Prognostic role of the Donor Risk Index, the Eurotransplant Donor Risk Index, and the Balance of Risk score on graft loss after liver transplantation.

This study aimed to identify cutoff values for donor risk index (DRI), Eurotransplant (ET)-DRI, and balance of risk (BAR) scores that predict the risk of liver graft loss. MEDLINE and Web of Science databases were searched systematically and unrestrictedly. Graft loss odds ratios and 95% confidence intervals were assessed by meta-analyses using Mantel-Haenszel tests with a random-effects model. Cutoff values for predicting graft loss at 3 months, 1 year, and 3 years were analyzed for each of the scores. Measures of calibration and discrimination used in studies validating the DRI and the ET-DRI were summarized. DRI ≥ 1.4 (six studies, n = 35 580 patients) and ET-DRI ≥ 1.4 (four studies, n = 11 666 patients) were associated with the highest risk of graft loss at all time points. BAR > 18 was associated with the highest risk of 3-month and 1-year graft loss (n = 6499 patients). A DRI cutoff of 1.8 and an ET-DRI cutoff of 1.7 were estimated using a summary receiver operator characteristic curve, but the sensitivity and specificity of these cutoff values were low. A DRI and ET-DRI score ≥ 1.4 and a BAR score > 18 have a negative influence on graft survival, but these cutoff values are not well suited for predicting graft loss.

Glycine protects partial liver grafts from Kupffer cell-dependent ischemia-reperfusion injury without negative effect on regeneration.

Donor preconditioning with glycine prevents Kupffer cell-dependent reperfusion injury to liver grafts. Partial liver grafts need to regenerate and grow in size after transplantation; however, glycine inactivates Kupffer cells, which are important for hepatic regeneration. Thus, this study was designed to evaluate the impact of donor preconditioning with glycine after partial liver transplantation (pLTx). PLTx was performed in 28 female Sprague-Dawley rats. Glycine (1.5 ml, 300 mM; i.v.) was given to 14 live donors before organ procurement. Liver enzymes and histology were investigated 8 h after reperfusion to index liver injury and leukocyte infiltration. Hepatic microperfusion and leukocyte-endothelium interaction were assessed using the in vivo fluorescence microscopy method. Ki-67 and TNF-α were detected by immunohistochemistry for regeneration and Kupffer cell activation. Glycine significantly increased survival from 0% in controls to 40%, while both liver enzyme levels and necrosis were decreased to about 50% of controls (p < 0.05). Sinusoidal blood flow increased by 40-80%, while leukocyte-endothelium interaction decreased to 30% of control values (p < 0.05). While Kupffer cell-derived TNF-α decreased to 70% of controls, there was no difference between groups in Ki-67 expression. Data presented here clearly demonstrate that glycine protects partial liver grafts from reperfusion injury without effects on regeneration.

Glycine Protects the Liver from Reperfusion Injury following Pneumoperitoneum.

BACKGROUND: Experimental pneumoperitoneum induces ischemia/reperfusion injury (IRI) in the liver, most likely via Kupffer cell (KC)-dependent mechanisms. Glycine has been shown to ameliorate IRI in various animal models. Thus, this study was performed to assess the effects of glycine on the liver after pneumoperitoneum. MATERIALS AND METHODS: Sprague-Dawley rats (220-250 g in weight) underwent CO2 pneumoperitoneum (12 mm Hg) for 90 min. Some rats received i.v. glycine (1.5 mL, 300 mM) 10 min before pneumoperitoneum. Controls were given the same volume of Ringer's solution. Transaminases, hepatic microcirculation, and phagocytosis of latex beads indexing both liver injury and KC activation were examined following pneumoperitoneum. Analysis of variance (ANOVA), plus a subsequent t test or χ2 test (or Fisher's exact test) were carried out as appropriate. Results are presented as mean ± SEM. RESULTS: Glycine significantly decreased lactate dehydrogenase at 1 h and both aspartate aminotransferase and alanine aminotransferase at 2 h after pneumoperitoneum from 477 ± 43, 154 ± 17, and 60 ± 6 U/L in controls to 348 ± 25, 101 ± 11, and 34 ± 3 U/L, respectively (p < 0.05). In parallel, glycine significantly decreased both the rate of permanent adherence of leukocytes to the endothelium by up to 35% and the rate of phagocytosis by > 50% compared to the control group. CONCLUSION: Glycine decreased IRI after pneumoperitoneum, most likely via KC-dependent mechanisms.

Increased expression and activation of absent in melanoma 2 inflammasome components in lymphocytic infiltrates of abdominal aortic aneurysms.

Chronic vascular inflammation is a key hallmark in the pathogenesis of abdominal aortic aneurysm (AAA). Recent investigations have suggested that the inflammasome, a cytosolic multiprotein complex that recognizes pathogen-associated molecular patterns, plays a role in atherosclerosis. However, its role in AAA inflammation has not yet been investigated. This pilot study analyzed inflammasome activation and its intramural localization in 24 biopsy samples from 11 patients with asymptomatic AAA versus 12 aortic samples from apparently healthy controls. Using a histological inflammation scale, we identified grade 2/3 inflammatory changes with lymphoid aggregates/tertiary lymphoid organs in 21 out of 24 AAA samples, whereas only 7 of the 12 control samples exhibited local grade 1 inflammatory changes. Strong expression levels of "apoptosis-associated speck-like protein with a caspase recruitment domain" (ASC), caspase-1, caspase-5 and "absent in melanoma 2" (AIM2) were detected by immunohistochemistry in both sporadic infiltrating lymphoid cells and lymphoid aggregates located in the outer media and adventitia of AAA samples. In contrast, inflammasome-positive cells were restricted to cholesterol plaque-associated areas and to single infiltrating cells in control aortas. Analysis of gene expression using real-time polymerase chain reaction (PCR) revealed significantly increased median mRNA levels of the inflammasome core components PYCARD (ASC), CASP1 (Caspase-1) and IL1B (IL-1ß) in AAA tissue compared with normal aorta. Moreover, significantly increased median amounts of AIM2 protein and mature caspase-5 (p20) were found in samples associated with high rupture risk compared with paired low rupture risk samples of the same AAA patient. We conclude from our data that AAA-associated lymphoid cells are capable of inflammasome signaling, suggesting that inflammasome activation is involved in the chronic inflammatory process driving AAA progression.

Do we need animal hands-on courses for transplantation surgery?

BACKGROUND: Transplantation surgery requires many years of training. This study evaluates and presents the results of our recent four-yr animal hands-on courses of transplantation surgery on participants' training. METHODS: Since 2008, five two-d hands-on courses of transplantation surgery were performed on swine models at our department. Sixty-one participants were asked to answer three questionnaires (pre-course, immediate post-course, subsequent post-course). The questions pertained to their past education, expectations, and evaluation of our courses, as well as our course's effectiveness in advancing their surgical abilities. The results were analyzed, compared and are presented herein. RESULTS: On average, 1.8 multiorgan procurements, 2.3 kidney, 1.5 liver, and 0.7 pancreas transplantations were performed by each participant. 41.7% of participants considered their previous practical training only satisfactory; 85% hoped for more opportunities to practice surgery; 73.3% evaluated our courses as very good; and 95.8% believed that our courses had fulfilled their expectations. 66% found the effectiveness of our course in advancing their surgical abilities very good; 30% good, and 4% satisfactory. CONCLUSION: Animal hands-on courses of transplantation surgery are one of the best options to learn and practice different operations and techniques in a near to clinical simulated model. Regular participation in such courses with a focus on practical issues can provide optimal opportunities for trainees with the advantage of direct mentoring and feedback.

Intestinal transplantation: review of operative techniques.

The improvement of outcomes in intestinal transplantation (ITx) over the last two decades has been made possible through standardization in surgical techniques, improvements in immunosuppressive and induction protocols, and post-operative patient care. From a surgical technical point of view, all different types of small bowel containing transplants can be categorized into three main prototypes, including isolated small bowel, liver-small bowel, and multivisceral transplantations. In this review, we describe these three main prototypes and discuss the most important technical modifications of each type, as well as donor and recipient procedures, and highlight the more recent operative technical topics of discussion in the literature.

Efficacy of Technical Modifications to the Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS) Procedure: A Systematic Review and Meta-Analysis.

To compare the outcomes of modified-Associating Liver Partition and Portal vein Ligation for Staged hepatectomy (ALPPS) techniques with those of conventional-ALPPS. Background: ALPPS is an established technique for treating advanced liver tumors. Methods: PubMed, Web of Science, and Cochrane databases were searched. The outcomes were assessed by single-arm and 2-arm analyses. Results: Seventeen studies containing 335 modified-ALPPS patients were included in single-arm meta-analysis. The estimated blood loss was 267 ± 29 mL (95% confidence interval [CI], 210-324 mL) during the first and 662 ± 51 mL (95% CI, 562-762 mL) during the second stage. The operation time was 166 ± 18 minutes (95% CI, 131-202 minutes) during the first and 225 ± 19 minutes (95% CI, 188-263 minutes) during the second stage. The major morbidity rate was 14% (95% CI, 9%-22%) after the first stage. The future liver remnant hypertrophy rate was 65.2% ± 5% (95% CI, 55%-75%) and the interstage interval was 16 ± 1 days (95% CI, 14-17 days). The dropout rate was 9% (95% CI, 5%-15%). The overall complication rate was 46% (95% CI, 37%-56%) and the major complication rate was 20% (95% CI, 14%-26%). The postoperative mortality rate was 7% (95% CI, 4%-11%). Seven studies containing 215 patients were included in comparative analysis. The hypertrophy rate was not different between 2 methods (mean difference [MD], -5.01; 95% CI, -19.16 to 9.14; P = 0.49). The interstage interval was shorter for partial-ALPPS (MD, 9.43; 95% CI, 3.29-15.58; P = 0.003). The overall complication rate (odds ratio [OR], 10.10; 95% CI, 2.11-48.35; P = 0.004) and mortality rate (OR, 3.74; 95% CI, 1.36-10.26; P = 0.01) were higher in the conventional-ALPPS. Conclusions: The hypertrophy rate in partial-ALPPS was similar to conventional-ALPPS. This shows that minimizing the first stage of the operation does not affect hypertrophy. Moreover, the postoperative overall morbidity and mortality rates were lower following partial-ALPPS.

Dietary glycine protects from chemotherapy-induced hepatotoxicity.

Hepatotoxic side effects of neoadjuvant chemotherapy for colorectal liver metastases increase perioperative morbidity and mortality. Glycine protects liver from injury in various animal models. Thus, this study was designed to assess its effect on liver after chemotherapy. Sprague-Dawley rats (200-220 g) were fed a synthetic diet containing 5% glycine for 5 days. Subsequently, chemotherapy (FOLFIRI: irinotecan, folinic acid and fluorouracil, or FOLFOX: oxaliplatin, folinic acid and fluorouracil) was administered at standard doses. Transaminases, histology, immunohistochemistry and in vivo microscopy were used to index liver injury, to monitor intrahepatic microperfusion and activation of Kupffer cells. Glycine significantly decreased transaminases after chemotherapy to 25-50% of control values (p < 0.05). Microvesicular steatosis was significantly reduced from 18.5 ± 3.4 and 57.1 ± 8.6% in controls to 9.5 ± 1.8 and 37.7 ± 4.4% after FOLFIRI and FOLFOX, respectively. Furthermore, phagocytosis of latex beads was reduced by about 50%, while leukocyte adherence in central and midzonal subacinar zones decreased to 60-80% after glycine (p < 0.05). Glycine significantly reduced expression of inducible nitric oxide synthase after chemotherapy, while hepatic microcirculation was increased (p < 0.05). This study shows for the first time that glycine reduces chemotherapy-induced liver injury. The underlying mechanisms most likely include Kupffer cells and an improved intrahepatic microperfusion.

Review of various techniques of small bowel transplantation in pigs.

Because of anatomical and physiological similarities to humans, porcine small bowel transplantation (SBTx) can be used as an appropriate experimental model in the field of surgical research. Various approaches to SBTx have been described in literature. The aim of this work is to present a review of different surgical techniques of SBTx which have been developed using the porcine model. Our analysis of Medline-cited studies dealing with different techniques of SBTx in porcine models was particularly focused on surgical aspects. With regard to graft procurement and enterectomy, the reported techniques vary widely. Arterial reconstruction is mainly conducted by performing the anastomosis between the superior mesenteric artery (SMA) of the donor and SMA or infrarenal aorta of the recipient. Alternatively, an aortic segment of the donor can be anastomosed to the infrarenal aorta of the recipient. Venous anastomosis is frequently performed between the superior mesenteric vein (SMV) of the donor and SMV or the inferior vena cava (IVC) of the recipient. Some studies also report venous anastomosis between the portal vein of the donor and the recipient. Bowel continuity is then restored by end-to-end or end-to-side anastomosis. Remarkable results were generated thanks to improved techniques which include proximal side-to-side ileo-ileal anastomosis with double-barrel ileostomy, or so-called "Paul-Mikulicz-Ileostomy". Most frequently used were jejunostomy and the "Bishop-Koop-Ileostomy"--where the proximal part of the bowel is anastomosed end-to-side to the distal part, which is then exteriorized as an ostomy. Based on the techniques presented in this review, one must select the most suitable surgical technique of porcine SBTx among those various models.

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

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.

Intervention on Spontaneous Splenorenal Shunt May Decrease the Incidence of Acute Kidney Injury After Liver Transplant.

OBJECTIVES: Spontaneous splenorenal shuntis a type of portosystemic shunt that develops frequently in the setting of chronic portal hypertension. It remains controversial whether shuntinterventions during liver transplant improve transplant outcomes. MATERIALS AND METHODS: We conducted a retrospective comparison between deceased-donor liver transplant recipients who received spontaneous splenorenal shunt intervention and those who did not at a tertiary center between 2012 and 2017. Primary outcomes of interest included intraoperative transfusion requirement, hospital length of stay, acute kidney injury posttransplant, portal vein thrombosis, thrombocytopenia, and 1-year graft and patient survival. RESULTS: Of 268 liver transplant recipients, 50 (18.6%) had large spontaneous splenorenal shunts pretransplant, with 45 patients having available radiologic and outcome data. Nine of 45 patients (20%) received shunt intervention, including pretransplant balloonoccluded retrograde transvenous obliteration (n = 5), intraoperative ligation of the left renal vein (n = 3), and intraoperative direct shunt ligation (n = 1). Demographic data, clinical characteristics, and Model for End-Stage Liver Disease scores were not different between the intervention and the nonintervention groups. Intraoperative transfusion, length of hospitalization, portal vein thrombosis, thrombocytopenia, and 1-year graft and patient survival were also similar between the 2 groups. However, the rate of posttransplant acute kidney injury was significantly lower in patients in the intervention group (0 cases vs 12 cases; odds ratio = 0.73; 95% confidence interval, 0.59-0.90). Patients with no SRS intervention (n = 36) were followed radiologically for 1 year posttransplant, with follow-up data showing complete resolution of spontaneous splenorenal shunt in just 4 patients (15%) and no changes in the remaining patients. CONCLUSIONS: Peritransplant interventions for spontaneous splenorenal shunt may reduce posttransplant acute kidney injury. In patients without intervention, spontaneous splenorenal shunt predominantly persisted 1 year posttransplant.

Oral Preconditioning of Donors After Brain Death With Calcineurin Inhibitors vs. Inhibitors of Mammalian Target for Rapamycin in Pig Kidney Transplantation.

Background: The systemic inflammatory cascade triggered in donors after brain death enhances the ischemia-reperfusion injury after organ transplantation. Intravenous steroids are routinely used in the intensive care units for the donor preconditioning. Immunosuppressive medications could be potentially used for this purpose as well. Data regarding donor preconditioning with calcineurin inhibitors or inhibitors of mammalian target for Rapamycin is limited. The aim of this project is to investigate the effects of (oral) donor preconditioning with a calcineurin inhibitor (Cyclosporine) vs. an inhibitor of mammalian target for Rapamycin (Everolimus) compared to the conventional administration of steroid in the setting of donation after brain death in porcine renal transplantation. Methods: Six hours after the induction of brain death, German landrace donor pigs (33.2 ± 3.9 kg) were randomly preconditioned with either Cyclosporine (n = 9) or Everolimus (n = 9) administered via nasogastric tube with a repeated dose just before organ procurement. Control donors received intravenous Methylprednisolone (n = 8). Kidneys were procured, cold-stored in Histidine-Tryptophane-Ketoglutarate solution at 4°C and transplanted in nephrectomized recipients after a mean cold ischemia time of 18 h. No post-transplant immunosuppression was given to avoid confounding bias. Blood samples were obtained at 4 h post reperfusion and daily until postoperative day 5 for complete blood count, blood urea nitrogen, creatinine, and electrolytes. Graft protocol biopsies were performed 4 h after reperfusion to assess early histological and immunohistochemical changes. Results: There was no difference in the hemodynamic parameters, hemoglobin/hematocrit and electrolytes between the groups. Serum blood urea nitrogen and creatinine peaked on postoperative day 1 in all groups and went back to the preoperative levels at the conclusion of the study on postoperative day 5. Histological assessment of the kidney grafts revealed no significant differences between the groups. TNF-α expression was significantly lower in the study groups compared with Methylprednisolone group (p = 0.01) Immunohistochemistry staining for cytochrome c showed no difference between the groups. Conclusion: Oral preconditioning with Cyclosporine or Everolimus is feasible in donation after brain death pig kidney transplantation and reduces the expression of TNF-α. Future studies are needed to further delineate the role of oral donor preconditioning against ischemia-reperfusion injury.

Evaluation of the impact of Tacrolimus-based immunosuppression on Heidelberg liver transplant cohort (HDTACRO): Study protocol for an investigator initiated, non-interventional prospective study.

BACKGROUND: Tacrolimus-based immunosuppression has resulted in enormous improvements on liver transplantation (LTx) outcomes. However, dose adjustment and medication adherence play a key role in post-transplant treatment success. The aim of the present study is to assess the trough levels and the need for adaptation of therapeutic doses in de novo LTx patients treated with Tacrolimus in the clinical routine, without any intervention to the treatment regimen. METHODS AND ANALYSIS: This is a pilot, prospective, exploratory, monocentric, non-interventional and non-randomized investigator-initiated study. Prospectively maintained data of 100 patients treated with various oral Tacrolimus-based immunosuppressants (Prograf or Envarsus) will be analyzed. The number of required dose adjustments of Tacrolimus formulations used in clinical routine for achieving the target trough level, Tacrolimus trough level, Tacrolimus dosing, concentration/dose ratio, routine laboratory tests, efficacy data (incl. survival, acute rejection, re-transplantation), patients therapy adherence, and infections requiring the need to reduce individual immunosuppressant dosing will be evaluated for each patient. RESULT: This study will evaluate the trough levels and the need for adaptation of therapeutic doses in de novo LTx patients treated with Tacrolimus in the clinical routine, without any intervention to the treatment regimen. CONCLUSION: The HDTACRO study will be the first study to systematically and prospectively evaluate various oral Tacrolimus-based immunosuppressants in de novo liver transplanted patients. If a difference between the therapy-subgroups is evident at the end of the trial, a randomized control trial will eventually be designed. Registration number: ClinicalTrials.gov: NCT04444817.

Rescue allocation for liver transplantation within Eurotransplant: the Heidelberg experience.

Organ shortage has driven many transplant centers to extend their criteria for organ acceptance. Graft allocation policies have been modified accordingly. This report focuses on the impact of applying the so-called rescue allocation (RA) strategy for liver transplantation (LT) in a single center within the Eurotransplant (ET) area. Liver grafts are considered for RA when the regular organ allocation is declined by at least three centers or is averted because of donor instability/unfavorable logistical reasons, thus entering a competitive or a single-recipient rescue organ offer procedure, respectively. The accepting center has the advantage to select a recipient from its own waiting list for these RA grafts. Among 253 livers accepted at the University of Heidelberg between January 2004 and December 2006, we transplanted 85 (34%) rescue-allocated livers. The indications for LT were hepatocellular carcinoma (HCC, 43%), chronic liver disease (55%), and acute liver failure (2%). Median cold ischemia time for RA grafts was 10 h (range: 4-17). The MELD score (mean +/- SD) was 13 +/- 7 (range: 6-40) and was 12 +/- 7 for recipients with HCC. Three (3.5%) primary non-functions (PNF) occurred after transplantation of RA livers. One-year patient and graft survival were 84% and 75%, respectively. A comparison between the recipients of RA livers and regularly allocated livers revealed no significant difference regarding initial poor function (IPF), PNF, and surgical complications. Furthermore, a median follow-up of 16 months revealed no significant difference regarding patient and graft survival between the two groups. The use of RA organs has increased the donor pool and transplantation dynamics with satisfying results. The unique possibility to match livers with recipients, which is left to the discretion of accepting center, should be judged according to the center's experience to decrease the waiting times for a timely rescue of organs/recipients while avoiding futile transplantations.

Melatonin protects from hepatic reperfusion injury through inhibition of IKK and JNK pathways and modification of cell proliferation.

Reactive oxygen species (ROS) are involved in pathophysiology of ischemia/reperfusion injury. Melatonin is a potent scavenger of ROS. Thus, this study was designed to elucidate its effects in a combined hepatic warm ischemia and resection model. The right lateral and caudate lobes (32% of liver volume) of Sprague-Dawley rats underwent warm ischemia for 30 min followed by reperfusion and subsequent resection of the nonischemic liver tissue. Some rats were gavaged with 50 mg/kg melatonin 2 hr before the onset of experiments. Controls received the same volume of microcrystalline cellulose. Survival, transaminases, histology, flow cytometry, inducible nitric oxide synthase (iNOS) expression, and activation of signal transduction pathways [c-Jun N-terminal kinase (JNK), cJUN, IkappaB kinase alpha (IKKalpha), proliferating cell nuclear antigen (PCNA), and Ki67] were assessed for hepatic injury, oxidative stress, and cell proliferation. Melatonin significantly improved animal survival and decreased transaminase levels, the indices for necrosis, liver damage, leukocyte infiltration, and iNOS expression. In parallel, the expression of IKKalpha, JNK1, and cJUN decreased by 35-50% after melatonin (P < 0.05). At the same time, melatonin reduced the expression of both PCNA and Ki67 in liver (P < 0.05). Melatonin is hepatoprotective most likely via mechanisms including inhibition of IKK and JNK pathways and regulation of cell proliferation.

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

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.

Ex Situ Liver Machine Perfusion as an Emerging Graft Protective Strategy in Clinical Liver Transplantation: the Dawn of a New Era.

The disparity between the number of available donor livers and patients awaiting a liver transplant has led transplant centers to accept suboptimal livers. There has been no universally accepted tool to predict the posttransplant function of these organs to safely increase the donor pool, protect these livers against ischemia-reperfusion injury, or improve their quality before implantation. Ex situ liver machine preservation has emerged as a promising novel graft protective strategy in the field of liver transplantation, with remarkable ongoing research and evolving clinical trials within Europe and the United States. This technology has been shown to be safe and feasible in the clinical liver transplantation field, has shown to reduce liver ischemia-reperfusion injury, and has shown to decrease the graft discard rate compared with conventional static cold storage. This review focuses on the current status of ex situ machine preservation in clinical liver transplantation, describing the most important technical aspects with the emphasis on the findings of the most recent clinical studies.

Signs of reperfusion injury following CO2 pneumoperitoneum: an in vivo microscopy study.

BACKGROUND: During laparoscopic surgery, pneumoperitoneum is generally established by means of carbon dioxide (CO(2)) insufflation which may disturb hepatic microperfusion. It has been suggested that the desufflation at the end of the procedure creates a model of reperfusion in a previously ischemic liver, thus predisposing it to reperfusion injury. METHODS: To study the effects of pneumoperitoneum on hepatic microcirculation, Sprague-Dawley rats underwent pneumoperitoneum with an intraabdominal pressure of 8 or 12 mmHg for 90 min. Subsequently, in vivo microscopy was performed to assess intrahepatic microcirculation and transaminases were measured to index liver injury. RESULTS: A CO(2) pneumoperitoneum of 8 mmHg did not change serum transaminases; however, further increase of intraperitoneal pressure to 12 mmHg significantly increased AST, ALT, and LDH measured after desufflation to almost 1.5 times as much as control values of 49 +/- 5 U/L, 31 +/- 3 U/L, and 114 +/- 12 U/L. In parallel, in all subacinar zones the permanent adherence of both leukocytes and platelets to the endothelium increased by about sixfold and threefold, respectively. Furthermore, Kupffer cells labeled with latex beads as an index for their activation were significantly increased compared to controls. CONCLUSION: This in vivo observation demonstrated traces of reperfusion injury in liver induced by the insufflation and desufflation of CO(2 )pneumoperitoneum. The clinical relevance of this finding and the issue of using hepatoprotective substances to prevent this injury should be further investigated.

PORTAL: pilot study on the safety and tolerance of preoperative melatonin application in patients undergoing major liver resection: a double-blind randomized placebo-controlled trial.

BACKGROUND: Major surgical procedures facilitate systemic endotoxinemia and formation of free radicals with subsequent inflammatory changes that can influence the postoperative course. Experimental data suggest that preoperative supraphysiological doses of melatonin, a potent immuno-modulator and antioxidant, would decrease postoperative infectious and non-infectious complications induced by major abdominal surgery. METHODS/DESIGN: A randomized controlled double blind single center clinical trial with two study arms comprising a total of 40 patients has been designed to assess the effects of a single preoperative dose of melatonin before major liver resection. Primary endpoints include the determination of safety and tolerance of the regimen as well as clinical parameters reflecting pathophysiological functions of the liver. Furthermore, data on clinical outcome (infectious and non-infectious complications) will be collected as secondary endpoints to allow a power calculation for a randomized clinical trial aiming at clinical efficacy. DISCUSSION: Based on experimental data, this ongoing clinical trial represents an advanced element of the research chain from bench to bedside in order to reach the highest level of evidence-based clinical facts to determine if melatonin can improve the general outcome after liver resection. TRIAL REGISTRATION: EudraCT200600530815.

Emerging graft protective strategies in clinical liver transplantation.

INTRODUCTION: There have been remarkable efforts to characterize the key responsible pathophysiologic mechanisms, as well as to ameliorate the organ preservation and ischemia reperfusion injury with the ultimate goal of expanding the donor pool and further improvement of the outcomes of liver transplantation. Attempts to translate the experimental results from bench to bedside have yielded no valid protective concepts in the field of clinical liver transplantation yet. Nonetheless, there has been a considerable amount of ongoing clinical research to develop clinically relevant graft protective strategies. Areas covered: This review focuses on the most recent evidence based findings and ongoing clinical trials that might lead to emerging graft protective strategies in the field of clinical liver transplantation. New evidence-based findings in the donor preconditioning, organ preservation, and perioperative pharmacologic graft protection strategies in the recipient are reviewed. Expert commentary: Few strategies have been shown to exert some graft protective effects against ischemia reperfusion injury in recent clinical trials in liver transplantation. Among others, 'dynamic graft preservation' techniques have been emerging as more promising graft optimization strategies.