Maximilian Schmeding

Erythropoietin reduces ischemia-reperfusion injury in the rat liver.

Background: Human recombinant erythropoietin (Epo) has recently been shown to be a potent protector of ischemic damage in various organ systems. A significant reduction of stroke injury following cerebral ischemia has been postulated as well as improved cardiomyocyte function after myocardial infarction in tissue pretreated with Epo. It was the aim of this study to evaluate the effects of Epo in liver ischemia. Material and Methods: Rats were subjected to 45 min of warm hepatic ischemia. Animals were either pretreated with 1,000 IU of Epo in three doses or received 1,000 IU into the portal vein 30 min before ischemia. Control animals received saline at the same time points before ischemia. Animals were than sacrificed 6, 12, 24, 48 h and 7 days after surgery and transaminases were measured. Liver specimens were evaluated regarding apoptosis, necrosis and regeneration capacity. Results: Apoptosis rates were dramatically reduced in animals pretreated with Epo while mRNA of tumor necrosis factor-α and STAT-3 were upregulated in all groups. Intraportal venous injection displayed superiority to subcutaneous preconditioning. Transaminases were significantly reduced among the Epo-treated animals after 6 and 12 h. Conclusion: Our data suggests a protective effect of Epo in warm hepatic ischemia and reperfusion injury in the rat.

Hepatitis C recurrence and fibrosis progression are not increased after living donor liver transplantation: A single-center study of 289 patients

Today, hepatitis C virus (HCV) is the leading cause for liver transplantation (LT) and viral recurrence is almost universal. It has been suggested that viral replication within the transplanted tissue might be increased in organs of reduced size such as LD grafts. In the current literature the data is controversial, with many studies lacking routine liver biopsies. We performed a retrospective analysis of 289 HCV‐LT (20 LD splits) patients receiving transplants between 1997 and 2005. Patient and organ survival, intensity of HCV recurrence, and fibrosis progression were analyzed with respect to deceased donor (DD) LT (DDLT) or living donor (LD) LT (LDLT). Organ and patient survival was significantly better for full‐size recipients than for split‐liver patients, with P = 0.037 for organ survival and P = 0.037 for patient survival; yet there were no significant differences when split‐liver patients with large hepatocellular carcinoma (HCC) beyond the Milan criteria (n = 3) were excluded from the analysis (P > 0.05). First year fibrosis progression was 1.29 in full‐size grafts and 1.07 in split‐livers (P = not significant). In conclusion, in our patient sample, intensity of HCV recurrence was not increased in LD graft recipients compared to full‐size recipients. Patient and organ survival were similar when patients with large HCC and early tumor recurrence were excluded from analysis. LDLT can therefore be advocated for HCV patients. Liver Transpl 13:687–692, 2007.

Erythropoietin promotes hepatic regeneration after extended liver resection in rats

Background and Aim:  It has been proven in various animal studies that recombinant human erythropoietin (rHuEPO) protects renal, cardiac and neuronal, as well as hepatic, tissue from ischemia, and promotes regeneration of adult central nervous system neurons. To date, no data are available as to whether rHuEPO has the ability to stimulate liver regeneration after liver resection.

A 7‐gene signature of the recipient predicts the progression of fibrosis after liver transplantation for hepatitis C virus infection

Fibrosis recurrence after liver transplantation (LT) for hepatitis C virus (HCV) is a universal event and strongly determines a patients prognosis. The recipient risk factors for fibrosis recurrence are still poorly defined. Here we assess a genetic risk score as a predictor of fibrosis after LT. The cirrhosis risk score (CRS), which comprises allele variants in 7 genes (adaptor‐related protein complex 3 S2, aquaporin 2, antizyme inhibitor 1, degenerative spermatocyte homolog 1 lipid desaturase, syntaxin binding protein 5‐like, toll‐like receptor 4, and transient receptor potential cation channel M5), was calculated for 137 patients who underwent LT for HCV infection and experienced HCV reinfection of the graft. The patients were stratified into 3 CRS categories: <0.5, 0.5 to 0.7, and >0.7. All patients underwent protocol biopsy after LT (median follow‐up = 5 years), and liver fibrosis was assessed according to the Desmet and Scheuer score. The data were analyzed with univariate and multivariate analyses. The results showed that the highest CRS category was strongly associated with the presence of F2 or F3 fibrosis in protocol biopsy samples 1, 3, and 5 years after LT (P = 0.006, P = 0.001, and P = 0.02, respectively). Overall, 75.0% of the patients with a CRS > 0.7 developed at least F2 fibrosis, whereas 51.5% developed F3 fibrosis during follow‐up. The predictive value of the CRS for fibrosis progression was independent of known clinical risk factors, including the age of the donor, the sex of the recipient, and the occurrence of acute rejection. A Kaplan‐Meier analysis confirmed the prognostic value of the CRS with respect to the recurrence of severe liver fibrosis in HCV‐infected patients after LT (log rank = 6.23, P = 0.03). In conclusion, the genetic signature of the recipient predicts the likelihood of severe liver fibrosis in the graft after HCV recurrence. The CRS might help with early clinical decision making (eg, the selection of patients for antiviral therapy after LT). Liver Transpl 18:298–304, 2012.

Erythropoietin reduces ischemia‐reperfusion injury after liver transplantation in rats

Human recombinant Erythropoietin (rHuEpo) has recently been shown to be a potent protector of ischemia‐ reperfusion injury in warm‐liver ischemia. Significant enhancement of hepatic regeneration and survival after large volume partial hepatic resection has also been demonstrated. It was the aim of this study to evaluate the capacities of rHuEpo in the setting of rat liver transplantation. One‐hundred‐and‐twenty Wistar rats were used: 60 recipients received liver transplantation following donor organ treatment (60 donors) with either 1000 IU rHuEpo or saline injection (controls) into portal veins (cold ischemia 18 h, University of Wisconsin (UW) solution). Recipients were allocated to two groups, which either received 1000 IU rHuEpo at reperfusion or an equal amount of saline (control). Animals were sacrificed at defined time‐points (2, 4.5, 24, 48 h and 7 days postoperatively) for analysis of liver enzymes, histology [hematoxylin‐eosin (HE) staining, periodic acid Schiff staining (PAS)], immunostaining [terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), Hypoxyprobe] and real‐time polymerase chain reaction (RT‐PCR) of cytokine mRNA (IL‐1, IL‐6). Lactate dehydrogenase (LDH) and alanine aminotransferase (ALT) values were significantly reduced among the epo‐treated animals 24 and 48 h after liver transplantation (LT). The TUNEL and Hypoxyprobe analyses as well as necrotic index evaluation displayed significant reduction of apoptosis and necrosis in rHuEpo‐treated graft livers. Erythropoietin reduces ischemia‐reperfusion injury after orthotopic liver transplantation in rats.

Mycophenolate mofetil in liver transplantation – is monotherapy safe?

Abstract:  Liver transplantation (LTX) today has become a routine procedure granting curative treatment for various hepatic diseases with excellent survival rates. Constant improvement of immuno‐suppressive regimens has led to significant reduction of rejection frequency and increased safety in long‐term management. Calcineurin‐inhibitors play the key role in most immunosuppressive protocols providing strong T‐cell suppression yet often associated with numerous side‐effects. Increasing renal insufficiency as well as hypertension, hyperglycaemia, hyperuricaemia, and increased risk of secondary malignancy account for the major problems in short‐ and long‐term follow‐up of LTX patients. Mycophenolate mofetil (MMF) as a purine‐synthesis inhibitor has proved to be a potent immunosuppressive agent largely free of the CI‐associated side‐effects. MMF therefore has been used to modulate immunosuppressive protocols in order to both increase efficacy and to reduce CI‐related side‐effects such as nephrotoxicity. In recent years, MMF‐monotherapy protocols have been suggested for LTX patients with renal insufficiency. This review provides an overview on the current role of MMF in immunosuppressive protocols after LTX and evaluates innovative therapeutic concepts.

ELISA-based detection of C4d after liver transplantation--a helpful tool for differential diagnosis between acute rejection and HCV-recurrence?

Hepatitis-C is the most common indication for liver transplantation. Recurrence of HCV is universal leading to graft failure in up to 40% of all patients. The differentiation between acute rejection and recurrent hepatitis-C is crucial as rejection treatments are likely to aggravate HCV-recurrence. Histological examination of liver biopsy remains the gold standard for diagnosis of acute rejection but has failed in the past to distinguish between acute rejection and recurrent hepatitis-C. In a retrospective study we have recently reported that C4d as a marker of the activated complement cascade is detectable in a hepatic specimen in acute rejection after liver transplantation and may serve as a valuable tool in differential diagnosis between ACR and HCV-recurrence. We performed a prospective analysis by ELISA measurement of C4d concentration in cryo-preserved liver biopsies of LTX patients who had either experienced acute rejection, hepatitis-C recurrence or displayed no pathological alterations (controls). Opposed to our immunohistologically based findings in paraffinized tissue we were unable to detect significant differences of C4d concentration in ELISA of cryo-preserved liver tissue. Consequently the role and potential value of C4d as a diagnostic marker may not be determined using ELISA-based tissue evaluation.

Erythropoietin reduces ischemia-reperfusion injury after fatty liver transplantation in ratsErythropoietin reduziert den Ischämie-Reperfusionsschaden und verbessert das Überleben nach Fettleber-Transplantation im Rattenmodell

Introduction: Liver transplantation (LT) remains the only curative option for treatment of liver cirrhosis today. However, the scarcity of available adequate donor organs accounts for a major challenge in virtually all transplant programs around the globe. Therefore, the enlargement of the so-called „donor pool“ by organs which normally would be regarded as inadequate offers a potential solution to the problem. The reduction of ischemia-reperfusion injury may enable potentially inferior grafts to perform satisfactory after transplantation. In the past, our group and others have demonstrated that erythropoietin (epo) reduces ischemia-reperfusion injury in rat livers and other organs such as brain, heart and kidney. Materials and Methods: In 60 Wistar rats fatty livers were induced by a special diet. These livers were transplanted into 60 recipient rats after perfusion with UW solution and cold ischemic time of 6 hours. 30 rats were treated with injection of 4.000 IU/kg of epo into the portal vein at reperfusion (additional injection of 4.000 IU/kg in donor animals before organ removal), while 30 animals received injection of the identical volume of saline at the same time points (controls). 2, 4.5, 24, 48 hours and 7 days after reperfusion we analysed organ function and tissue damage by AST, ALT, LDH, GLDH values as well as histological screening for apoptosis and necrosis (H/E, PAS, TUNEL, Hypoxyprobe). Results: In contrast to our data on non-fatty liver transplantation we did not detect significant differences in the enzyme levels at any time points between epo-treated and untreated animals. However, we did find a dramatic reduction in apoptosis and necrosis rates among epotreated animals, especially in the first 24 hours after reperfusion. Hypoxyprobe staining displayed a significantly smaller number of hypoxic cells in epo-treated liver tissue. 7-day survival was also increased in the epo-group. Conclusion: Erythropoietin enhances the postoperative liver function by reduction of hepatocellular apoptosis and necrosis after transplantation of fatty livers in rats.