Protective mechanisms of end-ischemic cold machine perfusion in DCD liver grafts.

BACKGROUND & AIMS: The aim of this study was to identify protective mechanisms of cold machine perfusion in liver grafts donated after cardiac death. METHODS: Pig livers exposed to 60-min warm ischemia were cold stored for 7 h or treated after 6-h cold storage with 1-h hypothermic oxygenated perfusion (HOPE) through the portal vein. Different physical (perfusion pressure) and chemical (oxygen, mitochondrial transition pore inhibition) parameters were analyzed during machine perfusion to dissect key steps of mechanism. RESULTS: HOPE treatment led to a significant slowdown of mitochondrial respiration rate during 1-h machine perfusion. After reperfusion following low pressure HOPE, mitochondrial injury, nuclear injury, Kupffer cell activation and endothelial injury were significantly improved, as tested on an isolated liver perfusion model. In contrast, machine perfusion with deoxygenated perfusate showed no protection from hepatocyte injury and Kupffer cell activation. However, endothelial injury was also prevented by low pressure machine perfusion in the absence of oxygen. Perfusion with higher pressure provoked endothelial damage and Kupffer cell activation. CONCLUSIONS: The mechanisms of protection by hypothermic machine perfusion appear to be at least twofold. First, oxygenation under hypothermic conditions protects from mitochondrial and nuclear injury by downregulation of mitochondrial activity before reperfusion. Second, cold perfusion itself, under low pressure conditions, prevents endothelial damage, independently of oxygen.

Portal uptake function in veno-occlusive regions evaluated by real-time fluorescent imaging using indocyanine green.

BACKGROUND & AIMS: Although recent advances in preoperative imaging have enabled accurate estimation of the regional liver volume with venous occlusion, the extent of functional decrease in such regions remains unclear. In this study, the portal uptake function in postoperative veno-occlusive regions and non-veno-occlusive regions was evaluated by intraoperative fluorescent imaging after intravenous injection of indocyanine green (ICG). METHODS: In 22 liver resection patients and 23 recipients and 18 donors of liver transplantation, fluorescent intensity on the remnant liver or the liver graft was evaluated in real time following intravenous injection of ICG (0.0025 mg per 1 ml of remnant liver volume). RESULTS: Plateau ICG concentrations were significantly lower in the veno-occlusive regions (C(VO)) than in the non-veno-occlusive regions (C(Non)) in liver resection patients (median [range], 0.75 [0.29-2.0]µg/ml vs. 3.0 [0.46-6.4]µg/ml, p<0.001), donors (0.69 [0.29-1.9]µg/ml vs. 2.4 [0.46-6.4]µg/ml, p<0.001), and recipients (0.75 [0.34-1.8]µg/ml vs. 1.8 [0.54-6.4]µg/ml, p<0.001). Distributions of the C(VO)/C(Non) and the ratio of the hepatic uptake rate constant in the veno-occlusive regions to that in non-veno-occlusive regions were both around 40% (mean ± standard deviation, 0.36 ± 0.17 and 0.42 ± 0.16, respectively). When the functional remnant liver volume was calculated as a sum of non-veno-occlusive regions and veno-occlusive regions multiplied by C(VO)/C(Non), its ratio to the total liver volume was correlated with the improved postoperative/preoperative ratio of prothrombin time. CONCLUSIONS: Portal uptake function in veno-occlusive regions is approximately 40% of that in non-veno-occlusive regions. Intraoperative ICG-fluorescent imaging enables real-time evaluation of the extent of the functional decrease in veno-occlusive regions, enhancing accurate estimation of the hepatic functional reserve for determining the surgical indications and procedures.

The hemostatic status of pediatric recipients of adult liver grafts suggests that plasma levels of hemostatic proteins are not regulated by the liver.

Plasma levels of coagulation factors differ profoundly between adults and children, but are remarkably stable throughout adulthood. It is unknown which factors determine plasma levels of coagulation factors in a given individual. We hypothesized that the liver, which synthesizes coagulation factors, also controls plasma levels. We measured a panel of coagulation factors in samples taken from either adults or young children who underwent a liver transplantation with adult donor livers. Samples were taken 1-3 months after transplantation, when the patients were clinically stable with adequate graft function. After liver transplantation, the hemostatic profile of the pediatric group was remarkably different from that of the adult group, and resembled the hemostatic profile of normal children. Thus, children transplanted with an adult liver graft maintain a pediatric hemostatic profile after transplantation despite receiving an adult liver graft. These findings suggest that plasma levels of hemostatic proteins are not controlled by the liver.

Remote ischemic preconditioning promotes early liver cell proliferation in a rat model of small-for-size liver transplantation.

BACKGROUND: The size of the liver donor graft is a major concern in living donor liver transplantation. Rapid regeneration is essential for the survival of these grafts. The purpose of this study was to investigate the effect of remote ischemic preconditioning (RIPC) on liver regeneration in a rat small-for-size liver transplantation model. METHODS: We established rat models of small-for-size liver transplantation (30%) in the presence or absence (control) of remote ischemic preconditioning. We observed liver mass regeneration, serum alanine aminotransferase, hepatic pathologic alterations, flow cytometry, and Ki-67 antigen immunohistochemistry. In addition, using Western blotting and reverse-transcriptase-polymerase chain reaction, we assessed the activation of cell cycle progression as well as tumor necrosis factor-α and interleukin-6 expression. RESULTS: Compared with the control group, serum alanine aminotransferase activity was significantly lower and histopathology changes were significantly attenuated in the RIPC group. Remote ischemic preconditioning induced a high level of interleukin-6 mRNA in small grafts, but suppressed the expression of tumor necrosis factor-α. The proliferation index, indicated by the S-phase and G2/M-phase ratio [(S+G2/M)/(G0/G1+S+G2/M)], was significantly increased in the RIPC group at 24 h (58.25% ± 0.506% versus 53.405% ± 1.25%; P = .007). Meanwhile, cell cycle progression and regeneration (Ki-67) were initiated early in liver grafts treated with RIPC. CONCLUSIONS: These results suggest that RIPC can protect liver cells against ischemia reperfusion injury in the small grafts and enhance liver regeneration. Interleukin-6 may be a critical mediator in the stimulatory effect on liver cell regeneration, which may make RIPC valuable as a hepatoprotective modality.

Liver graft pretreated in vivo or ex vivo by γ-aminobutyric acid receptor regulation.

BACKGROUND: γ-Aminobutyric acid exists throughout the body, and the brain γ-aminobutyric acid receptor (GABAR) regulation reduces oxidative stress (OS). Effects of GABAR regulation in the liver are unknown. Ischemia or reperfusion injury after orthotopic liver transplantation (OLT) or shear stress after split OLT (SOLT) with a small-for-size graft causes OS-induced graft damage. Here, the strategic potential of graft pretreatment in vivo and ex vivo by GABAR regulation was investigated. MATERIALS AND METHODS: Recipient rats were divided into seven groups according to the graft pretreatments and graft types: (1) laparotomy, (2) OLT, (3) GABAR regulation in vivo and OLT, (4) GABAR regulation ex vivo and OLT, (5) SOLT, (6) GABAR regulation in vivo and SOLT, and (7) GABAR regulation ex vivo and SOLT. Survival study, biochemical assays, histopathologic or immunohistologic assessments, and Western blotting were performed at 6 h after OLT or SOLT. RESULTS: Graft pretreatment in vivo prolonged survival after SOLT. Histopathologic and biochemical profiles verified that graft pretreatment in vivo reduced graft damage after OLT or SOLT. Immunohistologically, graft pretreatment in vivo prevented apoptotic inductions after OLT or SOLT. The 4-hydroxynonenal confirmed the OS after OLT or SOLT, and graft pretreatment in vivo improved the OS. Graft pretreatment in vivo decreased ataxia-telangiectasia-mutated kinase and H2AX after OLT or SOLT. Graft pretreatment in vivo increased phosphatidylinositol 3 kinase and Akt after SOLT. In contrast, GABAR regulation ex vivo did not work. CONCLUSIONS: Graft pretreatment in vivo, not ex vivo, prevented the ischemia or reperfusion injury-mediated OS after OLT or SOLT via the ataxia-telangiectasia-mutated kinase/H2AX pathway and the shear stress-mediated OS after SOLT with small-for-size graft via the phosphatidylinositol 3 kinase/Akt pathway.

Investigation of adaptation after liver transplantation using Roy's Adaptation Model.

In this study we explored the adaptation of transplant recipients in Turkey using the Roy Adaptation Model. A descriptive qualitative design was used with data collected from liver transplant recipients in either individual or group interviews between May 2009 and February 2010. Using deductive content analysis, four themes were identified in the data: physiological mode, self-concept mode, role function mode, and interdependence mode. Each theme included both adaptive and ineffective behaviors of liver transplant recipients. The findings of this study indicate that liver transplant recipients need information and support about their ineffective behaviors in all modes of the Roy Adaptation Model. The findings also support the use of a nursing model in the delivery of nursing care for liver transplantation recipients.

Twenty-year protocol liver biopsies: Invasive but useful for the management of liver recipients.

BACKGROUND & AIMS: Most liver transplant centres have discontinued the practice of protocol liver biopsies (LB), mainly because of the perceived lack of therapeutic benefit. This study aimed to examine the usefulness of 20-year LBs. METHODS: Ten, 15, and 20-year protocol LBs from 147 patients surviving for >20 years were reviewed. Twenty-year biopsy findings were correlated with clinical data. RESULTS: Twenty-year-biopsy patients (N=91) and 20-year-non-biopsy patients (N=56) were similar in terms of transplant data, adverse events, and liver function tests (LFTs). Twenty-year LBs revealed a 90% prevalence of abnormalities, among which viral chronic hepatitis (VCH) was the most common (46%). Between 15 and 20 years, hepatic structural abnormalities were the only disorder to increase (p=0.008). An individual progression of abnormalities occurred in 56% of patients. At 20 years, the negative and positive predictive values (PV) of LFTs with respect to histological abnormalities were 95% and 18%, respectively; in VCH, Fibrotest and transient elastography displayed poor discriminative ability for fibrosis (80% and 81% discordance, respectively), but were satisfactory regarding significant fibrosis (negative PV of 77.7% and 80%, respectively). A decrease in immunosuppression was less frequent (14/91 vs. 20/56, p=0.008) while an increase was more common (15/91 vs. 2/56, p=0.017) in 20-year-biopsy patients than in non-biopsy patients. Antiviral therapy was administered in seven of the 20-year biopsy patients, but in none of the non-biopsy patients (p=0.04). CONCLUSIONS: Twenty-year LBs provided important histological information on graft function that was available to a limited degree from LFTs and non-invasive markers. They exerted an impact on immunosuppressive and antiviral therapies.

PPARα is down-regulated following liver transplantation in mice.

BACKGROUND & AIMS: Graft dysfunction is one of the major complications after liver transplantation, but its precise mechanism remains unclear. Since steatotic liver grafts are susceptible to post-transplant dysfunction, and peroxisome proliferator-activated receptor (PPAR) α plays an important role in the maintenance of hepatic lipid homeostasis, we examined the role of PPARα in liver transplantation. METHODS: Livers were harvested from Sv/129 wild-type (Ppara(+/+)) mice and PPARα-null (Ppara(-/-)) mice and transplanted orthotopically into syngeneic Ppara(+/+) mice. RESULTS: Hepatocellular damage was unexpectedly milder in transplanted Ppara(-/-) livers compared with Ppara(+/+) ones. This was likely due to decreased lipid peroxides in the Ppara(-/-) livers, as revealed by the lower levels of fatty acid oxidation (FAO) enzymes, which are major sources of reactive oxygen species. Hepatic PPARα and its target genes, such as FAO enzymes and pyruvate dehydrogenase kinase 4, were strongly down-regulated after transplantation, which was associated with increases in hepatic tumor necrosis factor-α expression and nuclear factor-κB activity. Inhibiting post-transplant PPARα down-regulation by clofibrate treatment markedly augmented oxidative stress and hepatocellular injury. CONCLUSIONS: Down-regulation of PPARα seemed to be an adaptive response to metabolic alterations following liver transplantation. These results provide novel information to the understanding of the pathogenesis of early post-transplant events.

High intrahepatic HHV-6 virus loads but neither CMV nor EBV are associated with decreased graft survival after diagnosis of graft hepatitis.

BACKGROUND & AIMS: In liver transplant recipients with graft hepatitis, the relevance of herpesviruses is not well defined. METHODS: Viral loads of CMV, EBV, and HHV-6 were determined in blood and liver biopsies of 170 liver transplant recipients with graft hepatitis by quantitative PCR. RESULTS: HHV-6-, CMV-, and EBV-DNA were detected in 58%, 14%, and 44% of the biopsies, respectively, with coinfections in 34%. High intrahepatic HHV-6 DNA levels (>75th percentile, 11.27 copies/1000 cells) and detection of HHV-6 DNAemia were significantly associated with decreased graft survival after diagnosis of graft hepatitis (p=0.014 and p=0.003, respectively, median follow-up was 23.8 months). Multivariate analysis confirmed high intrahepatic HHV-6 loads as an independent factor associated with reduced graft survival (adjusted hazard ratio 2.61, 95%confidence interval 1.16-5.87). Low concentrations of HHV6 DNA in the liver, indicating latent infection, did not influence graft survival. Neither CMV nor EBV (qualitative detection and high virus loads) nor acute rejection (according to the BANFF score) affected graft survival. However, patients had been treated for CMV reactivations and acute rejections in this retrospective study. High age and high bilirubin levels were the other independent factors associated with reduced graft survival (adjusted hazard ratio 3.56CI 1.52-8.34 and 3.23CI 1.50-6.96, respectively). CONCLUSIONS: High intrahepatic HHV-6-DNA levels are associated with decreased graft survival in liver transplant recipients with graft hepatitis. The significance of HHV-6 as potential etiology of graft hepatitis needs further evaluation.

Homogenous phenomenon of graft liver CYP2C19 genotypes after living donor liver transplantation.

BACKGROUND: The donor liver grafts with different allelic patterns do not affect CYP2C19 genotypes in the peripheral blood of living donor liver transplantation (LDLT) recipients. AIM: This study investigated the influence of graft liver CYP2C19 genotypes on recipients who received the same or different CYP2C19 genotypes from donors after LDLT. METHODS: There were 30 donors and 30 recipients with the same CYP2C19 genotypes and 47 donors and 47 recipients with different CYP2C19 genotypes. Genomic DNA was isolated from the liver tissue of recipients. The CYP2C19 haplotypes were determined by polymerase chain reaction. RESULTS: A homogenous phenomenon in the sequences of graft liver CYP2C19 genotypes was indicated because the recipients showed mixed patterns that were similar to that of the original donor after LDLT. A significant decrease in homozygous extensive metabolizer (HomEM) and an increase in poor metabolizer (PM) distribution were observed in recipients with different CYP2C19 genotypes from their donors compared with recipients with the same CYP2C19 genotype as their donors (P < 0·05). CONCLUSIONS: Homogenous phenomenon of sequence changes in graft liver CYP2C19 from the different genotypes between the donors and the recipients may play a role in graft stability by causing decreased HomEM and increased PM after LDLT.

Porcine alanine transaminase after liver allo-and xenotransplantation.

Aspartate transaminase (AST) and alanine transaminase (ALT) are measured following liver transplantation as indicators of hepatocellular injury. During a series of orthotopic liver allo-and xenotransplants, we observed that there was an increase in AST in all cases. The anticipated concomitant rise in ALT did not occur when a wild-type (WT) pig was the source of the liver graft, but did occur when a baboon or a genetically engineered (α1,3-galactosyltransferase gene-knockout [GTKO]) pig was the source of the graft. We hypothesized that the cience of Galα1,3Gal in GTKO pig livers may render pig hepatocytes similar to human and baboon hepatocytes in their response to hepatocellular injury. Reviewing the literature, after WT pig liver allotransplantation or xenotransplantation, in the majority of reports, although changes in AST were reported, no mention was made of changes in ALT, suggesting that there was no change in ALT. However, Ramirez et al. reported two cases of liver xenotransplants from hCD55 pigs, following which there were increases in both AST and ALT, suggesting that it is not simply the cience of expression of Galα1,3Gal that is the cause. We acknowledge that our observation is based on a small number of experiments, but we believe it is worth recording.

Up to 9-day survival and control of thrombocytopenia following alpha1,3-galactosyl transferase knockout swine liver xenotransplantation in baboons.

BACKGROUND: With standard miniature swine donors, survivals of only 3 days have been achieved in primate liver-transplant recipients. The recent production of alpha1,3-galactosyl transferase knockout (GalT-KO) miniature swine has made it possible to evaluate xenotransplantation of pig organs in clinically relevant pig-to-non-human primate models in the absence of the effects of natural anti-Gal antibodies. We are reporting our results using GalT-KO liver grafts. METHODS: We performed GalT-KO liver transplants in baboons using an immunosuppressive regimen previously used by our group in xeno heart and kidney transplantation. Post-operative liver function was assessed by laboratory function tests, coagulation parameters and histology. RESULTS: In two hepatectomized recipients of GalT-KO grafts, post-transplant liver function returned rapidly to normal. Over the first few days, the synthetic products of the donor swine graft appeared to replace those of the baboon. The first recipient survived for 6 days and showed no histopathological evidence of rejection at the time of death from uncontrolled bleeding, probably caused by transfusion-refractory thrombocytopenia. Amicar treatment of the second and third recipients led to maintenance of platelet counts of over 40 000 per µl throughout their 9- and 8-day survivals, which represents the longest reported survival of pig-to-primate liver transplants to date. Both of the last two animals nevertheless succumbed to bleeding and enterococcal infection, without evidence of rejection. CONCLUSIONS: These observations suggest that thrombocytopenia after liver xenotransplantation may be overcome by Amicar therapy. The coagulopathy and sepsis that nevertheless occurred suggest that additional causes of coagulation disturbance must be addressed, along with better prevention of infection, to achieve long-term survival.

Differences in human and porcine platelet oligosaccharides may influence phagocytosis by liver sinusoidal cells in vitro.

BACKGROUND: Acute thrombocytopenia was revealed as a limiting factor to porcine liver xenotransplantation from in vitro and in vivo studies using porcine liver in human and baboon transplant models. The asialoglycoprotein receptor 1 (ASGR1) on liver sinusoidal endothelial cells (LSEC) and macrophage antigen complex-1 (Mac-1) on Kupffer cells (KC) mediate platelet phagocytosis and have carbohydrate-binding sites that recognize galactose and N-acetyl glucosamine in the beta conformation. Analysis of these receptor carbohydrate-binding domains and surface carbohydrates on human and porcine platelets may shed light on the mechanism of xenotransplantation-induced thrombocytopenia. METHODS: An amino acid sequence comparison of human and porcine ASGR1 lectin-binding domains was performed. Using fluorescent labeled-lectins, human platelets, domestic and α1,3 galactosyltransferase knockout/human decay accelerating factor, porcine platelets were characterized by flow cytometry and lectin blot analyses. After desialylation, human and porcine platelets were examined by flow cytometry to determine whether sialic acid capping of galactose and N-acetyl glucosamine oligosaccharides in the beta conformation was a factor. Further, desialylated human platelets were studied on primary porcine liver sinusoidal cells with regard to binding and phagocytosis. RESULTS: Human platelets have four times more exposed galactose ß1-4 N-acetyl glucosamine (Galß) and N-acetyl glucosamine ß1-4 N-acetyl glucosamine (ßGlcNAc) than fresh porcine platelets. Galß and ßGlcNAc moieties on porcine platelets were not masked by sialic acid. Removal of sialic acid from human platelets increased binding and phagocytosis by LSEC and KC. CONCLUSIONS: Differences between human and porcine ASGR1 and Mac-1, in combination with a significantly higher number of galactose and N-acetyl glucosamine-containing oligosaccharides on human platelets contribute, in part, to platelet loss seen in porcine liver xenotransplantation.

A technique of recipient portal venoplasty and cuff insertion for portal revascularization in orthotopic rat liver transplantation.

BACKGROUND: In addition to suprahepatic vena cava anastomosis in two-cuff rat liver transplantation, recipient portal vein revascularization is one of the most difficult procedures that must be performed, especially for beginners. MATERIALS AND METHODS: A total of 43 cases of liver transplantation were performed. Rats in Group 1 and Group 2 were subjected to transplant procedures that used the conventional and portal venoplasty techniques, respectively. The portal vein anastomosis duration, anhepatic phase length, portal vein surgical complications, and 1 wk post-transplant survival rates were recorded for each group. RESULTS: The portal revascularization duration was statistically significantly less for Group 2 versus Group 1 (1.50 ± 0.61 min and 4.32 ± 0.67 min, respectively, P < 0.05). The anhepatic phase length of Groups 1 and 2 were 21.79 ± 1.27 min and 18.55 ± 1.47 min, respectively (P < 0.05). No significant differences between the groups were observed in relation to either portal vein surgery complications or 1-week survival rates. CONCLUSIONS: The recipient portal venoplasty and cuff insertion technique is a safe and fast alternative surgical option for portal revascularization in two-cuff rat liver transplantations performed by a single trainee.

Prolonged cold ischemia does not trigger lethal rejection or accelerate the acute rejection in two allogeneic rat liver transplantation models.

BACKGROUND: Prolonged cold ischemia (CI) might induce lethal liver graft rejection and/or accelerate the course of lethal rejection in BN-Lew and ACI-Lew liver transplantation (LT) models, which have been successfully challenged by liver-size reduction. MATERIALS AND METHODS: Survival rate of recipients and body weight development after subjecting the grafts to prolonged CI in saline were assessed. Severity of rejection was assessed based on histology and the size of portal infiltration. Hepatic expression of CD25, CD28, CD38, granzyme B, and perforin were assessed to further judge the severity of allogeneic immune response. RESULTS: An enhancement of allogeneic immune response after prolonged CI was observed, indicated by up-regulated mRNA expression of CD25, CD28, CD38, granzyme B, and perforin. However, the enhancement of allogeneic immune response did not reverse the BN-Lew spontaneous liver graft acceptance to lethal rejection. Eight-hour CI led to 100% 4 wk survival rate and graft acceptance and did not impair postoperative body weight recovery. Nine-hour CI caused the death of 2/6 rats due to primary non-function (PNF) of the graft within 48 h. Ten-hour CI caused lethal PNF in all rats within 96 h. Histology of surviving recipients revealed an expansion of the portal tract due to an inflammatory infiltrate. In rats dying from PNF, extended centrilobular necrosis was observed, but no sign of rejection. In the ACI-Lew full-size LT model, 8 h CI did not accelerate the course of lethal rejection. CONCLUSION: Prolonged CI was associated with an discrete enhancement of allogeneic immune response, but did not trigger lethal rejection in BN-LEW spontaneous liver graft acceptance model and did not accelerate acute rejection in ACI-Lew rejection model.

Tacrolimus preconditioning of rat liver allografts impacts glutathione homeostasis and early reperfusion injury.

OBJECTIVE: To characterize the immunosuppressant tacrolimus as a protective antioxidant in rat liver transplantation. METHODS: Livers of male Lewis rats underwent 24 h of hypothermic preservation in UW solution and were rinsed with tacrolimus or placebo directly before transplantation. Markers of liver injury, such as enzymes and bile flow, were determined during a 2 h reperfusion period. Concentrations of reduced (GSH) and oxidized (GSSG) glutathione were analyzed in plasma, bile, and liver tissue for estimation of oxidant stress caused by reactive oxygen species (ROS). RESULTS: Administration of tacrolimus (10 ng/mL) resulted in decreased ALT plasma levels (1740 ± 1169 U/l versus 3691 ± 1144 U/l; P < 0.05) at 2 h of reperfusion. While endogenous intracellular GSH concentrations remained unchanged, GSSG, the oxidation product of GSH, was markedly decreased at 2 h of reperfusion in preconditioned livers (47.0 ± 10.4 nm/g versus 71.8 ± 30.6 nm/g; P < 0.05). Correspondingly, GSSG bile concentrations (0.19 ± 0.04 mM versus 0.13 ± 0.04 mM; P < 0.05) as well as plasma GSSG levels (2.4 ± 0.3 mM versus 1.4 ± 0.2 mM; P < 0.05) were significantly increased upon reperfusion. These findings suggest that tacrolimus impacts post-ischemic GSH metabolism when administered as a rinse solution for liver allografts through an unknown pathway. CONCLUSION: Hepatocellular injury following transplantation was significantly decreased by preconditioning with tacrolimus. One possible mechanism of action is the detoxification of ROS through the preservation of cytosolic and extracellular GSH/GSSG ratios.

Suppressive effects of interleukin-18 on liver function in rat liver allografts.

BACKGROUND: Interleukin-18 (IL-18) is a potent proinflammatory cytokine that augments both innate and acquired immune responses. It is also a crucial regulator of lymphocyte production of interferon-γ (IFN-γ), which can promote acute cellular rejection of transplanted solid organs. METHODS: To evaluate the role of IL-18 in liver transplantation, we constructed an adenoviral vector encoding IL-18 binding protein (Adex-IL18bp), which specifically suppressed the biologic activity of IL-18, and examined the effect of this suppression on liver allografts by using a high-responder rat model (ACI to Lewis) of orthotopic liver transplantation (OLTx). Donor rats were given one intravenous injection of Adex-IL18bp or Adex-LacZ (control vector) 2 d before OLTx. RESULTS: Seven days after OLTx, overexpression of IL-18bp resulting from the adenovirus gene transfer was associated with significantly decreased serum alanine aminotransferase levels and less histologic hepatic injury in recipient rats with Adex-IL18bp-pretreated donors compared with Adex-LacZ controls. Adex-IL18bp pretreatment also significantly prolonged rat/allograft survival, inhibited expression of IFN-γ, and reduced levels (versus control values) of both CXCL10 and CX3CL1, which can be induced by IFN-γ. CONCLUSION: These results suggest that IL-18 has an important role in liver allograft rejection through IFN-γ and chemokines and that specific suppression of IL-18 may improve liver function early after transplantation.

The assessment of GFR after orthotopic liver transplantation using cystatin C and creatinine-based equations.

The measurement of kidney function after orthotopic liver transplantation (OLT) is still a clinical challenge. Cystatin C (CysC) has been proposed as a more accurate marker of renal function than serum creatinine (sCr). The aim of this study was to evaluate sCr- and CysC-based equations including the Chronic kidney disease (CKD)-EPI to determine renal function in liver transplant recipients. CysC and sCr were measured in 49 patients 24 months after OLT. The glomerular filtration rate (GFR) was calculated using the MDRD 4, the Cockroft-Gault, Hoek, Larsson, and the CKD-EPI equations based on sCr and/or CysC. As reference method, inulin clearance (IC) was estimated. Bias, precision, and accuracy of each equation were assessed and compared with respect to IC. Forty-five percent had a GFR < 60 ml/min/1.73 m(2) according to the IC. The Larsson, the Hoek and the CKD-EPI-CysC formula identified the highest percentage of patients with CKD correctly (88%, 88%, and 84%, respectively). The sCr-based equations showed less bias than CysC-based formulas with a similar precision. All CysC-based equations were superior as compared with sCr-based equations in the assessment of renal function in patients with an IC < 60 ml/min/1.73 m(2).

Grade of deceased donor liver macrovesicular steatosis impacts graft and recipient outcomes more than the Donor Risk Index.

BACKGROUND AND AIM: Donor liver steatosis can impact on liver allograft outcomes. The aim of the present study was to comprehensively report on the impact of type and grade of donor steatosis, as well as donor and recipient factors, including the reported Donor Risk Index (DRI), on liver allograft outcomes. METHODS: A review of unit data for all adult liver transplant procedures from 2001 to 2007, as well as donor offers. Donor liver biopsies were regraded for steatosis by an experienced histopathologist. RESULTS: Steatosis was detected in 184/255 (72%) of biopsies, of which 114 (62%) had microvesicular steatosis (MiS; 68 mild, 22 moderate, 24 severe) and 70 (38%) macrovesicular steatosis (MaS; 59 mild, 7 moderate, 4 severe). The majority (66/70, 94%) of biopsies with MaS also contained MiS. Allograft steatosis was associated with increasing donor body mass index (P = 0.000), plus donor male sex (P < 0.05). Primary non function (P = 0.002), early renal failure (P = 0.040), and requirement for retransplantation (P = 0.012) were associated only with severe MaS. Early biliary complications were associated with moderate MaS (P = 0.039). Only severe MaS was significantly associated with inferior allograft survival at 3 months (relative risk = 12.09 [8.75-19.05], P = 0.000) and 1 year (P = 0.000). CONCLUSIONS: MiS is a common finding and frequently coexists with MaS on liver allograft biopsy, while isolated MaS is uncommon. Only the presence of moderate to severe MaS is associated with inferior early allograft outcomes. The impact of severe MaS on allograft survival appears greater than other donor factors, including the calculated DRI.

Higher tacrolimus blood concentration is related to hyperlipidemia in living donor liver transplantation recipients.

BACKGROUND: The arrival of tacrolimus has drastically improved AALDLT recipients' survival. However, little data of tacrolimus have been reported concerning its effects on lipid metabolism for AALDLT recipients. AIM: Out aim was to investigate the relationship between tacrolimus blood concentration and lipid metabolism in AALDLT recipients. METHODS: The pre and postoperative data of 77 adult patients receiving AALDLT between 2002 and December 2007 were retrospectively reviewed. The postoperative immune suppressive regimen was prednisone with tacrolimus ± mycophenolate mofetil. Prednisone was withdrawn within the first postoperative month. Blood lipids and tacrolimus concentration were detected at the first, third, and sixth month during follow-up. Episodes of acute rejection were diagnosed based on biopsy. RESULTS: Overall prevalence of post-transplantation hyperlipidemia was 29.9% (23/77) at the sixth postoperative month. The patients were divided into two groups, the hyperlipidemia group and the ortholipidemia group. In the 23 patients with hyperlipidemia, 15 (65%) were hypercholesterolemia, five (22%) were hypertriglyceridemia, and three (13%) patients had both hypercholesterolemia and hypertriglyceridemia. In univariate analysis, only tacrolimus blood concentration at the third and sixth post-transplantation months showed significant difference (8.7 ± 2.1 vs. 6.9 ± 3.2, p = 0.013; 9.2 ± 2.7 vs. 7.3 ± 3.8, p = 0.038, respectively). In multivariate logistic analysis, only two factors appear to be risk factors, namely, tacrolimus blood concentration at the third and sixth post-transplantation months (8.7 ± 2.1 vs. 6.9 ± 3.2, p = 0.043; 9.2 ± 2.7 vs. 7.3 ± 3.8 p = 0.035, respectively). CONCLUSIONS: Higher tacrolimus blood concentration was related to hyperlipidemia at an early postoperative period. This indicates that tacrolimus blood concentration should be controlled as low as possible in the premise that there is no risk of rejection to minimize post-transplant hyperlipidemia after AALDLT.