grade linear accelerator. The response was assessed by immunohistochemistry, flow cytometry, and TUNEL assays. Upon irradiation, CRC 3D spheroids were morphologically altered. After irradiation with 10 Gy, annexin V/PI staining revealed a 1.8- to 4-fold increase in the apoptosis rate in the 2D cell cultures (95% CI 3.24±0.96), and a 1.5- to 2.4-fold increase in the 3D spheroids (95% CI 1.56±0.41). Irradiation with 1 Gy caused 3- and 4-fold increases in TUNEL positive cells in the CaCo2 and HCT116 (p = 0.01) 2D cultures, respectively, compared with a 2-fold increase in the 3D spheroids. Furthermore, the 2D and 3D cultures responded differently to chemotherapy; the 3D cultures were more resistant to 5-FU and cisplatin, but not to doxorubicin and mitomycin C, than the 2D cultures. Taken together, CRC cells cultured as 3D spheroids displayed markedly higher resistance to irradiation therapy and selected chemotherapeutic drugs than 2D cultures. This in vitro difference must be considered in future approaches for determining the ideal in vitro systems that mimic human disease.

Selenium-binding protein 1 (SELENBP1) expression is reduced in various epithelial cancer entities compared to corresponding normal tissue and has already been described as a tumor suppressor involved in the regulation of cell proliferation, senescence, migration and apoptosis. We identified SELENBP1 to be down-regulated in cutaneous melanoma, a malignant cancer of pigment-producing melanocytes in the skin, which leads to the assumption that SELENBP1 also functions as tumor suppressor in the skin, as shown by others e.g. for prostate or lung carcinoma. However, in vitro analyses indicate that SELENBP1 re-expression in human melanoma cell lines has no impact on cell proliferation, migration or tube formation of the tumor cells themselves when compared to control-transfected cells. Interestingly, supernatant taken from melanoma cell lines transfected with a SELENBP1 re-expression plasmid led to suppression of vessel formation of HMEC cells. Furthermore, SELENBP1 re-expression alters the sensitivity of melanoma cells for Vemurafenib treatment. The data also hint to a functional interaction of SELENBP1 with GPX1 (Glutathione peroxidase 1). Low SELENBP1 mRNA levels correlate inversely with GPX1 expression in melanoma. The re-expression of SELENBP1 combined with down-regulation of GPX1 expression led to reduction of the proliferation of melanoma cells. In summary, SELENBP1 influences the tumor microenvironment and SELENBP1 action is functionally influenced by GPX1.

To evaluate the impact of CT scans on diagnosis or change of therapy in patients with systemic inflammatory response syndrome (SIRS) or sepsis and obscure clinical infection. CT records of patients with obscure clinical infection and SIRS or sepsis were retrospectively evaluated. Both confirmation of and changes in the diagnosis or therapy based on CT findings were analysed by means of the hospital information system and radiological information system. A sub-group analysis included differences with regard to anatomical region, medical history and referring department. Of 525 consecutive patients evaluated, 59% had been referred from internal medicine and 41% from surgery. CT examination had confirmed the suspected diagnosis in 26% and had resulted in a different diagnosis in 33% and a change of therapy in 32%. Abdominal scans yielded a significantly higher (p=0.013) change of therapy rate (42%) than thoracic scans (22%). Therapy was changed significantly more often (p=0.016) in surgical patients (38%) than in patients referred from internal medicine (28%). CT examination for detecting an unknown infection focus in patients with SIRS or sepsis is highly beneficial and should be conducted in patients with obscure clinical infection. • Evaluation of patients with obscure clinical infection is a challenging task. • CT examination of patients with SIRS or sepsis seems to be beneficial. • CT examination confirmed suspected diagnosis in 26% of patients. • CT examination yielded a new infection focus in 33% of patients. • CT examination changed therapy in up to 32% of patients.

Background Patients with acute mesenteric ischemia (AMI) often exhibit severe co-morbidities and significant surgical risks, leading to high perioperative morbidity. Purpose To investigate the feasibility of primary percutaneous stent-revascularization (PPSR) in atherosclerotic AMI and its impact on patients’ outcome. Material and Methods Retrospective analysis of 19 consecutive patients (7 women, 12 men; median age, 69 years) with AMI caused by atherosclerotic, non-embolic stenoses/occlusions of the splanchnic arteries and PPSR. Alternative minimally invasive techniques were excluded. Clinical characteristics including the Charlson Comorbidity Index adjusted by age (CCIa) and symptom duration, technical and clinical success of PPSR, clinical course, 30-day mortality, and follow-up were evaluated and compared to literature data for surgical approaches. Technical success was defined as residual stenosis of Results The majority of patients presented with severe co-morbidities (CCIa >4 in 17 of 19 patients, 89%). Median symptom duration was 50 h. Technical and clinical success rates of PPSR were 95% (21 of 22 arteries) and 53% (10 of 19 patients). Seven patients underwent subsequent laparotomy with bowel resection in four cases. Thirty-day mortality was 42% (8 of 19 patients). Conclusion In our study population of patients with atherosclerotic AMI, severe co-morbidities, prolonged acute symptoms, and significant perioperative risks PPSR of splanchnic stenoses were technically feasible and the clinical outcome was acceptable.

Transplant recipients face an increased risk of cancer compared with the healthy population. Although several studies have examined the direct effects of immunosuppressive drugs on cancer cells, little is known about the interactions between pharmacological immunosuppression and cancer immunosurveillance. We investigated the different effects of rapamycin (Rapa) versus cyclosporine A (CsA) on tumor-reactive CD8(+) T cells. After adoptive transfer of CD8(+) T cell receptor-transgenic OTI T cells, recipient mice received either skin grafts expressing ovalbumin (OVA) or OVA-expressing B16F10 melanoma cells. Animals were treated daily with Rapa or CsA. Skin graft rejection and tumor growth as well as molecular and cellular analyses of skin- and tumor-infiltrating lymphocytes were performed. Both Rapa and CsA were equally efficient in prolonging skin graft survival when applied at clinically relevant doses. In contrast to Rapa-treated animals, CsA led to accelerated tumor growth in the presence of adoptively transferred tumor-reactive CD8(+) OTI T cells. Further analyses showed that T-bet was downregulated by CsA (but not Rapa) in CD8(+) T cells and that cancer cytotoxicity was profoundly inhibited in the absence of T-bet. CsA reduces T-bet-dependent cancer immunosurveillance by CD8(+) T cells. This may contribute to the increased cancer risk in transplant recipients receiving calcineurin inhibitors.

For the first time in melanoma, novel therapies have recently shown efficacy in the adjuvant therapy setting, which makes companion diagnostics to guide treatment decisions a desideratum. Early spread of disseminated cancer cells (DCC) to sentinel lymph nodes (SLN) is indicative of poor prognosis in melanoma and early DCCs could therefore provide important information about the malignant seed. Here, we present a strategy for enrichment of DCCs from SLN suspensions using a microfluidic device (Parsortix™, Angle plc). This approach enables the detection and isolation of viable DCCs, followed by molecular analysis and identification of genetic changes. By optimizing the workflow, the established protocol allows a high recovery of DCC from melanoma patient-derived lymph node (LN) suspensions with harvest rates above 60%. We then assessed the integrity of the transcriptome and genome of individual, isolated DCCs. In LNs of melanoma patients, we detected the expression of melanoma-associated transcripts including MLANA (encoding for MelanA protein), analyzed the BRAF and NRAS mutational status and confirmed the malignant origin of isolated melanoma DCCs by comparative genomic hybridization. We demonstrate the feasibility of epitope-independent isolation of LN DCCs using Parsortix™ for subsequent molecular characterization of isolated single DCCs with ample application fields including the use for companion diagnostics or subsequent cellular studies in personalized medicine.

We propose a generic computational framework for solving large-scale infinite-horizon, discrete-time dynamic incentive problems with persistent hidden types. First, we combine set-valued dynamic programming techniques with unsupervised machine learning to determine irregularly-shaped feasible sets. Second, we generate training data from these pre-computed feasible sets to recursively solve the dynamic incentive problem by applying supervised and reinforcement machine learning. Third, to speed up the time-to-solution by orders of magnitude, we propose a generic parallelization scheme for dynamic incentive problems that allows for an efficient use of contemporary high-performance computing hardware. This combination enables us to analyze models of complexity that were previously considered to be intractable. To demonstrate the broad applicability of our method, we solve two very different types of dynamic incentive models: first, an adverse selection model with many discrete types; second, a problem with infinitely many types and multiple state variables.

This paper presents a new method for the analysis of moral hazard principal-agent problems. The new approach avoids the stringent assumptions on the distribution of outcomes made by the classical first-order approach and instead only requires the agent's expected utility to be a rational function of the action. This assumption allows for a reformulation of the agent's utility maximization problem as an equivalent system of equations and inequalities. This reformulation in turn transforms the principal's utility maximization problem into a nonlinear program. Under the additional assumptions that the principal's expected utility is a polynomial and the agent's expected utility is rational in the wage, the final nonlinear program can be solved to global optimality. The paper also shows how to first approximate expected utility functions that are not rational by polynomials, so that the polynomial optimization approach can be applied to compute an approximate solution to non-polynomial problems. Finally, the paper demonstrates that the polynomial optimization approach extends to principal-agent models with multi-dimensional action sets.

Introduction Complete lymph node dissection (CLND) after a positive sentinel node (SN) biopsy provides important prognostic information in melanoma patients but has been questioned for therapeutic use recently. We explored whether quantification of the tumour spread to SNs may replace histopathology of non-sentinel nodes (NSNs) for staging purposes. Patients and methods We quantified melanoma spread in SNs and NSNs in 128 patients undergoing CLND for a positive SN. In addition to routine histopathology, one-half of each of all 1496 SNs and NSNs was disaggregated into a single cell suspension and stained immunocytochemically to determine the number of melanoma cells per 106 lymph node cells, i.e. the disseminated cancer cell density (DCCD). Results We uncovered melanoma spread to NSNs in the majority of patients; however, the tumour load and the proportion of positive nodes were significantly lower in NSNs than in SNs. The relation between SN and NSN spread could be described by a mathematical function with DCCDNSN = DCCDSNc/101−c (c = 0.69; 95% confidence interval [CI]: 0.62–0.76). At a median follow-up of 67 months, multivariable Cox regression analyses revealed that DCCDSN (p = 0.02; HR 1.34, 95% CI: 1.05–1.71) and the total number of pathologically positive nodes (p = 0.02; HR 1.53, 95% CI: 1.07–2.22) were significant risk factors after controlling for age, gender, thickness of melanoma and ulceration status. A prognostic model based on DCCDSN and melanoma thickness predicted outcome as accurately as a model including pathological information of both SNs and NSNs. Conclusion The assessment of DCCDSN renders CLND for staging purposes unnecessary.

Objectives The aim of this study was to determine the diagnostic value of diffusion-weighted MRI of the liver at 3T to classify liver fibrosis/cirrhosis. Methods 62 patients who underwent both histopathological examination and diffusion-weighted imaging of the liver via 3T MRI within a period of 3 months were included in the study. The Ishak score (1-6) was used to determine the degree of fibrosis: No liver fibrosis (NLF; Ishak 0, n = 16), mild liver fibrosis (MLF; Ishak 1-2, n = 23), advanced liver fibrosis (ALF; Ishak 3-5, n = 12), and liver cirrhosis (LC; Ishak 6, n = 11). Results The corresponding ADC values for the individual patient groups were as follows: NLF: 1123 (SD 95.8); MLF: 1032 (SD 77.6); ALF: 962 (SD 68.8); LC: 1015 (SD 60.2) mm2/s. There is a significant difference between NLF and MLF (p = 0.004) and between MLF and ALF (p = 0.022). A significant difference between patients with ALF and LC (p = 0.117) could not be found. Conclusion Liver fibrosis/cirrhosis lowers the ADC values of the liver parenchyma in 3T MRI. However, the degree of fibrosis can only be conditionally determined on the basis of ADC values.

We studied the developmental and functional mechanisms behind NK cell–mediated antitumor responses against metastatic colorectal carcinoma (CRC) in mice. In particular, we focused on investigating the significance of T-box transcription factors and the immunotherapeutic relevance of IL-15 in the development and function of tumor-reactive NK cells. Pulmonary CRC metastases were experimentally seeded via an adoptive i.v. transfer of luciferase-expressing CT26 CRC cells that form viewable masses via an in vivo imaging device; genetically deficient mice were used to dissect the antitumor effects of developmentally different NK cell subsets. IL-15 precomplexed to IL-15 receptor-α was used in immunotherapy experiments. We found that mice deficient for the T-box transcription factor T-bet lack terminally differentiated antitumor CD27lowKLRG1+ NK cells, leading to a terminal course of rapid-onset pulmonary CRC metastases. The importance of this NK cell subset for effective antitumor immunity was shown by adoptively transferring purified CD27lowKLRG1+ NK cells into T-bet–deficient mice and, thereby, restoring immunity against lung metastasis formation. Importantly, immunity to metastasis formation could also be restored in T-bet–deficient recipients by treating mice with IL-15 precomplexed to IL-15 receptor-α, which induced the development of eomesodermin+KLRG1+ NK cells from existing NK cell populations. Thus, contingent upon their T-bet–dependent development and activation status, NK cells can control metastatic CRC in mice, which is highly relevant for the development of immunotherapeutic approaches in the clinic.

We present a new way to solve generalized Nash equilibrium problems. We assume the feasible set to be compact. Furthermore all functions are assumed to be polynomials. However we do not need any convexity assumptions on either the utility functions or the action sets. The key idea is to use Putinar's Positivstellensatz, a representation result for positive polynomials, to replace each agent's problem by a convex optimization problem. The Nash equilibria are then feasible solutions to a system of polynomial equations and inequalities. Our application is a model of the New Zealand electricity spot market with transmission losses based on a real dataset.

Multipotent adult progenitor cells (MAPCs) are an adherent stem cell population that belongs to the mesenchymal-type progenitor cell family. Although MAPCs are emerging as candidate agents for immunomodulation after solid organ transplantation, their value requires further validation in a clinically relevant cell therapy model using an organ donor- and organ recipient-independent, third-party cell product. We report that stable allograft survival can be achieved following third-party MAPC infusion in a rat model of fully allogeneic, heterotopic heart transplantation. Furthermore, long-term accepted heart grafts recovered from MAPC-treated animals can be successfully retransplanted to naïve animals without additional immunosuppression. This prolongation of MAPC-mediated allograft acceptance depends upon a myeloid cell population since depletion of macrophages by clodronate abrogates the tolerogenic MAPC effect. We also show that MAPC-mediated allograft acceptance differs mechanistically from drug-induced tolerance regarding marker gene expression, T regulatory cell induction, retransplantability, and macrophage dependence. MAPC-based immunomodulation represents a promising pathway for clinical immunotherapy that has led us to initiate a phase I clinical trial for testing safety and feasibility of third-party MAPC therapy after liver transplantation.

The prevalence of hepatic cirrhosis in Europe and the United States, currently 250 patients per 100000 inhabitants, is steadily increasing. Thus, we observe a significant increase in patients with cirrhosis and portal hypertension needing liver resections for primary or metastatic lesions. However, extended liver resections in patients with underlying hepatic cirrhosis and portal hypertension still represent a medical challenge in regard to perioperative morbidity, surgical management and postoperative outcome. The Barcelona Clinic Liver Cancer classification recommends to restrict curative liver resections for hepatocellular carcinoma in cirrhotic patients to early tumor stages in patients with Child A cirrhosis not showing portal hypertension. However, during the last two decades, relevant improvements in preoperative diagnostic, perioperative hepatologic and intensive care management as well as in surgical techniques during hepatic resections have rendered even extended liver resections in higher-degree cirrhotic patients with portal hypertension possible. However, there are few standard indications for hepatic resections in cirrhotic patients and risk stratifications have to be performed in an interdisciplinary setting for each individual patient. We here review the indications, the preoperative risk-stratifications, the morbidity and the mortality of extended resections for primary and metastatic lesions in cirrhotic livers. Furthermore, we provide a review of literature on perioperative management in cirrhotic patients needing extrahepatic abdominal surgery and an overview of surgical options in the treatment of hepatic cirrhosis., Open Access-Komponente aus einer Allianzlizenz

Peritoneal carcinomatosis (PC) is a dismal feature of gastric cancer that most often is treated by systemic palliative chemotherapy. In this retrospective matched pairs-analysis, we sought to establish whether specific patient subgroups alternatively should be offered a multimodal therapy concept, including cytoreductive surgery (CRS) and intraoperative hyperthermic chemotherapy (HIPEC). Clinical outcomes of 38 consecutive patients treated with gastrectomy, CRS and HIPEC for advanced gastric cancer with PC were compared to patients treated by palliative management (with and without gastrectomy) and to patients with advanced gastric cancer with no evidence of PC. Kaplan–Meier survival curves and multivariate Cox regression models were applied. Median survival time after gastrectomy was similar between patients receiving CRS-HIPEC and matched control patients operated for advanced gastric cancer without PC [18.1 months, confidence interval (CI) 10.1–26.0 vs. 21.8 months, CI 8.0–35.5 months], resulting in comparable 5-year survival (11.9 vs. 12.1 %). The median survival time after first diagnosis of PC for gastric cancer was 17.2 months (CI 10.1–24.2 months) in the CRS-HIPEC group compared with 11.0 months (CI 7.4–14.6 months) for those treated by gastrectomy and chemotherapy alone, resulting in a twofold increase of 2-year survival (35.8 vs. 16.9 %). We provide retrospective evidence that multimodal treatment with gastrectomy, CRS, and HIPEC is associated with improved survival for patients with PC of advanced gastric cancer compared with gastrectomy and palliative chemotherapy alone. We also show that patients treated with CRS-HIPEC have comparable survival to matched control patients without PC. However, regardless of treatment scheme, all patients subsequently recur and die of disease.

In this paper we present some new results for the dynamic agent model by Iossa and Rey (2014, "Building Reputation for Contract Renewal: Implications for Performance Dynamics and Contract Duration,'' Journal of the European Economic Association, 12, 549−574) while also correcting some errors in that article. Iossa and Rey study the performance of an agent who repeatedly receives multi-period contracts and determine the optimal duration of such contracts in the context of an infinitely repeated multi-period agent model. We amend the characterization of the unique Markov perfect equilibrium for this model. In addition, we review the original welfare analysis of the model and either provide corrected proofs when possible or provide counterexamples. Our counterexamples overturn the main comparative statics results of the original analysis. We demonstrate that both the agent's optimal investment decision and the optimal contract duration depend non-monotonically on the information persistence and the agent's discount factor. In the final part of the analysis, we establish new results on the agent's optimal investment decision.

This paper contributes to the theoretical and numerical analysis of discrete time dynamic principal-agent problems with continuous choice sets. We first provide a new and simplified proof for the recursive reformulation of the sequential dynamic principal-agent relationship. Next we prove the existence of a unique solution for the principal's value function, which solves the dynamic programming problem in the recursive formulation. By showing that the Bellman operator is a contraction mapping, we also obtain a convergence result for the value function iteration. To compute a solution for the problem, we have to solve a collection of static principal{agent problems at each iteration. Under the assumption that the agent's expected utility is a rational function of his action, we can transform the bi-level optimization problem into a standard nonlinear program. The final results of our solution method are numerical approximations of the policy and value functions for the dynamic principal-agent model. We illustrate our solution method by solving variations of two prominent social planning models from the economics literature.

Static and dynamic games are important tools for the analysis of strategic interactions among economic agents and have found many applications in economics. In many games, equilibria can be described as solutions of polynomial equations. In this paper, we describe state-of-the-art techniques for finding all solutions of polynomial systems of equations, and illustrate these techniques by computing all equilibria of both static and dynamic games with continuous strategies. We compute the equilibrium manifold for a Bertrand pricing game in which the number of equilibria changes with the market size. Moreover, we apply these techniques to two stochastic dynamic games of industry competition and check for equilibrium uniqueness.

Background Mesenchymal stem cells (MSCs) can be used for immunomodulation therapy after solid organ transplantation. Here, we focus on the immunoregulatory potential of combination therapies of MSCs and classic pharmacotherapy to mediate acceptance of solid organ grafts. Methods To determine which drugs influence the immunosuppressive effect of MSCs, we assessed the interaction of MSCs and common clinical immunosuppresants (MMF, sirolimus [Srl], and ciclosporin A [CiA]) in a parent-into-F1 cell transfer model. In this model, the transfer of parental strain T cells into semi-allogeneic F1 recipients induces a graft-versus-host reaction (GvHR). Re-isolated CFSE-labelled T lymphocytes were analyzed by flow cytometry. These findings were compared to a fully allogeneic heart transplantation model. Results We found that MSC treatment alone had no significant effect on allograft survival of heterotopic heart grafts. However, MSCs combined with short-term mycophenolate mofetil (MMF) significantly prolonged graft survival. Quantitative analysis of three different MSC – drug combinations in the F1 model revealed, that only the MSC–MMF combination led to a super-additive immunosuppressive effect. We also investigated the effect of MMF and CiA on IFNγ production of stimulated lymphocytes and found that MMF left the expression of IFNγ unaffected, whereas CiA completely abolished the production of IFNγ. Conclusion Our data show that the type of concurrent immunosuppression strongly influences the immunosuppressive effect of MSC, most likely through differential secretion of IFNγ. A regimen combining MSCs and MMF was most immunosuppressive.

Mesenchymal stem cells (MSCs) are promising candidate cells for immunomodulation therapy that are currently being tested in the preclinical and clinical setting. MSCs suppress the immune response in a variety of in vitro and disease models and may thus be of benefit for patients suffering from autoimmune disorders or transplant rejection. The mechanism by which MSCs modulate the immune response is still under thorough investigation, but it most likely involves expression of local factors such as indoleamine 2,3-dioxygenase, inducible nitric oxide synthase, and others as well as interactions with dendritic or antigen-presenting cells. Although MSCs have been evaluated in clinical phase I and II studies for graft-versus-host disease and heart, kidney, and bone disease, their introduction into solid organ transplantation is still eagerly awaited. In this short review, we summarize the current understanding of immunomodulation achieved by MSC therapies and introduce a possible outline for a clinical study that will use MSCs in the context of a calcineurin inhibitor-free induction protocol after liver transplantation.

Objective In murine models, transplantation of wild-type bone marrow cells (BMC) can counterbalance genetic liver defects by fusion between transplanted marrow cells and resident hepatocytes. This phenomenon, however, is of no immediate clinical use because all syngeneic BMC harbor the same underlying genetic defect. Materials and Methods Describing the fusion between transplanted allogeneic BMC and resident hepatocytes in a murine model of hereditary tyrosinemia type I (fumarylacetoacetate hydrolase [Fah] knockout mouse), we transplanted BMC from fully allogeneic BALB/c donors into Fah –/– recipients after lethal total body irradiation. Results Following hematopoietic reconstitution, recipients remained healthy without pharmacological support (withdrawal of 2-2-nitro-4-fluoromethylbenzoyl-1,3-cyclohexanedione [NTBC]). Metabolic serum parameters improved nearly to wild-type levels. Livers of recipient animals contained up to 10% functional hepatocytes that stained positive for wild-type Fah, as well as both donor and recipient major histocompatibility complex. Flow cytometry confirmed this coexpression on a single cell level. Application of T-cell–depleted bone marrow reduced onset of early graft-vs-host disease. Conclusions We introduce the observation that allogeneic bone marrow transplantation can lead to stable cell fusion of BMC with recipient hepatocytes and restored liver function in a model of otherwise lethal genetic liver disease. Thus, in principle, allogeneic cell fusion can be a possible management of hereditary liver diseases. Long-term immunological properties of fusion cells have to be further investigated.

Background & Aims NKp46 + cells are major effector cells in the pathogenesis of hepatic ischemia reperfusion injury (IRI). Nevertheless, the precise role of unconventional subsets like the IL-22-producing NKp46 + cells (NK22) remains unknown. The purpose of this study was to examine the role of NK22 cells in IRI in transplantation, particularly with respect to regulation by the transcription factor ROR-gamma-t (RORγt). Methods To explore the role of NK22 cells in IRI in the absence of adaptive immunity, B6. RORγt - gfp/wt -reporter and B6. RORγt - gfp/gfp -knockout (KO) mice on a Rag KO background underwent 90min partial warm ischemia, followed by 24h of reperfusion. Results Rag KO mice that possess fully functional NKp46 + cells, and Rag-common-γ-chain-double-KO ( Rag-γc -DKO) mice that lack T, B and NKp46 + cells, were used as controls. We found that Rag-γc -DKO mice lacking NK22 cells show more severe levels of hepatocellular damage (GPT, histological injury) when compared to both Rag-RORγt -reporter and Rag KO mice that possess NK22 cells. Importantly, Rag-RORγt -reporter and Rag KO mice undergoing IRI expressed high protein levels of both IL-22 and GFP (RORγt), suggesting a protective role for RORγt + NK22 cells in IRI. Therefore, we tested the hypothesis that RORγt critically protects from IRI through the induction of hepatic NK22 cells by studying Rag-Rorγt -DKO mice under IRI conditions. We found that the lack of RORγt + NK22 cells in Rag-Rorγt -DKO mice significantly enhanced IR-induced hepatocellular injury, a phenotype that could be reversed upon adoptive transfer of Rag-Rorγt -reporter NK22 cells into DKO mice. Conclusions RORγt + NK22 cells play an important protective role in IRI in mice.

According to current treatment guidelines, surgical resection of hepatocellular carcinoma (HCC) is mostly restricted to a limited subgroup of patients. Due to improved surgical techniques and perioperative management, liver resections may also be performed more extendedly and also in cirrhotic livers with clinical signs of portal hypertension in selected patients. In this study, the clinical and long-term outcomes of liver resection in HCC patients with or without liver cirrhosis were evaluated. One hundred fifty-eight patients undergoing liver resection for primary HCC at our institution were identified. Logistic and Cox regression analyses were used to identify prognostic parameters for postoperative complications and survival. In our cohort of patients, there was no association between clinical parameters or extent of surgical resection and postoperative morbidity. Only Barcelona Clinic Liver Cancer (BCLC) stage C patients were at significantly higher risk for major complications (OR 5.27, P = 0.009). Risk factors influencing long-term survival were patient age (HR 1.026, P = 0.027) and BCLC stage C (HR 3.47, P = 0.002). Compared to patients without liver cirrhosis, BCLC stage A and B patients undergoing resection were at similar risk for the development of severe complications and long-term mortality. Liver resection as potentially curative therapy can be performed in selected patients in BCLC stage B, as well as in patients with clinical signs of portal hypertension. The resection of HCC-classified BCLC stage C is feasible but associated with significant morbidity and mortality.

Natural killer (NK) cells play a dichotomous role in alloimmune responses because they are known to promote both allograft survival and rejection. The aim of this study was to investigate the role of functionally distinct NK cell subsets in alloimmunity with the hypothesis that this dichotomy is explained by the functional heterogeneity of distinct NK cell subsets.Because T-bet controls thematuration of NK cells from CD27high to terminally differentiated CD27low NK cells, we used Rag−/−T-bet−/− mice that lackmature CD27low NK cells to study the distinct roles of CD27low versus CD27high NK cells in a model of Tcell–mediated skin transplant rejection under costimulatory blockade conditions.We found that T cell–reconstituted Rag1−/− recipients (possessing CD27low NK cells) show significantly prolonged allograft survival on costimulatory blockade when compared to Rag1−/−T-bet−/− mice (lacking CD27low NK cells), indicating that CD27low but not CD27high NK cells enhance allograft survival. Critically, Rag1−/−T-bet−/− recipients showed strikingly increased alloreactive memory CD8+ Tcell responses, as indicated by increased CD8+ Tcell proliferation and interferon-γ production. Therefore, we speculated that CD27low NK cells directly regulate alloreactive CD8+ Tcell responses under costimulatory blockade conditions. To test this, we adoptively transferred CD27low NK cells into Rag1−/−T-bet−/− skin transplant recipients and found that the CD27low NK cells restore better allograft survival by inhibiting the proliferation of alloreactive interferon-γ+CD8+ T cells.In summary, mature CD27low NK cells promote allograft survival under costimulatory blockade conditions by regulating alloreactive memory CD8+ T-cell responses.

In this paper we look at a new way to combine both quantity precommitment and price competition in a dynamic games framework. In each period players choose to invest in production capacities for the next period and also engage in a price competition. Production is free up to capacity and has steeply increasing costs if exceeded. The demand is allocated according to a quadratic utility function, which allows for product differentiation. This way we avoid rationing rules, that are frequently used in these kind of models. We use real algebraic geometry to explicitly solve the subgames played each period. This information allows us to guess that the value function is piecewise quadratic. Our results are that if costs for exceeding production capacity go to infinity, then the equilibrium converges to an extreme case, where production is free up to capacity and excess has infinite marginal cost. This limiting approach allows us to compare our model to the ones with homogeneous goods and rationing. We also construct a similar Cournot like model as a benchmark. Computational experiments show that, in the limit, the outcome of the price competition with quantity precommitment equals the one in the Cournot case. This extends a similar result for static two stage games. However if we move away from the limit case, i.e. to a case where marginal costs are finite, the two models no longer agree.

Multiplicity of equilibria is a common problem in many economic models. In general, it is impossible to devise methods that always find all equilibria for any type of model. A notable exception are models in which all equilibria are solutions to a system of polynomial equations since there are powerful solution methods for finding all solutions to such polynomial systems. In many economic applications, equilibria can indeed be characterized as solutions to a system of polynomial equations. This handbook article provides a hands-on introduction to two solution methods for finding all solutions to polynomial systems; the first approach relies on Grobner bases, the second approach employs all-solution homotopy methods. Several economic examples show how to compute all equilibria using modern software implementations of these two methods.

Although Th1, Th2, and Th17 cells are thought to be major effector cells in adaptive alloimmune responses, their respective contribution to allograft rejection remains unclear. To precisely address this, we used mice genetically modified for the Th1 and Th17 hallmark transcription factors T-bet and RORγt, respectively, which allowed us to study the alloreactive role of each subset in an experimental transplant setting. We found that in a fully mismatched heterotopic mouse heart transplantation model, T cells deficient for T-bet (prone to Th17 differentiation) versus RORγt (prone to Th1 differentiation) rejected allografts at a more accelerated rate, indicating a predominance of Th17- over Th1-driven alloimmunity. Importantly, T cells doubly deficient for both T-bet and RORγt differentiated into alloreactive GATA-3–expressing Th2 cells, which promptly induced allograft rejection characterized by a Th2-type intragraft expression profile and eosinophilic infiltration. Mechanistically, Th2-mediated allograft rejection was contingent on IL-4, as its neutralization significantly prolonged allograft survival by reducing intragraft expression of Th2 effector molecules and eosinophilic allograft infiltration. Moreover, under IL-4 neutralizing conditions, alloreactive double-deficient T cells upregulated Eomesodermin (Eomes) and IFN-γ, but not GATA-3. Thus, in the absence of T-bet and RORγt, Eomes may salvage Th1-mediated alloimmunity that underlies IL-4 neutralization-resistant allograft rejection. We summarize that, whereas Th17 cells predictably promote allograft rejection, IL-4–producing GATA-3+ Th2 cells, which are generally thought to protect allogeneic transplants, may actually be potent facilitators of organ transplant rejection in the absence of T-bet and RORγt. Moreover, Eomes may rescue Th1-mediated allograft rejection in the absence of IL-4, T-bet, and RORγt.

Background Free jejunal interposition is a useful technique for reconstruction of the cervical esophagus. However, the distal anastomosis between the graft and the remaining thoracic esophagus or a gastric conduit can be technically challenging when located very low in the thoracic aperture. We here describe a modified technique for retrograde stapling of a jejunal graft to a failed gastric conduit using a circular stapler on a delivery system. Case presentation A 56 year-old patient had been referred for esophageal squamous cell carcinoma at 20 cm from the incisors. On day 8 after thoracoabdominal esophagectomy with gastric pull-up, an anastomotic leakage was diagnosed. A proximal-release stent was successfully placed by gastroscopy and the patient was discharged. Two weeks later, an esophagotracheal fistula occurred proximal to the esophageal stent. Cervical esophagostomy was performed with cranial closure of the gastric conduit, which was left in situ within the right hemithorax. Three months later, reconstruction was performed using a free jejunal interposition. The anvil of a circular stapler (Orvil®, Covidien) was placed transabdominally through an endoscopic rendez-vous procedure into the gastric conduit. A free jejunal graft was retrogradely stapled to the proximal end of the conduit. Microvascular anastomoses were performed subsequently. The proximal anastomosis of the conduit was completed manually after reperfusion. Conclusions This modified technique allows stapling of a jejunal interposition graft located deep in the thoracic aperture and is therefore a useful method that may help to avoid reconstruction by colonic pull-up and thoracotomy.

Over the past four decades, the transplantation of solid organs (liver, kidney, heart, pancreas, and lung) has become standard clinical therapy. Despite its overall success, the shortage of donor organs and the need for lifelong immunosuppression continue to pose major challenges that need to be addressed. This chapter summarizes the preclinical efforts undertaken to investigate the potential use of mesenchymal stromal cells in the field of solid organ transplantation and presents insights into the concepts of ongoing early clinical studies.

Mesenteric ischemia is a condition well-known among physicians treating patients with abdominal symptoms. Even so, mortality rates have not decreased significantly over the last decades. The purpose of this article is to review current treatment concepts of acute and chronic mesenteric ischemia.Early diagnosis is one of the most important features that determine a patient's prognosis. Conventional angiography and multidetector computed tomography are therefore appropriate to quickly diagnose mesenteric ischemia, the latter being commonly more available. Once a patient presents with signs of peritonitis, instant laparotomy is indicated, and infarcted bowel segments need to be resected, followed by a second-look operation if necessary. If bowel necrosis is clinically not suspected, different approaches should be applied according to source and nature of mesenteric ischemia. Besides established surgical treatment concepts, more and more interventional procedures are developed and evaluated. However, superiority of these new techniques could only be shown for selected patient groups so far. In chronic mesenteric ischemia, interventional approaches seem to be an attractive alternative in patients who are in a condition too bad to undergo surgery. Patients with colonic ischemia are treated best in a conservative manner and by resolving the underlying cause, if identified.Patients with acute mesenteric ischemia are still at highest risk for a fatal course of disease. New diagnostic and therapeutic developments have not been tested in larger studies yet, neither has any of these methods led to an increased survival in studies published so far. Taken together, mesenteric ischemia requires high awareness, earliest possible diagnosis, and treatment by an experienced interdisciplinary team of gastroenterologists, radiologists, and surgeons.

Despite pharmaceutical treatment with NTBC (2-2-nitro-4-fluoromethylbenzoyl-1,3-cyclohexanedione), a high incidence of liver malignancies occur in humans and mice suffering from hereditary tyrosinemia type 1 (HT1) caused by mutation of the fumarylacetoacetate hydrolase (fah) gene.To evaluate the efficacy of a definitive treatment for HT1, we transfected fah knockout mice with naked plasmid DNA using high volume tail-vein injection. This approach was chosen to reduce the occurrence of insertional mutagenesis that is frequently observed when using other (retro-)viral vectors. To prolong gene expression, the fah gene was cloned between adeno-associated virus (AAV)-specific inverted terminal repeats (ITRs).All animals treated with high volume plasmid DNA injections could be successfully weaned off NTBC and survived in the long term without any further pharmacological support. Up to 50% fah positive hepatocytes were detected in livers of naked plasmid DNA-treated animals and serum liver function tests approximated those of wild-type controls.Naked plasmid DNA transfection offers a promising alternative treatment for HT1. Minimizing side-effects makes this approach especially appealing.

The long-term prognosis of patients with peritoneal malignancies has greatly improved since the introduction of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Nevertheless, CRS can be associated with high postoperative morbidity. In this retrospective study, we analyzed the influence of hepatobiliary surgery as part of CRS on postoperative short-term patient outcome. Between 2005 and 2008, a total of 63 (25%) of 252 patients with peritoneal surface malignancies undergoing CRS and HIPEC required hepatobiliary surgery. Liver resection was performed in 22, resection of Glisson capsule in 39, and bile duct resection in 2 patients. The mean age of the study population was 49.3 years. Thirty-four patients (54%) were women. Complete macroscopic cytoreduction (CC-0/1) was reached in 59 patients (93.7%). The median hospital stay was 18 days. Twenty-two patients developed minor complications (35%), such as moderate fever, pain, or secondary wound healing. In 21 patients (33%), severe complications occurred, most commonly pancreatitis and abdominal abscess. Three patients (4.8%) developed a biliary leakage. Of these, 2 had to be reoperated. In our experience, hepatobiliary procedures have to be performed in up to one-third of patients and are associated with a low rate of specific complications, such as biliary leakages.

Static and dynamic games are important tools for the analysis of strategic interactions among economic agents and have found many applications in economics. In many games equilibria can be described as solutions of polynomial equations. In this paper we describe state-of-the-art techniques for finding all solutions of polynomial systems of equations and illustrate these techniques by computing all equilibria of both static and dynamic games with continuous strategies. We compute the equilibrium manifold for a Bertrand pricing game in which the number of equilibria changes with the market size. Moreover, we apply these techniques to two stochastic dynamic games of industry competition and check for equilibrium uniqueness.