Comparison of the LiMAx test vs. the APRI+ALBI score for clinical utility in preoperative risk assessment in patients undergoing liver surgery - A European multicenter study.

INTRODUCTION: Posthepatectomy liver failure (PHLF) remains the main reason for short-term mortality after liver surgery. APRI+ALBI, aspartate aminotransferase to platelet ratio (APRI) combined with albumin-bilirubin grade (ALBI), score and the liver function maximum capacity test (LiMAx) are both established preoperative (preop) liver function tests. The aim of this study was to compare both tests for their predictive potential for clinically significant PHLF grade B and C (B+C). MATERIALS AND METHODS: 352 patients were included from 4 European centers. Patients had available preop APRI+ALBI scores and LiMAx results. Predictive potential for PHLF, PHLF B+C and 90-day mortality was compared using receiver operating characteristic (ROC) curve analysis and calculation of the area under the curve (AUC). Published cutoffs of ≥ -2.46 for APRI+ALBI and of <315 for LiMAx were assessed using chi-squared test. RESULTS: APRI+ALBI showed superior predictive potential for PHLF B+C (N = 34; AUC = 0.766), PHLF grade C (N = 20; AUC = 0.782) and 90-day mortality (N = 15; AUC = 0.750). When comparing the established cutoffs of both tests, APRI+ALBI outperformed LiMAx in prediction of PHLF B+C (APRI+ALBI ≥2.46: Positive predictive value (PPV) = 19%, negative predictive value (NPV) = 97%; LiMAx <315: PPV = 3%, NPV = 90%) and 90-day mortality (APRI+ALBI ≥2.46: PPV = 12%, NPV = 99%; LiMAx <315: PPV = 0%, NPV = 94%) CONCLUSION: In our analysis, APRI+ALBI outperformed LiMAx measurement in the preop prediction of PHLF B+C and postoperative mortality, at a fraction of the costs, manual labor and invasiveness.

Learning surgical knot tying and suturing technique - effects of different forms of training in a controlled randomized trial with dental students.

Objective: The acquisition of surgical skills requires motor learning. A special form of this is intermanual transfer by transferring motor skills from the nondominant hand (NDH) to the dominant hand (DH). The purpose of this study was to determine the learning gains that can be achieved for the DH by training with the DH, the NDH, and by non-surgical alternative training (AT). Methods: 124 preclinical (n=62) and clinical (n=62) dental students completed surgical knot tying and suturing technique training with the DH, with the NDH, and an AT in a controlled randomized trial. Results: A statistically significant learning gain in knot tying and suture technique with the DH was evident only after training with the DH when compared to training with the NDH (p<0.001 and p=0.004, respectively) and an AT (p=0.001 and p=0.010, respectively). Of those students who achieved a learning gain ≥4 OSATS points, 46.4% (n=32) benefited in their knot tying technique with the DH from training with the DH, 29.0% (n=20) from training with the NDH, and 24.6% (n=17) from an AT while 45.7% (n=32) benefited in their suturing technique with the DH from training with the DH, 31.4% (n=22) from training with the NDH, and 22, 9% (n=16) from an AT. Conclusions: Training with the DH enabled significantly better learning gains in the surgical knot tying and suturing techniques with the DH.

Proposal of a Multivariable Prediction Model for Graded Morbidity after Liver Resection for Colorectal Metastases.

BACKGROUND: Prognostic models to predict individual early postoperative morbidity after liver resection for colorectal liver metastases (CLM) are not available but could enable optimized preoperative patient selection and postoperative surveillance for patients at greater risk of complications. The aim of this study was to establish a prognostic model for the prediction of morbidity after liver resection graded according to Dindo. METHODS: N = 679 cases of primary liver resection for CLM were retrospectively analyzed using univariable and multivariable ordinal regression analyses. Receiver operating characteristics curve (ROC) analysis was utilised to assess the sensitivity and specificity of predictions and their potential usefulness as prognostic models. Internal validation of the score was performed using data derived from 129 patients. RESULTS: The final multivariable regression model revealed lower preoperative levels, a greater number of units of intraoperatively transfused packed red blood cells (pRBCs), longer duration of surgery, and larger metastases to independently influence postoperatively graded morbidity. ROC curve analysis demonstrated that the multivariable regression model is able to predict each individual grade of postoperative morbidity with high sensitivity and specificity. The areas under the receiver operating curves (AUROC) for all of these predictions of individual grades of morbidity were > 0.700, indicating potential usefulness as a predictive model. Moreover, a consistent concordance in Grades I, II, IV, and V according to the classification proposed by Dindo et al. was observed in the internal validation. CONCLUSION: This study proposes a prognostic model for the prediction of each grade of postoperative morbidity after liver resection for CLM with high sensitivity and specificity using pre- and intraoperatively available variables.

Interleukin-18 and High-Mobility-Group-Protein B1 are Early and Sensitive Indicators for Cell Damage During Normothermic Machine Perfusion after Prolonged Cold Ischemic Storage of Porcine Liver Grafts.

In the era of organ machine perfusion, experimental models to optimize reconditioning of (marginal) liver grafts are needed. Although the relevance of cytokine signatures in liver transplantation has been analyzed previously, the significance of molecular monitoring during normothermic machine perfusion (NMP) remains elusive. Therefore, we developed a porcine model of cold ischemic liver graft injury after prolonged static cold storage (SCS) and subsequent NMP: Livers obtained from ten minipigs underwent NMP for 6 h directly after procurement (control group) or after 20 h of SCS. Grafts after prolonged SCS showed significantly elevated AST, ALT, GLDH and GGT perfusate concentrations, and reduced lactate clearance. Bile analyses revealed reduced bile production, reduced bicarbonate and elevated glucose concentrations after prolonged SCS. Cytokine analyses of graft perfusate simultaneously demonstrated an increase of pro-inflammatory cytokines such as Interleukin-1α, Interleukin-2, and particularly Interleukin-18. The latter was the only significantly elevated cytokine compared to controls, peaking as early as 2 h after reperfusion (11,012 ng/ml vs. 1,493 ng/ml; p = 0.029). Also, concentrations of High-Mobility-Group-Protein B1 were significantly elevated after 2 h of reperfusion (706.00 ng/ml vs. 148.20 ng/ml; p < 0.001) and showed positive correlations with AST (r 2 = 0.846) and GLDH (r 2 = 0.918) levels. Molecular analyses during reconditioning of liver grafts provide insights into the degree of inflammation and cell damage and could thereby facilitate future interventions during NMP reducing acute and chronic graft injury.

Porcine Liver Transplantation Without Veno-venous Bypass As an Extended Criteria Donor Model.

Liver transplantation is regarded as the gold standard for the treatment of a variety of fatal hepatic diseases. However, unsolved issues of chronic graft failure, ongoing organ donor shortages, and the increased use of marginal grafts call for the improvement of current concepts, such as the implementation of organ machine perfusion. In order to evaluate new methods of graft reconditioning and modulation, translational models are required. With respect to anatomical and physiological similarities to humans and recent progress in the field of xenotransplantation, pigs have become the main large animal species used in transplantation models. After the initial introduction of a porcine orthotopic liver transplant model by Garnier et al. in 1965, several modifications have been published over the past 60 years. Due to specifies-specific anatomical traits, a veno-venous bypass during the anhepatic phase is regarded as a necessity to reduce intestinal congestion and ischemia resulting in hemodynamic instability and perioperative mortality. However, the implementation of a bypass increases the technical and logistical complexity of the procedure. Furthermore, associated complications such as air embolism, hemorrhage, and the need for a simultaneous splenectomy have been reported previously. In this protocol, we describe a model of porcine orthotopic liver transplantation without the use of a veno-venous bypass. The engraftment of donor livers after static cold storage of 20 h - simulating extended criteria donor conditions - demonstrates that this simplified approach can be performed without significant hemodynamic alterations or intraoperative mortality and with regular uptake of liver function (as defined by bile production and liver-specific CYP1A2 metabolism). The success of this approach is ensured by an optimized surgical technique and a sophisticated anesthesiologic volume and vasopressor management. This model should be of special interest for workgroups focusing on the immediate postoperative course, ischemia-reperfusion injury, associated immunological mechanisms, and the reconditioning of extended criteria donor organs.

Preoperative leukocytosis is an independent risk factor for morbidity and survival after resection of colorectal liver metastases.

BACKGROUND: Although surgical resection of colorectal liver metastases (CRLM) remains to be the only option for long term survival, traditional surgical concepts have been challenged by the introduction of the liver first approach or neoadjuvant chemotherapy in resectable CRLM and interventional therapies. The aim of this study was to identify prognostic factors for postoperative morbidity and survival and to externally evaluate the recently introduced resection severity index (RSI), in order to optimize patient selection and treatment strategies. METHODS: This is a retrospective single centre analysis of 213 patients undergoing surgery for CRLM in curative intent between January 2010 and December 2018. RESULTS: Median follow up after liver resection was 28.56 (0.01-111.46) months. Severe postoperative complications (Clavien-Dindo ≥ IIIa) were observed in 46 (21.6%) cases. Preoperative leukocytosis (OR: 3.114, CI-95%: 1.089-8.901; p = 0.034) and operation time in minutes (OR: 1.007, CI-95%: 1.002-1.011; p = 0.002) were determined as independent risk factors. Overall survival (OS) was 46.68 months with a 5-year survival rate of 40.5%. Independent prognostic factors were preoperative leukocytosis (HR: 2.358, CI-95%: 1.170-4.752; p = 0.016), major hepatectomy (HR: 1.741, CI-95%: 1.098-2.759; p = 0.018) and low grading of the primary intestinal tumour (HR: 0.392, CI-95%: 0.231-0.667; p < 0.001). The RSI (ASAT (U/l) divided by Quick (%) multiplied by the extent of liver resection in points) was identified as independent risk factor for OS only in patients without neoadjuvant chemotherapy. CONCLUSIONS: Detection of leukocytosis in patients prior resection of CRLM was associated with increased postoperative morbidity and decreased OS and could therefore prove valuable for perioperative risk stratification.

Impact of perioperative blood transfusions on postoperative renal function and survival after resection of colorectal liver metastases.

BACKGROUND AND AIMS: Recent studies focusing on thoracic surgery suggest postoperative kidney injury depending on the amount of perioperative blood transfusions. Data investigating similar effects after resection of colorectal liver metastases (CRLM) are not available. Aim of this study was therefore to evaluate the influence of perioperative blood transfusions on postoperative renal function and survival after resection of CRLM. METHODS: Seven hundred twenty-seven cases of liver resection for CRLM were retrospectively analyzed. Renal function was measured via estimated glomerular filtration rate (eGFR) and a postoperative decline of ≥ 10% was considered substantial. Potential influences on postoperative kidney function were assessed using univariable and multivariable logistic regression analyses. Cox-regression analyses were performed to estimate the impact on overall survival (OS). RESULTS: Preoperative impaired kidney function (p = 0.001, OR 2.477) and transfusion of > 2 units of packed red blood cells (PRBC) (p = 0.046; OR 1.638) were independently associated with an increased risk for ≥ 10% loss of renal function. Neither a pre-existing renal impairment, nor the additional loss of renal function were associated with reduced survival. Chemotherapies in the context of primary colorectal cancer treatment (p = 0.002), age > 70 years at liver resection (p = 0.005), number (p = 0.001), and size of metastases > 50 mm (p = 0.018), duration of resection > 120 min (p = 0.006) and transfusions of > 2 units of PRBC (p = 0.039) showed a negative independent influence on OS. CONCLUSION: The results demonstrate a negative impact of perioperative blood transfusions on the postoperative renal function and OS. Hence, efforts to reduce blood transfusions should be intensified.

Antibiotic-Resistant Bacteria Colonizing the Bile Duct Are Associated with Increased Morbidity and Mortality after Resection of Extrahepatic Cholangiocarcinoma.

Background: Patients with extrahepatic cholangiocarcinoma (CCA) face considerable morbidity including septic complications after surgery. The aim of this study was to characterize the bacterial spectrum of the common hepatic duct (CHD) and its clinical relevance regarding morbidity and mortality after resection of extrahepatic CCA. Methods: We retrospectively analyzed data from 205 patients undergoing surgery for extrahepatic CCA in our department between January 2000 and March 2015. Patients were reviewed for pre-operative medical conditions, biliary bacterial flora obtained from intra-operative swabs, different septic complications, and post-operative outcome. Results: Bacterial colonization of the CHD was observed in 84.9% of the patients, with Enterococcus faecalis being detected most frequently (28.3%). Wound infections occurred in 30.7% of patients. Bacterial flora of the CHD and of the post-operatively colonized wounds coincided in 51.5% and of intra-abdominal swabs obtained during surgical revisions in 40.0%. Ciprofloxacin-resistant bacteria in the CHD were identified as independent risk factor for wound infections (odds ratio [OR], 3.330; 95% confidence interval [CI], 1.771-6.263; p < 0.001) and for complications requiring surgical revision (OR, 2.417; 95% CI, 1.288-4.539; p = 0.006). Most important independent risk factors for intra-hospital mortality were ampicillin-sulbactam-resistant bacteria in the CHD (OR, 3.969; 95% CI, 1.515-10.399; p = 0.005) and American Society of Anesthesiologists (ASA) grading >2 (OR, 2.936; 95% CI, 1.337-6.451; p = 0.007). Conclusions: Antibiotic-resistant bacteria from the CHD are associated with increased morbidity and mortality in patients undergoing resection for extrahepatic CCA.

The rate of cholangiocarcinoma in Caroli Disease A German multicenter study.

BACKGROUND: Caroli Disease (CD) and Caroli Syndrome (CS) are rare disorders presenting with dilation of the intrahepatic bile ducts. CD/CS are associated with cholangiocarcinoma (CCA). However, the true incidence of CCA is still unclear, although it may serve as an indication for surgery. In this paper, we analyzed (I) the incidence of CCA in German centers, (II) reviewed our single center population together with its clinical presentation and (III) performed a thorough literature review. METHODS: 17 large HPB-centers across Germany were contacted and their patients after surgical treatment due to CD/CS with histopathology were included. Medline search for all studies published in English or German literature was performed. Patients who underwent surgery at our department between 2012 and 2020 due to CD or CS were analyzed. RESULTS: In the multicenter study, 79 patients suffered from CD and 119 patients from CS, with a total number of 198 patients. In 14 patients, CCA was found (Overall: 7,1%; CD: 6,3%, CS 7,6%). Between 2012 and 2020, 1661 liver resections were performed at our department. 14 patients underwent surgery due to CD or CS. Histological examination showed synchronous cholangiocarcinoma in one patient. The literature review revealed a CCA-rate of 7,3% in large series, whereas in case reports a rate of 6,8% was found. CONCLUSION: There is risk of malignant transformation and patients with CD might also benefit from resection due to improvement of symptoms. Therefore, resection is strongly advised. As certain patients with CS require transplantation, treatment should not be guided by the relatively low rate of CCA but by the concomitant diseases that come along with hepatic failure.

Proposal of a New Definition of "Very Early" Intrahepatic Cholangiocarcinoma-A Retrospective Single-Center Analysis.

Intrahepatic cholangiocarcinoma (ICC) is a rare disease with poor outcome, despite advances in surgical and non-surgical treatment. Recently, studies have reported a favorable long-term outcome of "very early" ICC (based on tumor size and absence of extrahepatic disease) after hepatic resection and liver transplantation, respectively. However, the prognostic value of tumor size and a reliable definition of early disease remain a matter of debate. Patients undergoing resection of histologically confirmed ICC between February 1996 and January 2021 at our institution were reviewed for postoperative morbidity, mortality, and long-term outcome after being retrospectively assigned to two groups: "very early" (single tumor ≤ 3 cm) and "advanced" ICC (size > 3 cm, multifocality or extrahepatic disease). A total of 297 patients were included, with a median follow-up of 22.8 (0.1-301.7) months. Twenty-one (7.1%) patients underwent resection of "very early" ICC. Despite the small tumor size, major hepatectomies (defined as resection of ≥3 segments) were performed in 14 (66.7%) cases. Histopathological analyses revealed lymph node metastases in 5 (23.8%) patients. Patients displayed excellent postoperative outcome compared to patients with "advanced" disease: intrahospital mortality was not observed, and patients displayed superior long-term survival, with a 5-year survival rate of 58.2% (versus 24.3%) and a median postoperative survival of 62.1 months (versus 25.3 months; p = 0.013). In conclusion, although the concept of a "very early" ICC based solely on tumor size is vague as it does not necessarily reflect an aggressive tumor biology, our proposed definition could serve as a basis for further studies evaluating the efficiency of either surgical resection or liver transplantation for this malignant disease.

Supportive Hepatocyte Transplantation after Partial Hepatectomy Enhances Liver Regeneration in a Preclinical Pig Model.

BACKGROUND: Hepatocyte transplantation (HTx) is regarded as a potential treatment modality for various liver diseases including acute liver failure. We developed a preclinical pig model to evaluate if HTx could safely support recovery from liver function impairment after partial hepatectomy. METHODS: Pigs underwent partial hepatectomy with reduction of the liver volume by 50% to induce a transient but significant impairment of liver function. Thereafter, 2 protocols for HTx were evaluated and compared to a control group receiving liver resection only (group 1, n = 5). Portal pressure-controlled HTx was performed either immediately after surgery (group 2, n = 6) or 3 days postoperatively (group 3, n = 5). In all cases, liver regeneration was monitored by conventional laboratory tests and the novel noninvasive maximum liver function capacity (LiMAx) test with a follow-up of 4 weeks. RESULTS: Partial hepatectomy significantly impaired liver function according to conventional liver function tests as well as LiMAx in all groups. A mean of 4.10 ± 1.1 × 108 and 3.82 ± 0.7 × 108 hepatocytes were transplanted in groups 2 and 3, respectively. All animals remained stable with respect to vital parameters during and after HTx. The animals in group 2 showed enhanced liver regeneration as observed by mean postoperative LiMAx values (621.5 vs. 331.3 µg/kg/h on postoperative day 7; p < 0.001) whereas HTx in group 3 led to a significant increase in mean liver-specific coagulation factor VII (112.2 vs. 54.0% on postoperative day 7; p = 0.003) compared to controls (group 1), respectively. In both experimental groups, thrombotic material was observed in the portal veins and pulmonary arteries on histology, despite the absence of clinical symptoms. CONCLUSION: HTx can be performed safely and effectively immediately after a partial (50%) hepatectomy as well as 3 days postoperatively, with comparable results regarding the enhancement of liver function and regeneration.

[Machine Perfusion for Liver Transplantation - What is Possible and Where Do We Stand in Germany? Review of the Literature and Results of a National Survey]. / Maschinenperfusion in der Lebertransplantation ­ was ist möglich und wo stehen wir in Deutschland? Übersicht der Literatur und Ergebnisse einer nationalen Umfrage.

Machine perfusion of donor livers is currently regarded as the most important innovation in transplant surgery to address the continuing shortage of organs in liver transplantation. Hypothermic machine perfusion (HMP) is safe to use and appears to reduce the risk of biliary complications and improve the long-term survival of transplanted organs following preservation by cold static storage - even in donors after cardiac death. A potential functional test of donor organs during HMP uses flavin mononucleotide and is still under clinical investigation. Normothermic machine perfusion (NMP) has a greater risk of technical problems, but functional testing using conventional laboratory parameters during NMP allows significant expansion of the donor pool, even though no prospective randomised study has been able to demonstrate a survival advantage for transplanted organs after NMP. In addition, the preservation time of the donor organs can be significantly extended with the help of NMP, which is particularly advantageous for complex recipient operations and/or logistics. Both methods could be applied for various scenarios in transplantation medicine - theoretically also in combination. The majority of German transplant centres regard machine perfusion as an important innovation and already actively perform perfusions or are in preparation for doing so. However, the overall practical experience in Germany is still relatively low, with only 2 centres having performed more than 20 perfusions. In the coming years, multi-centre efforts to conduct clinical trials and to develop national guidelines on machine perfusion will therefore be indispensable in order to define the potential of these technological developments objectively and to exploit it optimally for the field of transplantation medicine.

Repeated resection for recurrent intrahepatic cholangiocarcinoma: A retrospective German multicentre study.

BACKGROUND: Tumour recurrence is common after resection of intrahepatic cholangiocarcinoma (ICC). Repeated resection is a potential curative treatment, but outcomes are not well-defined thus far. The aim of this retrospective multicentre cohort study was to show the feasibility and survival of repeated resection of ICC recurrence. METHODS: Data were collected from 18 German hepato-pancreatico-biliary centres for patients who underwent repeated exploration of recurrent ICC between January 2008 and December 2017. Primary end points were overall (OS) and recurrence-free survival from the day of primary and repeated resection. RESULTS: Of 156 patients who underwent repeated exploration for recurrent ICC, 113 underwent re-resection. CA19-9 prior to primary resection, R status of first liver resection and median time to recurrence were significant determinants of repeated resectability. Median OS in the repeated resection group was 65.2 months, with consecutive 1-, 3- and 5-year OS of 98%, 78% and 57% respectively. After re-exploration, median OS from primary resection was 46.7 months, with a consecutive 1-, 3- and 5-year OS of 95%, 55% and 22% respectively. From the day of repeated resection, the median OS was 36.8 months, with a consecutive 1-, 3- and 5-year OS of 86%, 51% and 34% respectively. Minor morbidity (grade I+II) was present in 27%, grade IIIa-IVb morbidity in 20% and mortality in 3.5% of patients. CONCLUSION: Repeated resection of ICC has acceptable morbidity and mortality and seems to be associated with improved long-term survival. Structured follow-up after resection of ICC is necessary for early identification of these patients.

Preoperative leukocytosis and the resection severity index are independent risk factors for survival in patients with intrahepatic cholangiocarcinoma.

PURPOSE: The incidence of intrahepatic cholangiocarcinoma is increasing worldwide. Despite advances in surgical and non-surgical treatment, reported outcomes are still poor and surgical resection remains to be the only chance for long-term survival of affected patients. The identification and validation of prognostic factors and scores, such as the recently introduced resection severity index, for postoperative morbidity and mortality are essential to facilitate optimal therapeutic regimens. METHODS: This is a retrospective analysis of 269 patients undergoing resection of histologically confirmed intrahepatic cholangiocarcinoma between February 1996 and September 2018 at a tertiary referral center for hepatobiliary surgery. Regression analyses were performed to evaluate potential prognostic factors, including the resection severity index. RESULTS: Median postoperative follow-up time was 22.93 (0.10-234.39) months. Severe postoperative complications (≥ Clavien-Dindo grade III) were observed in 94 (34.9%) patients. The body mass index (p = 0.035), the resection severity index (ASAT in U/l divided by Quick in % multiplied by the extent of liver resection graded in points; p = 0.006), additional hilar bile duct resection (p = 0.005), and number of packed red blood cells transfused during operation (p = 0.036) were independent risk factors for the onset of severe postoperative complications. Median Kaplan-Meier survival after resection was 27.63 months. Preoperative leukocytosis (p = 0.003), the resection severity index (p = 0.005), multivisceral resection (p = 0.001), and T stage ≥ 3 (p = 0.013) were identified as independent risk factors for survival. CONCLUSION: Preoperative leukocytosis and the resection severity index are useful variables for preoperative risk stratification since they were identified as significant predictors for postoperative morbidity and mortality, respectively.

Abdominal Surgery in Patients with Ventricular Assist Devices: a Single-Center Report.

This study was performed to evaluate the incidence and outcome of patients with ventricular assist devices (VADs) undergoing abdominal surgery at our institution. A total of 604 adult patients who underwent VAD implantation between February 2004 and February 2018 were analyzed retrospectively with a median follow-up time of 66 (6-174) months. Thirty-nine patients (6.5%) underwent abdominal surgery. Elective surgical procedures were performed in 22 patients (56.4%), mainly for abdominal wall hernia repairs, partial colectomies, and cholecystectomies. Early after elective abdominal surgery no patient died, resulting in a median survival of 23 (1-78) months. Emergency surgery was performed in 17 patients (43.6%). The most common emergency indications were intestinal ischemia and/or perforation. Eight patients undergoing emergent surgery (44.4%) died within the first 30 days after primary abdominal operation, mainly due to sepsis and consecutive multiple organ failure, resulting in a dismal median survival of one month (0-52). Patients undergoing abdominal surgery had significantly lower rates of realized heart-transplantation (p = 0.031) and a significantly higher rate of VAD exchange, before or after abdominal surgery, due to thromboses or infections (p = 0.037). Nonetheless, overall survival after primary VAD implantation in these patients (median 38 months; 0-107) was not significantly impaired when compared to all other patients undergoing VAD implantation (median 30 months; 0-171). In summary, elective abdominal surgery can be performed safely when well planned by an experienced multidisciplinary team. Abdominal complications in VAD patients requiring emergent surgery, however, lead to a significant increase in short-term morbidity and a high 30-day mortality rate.

The importance of MHC class II in allogeneic bone marrow transplantation and chimerism-based solid organ tolerance in a rat model.

Mixed hematopoietic chimerism enables donor-specific tolerance for solid organ grafts. This study evaluated the influence of different serological major histocompatibility complex disparities on chimerism development, graft-versus-host disease incidence and subsequently on solid organ tolerance in a rat model. For bone marrow transplantation conditioning total body irradiation was titrated using 10, 8 or 6 Gray. Bone marrow transplantation was performed across following major histocompatibility complex mismatched barriers: complete disparity, MHC class II, MHC class I or non-MHC mismatch. Recipients were clinically monitored for graft-versus-host disease and analyzed for chimerism using flow cytometry. After a reconstitution of 100 days, composition of peripheral leukocytes was determined. Mixed chimeras were challenged with heart grafts from allogeneic donor strains to define the impact of donor MHC class disparities on solid organ tolerance on the basis of stable chimerism. After myeloablation with 10 Gray of total body irradiation, chimerism after bone marrow transplantation was induced independent of MHC disparity. MHC class II disparity increased the incidence of graft-versus-host disease and reduced induction of stable chimerism upon myelosuppressive total body irradiation with 8 and 6 Gray, respectively. Stable mixed chimeras showed tolerance towards heart grafts from donors with MHC matched to either bone marrow donors or recipients. Isolated matching of MHC class II with bone marrow donors likewise led to stable tolerance as opposed to matching of MHC class I. In summary, MHC class II disparity was critically associated with the onset of graft-versus host disease and was identified as obstacle for successful development of chimerism after bone marrow transplantation and subsequent donor-specific solid organ tolerance.

Long-term Functional Maintenance of Exteriorized Portal Venous Catheters in a Porcine Animal Model.

BACKGROUND: Portal venous access for blood sampling, infusion therapy, and measurement of portal venous pressure is of special interest for experimental studies in surgery, pharmacology, and hepatology. Chronic animal models with continuous portal venous access are rare and especially thrombosis or clotting of permanent catheters is a frequent complication. Aim of this study was to establish a preclinical pig model with a permanent portal venous catheter (PVC). MATERIALS AND METHODS: PVC implantation was performed in 21 LEWE mini pigs. The catheter was inserted in the distal part of the superior mesenteric vein and fixated with a tobacco-pouch suture. Animals were followed up for 4 wk, directly after implantation of the PVC. Blood gas analyses and portal venous pressures were recorded. Three different groups with continuous infusion via the catheters were defined: NaCl solution (2 mL/h) (group 1), NaCl solution (2 mL/h) + enoxaparin sodium injection (anti-Xa levels of 0.3-0.8 U/mL) (group 2) and heparinized NaCl (2 I.E./mL, 2 mL/h) (group 3). RESULTS: All 21 PVC implantations were performed without any complications. Application of continuous perfusion with heparinized NaCl (group 3) enabled portal venous access for the entire experiment in 8 of 10 cases (mean of 23.7 d) without any signs of dysfunction. However, for use of NaCl alone or in combination with enoxaparin sodium, catheters were only functional for 6.8 d and 6.9 d, respectively. CONCLUSIONS: Permanent portal venous access through PVC in mini pigs is achievable by continuous infusion of low-dose heparinized NaCl solution.

Extended hepatic metastasectomy for renal cell carcinoma-new aspects in times of targeted therapy: a single-center experience over three decades.

PURPOSE: Despite the introduction of novel targeted therapies on patients with renal cell carcinoma, syn- and metachronous metastases (including hepatic lesions) are observed frequently and significantly influence patient survival. With introduction of targeted therapies as an effective alternative to surgery, therapeutical strategies in stage IV disease must be reevaluated. METHODS: This is a retrospective analysis of 40 patients undergoing hepatic resection of histologically confirmed RCC metastases at our institution between April 1993 and April 2017. RESULTS: The interval between nephrectomy for renal cell carcinoma and hepatic metastasectomy was 44.0 months (3.3-278.5). Liver resections of different extents were performed, including multivisceral resections. The median follow-up was 37.8 months (0.5-286.5). Tumor recurrence after resection of hepatic metastases occurred in 19 patients resulting in a median disease-free survival of 16.2 months (0.7-265.1) and a median overall survival of 37.8 months (0.5-286.5). Multivariable analysis identified multivisceral resection as an independent risk factor for disease-free and overall survival (p = 0.043 and p = 0.001, respectively). A longer interval between nephrectomy and hepatic metastasectomy was identified as an independent significant protective factor for overall survival (p < 0.001). Patients undergoing metastasectomy after introduction of sunitinib in Europe in 2006 (n = 15) showed a significantly longer overall survival (45.2 (9.1-111.0) versus 27.5 (0.5-286.52) months in the preceding era; p = 0.038). CONCLUSION: Hepatic metastasectomy, including major and extended resections, on patients with metastasized renal cell carcinoma can be performed safely and may facilitate long-term survival. Due to significant morbidity and increased mortality, multivisceral resections must be weighed against other options, such as targeted therapy.

Alloresponses of Mixed Lymphocyte Hepatocyte Culture to Immunosuppressive Drugs as an In-Vitro Model of Hepatocyte Transplantation.

BACKGROUND Hepatocyte transplantation (HCTx) has the potential for the treatment of end-stage liver disease. However, failure of engraftment and the long-term acceptance of cellular allografts remain significant challenges for its clinical application. The aim of this study was to investigate the efficacy of the immunosuppressive agents, Cyclosporine, Everolimus, and Belatacept to suppress the alloresponse of primary human hepatocytes in a mixed lymphocyte-hepatocyte culture (MLHC) and their potential hepatotoxicity in vitro. MATERIAL AND METHODS Primary human hepatocytes were co-cultured with allogeneic peripheral blood mononuclear cells (PBMCs) in an MLHC. Proliferative alloresponses were determined by flow cytometry, and cytokine secretion was measured using Luminex-based multiplex technology. Using an MLHC, the alloresponses of primary human hepatocytes were compared in the presence and absence of Cyclosporine, Everolimus, and Belatacept. Cultured primary human hepatocytes were assessed for the production of albumin, urea, aspartate transaminase (AST) and DNA content. Metabolic activity was determined with the MTT assay. RESULTS Immune responses induced by primary human hepatocytes were effectively suppressed by Cyclosporine, Everolimus, and Belatacept. Everolimus significantly reduced the metabolic activity of primary human hepatocytes in vitro, suggesting impairment of cell viability. However, further functional analysis showed no significant differences between treated and untreated controls. CONCLUSIONS Cyclosporine, Everolimus, and Belatacept suppressed the alloresponse of primary human hepatocytes in an MLHC without significant cytotoxicity or functional cell impairment.