Yanli Gu

Neurological complications after cadaveric and living donor liver transplantation.

AbstractProblems related to the central nervous system have a major impact on survival and quality of life. The aim of this retrospective study was to evaluate the incidence of neurological complications after liver transplantation (LT), including both cadaveric and living donor liver transplantation. Between April 2001 and March 2004 174 patients (120 cadaveric liver transplantations, 54 living donor transplantations) were admitted to our intensive care after liver transplantation. Of the transplanted patients 24.7% developed neurological complications. These patients’ stay in the intensive care (14.2 ± 17.2 days) was much longer than that of all admitted patients (8.4 ± 10.5 days, p < 0.05). The most common neurological complications were encephalopathy (72.1%) and seizures (11.6 %). The incidence of neurological complications in living donor liver transplanted patients was significantly lower than in cadaveric transplantation patients (20.4% vs 26.7 %). The cold ischemia time in living donor transplanted patients was significantly shorter in comparison with cadaveric transplanted patients (215 ± 119.3 vs. 383.7 ± 214.7). The survival rate after liver transplantation of patients with neurological complications was lower than that of patients without, but not significantly different (79.1 % vs. 82.4%, p > 0.05). The incidence of neurological symptoms was found to be similar between the patients treated with cyclosporine (25%) and tacrolimus (23.8 %) in this study. In conclusion, there was a high incidence of neurological complications after LT, prolonging the patients’ stay in intensive care significantly. The major neurological manifestation in our patients was encephalopathy followed by seizures. Living donor liver transplantation was associated with a significantly lower incidence of neurological complications compared with patients who had received a cadaveric graft. This might be due to the good quality of the organ and the much shorter cold ischemia time of the graft when the donor was alive.

Steatosis does not impair liver regeneration after partial hepatectomy

Hepatic steatosis is a key feature of non-alcoholic fatty liver disease (NAFLD). While storage of lipid droplet-bound triglycerides in simple steatosis is physiologically inert, non-alcoholic steatohepatitis (NASH) is associated with hepatocyte damage and apoptosis. Mitochondrial oxidation of free fatty acids (FFA), derived from lipid droplets and hepatocellular uptake, is a rapid and effective way of energy supply for proliferating cells and FFA esterification provides substrates for lipid synthesis and cell proliferation. Thus, we investigated whether simple steatosis induced by western diet (WD) improves liver regeneration after partial hepatectomy (PHx). WD feeding for 6 weeks caused simple steatosis with hepatic lipid droplet and triglyceride accumulation accompanied by induction of fatty acid transport proteins (FATP), death receptors (DR), pro- and anti-apoptotic genes, hepatocyte growth factor (Hgf) as well as increased serum leptin levels in a mouse model. After PHx, liver cell proliferation was higher in WD-fed mice and associated with FATP and Hgf induction. In addition, Erk1/2 (extracellular-related MAP kinase 1/2) dephosphorylation observed in standard diet (SD) mice was reduced in WD animals. PHx in steatotic livers did not affect hepatocyte apoptosis, despite DR upregulation. WD-induced steatosis enhances liver cell proliferation, which is accompanied by increased Hgf and leptin signaling as well as Erk1/2 phosphorylation. Induction of mild steatosis may therefore be beneficial for surgical outcome of hepatectomies.

Impact of donor gender on male rat recipients of small-for-size liver grafts

The aim of this study was to assess the impact of donor gender on small‐for‐size (SFS) liver transplantation in male recipients using a rat model. Adult female or male Lewis rats were used as donors and male Lewis rats as recipients. Size‐matched (SM) and SFS liver grafts from either male or female donors were transplanted into male recipients. Animals receiving SFS grafts were sacrificed at postoperative week 1, week 4, and week 12, respectively (n = 6‐8 per group), those receiving SM grafts after 3 months. The cumulative survival rate (SVR) in the female‐to‐male (F‐M) SFS group was significantly lower (62%; 13 of 21) compared with the male‐to‐male (M‐M) group (90%; 18 of 20) (P < 0.05). Spontaneous death occurred in the F‐M SFS combination either in the early postoperative period (<3 weeks) in animals with confluent hepatic necrosis or in the late postoperative period (>8 weeks) in animals with biliary obstruction. In contrast, no death was observed in the early posttransplantation period after M‐M liver transplantation. The relative graft size in the SM F‐M group was significantly higher (graft‐to‐recipient weight ratio [GRWR] 2.40% ± 0.8%) than in the SFS M‐M group (GRWR 1.35% ± 0.2%; P < 0.001). Regardless of graft size, the outcome was worse in terms of SVR as well as regarding the incidence and severity of biliary complications in F‐M compared with M‐M liver transplantation. In conclusion, male recipients of female livers had a less favorable outcome irrespective of graft size. Confluent hepatic necrosis as well as biliary obstruction were perceived as consequence of a severe perfusion problem in F‐M liver transplantation, which was possibly related to an enhancement of ischemia‐reperfusion (I/R) injury by the lack of estrogen in male recipients of female grafts. (Liver Transpl 2005;11:669–678.)

Survivin is upregulated during liver regeneration in rats and humans and is associated with hepatocyte proliferation

Background: Survivin regulates cell division and inhibits apoptosis. Liver regeneration is a complex process involving both proliferation and apoptosis. The role of survivin is not well elucidated and no data exist in humans.

Glycine Pretreatment Ameliorates Liver Injury After Partial Hepatectomy in the Rat

ABSTRACT Background: Living donor liver transplantation subjects the donor to a major hepatectomy. Pharmacological or nutritive protection of the liver during the procedure is desirable to ensure that the remnant is able to maintain sufficient function. The aim of our study was to analyze the effects of pretreatments with α-tocopherol (vitamin E), the flavonoid silibinin and/or the amino acid L-glycine on the donor in a rat model. Methods: Male Wistar rats were pretreated with L-glycine (5%% in chow, 5 days), α-tocopherol (100 mg/kg body weight by gavage, 3 days) and/or silibinin (100 mg/kg body weight, i.p., 5 days). Thereafter, 90%% partial hepatectomy was performed without portal vein clamping. Results: Glycine pretreatment markedly decreased transaminase release (AST, 12 hr: glycine 1292 ± 192 U/L, control 2311 ± 556 U/L, p < .05; ALT, 12 hr: glycine 1013 ± 278 U/L, control 2038 ± 500 U/L, p < .05), serum ALP activity and serum bilirubin levels (p < .05). Prothrombin time was reduced, and histologically, liver injury was also decreased in the glycine group. Silibinin pretreatment was less advantageous and pretreatment with α-tocopherol at this very high dose showed some adverse effects. Combined, i.e., triple pretreatment was less advantageous than glycine alone. Liver resection induced HIF-1α accumulation and HIF-1α accumulation was also decreased by glycine pretreatment. Conclusion: The decrease of liver injury and improvement of liver function after pretreatment with glycine suggests that glycine pretreatment might be beneficial for living liver donors as well as for patients subjected to partial hepatectomy for other reasons.

Adoptive transfer of HBV immunity by kidney transplantation and the effect of postoperative vaccination

Transfer of hepatitis B immunity occurs upon the transfer of immunologically active cells from the donor to the recipient by means of an organ graft. This has been repeatedly demonstrated for bone marrow and liver transplantations. Evidence is now presented for the transfer of anti-hepatitis B surface antibodies (anti-HBs) after kidney transplantation in rats. Kidney donors from one syngeneic and two allogeneic rat strains were immunized twice with 4 microg of recombinant hepatitis B vaccine. In week 6 after the first vaccination, kidney grafts were transplanted into Lewis (LEW) rats. Half of the recipients underwent daily immunosuppressive treatment with cyclosporin A (CsA). All recipients were vaccinated either after 10 weeks or 1 week postoperatively. Anti-HBs titer was measured weekly. Effective anti-HBs titers (10-227 mIU/ml, lasting for 1-7 weeks) were detected in 86% (25/29) of recipient rats, whose corresponding donors all had a titer above 15,000 mIU/ml. Immunosuppression enhanced the donor-derived immunity in terms of recipient-to-donor titer ratio, maximal titer and titer persistence.

Vascular endothelial growth factor improves liver regeneration and survival after 90% hepatectomy in a rat model of diet-induced steatosis.

Background/Aims: Fatty liver disease increases the risk in major liver resection for patients. As previous studies suggested that vascular endothelial growth factor (VEGF) and erythropoietin (EPO) might improve liver regeneration in nonobese animals, we investigated their effect after subtotal hepatectomy (SH) in rats with diet-induced steatosis. Methods: Male Wistar rats were fed with fatty liver-inducing diet (FLD) or normal diet (control) for 11-12 weeks followed by 90% SH. Animals were treated either with EPO, VEGF or NaCl on postoperative days 0, 1 and 3 and sacrificed 24 h or 7 days after SH. Survival rate, liver regeneration and biochemical markers were assessed. Expression of inflammatory cytokines (TNF-α, IL-6) and apoptosis-related genes (PUMA, Bcl-2) was measured by qRT-PCR. Results: Seven-day survival after SH was significantly decreased in the FLD group compared to controls (50 vs. 100%, p < 0.05). In FLD animals, treatment with VEGF increased 7-day survival to 90% compared to only 40% in the EPO group. After surgery, blood glucose levels of VEGF but not EPO- or NaCl-treated animals remained normal. Inflammatory genes were markedly upregulated in the EPO group 24 h after SH. Conclusions: Steatosis severely impairs survival and regeneration after extensive liver resection, which can be counteracted at least in part by perioperative treatment with VEGF.

Assessment of a Chloride-Poor Versus a Chloride- Containing Version of a Modified Histidine- Tryptophan-Ketoglutarate Solution in a Rat Liver Transplantation Model

Recent in vitro studies of cold‐induced cell injury have revealed the detrimental effects of extracellular chloride on cold‐stored isolated rat hepatocytes; however, its influence on endothelial cells is beneficial. To determine which of these effects is predominant in vivo, we tested both a chloride‐poor variant of a new histidine‐tryptophan‐ketoglutarate (HTK)–based preservation solution and a chloride‐containing variant in a rat liver transplantation model. The study, which was carried out in a blinded fashion with 7 or 8 rats per group, was divided into 2 parts: (1) a comparison of survival in 3 series under different conditions [different microsurgeons, rat strains, cold ischemia times (3, 12, and 24 hours), and warm ischemia times] and (2) an assessment of the microcirculation (30‐90 minutes after reperfusion), laboratory data, bile production, and histology. In each of the survival experiments, a (strong) tendency toward prolonged survival was observed with the new chloride‐containing solution (50% versus 12.5%, 75% versus 37.5%, and 100% versus 71.4% [chloride‐containing vs. chloride‐poor], overall P < 0.05). Additionally, the sinusoidal perfusion rates (83.9% ± 4.0% versus 69.2% ± 10.8%, P < 0.01) and the red blood cell velocities in sinusoids (147.7 ± 26.7 versus 115.5 ± 26.0 μm/second, P < 0.05) and in postsinusoidal venules (332.4 ± 87.3 versus 205.5 ± 53.5 μm/second, P < 0.01) were clearly higher with chloride. Moreover, the serum activities of liver enzymes were slightly reduced (not significantly), and bile production was significantly increased. These results suggest an overall beneficial effect of chloride in HTK‐based liver preservation solutions. Liver Transpl 17:650‐660, 2011.

Vergleich einer chloridarmen mit einer chloridhaltigen modifizierten HTK-Lösung in einem Rattenmodell der Lebertransplantation

Introduction: Recent in vitro studies on cold-induced cell injury revealed detrimental effects of extracellular chloride during cold storage of isolated rat hepatocytes while the influence of chloride on various endothelial cells was beneficial. To determine which of these effects predominates in vivo, we here tested a chloride-poor versus a chloride-containing variant (0.04 vs. 34.04 mM Cl-) of a new developed HTK-based preservation solution in a rat liver transplantation model. Methods: The study, carried out in a blinded fashion with 7–8 rats/group, was divided into two parts: 1) comparison of survival in three series under different conditions (different microsurgeons, rat strains, cold [24 h/12 h/3 h] and warm [17.1 ± 1.6 min/19.7 ± 3.2 min/25.0 ± 0.0 min] ischemic times), 2) assessment of microcirculation by means of intravital microscopy (30–90 min after reperfusion), laboratory data, bile production and histology. Results: In each of the survival experiments a (strong) tendency towards a prolonged survival rate was observed with the chloride-containing modified solution (50 % vs. 12.5 %; 75 % vs. 37.5 %; 100 % vs. 71.4 %). Additionally, post-reperfusion sinusoidal perfusion rates (83.9 ± 4.0 % vs. 69.2 ± 10.8 %; p < 0.01) as well as red blood cell (RBC) velocities in sinusoids (147.7 ± 26.7 μm/s vs. 115.5 ± 26.0 μm/s; p < 0.05) and postsinusoidal venules (332.4 ± 87.3 μm/s vs. 205.5 ± 53.5 μm/s; p < 0.01) were clearly higher with chloride. Moreover, serum activities of liver enzymes were slightly reduced (n. s.) while bile production was significantly increased after cold storage in the chloride-containing new solution. Conclusions: Our data suggest that in vivo beneficial effects of chloride-containing media on the endothelium/microcirculation exceed chloride-dependent hepatocyte injury occurring during cold storage. Therefore, preservation solutions for liver grafts should contain chloride.

341 Liver Regeneration and Survival After Subtotal Hepatectomy in a Fatty Liver Model is Improved by VEGF

Background and Aims: Westernized dietary habits around the world lead to higher incidence of fatty liver disease, which enhance morbidity and mortality after major liver resection. Previous works in our group suggested that liver regeneration in a model of subtotal (90%) hepatectomy (PH) using normal rats may be improved by Vascular Endothelial Growth Factor (VEGF) and Erythropoietin (EPO). Thus, we investigated the role of these mediators after PH in animals with diet-induced steatosis. Methods: Male Wistar rats were fed with a high-fat diet (HFD) for 11-12 weeks and then subjected to 90% PH. On postoperative day 0, 1 and 3 animals were treated either with EPO, VEGF or NaCl and sacrificed at 24h or 7 days after hepatectomy. Rats receiving 90% PH without HFD were used as control group. The survival rate (SV), liver regeneration and biochemical markers were assessed. Expression of inflammatory (TNF-α, IL-6) and apoptosis related (PUMA, Bcl-2) genes were measured by quantitative RT-PCR. Results: After 11-12 weeks high-fat diet led to steatosis (20%60% hepatocytes affected) as confirmed by histopathology. HFD NaCl animals exhibited a significantly impaired SV in comparison to the control group (50% vs. 100%, p<0.05) within 7 days. VEGF treatment improved the survival rate to 90%, whereas only 40% of the animals survived in the EPO group. Significantly elevated serum bilirubin and PTT values (p<0.05) were detected after EPO treatment compared to the NaCl group. Liver body weight ratio (LBWR), as indicator for regeneration, was significantly lower in the NaCl group than in the control group. VEGF improved LBWR significantly in comparison to animals treated with NaCl or EPO (P < 0.05). In contrast, the pro-regenerative genes TNF-α and IL-6 were markedly up-regulated in the EPO group at 24 hours after surgery. Bcl-2 and PUMA exhibited no significant changes in all groups. Conclusion: Survival and regeneration after extensive liver resection is severely impaired by steatosis.While VEGF administration improved survival and enhanced liver regeneration, EPO treatment was not beneficial. Short-term perioperative VEGF-treatment as possible new therapeutic option could improve the clinical outcome after major liver resection in patients with fatty liver disease.