How Old Is Old? An Age-Stratified Analysis of Elderly Liver Donors above 65.

In liver transplantation, older donor age is a well-known risk factor for dismal outcomes, especially due to the high susceptibility of older grafts to ischemia-reperfusion injury. However, whether the factors correlating with impaired graft and patient survival following the transplantation of older grafts follow a linear trend among elderly donors remains elusive. In this study, liver transplantations between January 2006 and May 2018 were analyzed retrospectively. Ninety-two recipients of grafts from donors ≥65 years were identified and divided into two groups: (1) ≥65-69 and (2) ≥ 70 years. One-year patient survival was comparable between recipients of grafts from donors ≥65-69 and ≥70 years (78.9% and 70.0%). One-year graft survival was 73.1% (donor ≥65-69) and 62.5% (donor ≥ 70), while multivariate analysis revealed superior one-year graft survival to be associated with a donor age of ≥65-69. No statistically significant differences were found for rates of primary non-function. The influence of donor age on graft and patient survival appears not to have a distinct impact on dismal outcomes in the range of 65-70 years. The impact of old donor age needs to be balanced with other risk factors, as these donors provide grafts that offer a lifesaving graft function.

Merendino Resection vs. Transhiatal Gastric Conduit After Resection of the Cardia and the Gastroesophageal Junction.

BACKGROUND: Reconstruction after combined cardia resection and removal of the gastroesophageal junction can be carried out by the Merendino procedure or via a gastric conduit. This study compares postoperative complications and quality of life for both approaches. METHODS: All patients who underwent Merendino or gastric conduit reconstruction from 2011-2017 were included. Both groups were investigated regarding postoperative length of stay, complications, and gastrointestinal quality of life. RESULTS: 45 patients were identified, of which, 39 remained for analysis: 22 patients in the Merendino group and 17 patients in the gastric conduit group. The median age of patients in the gastric conduit group (71 (53-92) years) was significantly higher than in the Merendino group (58 (19-75) years), P = .0002. Hospital stay was significantly longer in the gastric conduit group (35.9 (11-82) days vs. 18.2 (7-43) days, P = .0299) and incidence of anastomotic leakage was higher (24% vs. 9%, P = .0171). General incidence of complications (Clavien-Dindo) did not vary (P = .1694). However, grade 5 complications only occurred in the Merendino group (n = 1). Evaluation of long-term outcome and quality of life showed dysphagia to only have occurred in the Merendino group (n = 3, 14%). DISCUSSION: Both approaches have advantages and disadvantages: The Merendino procedure showed reduced incidence of anastomotic leakage and shorter hospital stay but was associated with a higher in-hospital mortality rate. Discrepancies in subgroup populations as well as small patient numbers limit the interpretation of the findings. This study does however provide a first comparison of these surgical approaches and may serve as a basis for further investigation.

Tumor Recurrence and Graft Survival in Renal Transplant Recipients with a History of Pretransplant Malignancy: A Matched Pair Analysis.

Organ scarcity demands critical decision-making regarding eligible transplant candidates and graft allocation to ensure best benefit from renal transplantation (RTx). Among the controversial relative contraindications is a history of pretransplant malignancy (PTM). While oncological outcomes of PTM-RTx recipients are well described, data on graft-specific outcome are scarce. A retrospective double case control matched pair analysis (60 months follow-up) was carried out and RTx-recipients were stratified for history of PTM. First, PTM-RTx recipients were matched according to age, sex and duration of immunosuppressive therapy. Next, PTM-RTx recipients were matched 1:1 for age, sex and cause of end-stage renal disease. Five-year patient and graft survival as well as oncological outcomes were analyzed. A total of 65 PTM-RTx recipients were identified. Post-RTx recurrence rate was 5%, while 20% developed second de novo malignancy, comparable to 14% in the control group. PTM-RTx recipients had a noticeable lower five-year death-censored as well as overall graft survival and Cox proportional hazard modeling showed a correlation between PTM and inferior graft survival. Although underlying reasons remain not fully understood, this study is the first to show inferior graft survival in PTM-RTx recipients and advocates necessity to focus on more meticulous graft monitoring in PTM recipients in addition to heightened surveillance for cancer recurrence.

Microsurgical training course for clinicians and scientists: a 10-year experience at the Münster University Hospital.

BACKGROUND: Microsurgical techniques are an important part of clinical and experimental research. Here we present our step-by-step microsurgery training course developed at the Münster University Hospital. The goal of this course was to create a short, modular curriculum with clearly described and easy to follow working steps in accordance with the Guidelines for Training in Surgical Research in Animals by the Academy of Surgical Research. METHODS: Over the course of 10 years, we conducted an annual 2.5 day (20 h) microsurgical training course with a total of 120 participants. RESULTS: Prior to the course, 90% of the participants reported to have never performed a microanastomosis before. During the 10 years a total of 84.2% of the participants performed microanastomoses without assistance, 15% required assistance and only 0.8% failed. CONCLUSIONS: Our step-by-step microsurgery training course gives a brief overview of the didactic basics and the organization of a microsurgical training course and could serve as a guide for teaching microsurgical skills. During the 2.5-day curriculum, it was possible to teach, and for participants to subsequently perform a microsurgical anastomosis. The independent reproducibility of the learned material after the course is not yet known, therefore further investigations are necessary. With this step-by-step curriculum, we were able to conduct a successful training program, shown by the fact that each participant is able to perform microvascular anastomoses on a reproducible basis.

Management of Nonmalignant Tracheo- and Bronchoesophageal Fistula after Esophagectomy.

BACKGROUND: Tracheo- or bronchoesophageal fistula (TBF) occurring after esophagectomy represent a rare but devastating complication. Management remains challenging and controversial. Therefore, the purpose of this study was to evaluate the outcome of different treatment approaches and to propose recommendations for the management of TBF. METHODS: From 2008 to 2018, 15 patients were treated because of TBF and were analyzed with respect to fistula appearance, treatment strategy (stenting, endoscopic vacuum therapy and/or surgical reintervention) and outcome. RESULTS: In each case, the fistula was small, located close to the tracheal bifurcation and associated simultaneously (n = 6, 40%) or metachronously (n = 9, 60%) with an anastomotic leakage. Latter was covered by esophageal stents in six patients which in turn resulted in occurrence of TBF at a later time in five patients. Management of TBF included conservative therapy (n = 3), stenting (n = 6), or suturing (n = 6). Ten patients underwent rethoracotomy. Treatment failure was observed in eight patients (53%). In all patients, treatment was accompanied by progressive sepsis. On the contrary, all seven patients with successful defect closure remained in good general condition. CONCLUSION: Fistula appearance was similar in all patients. Implementation of esophageal stents cannot be recommended because of possibility of TBF at a later time point. Surgery is usually required and should preferably be performed when the patient's condition has been optimized at a single-stage repair. Esophageal diversion can only be recommended in patients with persisting mediastinitis. The key element for successful treatment of TBF, however, is control over sepsis; otherwise, outcome of TBF is devastating.

Comparison of kidney allograft survival in the Eurotransplant senior program after changing the allocation criteria in 2010-A single center experience.

AIMS: The European Senior Program (ESP) aims to avoid waiting list competition between younger and elderly patients applying for renal transplantation. By listing patients ≥65 years on a separate waiting list and locally allocating of grafts ≥65 years exclusively to this cohort, waiting and cold ischemia times are predicted to be shortened, potentially resulting in improved kidney transplantation outcomes. This study compared a historic cohort of renal transplant recipients being simultaneously listed on the general and the ESP waiting lists with a collective exclusively listed on the ESP list in terms of surrogates of the transplantation outcome. METHODS: Total 151 eligible patients ≥ 65 years from Münster transplant Center, Germany, between 1999 and 2014 were included. Graft function, graft and patient survival were compared using surrogate markers of short- and long-term graft function. Patients were grouped according to their time of transplantation. RESULTS: Recipients and donors in the newESP (nESP) cohort were significantly older (69.6 ± 3.5 years vs 67.1 ± 2 years, p<0.05; 72.0 ± 5.0 years vs 70.3 ± 5.0 years, p = 0.039), had significantly shorter dialysis vintage (19.6 ± 21.7 months vs 60.2 ± 28.1 months, p<0.001) and suffered from significantly more comorbidities (2.2 ± 0.9 vs 1.8 ± 0.8, p = 0.009) than the historic cohort (HC). Five-year death-censored graft survival was better than in the HC, but 5-year graft and patient survival were better in the ESP cohort. After 2005, cold ischemia time between groups was comparable. nESP grafts showed more primary function and significantly better long-term graft function 18 months after transplantation and onwards. CONCLUSION: nESP recipients received significantly older grafts, but experienced significantly shorter time on dialysis. Cold ischemia times were comparable, but graft function in the nESP cohort was significantly better in the long term.

Impact of nighttime procedures on outcomes after liver transplantation.

BACKGROUND: Sleep deprivation is a well-known risk factor for the performance of medical professionals. Solid organ transplantation (especially orthotopic liver transplantation (oLT)) appears to be vulnerable since it combines technically challenging operative procedures with an often unpredictable start time, frequently during the night. Aim of this study was to analyze whether night time oLT has an impact on one-year graft and patient survival. MATERIAL AND METHODS: Deceased donor oLTs between 2006 and 2017 were retrospectively analyzed and stratified for recipients with a start time at day (8 a.m. and 6 p.m.) or at night (6 p.m. to 8 a.m.). We examined donor as well as recipient demographics and primary outcome measure was one-year patient and graft survival. RESULTS: 350 oLTs were conducted in the study period, 154 (44%) during daytime and 196 (56%) during nighttime. Donor and recipient variables were comparable. One-year patient survival (daytime 75.3% vs nighttime 76.5%, p = 0.85) as well as graft survival (daytime 69.5% vs nighttime 73.5%, p = 0.46) were similar between the two groups. Frequencies of reoperation (daytime 53.2% vs nighttime 55.1%, p = 0.74) were also not significantly different. CONCLUSION: Our retrospective single center data derived from a German transplant center within the Eurotransplant region provides evidence that oLT is a safe procedure irrespective of the starting time. Our data demonstrate that compared to daytime surgery nighttime liver transplantation is not associated with a greater risk of surgical complications. In addition, one-year graft and patient survival do not display inferior results in patients undergoing nighttime transplantation.

Expanding the donor pool in kidney transplantation: Should organs with acute kidney injury be accepted?-A retrospective study.

BACKGROUND: Given the gap between patients in need of a renal transplantation (RTx) and organs available, transplantation centers increasingly accept organs of suboptimal quality, e.g. from donors with acute kidney injury (AKI). METHODS: To determine the outcome of kidney transplants from deceased donors with AKI (defined as ≥ AKIN stage 1), all 107 patients who received a RTx from donors with AKI between August 2004 and July 2014 at our center were compared to their respective consecutively transplanted patients receiving kidneys from donors without AKI. 5-year patient and graft survival, frequencies of delayed graft function (DGF), acute rejections and glomerular filtration rate (eGFR, CKD-EPI) were assessed. RESULTS: Patient survival was similar in both groups, whereas death-censored and overall graft survival were decreased in AKI kidney recipients. AKI kidney recipients showed higher frequencies of DGF and had a reduced eGFR at 7 days, three months and one and three years after RTx. However, mortality was noticeably lower compared to waiting list candidates. Rejection-free survival was similar between groups. CONCLUSIONS: In our cohort, both short-term and long-term renal function was inferior in recipients of AKI kidneys, while patient survival was similar. Our data indicates that recipients of donor AKI kidneys should be carefully selected and additional factors impairing short- and long-term outcome should be minimized to prevent further deterioration of graft function.

The weekend effect in liver transplantation.

BACKGROUND: The weekend effect describes a phenomenon whereby patients admitted to hospitals on weekends are at higher risk of complications compared to those admitted during weekdays. However, if a weekend effect exists in orthotopic liver transplantation (oLT). METHODS: We analyzed oLT between 2006 and 2016 and stratified patients into weekday (Monday to Friday) and weekend (Saturday, Sunday) groups. Primary outcome measures were one-year patient and graft survival. RESULTS: 364 deceased donor livers were transplanted into 329 patients with 246 weekday (74.77%) and 83 weekend (25.23%) patients. Potential confounders (e.g. age, ischemia time, MELD score) were comparable. One-year patient and graft survival were similar. Frequencies of rejections, primary-non function or re-transplantation were not different. The day of transplantation was not associated with one-year patient and graft survival in multivariate analysis. CONCLUSIONS: We provide the first data for the Eurotransplant region on oLT stratified for weekend and weekday procedures and our findings suggest there was no weekend effect on oLT. While we hypothesize that the absent weekend effect is due to standardized transplant procedures and specialized multidisciplinary transplant teams, our results are encouraging showing oLT is a safe and successful procedure, independent from the day of the week.

Effect of Continuous Motion Parameter Feedback on Laparoscopic Simulation Training: A Prospective Randomized Controlled Trial on Skill Acquisition and Retention.

OBJECTIVE: To investigate the effect of motion parameter feedback on laparoscopic basic skill acquisition and retention during a standardized box training curriculum. DESIGN: A Lap-X Hybrid laparoscopic simulator was designed to provide individual and continuous motion parameter feedback in a dry box trainer setting. In a prospective controlled trial, surgical novices were randomized into 2 groups (regular box group, n = 18, and Hybrid group, n = 18) to undergo an identical 5-day training program. In each group, 7 standardized tasks on laparoscopic basic skills were completed twice a day on 4 consecutive days in fixed pairs. Additionally, each participant performed a simulated standard laparoscopic cholecystectomy before (day 1) and after training (day 5) on a LAP Mentor II virtual reality (VR) trainer, allowing an independent control of skill progress in both groups. A follow-up assessment of skill retention was performed after 6 weeks with repetition of both the box tasks and VR cholecystectomy. SETTING: Muenster University Hospital Training Center, Muenster, Germany. PARTICIPANTS: Medical students without previous surgical experience. RESULTS: Laparoscopic skills in both groups improved significantly during the training period, measured by the overall task performance time. The 6 week follow-up showed comparable skill retention in both groups. Evaluation of the VR cholecystectomies demonstrated significant decrease of operation time (p < 0.01), path length of the left and right instrument, and the number of movements of the left and right instruments for the Hybrid group (all p < 0.001), compared to the box group. Similar results were found at the assessment of skill retention. CONCLUSION: Simulation training on both trainers enables reliable acquisition of laparoscopic basic skills. Furthermore, individual and continuous motion feedback improves laparoscopic skill enhancement significantly in several aspects. Thus, training systems with feedback of motion parameters should be considered to achieve long-term improvement of motion economy among surgical trainees.

EPOR2/ßcR2-independendent effects of low-dose epoetin-α in porcine liver transplantation.

Ischemia-reperfusion injury (IRI) remains a key component of graft damage during transplantation. Erythropoietin (EPO) induces anti-inflammatory and anti-apoptotic effects via the EPOR2/ßcR2 complex, with a potential risk of thrombosis. Previous work indicates that EPO has EPOR2/ßcR2-independent protective effects via direct effects on the endothelium. As the EPOR2/ßcR2 receptor has a very low affinity for EPO, we aimed to test the hypothesis that EPO doses below the level that stimulate this receptor elicit cytoprotective effects via endothelial stimulation in a porcine liver transplantation model. Landrace pigs underwent allogenic liver transplantation (follow-up: 6 h) with a portojugular shunt. Animals were divided into two groups: donor and recipient treatment with low-dose EPO (65 IU/kg) or vehicle, administered 6 h before cold perfusion and 30 min after warm reperfusion. Fourteen of 17 animals (82.4%) fulfilled the inclusion criteria. No differences were noted in operative values between the groups including hemoglobin, cold or warm ischemic time. EPO-treated animals showed a significantly lower histopathology score, reduced apoptosis, oxidative stress, and most important a significant up-regulation of endothelial nitric oxide (NO) synthase (eNOS). Donor and recipient treatment with low-dose EPO reduces the hepatic IRI via EPOR2/ßcR2-independent cytoprotective mechanisms and represents a clinically applicable way to reduce IRI.

Successful management of passenger lymphocyte syndrome in an ABO-compatible, nonidentical isolated bowel transplant: a case report and review of the literature.

BACKGROUND: Passenger lymphocyte syndrome (PLS), a subtype of graft-versus-host disease, is a rare disorder encountered mainly in ABO-mismatched hematopoietic stem cell transplantation and infrequently in all types of ABO-mismatched solid organ transplantation. We here report the fifth case of PLS in small bowel transplantation (SBTx) and the first one describing the successful management of PLS in a cadaveric, isolated SBTx. CASE REPORT: A 60-year-old Caucasian female with blood group A D+ suffering from short bowel syndrome received a small bowel transplant from a 32-year-old Caucasian female with blood group O D+ (HLA mismatch 2/6). After onset of massive hemolysis on Postoperative Day 9 the positive direct and indirect antiglobulin tests showing antibodies against A1 and A2 red blood cells (RBCs) led to the diagnosis of PLS. This complication was successfully treated by transfusion of blood group O RBC transfusions, increased immunosuppression, and plasmapheresis. CONCLUSION: In the event of severe hemolysis and anemia after ABO-mismatched SBTx, PLS should be considered. In our case successful treatment consisted of transfusion of donor-specific RBCs, increased immunosuppression, and plasmapheresis.

Box- or Virtual-Reality Trainer: Which Tool Results in Better Transfer of Laparoscopic Basic Skills?-A Prospective Randomized Trial.

OBJECTIVE: Simulation training improves laparoscopic performance. Laparoscopic basic skills can be learned in simulators as box- or virtual-reality (VR) trainers. However, there is no clear recommendation for either box or VR trainers as the most appropriate tool for the transfer of acquired laparoscopic basic skills into a surgical procedure. DESIGN: Both training tools were compared, using validated and well-established curricula in the acquirement of basic skills, in a prospective randomized trial in a 5-day structured laparoscopic training course. Participants completed either a box- or VR-trainer curriculum and then applied the learned skills performing an ex situ laparoscopic cholecystectomy on a pig liver. The performance was recorded on video and evaluated offline by 4 blinded observers using the Global Operative Assessment of Laparoscopic Skills (GOALS) score. Learning curves of the various exercises included in the training course were compared and the improvement in each exercise was analyzed. SETTING: Surgical Skills Lab of the Department of General and Visceral Surgery, University Hospital Muenster. PARTICIPANTS: Surgical novices without prior surgical experience (medical students, n = 36). RESULTS: Posttraining evaluation showed significant improvement compared with baseline in both groups, indicating acquisition of laparoscopic basic skills. Learning curves showed almost the same progression with no significant differences. In simulated laparoscopic cholecystectomy, total GOALS score was significantly higher for the box-trained group than the VR-trained group (box: 15.31 ± 3.61 vs. VR: 12.92 ± 3.06; p = 0.039; Hedge׳s g* = 0.699), indicating higher technical skill levels. CONCLUSIONS: Despite both systems having advantages and disadvantages, they can both be used for simulation training for laparoscopic skills. In the setting with 2 structured, validated and almost identical curricula, the box-trained group appears to be superior in the better transfer of basic skills into an experimental but structured surgical procedure.

Diagnosis of abnormal biliary copper excretion by positron emission tomography with targeting of (64)Copper-asialofetuin complex in LEC rat model of Wilson's disease.

Identification by molecular imaging of key processes in handling of transition state metals, such as copper (Cu), will be of considerable clinical value. For instance, the ability to diagnose Wilson's disease with molecular imaging by identifying copper excretion in an ATP7B-dependent manner will be very significant. To develop highly effective diagnostic approaches, we hypothesized that targeting of radiocopper via the asialoglycoprotein receptor will be appropriate for positron emission tomography, and examined this approach in a rat model of Wilson's disease. After complexing (64)Cu to asialofetuin we studied handling of this complex compared with (64)Cu in healthy LEA rats and diseased homozygous LEC rats lacking ATP7B and exhibiting hepatic copper toxicosis. We analyzed radiotracer clearance from blood, organ uptake, and biliary excretion, including sixty minute dynamic positron emission tomography recordings. In LEA rats, (64)Cu-asialofetuin was better cleared from blood followed by liver uptake and greater biliary excretion than (64)Cu. In LEC rats, (64)Cu-asialofetuin activity cleared even more rapidly from blood followed by greater uptake in liver, but neither (64)Cu-asialofetuin nor (64)Cu appeared in bile. Image analysis demonstrated rapid visualization of liver after (64)Cu-asialofetuin administration followed by decreased liver activity in LEA rats while liver activity progressively increased in LEC rats. Image analysis resolved this difference in hepatic activity within one hour. We concluded that (64)Cu-asialofetuin complex was successfully targeted to the liver and radiocopper was then excreted into bile in an ATP7B-dependent manner. Therefore, hepatic targeting of radiocopper will be appropriate for improving molecular diagnosis and for developing drug/cell/gene therapies in Wilson's disease.

The microRNA-200 family--a potential diagnostic marker in hepatocellular carcinoma?

BACKGROUND: Hepatocellular carcinoma (HCC) represents the main cause of death among patients with cirrhotic liver disease, but little is known about mechanisms of cirrhosis associated carcinogenesis. We investigated the diagnostic impact of microRNA-200 (miR-200) family members as important epigenetic regulators of epithelial-mesenchymal transition (EMT) to differentiate between patients with HCC and liver cirrhosis. METHODS: Expression of the miR-200 family was investigated by qRT-PCR in specimens of HCC patients with and without cirrhosis. Benign specimens with and without cirrhosis served as controls. Expression of the EMT markers ZEB-1, E-cadherin and vimentin was examined using immunohistochemistry. RESULTS: MiR-200a and miR-200b were significantly downregulated in HCC (miR-200a: -40.1% (P = 0.0002); miR-200b: -52.3% (P = 0.0002)), and in HCC cirrhotic tissue (miR-200a: -40.2% (P = 0.004); miR-200b: -51.1% (P = 0.007)) compared to liver cirrhosis. Spearman's Rho analysis revealed a significant negative correlation of miR-200a and miR-200b to the expression of the mesenchymal markers Vimentin (P < 0.007) and ZEB-1 (P < 0.0005) and a significant positive correlation to the epithelial marker E-cadherin (P < 0.0002). CONCLUSIONS: MiR-200 family members and their targets are significantly deregulated in HCC and liver cirrhosis. The miR-200 family is able to distinguish between cirrhotic and HCC tissue and could serve as an early marker for cirrhosis-associated HCC.

Prognostic factors for kidney allograft survival in the Eurotransplant Senior Program.

BACKGROUND: The shortage of organ donors has led to the introduction of the Eurotransplant Senior Program (ESP) to optimize the allocation of kidneys from elderly donors by age-matching. In the face of a rapidly aging population, identification of prognostic factors for kidney allograft survival within the ESP population will be of enormous significance. MATERIAL AND METHODS: Donor and recipient data from 89 patients transplanted under the ESP protocol between 1999 and 2007 were retrospectively analyzed. Data were correlated with initial graft function, graft survival, acute rejection episodes, serum creatinine levels, glomerular filtration rates, and patient survival using univariate and multivariate analysis. Maximum follow-up was 5 years. RESULTS: Cold ischemia time (CIT) >16 hours, body mass index (BMI) ≥25 kg/m(2), and kidney re-transplantation were significant risk factors for delayed graft function (DGF). Odds ratio for primary non-function was significantly increased with prolonged CIT, BMI ≥25 kg/m(2), and duration of renal replacement therapy >69 months. CIT >15 h, DGF, and kidney re-transplantation were associated with poor graft survival (P<0.05). CONCLUSIONS: Risk reduction (e.g., aiming at CIT <15 h) and close surveillance of patients at risk appear to be crucial for allograft survival in the ESP.

Nonselective inhibition of prostaglandin-endoperoxide synthases by naproxen ameliorates acute or chronic liver injury in animals.

The rising prevalence of hepatic injury due to toxins, metabolites, viruses, etc., necessitates development of further mechanisms for protecting the liver and for treating acute or chronic liver diseases. To examine whether inhibition of inflammation is directed by cyclo-oxygenase pathways, we performed animal studies with naproxen, which inhibits prostaglandin-endoperoxide synthases 1 and 2 and is in extensive clinical use. We administered carbon tetrachloride to induce acute liver injury and ligated the common bile duct to induce chronic liver injury in adult rats. These experimental manipulations produced abnormalities in liver tests, tissue necrosis, compensatory hepatocyte or biliary proliferation, and onset of fibrosis, particularly after bile duct ligation. After carbon tetrachloride-induced acute injury, naproxen decreased liver test abnormalities, tissue necrosis and compensatory hepatocellular proliferation. After bile duct ligation-induced chronic injury, naproxen decreased liver test abnormalities, tissue injury and compensatory biliary hyperplasia. Moreover, after bile duct ligation, naproxen-treated rats showed more periductular oval liver cells, which have been classified as hepatic progenitor cells. In naproxen-treated rats, we found greater expression in hepatic stellate cells and mononuclear cells of cytoprotective factors, such as vascular endothelial growth factor. The ability of naproxen to induce expression of vascular endothelial growth factor was verified in cell culture studies with CFSC-8B clone of rat hepatic stellate cells. Whereas assays for carbon tetrachloride toxicity using cultured primary hepatocytes established that naproxen was not directly cytoprotective, we found conditioned medium containing vascular endothelial growth factor from naproxen-treated CFSC-8B cells protected hepatocytes from carbon tetrachloride toxicity. Therefore, naproxen was capable of ameliorating toxic liver injury, which involved naproxen-induced release of physiological cytoprotective factors in nonparenchymal liver cells. Such drug-induced release of endogenous cytoprotectants will advance therapeutic development for hepatic injury.

Endothelin-1 receptor A blocker darusentan decreases hepatic changes and improves liver repopulation after cell transplantation in rats.

UNLABELLED: Cell transplantation-induced hepatic ischemia and recruitment of vasoconstrictors (e.g., endothelin-1; Edn1) leads to clearance of transplanted cells and poses problems for liver repopulation. Therefore, we determined whether darusentan (DAR), which potently blocks Edn1 receptor type A, could benefit cell engraftment. We transplanted primary F344 rat hepatocytes with or without DAR in dipeptidyl peptidase IV-deficient rats. Analysis of microcirculatory events included hepatic ischemia, endothelial injury, including with gene expression arrays, and activations of Kupffer cells (KCs), neutrophils, or hepatic stellate cells (HSCs). The retrorsine-partial hepatectomy model was used for liver repopulation studies. Whether DAR was directly cytoprotective was examined in cultured rat hepatocytes or CFSC-8B rat HSCs. We found that DAR induced hepatic sinusoidal vasodilation, caused more transplanted cells to be deposited in liver parenchyma, and decreased hepatic ischemia and endothelial injury. This lessened perturbations in expression of endothelial biology genes, including regulators of vessel tone, inflammation, cell adhesion, or cell damage, versus drug-untreated controls. Moreover, in DAR-treated animals, cell transplantation-induced activation of KCs, albeit not of neutrophils, decreased, and fewer HSCs expressed desmin. In DAR-treated rats, improvements in cell engraftment led to greater extent of liver repopulation, compared to drug-untreated controls. In cell-culture assays, DAR did not stimulate release of cytoprotective factors, such as vascular endothelial growth factor, from HSCs. Moreover, DAR did not protect hepatocytes from tumor necrosis factor alpha- or oxidative stress-induced toxicity. Endothelin receptor A blockade in vitro did not improve engraftment of subsequently transplanted hepatocytes. CONCLUSION: Systemic administration of DAR decreases hepatic ischemia-related events and thus indirectly improves cell engraftment and liver repopulation. This vascular mechanism may permit the development of combinatorial drug-based regimens to help optimize cell therapy.

Directly acting drugs prostacyclin or nitroglycerine and endothelin receptor blocker bosentan improve cell engraftment in rodent liver.

UNLABELLED: To optimize strategies for liver-directed cell therapy, prevention of initial transplanted cell losses is particularly important for subsequent liver repopulation. After cell transplantation in hepatic sinusoids, perturbations in hepatic microcirculation along with changes in various liver cell types are among the earliest changes. Therefore, for advancing further concepts in cell engraftment we studied vascular and related events in the liver after transplanting syngeneic hepatocytes into dipeptidyl peptidase IV-deficient rats. We treated rats with vascular drugs to define whether deleterious cell transplantation-induced events could be controlled followed by improvements in transplanted cell engraftment and proliferation. We found cell transplantation altered liver gene expression related to vessel tone, inflammation, cell adhesion, thrombosis, or tissue damage/remodeling. This was due to hepatic ischemia, endothelial injury, and activation of neutrophils, Kupffer cells, and hepatic stellate cells. Treatment of rats before cell transplantation with the angiotensin converting enzyme blocker, lisinopril, or angiotensin II receptor blocker, losartan, did not improve cell engraftment. By contrast, direct-acting nitroglycerine or prostacyclin improved cell engraftment and also kinetics of liver repopulation. These drugs lowered hepatic ischemia and inflammation, whereas pretreatment of rats with the dual endothelin-1 receptor blocker, bosentan, improved cell engraftment independently of hepatic ischemia or inflammation, without improving liver repopulation. However, incubation of hepatocytes with bosentan protected cells from cytokine toxicity in vitro and produced superior cell engraftment and proliferation in vivo. CONCLUSION: Cell transplantation-induced changes in hepatic microcirculation contributed to transplanted cell clearances from liver. Vascular drugs, such as nitroglycerine, prostacyclin, and bosentan, offer opportunities for improving cell therapy results through superior cell engraftment and liver repopulation. Ongoing clinical use of these drugs will permit rapid translation of the findings in people.