Helge Bruns

Immunodominance and functional alterations of tumor‐associated antigen‐specific CD8+ T‐cell responses in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide with a poor prognosis and limited therapeutic options. To aid the development of novel immunological interventions, we studied the breadth, frequency, and tumor‐infiltration of naturally occurring CD8+ T‐cell responses targeting several tumor‐associated antigens (TAA). We used overlapping peptides spanning the entire alpha‐fetoprotein (AFP), glypican‐3 (GPC‐3), melanoma‐associated gene‐A1 (MAGE‐A1) and New York‐esophageal squamous cell carcinoma‐1 (NY‐ESO‐1) proteins and major‐histocompatibility‐complex‐class‐I‐tetramers specific for epitopes of MAGE‐A1 and NY‐ESO‐1 to analyze TAA‐specific CD8+ T‐cell responses in a large cohort of HCC patients. After nonspecific expansion in vitro, we detected interferon‐γ (IFN‐γ)‐producing CD8+ T cells specific for all four TAA in the periphery as well as in liver and tumor tissue. These CD8+ T‐cell responses displayed clear immunodominance patterns within each TAA, but no consistent hierarchy was observed between different TAA. Importantly, the response breadth was highest in early‐stage HCC and associated with patient survival. After antigen‐specific expansion, TAA‐specific CD8+ T cells were detectable by tetramer staining but impaired in their ability to produce IFN‐γ. Furthermore, regulatory T cells (Treg) were increased in HCC lesions. Depletion of Treg from cultures improved TAA‐specific CD8+ T‐cell proliferation but did not restore IFN‐γ‐production. Conclusion: Naturally occurring TAA‐specific CD8+ T‐cell responses are present in patients with HCC and therefore constitute part of the normal T‐cell repertoire. Moreover, the presence of these responses correlates with patient survival. However, the observation of impaired IFN‐γ production suggests that the efficacy of such responses is functionally limited. These findings support the development of strategies that aim to enhance the total TAA‐specific CD8+ T‐cell response by therapeutic boosting and/or specificity diversification. However, further research will be required to help unlock the full potential of TAA‐specific CD8+ T‐cell responses. (Hepatology 2014;59:1415‐1426)

Melatonin protects kidney grafts from ischemia/reperfusion injury through inhibition of NF-kB and apoptosis after experimental kidney transplantation.

Abstract:  Free radicals are involved in pathophysiology of ischemia/reperfusion injury (IRI). Melatonin is a potent scavenger of reactive oxygen and nitrogen species. Thus, this study was designed to elucidate its effects in a model of rat kidney transplantation. Twenty Lewis rats were randomly divided into 2 groups (n = 10 animals each). Melatonin (50 mg/kg BW) dissolved in 5 mL milk was given to one group via gavage 2 hr before left donor nephrectomy. Controls were given the same volume of milk only. Kidney grafts were then transplanted into bilaterally nephrectomized syngeneic recipients after 24 hr of cold storage in Histidine–Tryptophan–Ketoglutarate solution. Both graft function and injury were assessed after transplantation through serum levels of blood urea nitrogen (BUN), creatinine, transaminases, and lactate dehydrogenase (LDH). Biopsies were taken to evaluate tubular damage, the enzymatic activity of superoxide dismutase (SOD) and lipid hydroperoxide (LPO), and the expression of NF‐kBp65, inducible nitric oxide synthase (iNOS), caspase‐3 as indices of oxidative stress, necrosis, and apoptosis, respectively. Melatonin improved survival (P < 0.01) while decreasing BUN, creatinine, transaminases, and LDH values up to 39–71% (P < 0.05). Melatonin significantly reduced the histological index for tubular damage, induced tissue enzymatic activity of SOD while reducing LPO. At the same time, melatonin down‐regulated the expression of NF‐kBp65, iNOS, and caspase‐3. In conclusion, donor preconditioning with melatonin protected kidney donor grafts from IRI‐induced renal dysfunction and tubular injury most likely through its anti‐oxidative, anti‐apoptotic and NF‐kB inhibitory capacity.

The use of high‐dose melatonin in liver resection is safe: first clinical experience

Abstract:  Experimental data suggest that melatonin decreases inflammatory changes after major liver resection, thus positively influencing the postoperative course. To assess the safety of a preoperative single dose of melatonin in patients undergoing major liver resection, a randomized controlled double‐blind pilot clinical trial with two parallel study arms was designed at the Department of General and Transplantation Surgery, Ruprecht‐Karls‐University, Heidelberg. A total of 307 patients, who were referred for liver surgery, were screened. One hundred and thirteen patients, for whom a major liver resection (≥3 segments) was scheduled, were eligible. Sixty‐three eligible patients refused to participate, and therefore, 50 patients were randomized. A preoperative single dose of melatonin (50 mg/kg BW) dissolved in 250 mL of milk was administered through the gastric tube after the intubation for general anesthesia. Controls were given the same amount of microcrystalline cellulose. Primary endpoint was safety. Secondary endpoints were postoperative complications. Melatonin was effectively absorbed with serum concentrations of 1142.8 ± 7.2 ng/mL (mean ± S.E.M.) versus 0.3 ± 7.8 ng/mL in controls (P < 0.0001). Melatonin treatment resulted in lower postoperative transaminases over the study period (P = 0.6). There was no serious adverse event in patients after melatonin treatment. A total of three infectious complications occurred in either group. A total of eight noninfectious complications occurred in five control patients, whereas three noninfectious complications occurred in three patients receiving preoperative melatonin (P = 0.3). There was a trend toward shorter ICU stay and total hospital stay after melatonin treatment. Therefore, a single preoperative enteral dose of melatonin is effectively absorbed and is safe and well tolerated in patients undergoing major liver surgery.

Suitability of human mesenchymal stem cells for gene therapy depends on the expansion medium

Great hope is set in the use of mesenchymal stem cells for gene therapy and regenerative medicine. Since the frequency of this subpopulation of stem cells in bone marrow is low, mesenchymal stem cells are expanded ex vivo and manipulated prior to experimental or clinical use. Different methods for isolation and expansion are available, but the particular effect on the stem cell character is unclear. While the isolation of mesenchymal stem cells by density centrifugation followed by selection of the plastic adherent fraction is frequently used, the composition of expansion media differs. Thus, in the present study we cultured mesenchymal stem cells isolated from five healthy young volunteers in three widely used expansion media and performed a detailed analysis of the effect on morphology, proliferation, clonogenicity, passaging, differentiation and senescence. By this way we clearly show that the type of expansion medium used determines the stem cell character and time of senescence which is critical for future gene therapeutic and regenerative approaches using mesenchymal stem cells.

Glycine and Taurine Equally Prevent Fatty Livers from Kupffer Cell-Dependent Injury: An In Vivo Microscopy Study

Please cite this paper as: Bruns, Watanpour, Gebhard, Flechtenmacher, Galli, Schulze‐Bergkamen, Zorn, Büchler and Schemmer (2011). Glycine and Taurine Equally Prevent Fatty Livers from Kupffer Cell‐Dependent Injury: An In Vivo Microscopy Study. Microcirculation 18(3), 205–213.

Prediction of Postoperative Mortality in Liver Transplantation in the Era of MELD-Based Liver Allocation: A Multivariate Analysis

Background and Aims Liver transplantation is the only curative treatment for end-stage liver disease. While waiting list mortality can be predicted by the MELD-score, reliable scoring systems for the postoperative period do not exist. This studys objective was to identify risk factors that contribute to postoperative mortality. Methods Between December 2006 and March 2011, 429 patients underwent liver transplantation in our department. Risk factors for postoperative mortality in 266 consecutive liver transplantations were identified using univariate and multivariate analyses. Patients who were <18 years, HU-listings, and split-, living related, combined or re-transplantations were excluded from the analysis. The correlation between number of risk factors and mortality was analyzed. Results A labMELD ≥20, female sex, coronary heart disease, donor risk index >1.5 and donor Na+>145 mmol/L were identified to be independent predictive factors for postoperative mortality. With increasing number of these risk-factors, postoperative 90-day and 1-year mortality increased (0–1: 0 and 0%; 2: 2.9 and 17.4%; 3: 5.6 and 16.8%; 4: 22.2 and 33.3%; 5–6: 60.9 and 66.2%). Conclusions In this analysis, a simple score was derived that adequately identified patients at risk after liver transplantation. Opening a discussion on the inclusion of these parameters in the process of organ allocation may be a worthwhile venture.

Liver transection using vascular stapler: a review.

The clinical experience using a novel technique of liver resection with vascular staplers for dissection of hepatic parenchyma, was documented most recently in a prospective manner. These data have clearly demonstrated for the first time that stapler hepatectomy is a safe and fast dissection technique in major liver surgery (e.g. hepatectomy) which is feasible in a routine clinical setting.

Perioperative management in distal pancreatectomy: results of a survey in 23 European participating centres of the DISPACT trial and a review of literature

BackgroundConcomitant treatment in addition to intervention may influence the primary outcome, especially in complex interventions such as surgical trials. Evidence-based standards for perioperative care after distal pancreatectomy, however, have been rarely defined. This studys objective was therefore to identify and analyse the current basis of evidence for perioperative management in distal pancreatectomy.MethodsA standardised questionnaire was sent to 23 European centres recruiting patients for a randomized controlled trial (RCT) on open distal pancreatectomy that would compare suture versus stapler closure of the pancreatic remnant (DISPACT trial, ISRCTN 18452029). Perioperative strategies (e.g., bowel preparation, pain management, administration of antibiotics, abdominal incision, drainages, nasogastric tubes, somatostatin, mobilisation and feeding regimens) were assessed. Moreover, a systematic literature search in the Medline database was performed and retrieved meta-analyses and RCTs were reviewed.ResultsAll 23 centres returned the questionnaire. Consensus for thoracic epidural catheters (TECs), pain treatment and transverse incisions was found, as well as strong consensus for the placement of intra-abdominal drainages and perioperative single-shot antibiotics. Also, there was consensus that bowel preparation, somatostatin application, postoperative nasogastric tubes and intravenous feeding might not be beneficial. The literature search identified 16 meta-analyses and 19 RCTs demonstrating that bowel preparation, somatostatin therapy and nasogastric tubes can be omitted. Early mobilisation, feeding and TECs seem to be beneficial for patients. The value of drainages remains unclear.ConclusionMost perioperative standards within the centres participating in the DISPACT trial are in accordance with current available evidence. The need for drainages requires further investigation.Trial registrationClinical trial registration: ISRCTN 18452029

Thrombopoietin is a growth factor for rat hepatic progenitors.

Objective The liver is the primary site of hematopoiesis during fetal development; it has been shown that thrombopoietin (TPO) produced by the liver during fetal development is a major regulator of megakaryocytopoiesis. As maximum liver growth and hematopoiesis occur simultaneously, we hypothesized that TPO may act as a growth factor for hepatic progenitors. Therefore, the influence of TPO on the proliferation of fetal hepatic progenitors in vitro compared with that of adult hepatocytes was analyzed. The expression of the TPO receptor, c-mpl, was investigated in fetal and adult liver. Methods Cell proliferation was measured by bromodeoxyuridine incorporation and total cell counts. TPO and c-mpl gene expression was investigated by reverse transcription polymerase chain reaction. The cell surface expression of c-mpl was analyzed in fetal and adult human liver by immunohistochemistry. Results Hepatic progenitors of fetal and adult liver but not hepatocytes expressed the TPO receptor, c-mpl, on the cell surface. Fetal hepatic progenitors expressed mRNA for TPO and its receptor. TPO stimulated cell proliferation and increased cell numbers of cultured rat fetal hepatic progenitors but not adult hepatocytes. Conclusion We conclude that TPO acts in addition to its known role in megakaryocytopoiesis as a growth factor for hepatic progenitors but not hepatocytes in vitro; thus, TPO represents a growth factor for hepatic progenitors during fetal liver development.

Danshen protects liver grafts from ischemia/reperfusion injury in experimental liver transplantation in rats

Reperfusion injury remains one of the major problems in transplantation. Free radicals and disturbance of microcirculation are the supposed main contributors. Recent evidence shows that Danshen, a traditional Chinese drug used in vascular diseases, can scavenge radicals and improve microcirculation. This study investigates its effect on liver transplantation (LTx). Before organ recovery, female Sprague‐Dawley rats (210–240 g) received intravenous Danshen or the same volume of Ringer solution as control. LTx was performed after 1 h of cold storage. Microperfusion, leukocyte‐endothelium interaction and latex‐bead phagocytosis were evaluated with in vivo microscopy. Survival, transaminases and histology were assessed. Immunohistology was used for TNF‐α levels. anova and Fisher’s exact test were employed for statistical analyses as appropriate. Survival increased from 60% in controls to 100% (P < 0.05). AST and LDH decreased from 3969 ± 1255 U/l and 15444 ± 5148 U/l in controls to 1236 ± 410 U/l and 5039 ± 1594 U/l, respectively (P < 0.05). In vivo microscopy revealed decreased leukocyte‐adherence and increased blood flow velocity in sinusoidal zones after administration of Danshen (P < 0.05), while latex‐bead phagocytosis was found in 60% of controls (P < 0.05). The TNF‐α index decreased from 2.08 ± 0.09 in controls to 1.09 ± 0.09 (P < 0.05). This study clearly demonstrates hepatoprotective effects after experimental LTx, which can be explained via anti‐oxidative effects, improved microcirculation and decreased Kupffer cell activation.