Intrahepatic cholestasis after liver transplantation

Tacrolimus Monitoring in Liver Transplant Recipients, Posttransplant Cholestasis: A Comparative Between 2 Commercial Immunoassays and a Liquid Chromatography-Tandem Mass Spectrometry Method

BACKGROUND

Cholestasis commonly occurs after orthotopic liver transplantation. It can be extrahepatic because of mechanical obstruction or intrahepatic because of various causes. During cholestasis episodes, blood concentrations of tacrolimus (TAC) metabolites may increase, potentially affecting TAC concentrations measured by immunoassays. This study aimed to simultaneously evaluate the analytical performance of 2 TAC immunoassays, a quantitative microsphere system (QMS) immunoassay, and chemiluminescence microparticle immunoassay, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a reference method in liver transplant recipients.

METHODS

This single-center study included 265 patients who underwent orthotopic liver transplantation. In total, 942 blood samples were collected. TAC trough concentrations were measured using LC-MS/MS and 2 immunoassays in parallel. The plasma concentrations of conjugated bilirubin were measured in all samples. The results were analyzed using Bland-Altman plots and Passing-Bablok regressions.

RESULTS

The Bland-Altman plot analysis showed that the TAC QMS immunoassay has a significant bias (+37%) compared with LC-MS/MS, and this bias was higher in patients with cholestasis with hyperbilirubinemia (≤+70% in patients with conjugated bilirubin >150 µmol/L). In comparison, the chemiluminescence microparticle immunoassay showed acceptable analytical performance in patients with hyperbilirubinemia (bias <10%).

CONCLUSIONS

In agreement with previous findings, the TAC QMS immunoassay showed a positive bias compared with LC-MS/MS. This bias is remarkably high in patients with cholestasis and hyperbilirubinemia, suggesting the cross-reactivity of TAC metabolites with the monoclonal antibody used in the QMS immunoassay.

Systematic review: efficacy of therapies for cholestatic pruritus

Background

Pruritus is a symptom of several cholestatic liver diseases (CLDs) that can impair health-related quality of life (HRQoL). Despite evidence-based guideline therapy, managing cholestatic pruritus (CP) remains challenging, thus making the need for newer, more effective therapeutic agents more evident.

Objective

Our study evaluated the efficacy of existing CP therapies.

Design

Systematic review.

Data sources

From inception until March 2023, we conducted a comprehensive search of MEDLINE, Cochrane, EMBASE, Scopus, ClinicalTrial.gov, and other sources, including pharmaceutical webpages and conference proceedings published in English that reported on CP interventions.

Methods

Two reviewers independently conducted screening and full-text review of articles with extraction conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The methodological quality of studies included in our qualitative synthesis was assessed by using the Cochrane ROBINS-I and ROBINS-II tools for interventional studies and the National Heart, Lung, and Blood Institute Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. The primary outcome assessed in our systematic review was the severity of CP after therapy.

Results

Of 3293 screened articles, 92 studies were eligible for inclusion in the qualitative synthesis. Some patients' HRQoL improved with evidence-based standard therapy. Others, particularly those with severe and refractory CP, often required conversion to or addition of experimental noninvasive (e.g., ondansetron) or extracorporeal liver support to alleviate CP. In addition, studies investigating a newer class drug, the ileal bile acid transporter inhibitor (IBATi), demonstrate its effectiveness in reducing serum bile acid and alleviating CP with sustained improvement noted in patients with the inherited childhood cholestatic disorders - progressive familial intrahepatic cholestasis and Alagille syndrome.

Conclusion

Our findings consolidate data on the efficacy of guideline-based approaches and newer therapies for CP. While the initial findings are promising, additional clinical trials will be needed to determine the full extent of IBATi's efficacy and potential use in treating other common CLDs. These results provide a foundation for future research and highlight the need for continued investigation into the management and treatment of CLDs.

Clinical Significance of Plasma Tenascin-C Levels in Recipients With Prolonged Jaundice After Living Donor Liver Transplantation

BACKGROUND

Focusing on tenascin-C (TNC), whose expression is enhanced during the tissue remodeling process, the present study aimed to clarify whether plasma TNC levels after living donor liver transplantation (LDLT) could be a predictor of irreversible liver damage in the recipients with prolonged jaundice (PJ).

METHODS

Among 123 adult recipients who underwent LDLT between March 2002 and December 2016, the subjects were 79 recipients in whom we could measure plasma TNC levels preoperatively (pre-) and on postoperative days 1 to 14 (POD1 to POD14). Prolonged jaundice was defined as serum total bilirubin level >10 mg/dL on POD14, and 79 recipients were divided into 2 groups: 56 in the non-PJ (NJ) group and 23 in the PJ group.

RESULTS

The PJ group had significantly increased pre-TNC; smaller grafts; decreased platelet counts POD14; increased TB-POD1, -POD7, and -POD14; increased prothrombin time-international normalized ratio on POD7 and POD14; and higher 90-day mortality than the NJ group. As for the risk factors for 90-day mortality, multivariate analysis identified TNC-POD14 as a single significant independent prognostic factor (P = .015). The best cut-off value of TNC-POD14 for 90-day survival was determined to be 193.7 ng/mL. In the PJ group, the patients with low TNC-POD14 (<193.7 ng/mL) had satisfactory survival, with 100.0 % at 90 days, while the patients with high TNC-POD14 (≥193.7 ng/mL) had significantly poor survival, with 38.5 % at 90 days (P = .004).

CONCLUSIONS

In PJ after LDLT, plasma TNC-POD14 is very useful for diagnosing postoperative irreversible liver damage early.

Dysbiosis and Depletion of Fecal Organic Acids Correlate With the Severity of Rejection After Rat Liver Transplantation

The impact of T cell-mediated rejection (TCMR) after liver transplantation (LT) on the alterations in the gut microbiota (GM) and associated intestinal environment represented by fecal organic acids (OAs) require further elucidation. A rat allogeneic LT model was prepared without immunosuppressants or antibiotics, and a syngeneic model was used as a control. Qualitative and quantitative analyses of fecal samples at fixed time points were performed. Correlation analyses were also performed between liver function and GMs and OA levels. In the allogeneic TCMR group, the number of predominant obligate anaerobes decreased as liver function declined. Clostridioides difficile, Enterobacteriaceae, Enterococcus, Streptococcus, and Staphylococcus were significantly increased. Regarding fecal OA concentration, short-chain fatty acid (SCFA) concentrations were depleted as liver function declined. In contrast, in the syngeneic group, GM and OAs exhibited only slight, transient, and reversible disturbances. In addition, alanine aminotransferase and total bilirubin were positively correlated with the number of Enterobacteriaceae and Enterococcus, and negatively correlated with the fecal concentration of SCFAs. The allogeneic TCMR model demonstrated distinct dysbiosis and depletion of fecal OAs as TCMR progressed after LT. The degree of graft injury was closely related to the number of specific bacterial strains and the concentrations of fecal SCFAs.

Incidence of Cholangitis and Sepsis Associated with Percutaneous Transhepatic Cholangiography in Pediatric Liver Transplant Recipients

Background. Percutaneous transhepatic cholangiography (PTC) is an established treatment in the management of biliary strictures. The aim of our study was to determine the incidence of PTC-related infectious complications in transplanted children, and identify their precise aetiol-ogy. Methods. We retrospectively reviewed all PTC performed from January 2017 to October 2020 in our center. Before the procedure, all patients received antibiotic prophylaxis defined as first line, while second line was used in case of previously microbiological isolation. Cholangitis was defined as fever (>38.5°) and elevated inflammatory markers after PTC, while sepsis included hemodynamic instability in addition to cholangitis. Results. One hundred and fifty-seven PTCs from 50 pediatric recipients were included. The overall incidence of cholangitis and sepsis after PTC was 44.6% (70/157) and 3.2% (5/157), respectively, with no fatal events. Blood cultures yielded positive results in 15/70 cases (21.4%). Enterococcus faecium and Pseudomonas aeruginosa were the most common isolated pathogens. Multidrug-resistant (MDR) pathogens were found in 11/50 patients (22%). Conclusion. PTC is associated with a relatively high rate of post-procedural cholangitis, although with low rate of sepsis and no fatal events. Blood cultures allowed to find a precise aetiology in roughly a quarter of the cases, showing prevalence of Enterococcus faecium and Pseudomonas aeruginosa.

Preliminary clinical experience applying donor-derived cell-free DNA to discern rejection in pediatric liver transplant recipients

Donor-derived cell-free DNA (dd-cfDNA) has been of major interest recently as a non-invasive marker of graft injury, but has not yet been extensively tested in children. From May to September in 2019, a total of 76 pediatric patients receiving a liver graft were enrolled and there were 27 patients excluded. Ultimately plasma samples and matched liver specimens from 49 patients were successfully collected whenever rejection was suspected clinically. Dd-cfDNA were analyzed and then compared to biopsy. Of these, 11 (22.4%) patients were found to have rejection by biopsy. Dd-cfDNA levels were higher among patients with rejection compared to those with no rejection. In subgroup analysis, dd-cfDNA% among patients with rejection differed from those with EBV/CMV infection and DILI patients. Similarly, observations were available concerning dd-cfDNA (cp/mL). The AUC for dd-cfDNA% and dd-cfDNA (cp/mL) were 0.878, 0.841, respectively, both of which were higher than conventional LFTs. For rejection, dd-cfDNA% ≥ 28.7% yielded a sensitivity of 72.7%, specificity 94.7% and dd-cfDNA (cp/mL) ≥ 2076 cp/mL, yielded a sensitivity of 81.8%, specificity 81.9%. Of note, the dd-cfDNA distribution was significantly different between whole liver and LLS transplantation. In the setting of pediatric LTx, dd-cfDNA appears to be a sensitive biomarker indicating the presence of rejection.International Clinical Trails Registry Platform: ChiCTR1900022406.

Subclinical biliary strictures as a cause of long-term allograft dysfunction in children who underwent liver transplantation

We aimed to evaluate the role of liver biopsy to predict subclinical biliary strictures (BS) and assess the impact of BS on long-term allograft dysfunction following liver transplantation in children (LT). We reviewed all liver biopsies performed from 2012-2018. Percutaneous transhepatic cholangiography (PTC) was performed in patients presenting cholangiolar proliferation on cytokeratin-7 stained sections. We performed 271 biopsies in 161 children (86% with a left lateral segment); 44/161 (27%) presented with diffuse or multifocal cholangiolar proliferation. Among them, a tight BS was confirmed in 38/44 (86%, 24% of total) and it was managed by balloon dilatation. Cholangiolar proliferation showed a positive predictive value (PPV) for BS of 86.4%. Levels of alkaline phosphatase >325 IU/L predicted BS (P = .007). Dilatation of intrahepatic bile ducts on ultrasound was found only in 44% of patients with BS. Following a median follow-up of 9.2 years, only 15/38 (39%) patients resolved the BS. In conclusion subclinical BS is very common and probably underdiagnosed in these patients. Histological evidence of cholangiolar proliferation detectable by cytokeratin-7 immunostain should be preferred to liver function tests and ultrasound to suspect BS. BS in this setting should be regarded as a main cause of long-term allograft dysfunction.

Cholangitis lenta: An underdiagnosed lesion associated with severe cholestasis following liver transplantation

BACKGROUND

Cholangitis lenta (CL) represents a specific histological lesion associated with severe cholestasis and related to sepsis. Despite being well known by pathologists, CL has been poorly studied in liver transplantation (LT).

METHODS

We performed a retrospective 12-year analysis of the incidence, risk factors, and outcome of CL in LT recipients. Biopsy samples performed within 3 months after LT underwent blinded rereading to identify recipients with CL.

RESULTS

Among 587 LT performed, 45 (7.7%) developed CL. Of these, 7 (15.6%) had no signs of clinical sepsis at the time of biopsy, but further investigations revealed positive cultures. Independent factors associated with CL were sepsis at the time of LT (OR = 3.62 [95%CI = 1.63-8.06]), donor age (OR = 1.05 [1.03-1.08]), and operative time (OR = 1.23 [95%CI = 1.02-1.48]). Cholangitis lenta was associated with increased severe morbidity (71.1% vs 33.0%, P < .001), 90-day mortality (24.4% vs 5.9%, P < .001) and decreased one-year graft (62.1% vs 89.4%, P < .001) and patient survival (55.6% vs 87.9%, P < .001).

CONCLUSION

Cholangitis lenta represents a possible lesion associated with cholestasis after LT, which strongly affects its outcome. In the event of an unexplained post-transplant cholestasis, the diagnosis of CL must be considered, even in the absence of clinically evident sepsis.

Pharmacokinetics of Dexmedetomidine in Infants and Children After Orthotopic Liver Transplantation

BACKGROUND

Dexmedetomidine (DEX) is a sedative and analgesic medication that is frequently used postoperatively in children after liver transplantation. Hepatic dysfunction, including alterations in drug clearance, is common immediately after liver transplantation. However, the pharmacokinetics (PK) of DEX in this population is unknown. The objective of this study was to determine the PK profile of DEX in children after liver transplantation.

METHODS

This was a single-center, open-label PK study of DEX administered as an intravenous loading dose of 0.5 μg/kg followed by a continuous infusion of 0.5 μg/kg/h. Twenty subjects, 1 month to 18 years of age, who were admitted to the pediatric intensive care unit after liver transplantation were enrolled. Whole blood was collected and analyzed for DEX concentration using a dried blood spot method. Nonlinear mixed-effects modeling was used to characterize the population PK of DEX.

RESULTS

DEX PK was best described by a 2-compartment model with first-order elimination. A typical child after liver transplantation with an international normalized ratio (INR) of 1.8 was found to have a whole blood DEX clearance of 52 L/h (95% confidence interval [CI], 31-73 L/h). In addition, intercompartmental clearance was 246 L/h (95% CI, 139-391 L/h), central volume of distribution was 186 L/70 kg (95% CI, 140-301 L/70 kg), and peripheral volume of distribution was 203 L (95% CI, 123-338 L). Interindividual variability ranged from 11% to 111% for all parameters. Clearance was not found to be associated with weight but was found to be inversely proportional to INR. An increase in INR to 3.2 resulted in a 50% decrease in DEX clearance. Weight was linearly correlated with central volume of distribution. All other covariates, including age, ischemic time, total bilirubin, and alanine aminotransferase, were not found to be significant predictors of DEX disposition.

CONCLUSIONS

Children who received DEX after liver transplantation have large variability in clearance, which was not found to be associated with weight but is influenced by underlying liver function, as reflected by INR. In this population, titration of DEX dosing to clinical effect may be important because weight-based dosing is poorly associated with blood concentrations. More attention to quality of DEX sedation may be warranted when INR values are changing.

Dual Role of Bile Acids on the Biliary Epithelium: Friend or Foe?

Bile acids are a family of amphipathic compounds predominantly known for their role in solubilizing and absorbing hydrophobic compounds (including liposoluble vitamins) in the intestine. Bile acids also are key signaling molecules and inflammatory agents that activate transcriptional factors and cell signaling pathways that regulate lipid, glucose, and energy metabolism in various human disorders, including chronic liver diseases. However, in the last decade increased awareness has been founded on the physiological and chemical heterogeneity of this category of compounds and their possible beneficial or injurious effects on the biliary tree. In this review, we provide an update on the current understanding of the molecular mechanism involving bile acid and biliary epithelium. The last achievements of the research in this field are summarized, focusing on the molecular aspects and the elements with relevance regarding human liver diseases.

Proteomic Analysis of Liver Preservation Solutions Prior to Liver Transplantation

Material/Methods:

Samples were collected from the pre-transplant preservation mediums of 23 liver donors. For all donors, the cases involved Donation after Brain Death (DBD). 2D-PAGE and LCMSMS methodologies were used to detect the proteins and peptides from the preservation mediums.

Results:

A total of 198 proteins originating from the liver were detected.

Conclusion:

The data provide valuable insights into biomarkers that may be used to evaluate organ injury, functional status, and suitability for transplantation. Additionally, the findings could be valuable for the development of new strategies for effective preservation of solid organs prior to transplantation.

Graft Dysfunction and Management in Liver Transplantation

Graft dysfunction of the liver allograft manifests across a spectrum in both timing posttransplantation and clinical presentation. This can range from mild transient abnormalities of liver tests to acute liver failure potentially leading to graft failure. The causes of graft dysfunction can be divided into those resulting in early and late graft dysfunction. Although nonspecific, liver biochemistry abnormalities are still the mainstay investigation used in monitoring for dysfunction. This article provides a summary of the main causes and management strategies for liver graft dysfunction in the early through late posttransplant stages.

Anti-inflammatory consequences of bile acid accumulation in virus-infected bile duct ligated mice

Cholestatic patients exhibiting high bile acid serum levels were reported to be more susceptible to bacterial and viral infections. Animal studies in bile duct ligated (BDL) mice suggest that cholestasis leads to an aggravation of hepatic bacterial infections. We have investigated the impact of cholestasis on mouse cytomegalovirus (MCMV)-induced immune responses and viral replication. While MCMV did not aggravate BDL-induced liver damage, BDL markedly reduced MCMV-triggered chemokine expression and immune cell recruitment to the liver. MCMV-infected BDL mice showed diminished trafficking of Ly6C+/F4/80+ myeloid cells and NK1.1+ NK cells to the liver compared to MCMV infected control mice. Moreover, virus-driven expression of CCL7, CCL12, CXCL9 and CXCL10 was clearly impaired in BDL- compared to sham-operated mice. Furthermore, production of the anti-inflammatory cytokine IL-10 was massively augmented in infected BDL mice. In contrast, intra- and extrahepatic virus replication was unaltered in BDL-MCMV mice when compared to sham-MCMV mice. Cholestasis in the BDL model severely impaired pathogen-induced chemokine expression in the liver affecting CCR2- and CXCR3-dependent cell trafficking. Cholestasis resulted in reduced recruitment of inflammatory monocytes and NK cells to the liver.

Liver allograft biopsies with histological cholestasis: a clinicopathological study of 254 cases from a single centre

AIMS

Liver allograft biopsy is important in the management of liver transplant (LT) recipients. Cholestasis is an indicator of liver dysfunction, and histological evidence of cholestasis can be observed in a wide range of pathological entities in the post-LT setting. In this study, we describe the clinicopathological features and significance of liver allograft biopsies with histological cholestasis over 11 years in our centre.

METHODS

Liver allograft biopsies performed in Queen Mary Hospital, Hong Kong from 2004 to 2014 showing histological cholestasis were retrieved from the pathology archive. Clinical and pathological data were retrospectively reviewed and analyzed.

RESULTS

Among the 254 biopsies from 167 patients, large duct obstruction (LDO) and acute cellular rejection (ACR) were the two main aetiologies associated with cholestasis. There was a decrease in sepsis as a cause over the study duration. In cases showing cholestasis at 6 months or more after LT, LDO was more common than ACR. Over half (61%) of the 254 biopsies showed mild cholestasis. Severe panacinar cholestasis was more often observed in LDO. Mild cholestasis was most commonly observed regardless of the severity of ACR. Severe cholestasis was associated with poorer 1-year and 3-year graft survival and patient survival, as well as higher 3-month and 6-month post-biopsy mortality.

CONCLUSION

Histological cholestasis and its severity in liver allograft biopsies has clinical and prognostic significance. Our study summarizes our previous experience and provides further insights into the management of post-LT patients.

Liver Graft Susceptibility during Static Cold Storage and Dynamic Machine Perfusion: DCD versus Fatty Livers

We compared static preservation (cold storage, CS, 4 °C) with dynamic preservation (machine perfusion, MP, 20 °C) followed by reperfusion using marginal livers: a model of donation after cardiac death (DCD) livers and two models of fatty livers, the methionine-choline deficient (MCD) diet model, and obese Zucker (fa/fa) rats. CS injury in DCD livers was reversed by an oxygenated washout (OW): hepatic damage, bile flow, and the ATP/ADP ratio in the OW + CS group was comparable with the ratio obtained with MP. Using fatty livers, CS preservation induced a marked release in hepatic and biliary enzymes in obese Zucker rats when compared with the MCD group. The same trend occurred for bile flow. No difference was found when comparing MP in MCD and obese Zucker rats. Fatty acid analysis demonstrated that the total saturated (SFA)/polyunsaturated fatty acid (PUFA) ratio was, respectively, 1.5 and 0.71 in obese Zucker and MCD rats. While preservation damage in DCD livers is associated with the ATP/ADP recovered with OW, injury in fatty livers is linked to fatty acid constituents: livers from obese. Zucker rats, with greater content in saturated FA, might be more prone to CS injury. On the contrary, MCD livers with elevated PUFA content might be less susceptible to hypothermia.

Cholesterol metabolism in cholestatic liver disease and liver transplantation: From molecular mechanisms to clinical implications

The aim of this review is to enlighten the critical roles that the liver plays in cholesterol metabolism. Liver transplantation can serve as gene therapy or a source of gene transmission in certain conditions that affect cholesterol metabolism, such as low-density-lipoprotein (LDL) receptor gene mutations that are associated with familial hypercholesterolemia. On the other hand, cholestatic liver disease often alters cholesterol metabolism. Cholestasis can lead to formation of lipoprotein X (Lp-X), which is frequently mistaken for LDL on routine clinical tests. In contrast to LDL, Lp-X is non-atherogenic, and failure to differentiate between the two can interfere with cardiovascular risk assessment, potentially leading to prescription of futile lipid-lowering therapy. Statins do not effectively lower Lp-X levels, and cholestasis may lead to accumulation of toxic levels of statins. Moreover, severe cholestasis results in poor micellar formation, which reduces cholesterol absorption, potentially impairing the cholesterol-lowering effect of ezetimibe. Apolipoprotein B-100 measurement can help distinguish between atherogenic and non-atherogenic hypercholesterolemia. Furthermore, routine serum cholesterol measurements alone cannot reflect cholesterol absorption and synthesis. Measurements of serum non-cholesterol sterol biomarkers - such as cholesterol precursor sterols, plant sterols, and cholestanol - may help with the comprehensive assessment of cholesterol metabolism. An adequate cholesterol supply is essential for liver-regenerative capacity. Low preoperative and perioperative serum cholesterol levels seem to predict mortality in liver cirrhosis and after liver transplantation. Thus, accurate lipid profile evaluation is highly important in liver disease and after liver transplantation.

Role of matrix metalloproteinases in cholestasis and hepatic ischemia/reperfusion injury: A review

Matrix metalloproteinases (MMPs) are a family of proteases using zinc-dependent catalysis to break down extracellular matrix (ECM) components, allowing cell movement and tissue reorganization. Like many other proteases, MMPs are produced as zymogens, an inactive form, which are activated after their release from cells. Hepatic ischemia/reperfusion (I/R) is associated with MMP activation and release, with profound effects on tissue integrity: their inappropriate, prolonged or excessive expression has harmful consequences for the liver. Kupffer cells and hepatic stellate cells can secrete MMPs though sinusoidal endothelial cells are a further source of MMPs. After liver transplantation, biliary complications are mainly attributable to cholangiocytes, which, compared with hepatocytes, are particularly susceptible to injury and ultimately a major cause of increased graft dysfunction and patient morbidity. This paper focuses on liver I/R injury and cholestasis and reviews factors and mechanisms involved in MMP activation together with synthetic compounds used in their regulation. In this respect, recent data have demonstrated that the role of MMPs during I/R may go beyond the mere destruction of the ECM and may be much more complex than previously thought. We thus discuss the role of MMPs as an important factor in cholestasis associated with I/R injury.

Clinical significance of donor-specific human leukocyte antigen antibodies in liver transplantation

Antibody-mediated rejection (AMR) caused by donor-specific anti-human leukocyte antigen antibodies (DSA) is widely accepted to be a risk factor for decreased graft survival after kidney transplantation. This entity also plays a pathogenic role in other solid organ transplants as it appears to be an increasingly common cause of heart graft dysfunction and an emerging issue in lung transplantation. In contrast, the liver appears relatively resistant to DSA-mediated injury. This “immune-tolerance” liver property has been sustained by a low rate of liver graft loss in patients with preformed DSA and by the intrinsic liver characteristics that favor the absorption and elimination of DSA; however, alloantibody-mediated adverse consequences are increasingly being recognized, and several cases of acute AMR after ABO-compatible liver transplant (LT) have been reported. Furthermore, the availability of new solid-phase assays, allowing the detection of low titers of DSA and the refinement of objective diagnostic criteria for AMR in solid organ transplants and particularly in LT, have improved the recognition and management of this entity. A cost-effective strategy of DSA monitoring, avoidance of class II human leukocyte antigen mismatching, judicious immunosuppression attached to a higher level of clinical suspicion of AMR, particularly in cases unresponsive to conventional anti-rejection therapy, can allow a rational approach to this threat.

Liver transplantation with a strongly positive crossmatch: case study and literature review

A positive crossmatch has been associated with increased risk in liver transplantation. To study the clinical significance of preformed donor-specific human leukocyte antigen antibodies (DSAs) in liver transplantation, we reviewed patients who underwent liver transplantation with a strongly positive flow cytometry crossmatch. DSAs were evaluated with a Luminex solid phase assay. The complement-fixing ability of DSAs was tested with a complement component 1q (C1q) assay. Using an assay correlation between complement-dependent cytotoxicity crossmatch, flow cytometry crossmatch, and DSA results, we reviewed the effects of DSAs on the outcomes of our patients as well as reported cases in the literature. Five of 69 liver recipients had a strongly positive crossmatch: 4 had a positive T cell crossmatch [median channel shift (MCS) = 383.5 ± 38.9], and 5 had a positive B cell crossmatch (MCS = 408.8 ± 52.3). The DSAs were class I only in 1 patient, class I and II in 3 patients, and class II only in 1 patient. Cholestasis, acute rejection, or both were observed in 3 of the 4 patients with a positive T cell crossmatch with an MCS approximately greater than 300. The C1q assay was positive for 3 patients. Two had either persistent cholestasis or early acute rejection. One patient who was treated with preemptive intravenous immunoglobulin had an unremarkable outcome despite a positive C1q result. One of the 2 patients with a negative C1q assay experienced persistent cholestasis and early and recurrent acute rejection; the other had an unremarkable outcome. None of the patients died or lost a graft within the first year of transplantation. Our study suggests that human leukocyte antigen antibody screening, flow cytometry crossmatch MCS levels, DSA mean fluorescent intensity levels, and C1q assays may be useful in assessing the risk of antibody-mediated rejection and timely interventions in liver transplantation.

Frequency, clinical presentation, and outcomes of drug-induced liver injury after liver transplantation

Drug-induced liver injury (DILI) is increasingly being recognized as a common cause of acute hepatitis. The clinical impact of DILI after liver transplantation (LT) is not known. The aim of this study was to describe the frequency, clinical presentation, and outcomes of DILI in LT recipients. LT recipients with possible DILI were identified with electronic pathology records and clinical note database retrieval tools. Diagnostic criteria were applied to identify cases of DILI. Twenty-nine of 1689 LT recipients (1.7%) were identified with DILI. The mean age was 52 years, and 52% were women. The major indications for LT were primary sclerosing cholangitis (28%), cholangiocarcinoma (14%), and hepatocellular carcinoma (14%). The severity of DILI was mild or moderate in 92% of the cases. Nausea or diarrhea (31%), jaundice (24%), and pruritus (10%) were the most common symptoms at the time of diagnosis. The mean biochemistry values were as follows: alanine aminotransferase, 204 ± 263 U/L; aspartate aminotransferase, 108 ± 237 U/L; alkaline phosphatase, 469 ± 689 U/L; and total bilirubin, 1.9 ± 10.3 mg/dL. The median duration of medication use until the diagnosis of DILI was 57 days, and the major agent classes were antibiotics (48%), immunosuppressive agents (14%), and antihyperlipidemic drugs (7%). Trimethoprim-sulfamethoxazole was the most common implicated agent (n = 11). Serum liver enzymes improved within a median time of 34 days (range = 5-246 days) after drug withdrawal. Hepatic retransplantation or death did not occur. Among the 50 cases with possible DILI explained by other causes, 13 individuals (26%) had no alternative diagnosis despite histological findings compatible with DILI. In conclusion, DILI is a rare yet underrecognized event among LT recipients. The majority of cases are not clinically severe, and they resolve after drug cessation without hepatic retransplantation or death.

Ischemia-Reperfusion Injury and Ischemic-Type Biliary Lesions following Liver Transplantation

Ischemia-reperfusion (I-R) injury after liver transplantation (LT) induces intra- and/or extrahepatic nonanastomotic ischemic-type biliary lesions (ITBLs). Subsequent bile duct stricture is a significant cause of morbidity and even mortality in patients who underwent LT. Although the pathogenesis of ITBLs is multifactorial, there are three main interconnected mechanisms responsible for their formation: cold and warm I-R injury, injury induced by cytotoxic bile salts, and immunological-mediated injury. Cold and warm ischemic insult can induce direct injury to the cholangiocytes and/or damage to the arterioles of the peribiliary vascular plexus, which in turn leads to apoptosis and necrosis of the cholangiocytes. Liver grafts from suboptimal or extended-criteria donors are more susceptible to cold and warm I-R injury and develop more easily ITBLs than normal livers. This paper, focusing on liver I-R injury, reviews the risk factors and mechanisms leading to ITBLs following LT.

A combination of ischemic preconditioning and allopurinol protects against ischemic injury through a nitric oxide-dependent mechanism

This study examined the cytoprotective mechanisms of a combination of ischemic preconditioning (IPC) and allopurinol against liver injury caused by ischemia/reperfusion (I/R). Allopurinol (50mg/kg) was intraperitoneally administered 18 and 1h before sustained ischemia. A rat liver was preconditioned by 10 min of ischemia, followed by 10 min of reperfusion, and then subjected to 90 min of ischemia, followed by 5h of reperfusion. Rats were pretreated with adenosine deaminase (ADA), 3,7-dimethyl-1-[2-propargyl]-xanthine (DMPX), and N-nitro-l-arginine methyl ester (l-NAME) before IPC. Hepatic nitrite and nitrate and eNOS protein expression levels were increased by the combination of IPC and allopurinol. This increase was attenuated by ADA, DMPX, and l-NAME. I/R induced an increase in alanine aminotransferase activity, whereas it decreased the hepatic glutathione level. A combination of IPC and allopurinol attenuated these changes, which were abolished by ADA, DMPX, and l-NAME. The increase in the liver wet weight-to-dry weight ratio after I/R was attenuated by the combination of IPC and allopurinol. In contrast, hepatic bile flow was decreased after I/R, which was attenuated by the combination of IPC and allopurinol. These changes were restored by l-NAME. I/R induced a decrease in the level of mitochondrial dehydrogenase, whereas it increased mitochondrial swelling. A combination of IPC and allopurinol attenuated these changes, which were restored by ADA, DMPX, and l-NAME. Our findings suggest that a combination of IPC and allopurinol reduces post-ischemic hepatic injury by enhancing NO generation.

Incidence and risk factors for the development of prolonged severe intrahepatic cholestasis after pediatric living-donor liver transplantation

The aim of this study is to evaluate the incidence, etiology, and risk facrors for prolonged severe intrahepatic cholestasis (PSIC) after 129 pediatric living-donor liver transplantations (LDLT). The incidence of PSIC was 25.6% (n = 33). Twenty-eight (84.8%) versus 5 (15.2%) children experienced early versus late PSIC, respectively. Among these 33 children with PSIC, 8 (24.2%) received a donor liver with mild to moderate fatty change, 4 (12.1%) with low graft-body weight ratios, and 4 (12.1%) with ABO incompatibility. The predominant etiologies were acute rejection (n = 15; 45.5%), chronic rejection (n = 6; 18.2%), virus (n = 3; 9.1%), vascular complications (n = 4; 12.1%), and initial graft dysfunction (n = 10; 30.3%). ABO incompatibility (P = .032; odds ratio [OR] 3.25), chronic rejection (P = .012; OR 4.76), and vascular complications (P = .046; OR 1.82) were significant variables associated with PSIC. Donor selection with ABO compatibility as well as early detection and management of chronic rejection and vascular complications may be important to prevet PSIC in LDLT.

Taurocholic acid prevents biliary damage induced by hepatic artery ligation in cholestatic rats

BACKGROUND

Ischemic injury by hepatic artery ligation (HAL) during obstructive cholestasis induced by bile duct ligation (BDL) results in bile duct damage, which can be prevented by administration of VEGF-A. The potential regulation of VEGF and VEGF receptor expression and secretion by bile acids in BDL with HAL is unknown.

AIMS

We evaluated whether taurocholic acid (TC) can prevent HAL-induced cholangiocyte damage via the alteration of VEGFR-2 and/or VEGF-A expression.

METHODS

Utilizing BDL, BDL+TC, BDL+HAL, BDL+HAL+TC, and BDL+HAL+wortmannin+TC treated rats, we evaluated cholangiocyte apoptosis, proliferation, and secretion as well VEGF-A and VEGFR-2 expression by immunohistochemistry. In vitro, we evaluated the effects of TC on cholangiocyte secretion of VEGF-A and the dependence of TC-induced proliferation on the activity of VEGFR-2.

RESULTS

In BDL rats with HAL, chronic feeding of TC prevented HAL-induced loss of bile ducts and HAL-induced decreased cholangiocyte secretion. TC also prevented HAL-inhibited VEGF-A and VEGFR-2 expression in liver sections and HAL-induced circulating VEGF-A levels, which were blocked by wortmannin administration. In vitro, TC stimulated increased VEGF-A secretion by cholangiocytes, which was blocked by wortmannin and stimulated cholangiocyte proliferation that was blocked by VEGFR-2 kinase inhibitor.

CONCLUSION

TC prevented HAL-induced biliary damage by upregulation of VEGF-A expression.

Intermittent ischaemia maintains function after ischaemia reperfusion in steatotic livers

BACKGROUND

Ischaemic preconditioning (IPC) and intermittent ischaemia (INT) reduce liver injury after ischaemia reperfusion (IR). Steatotic livers are at a higher risk of IR injury, but the protection offered by IPC and INT is not well understood. The aim of the present study was to determine the effectiveness of IPC and INT in maintaining liver function in steatotic livers.

MATERIAL AND METHODS

A model of segmental hepatic ischaemia (45 min) and reperfusion (60 min) was employed using lean and obese Zucker rats. Bile flow recovery was measured to assess dynamic liver function, hepatocyte fat content quantified and blood electrolytes, metabolites and bile calcium measured to assess liver and whole body physiology. Liver marker enzymes and light and electron microscopy were employed to assess hepatocyte injury.

RESULTS

IPC was not effective in promoting bile flow recovery after IR in either lean or steatotic livers, whereas INT promoted good bile flow recovery in steatotic as well as lean livers. However, the bile flow recovery in steatotic livers was less than that in lean livers. In steatotic livers, ischaemia led to a rapid and substantial decrease in fat content. Steatotic livers were more susceptible to IR injury than lean livers, as indicated by increased blood ALT concentrations and major histological injury.

CONCLUSION

INT is more effective than IPC in restoring liver function in the acute phase of IR in steatotic livers. In obese patients, INT may be useful in promoting better liver function after IR after liver resection.

Ischemic preconditioning protects the pig liver by preserving the mitochondrial structure and downregulating caspase-3 activity

BACKGROUND DATA

The beneficial effects of ischemic preconditioning (IPC) on hepatic ischemia-reperfusion injury (I/RI) have been described. However, the way in which IPC causes the changes in mitochondrial ultrastructure seen in hepatic I/RI is not well understood.

OBJECTIVE

The objective of the present study was to determine whether IPC protects the liver from changes in mitochondrial structure and caspase 3 activity in the early phase of post-ischemic injury.

METHODS

A pig model consisting of 90 min of hepatic ischemia and 180 min of reperfusion was employed. Eighteen female pigs were randomly divided into three groups: sham-operated, non-preconditioned, and ischemic preconditioned (10 min ischemia followed by 10 min reperfusion). Serum concentrations of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and thiobarbituric acid reactive substances (TBARS), as well as bile flow, were measured. Liver biopsies were taken after reperfusion for histological, immunohistochemical (anti-caspase 3), and ultrastructural examinations.

RESULTS

The IPC procedure increased bile flow (p < 0.01), reduced serum AST level (p < 0.01), and reduced serum concentration of TBARS at 180 min of reperfusion (p = 0.05). Ischemic-preconditioned liver cells had less caspase 3 activity than the non-preconditioning group (p < 0.01), and changes in mitochondrial ultrastructure were reduced (p < 0.01).

CONCLUSION

IPC exerts a powerful protective effect against hepatic I/RI in the early phase of reperfusion, which may be mediated by preservation of mitochondrial structure and inhibition of caspase-3 activity.

Chemokine Receptor-5Delta32 Mutation is No Risk Factor for Ischemic-Type Biliary Lesion in Liver Transplantation

It has been shown that certain chemokine receptor polymorphisms may correspond to certain complications after organ transplantation. Ischemic-type biliary lesion (ITBL) encounters for major morbidity and mortality in liver transplant recipients. So far, the exact cause for ITBL remains unclear. Certain risk factors for the development of ITBL like donor age and cold ischemic time are well described. In a previous study, a 32-nucleotide deletion of the chemokine receptor-5Δ32 (CCR-5Δ32) was strongly associated with the incidence of ITBL in adult liver transplantation. This study re-evaluates the association of CCR-5Δ32 gene polymorphism and the incidence of ITBL. 169 patients were included into this retrospective analysis. 134 patients were homozygous for wild-type CCR-5, 33 patients heterozygous, and 2 patients were homozygous for CCR-5Δ32 mutation. There were no major differences in donor or recipients demographics. No association was found between CCR-5Δ32 mutation and the development of ITBL. We conclude that CCR-5Δ32 is no risk factor for the development of ITBL in our patient cohort.

Biliary complications after liver transplantation from maastricht category-2 non-heart-beating donors

BACKGROUND

There are unresolved issues regarding the security of liver transplantation with non-heart-beating donors (NHBDs). Recently, an increased incidence of biliary complications, mainly intrahepatic ischemic-type biliary strictures, has been described after controlled NHBDs.

METHODS

We studied the incidence and risk factors for biliary complications among uncontrolled NHBDs recipients compared with a large population of HBD recipients.

RESULTS

Overall, 16.8% of patients in the HBD group and 41.7% of patients in the NHBD group suffered any type of biliary complication (P=0.66). However, the incidence of nonanastomotic biliary strictures was significantly greater in the NHBD group (P<0.001). Multivariate analysis showed that independent risk factors for nonanastomotic strictures were hepatic artery thrombosis (relative risk; 98.7) and receiving a liver from a NHBD (relative risk; 47.1).

CONCLUSIONS

If this type of donors is accepted as a source of liver organs, the high incidence of biliary complications should be considered and efforts should be made to decrease ischemic injury.

Intrahepatic cholestasis after liver transplantation

Biochemical cholestasis after liver transplantation is common and often has no clinical significance if biliary anastomosis strictures and leaks have been excluded. There is no agreed upon definition for severe cholestasis, but it is associated with a worse mortality. There has been little evaluation on risk factors, but these include cryoprecipitate and platelet transfusion intraoperatively, nonidentical blood group, suboptimal graft appearance, inpatient status before transplant, and bacteremia within the first month. Associated causes considered as early (<6 months) include ischemia-reperfusion injury, primary nonfunction, small-for-size graft syndrome, infection, drugs and acute cellular rejection. Late causes include hepatic artery thrombosis, chronic rejection, biliary complications, recurrent viral and cholestatic disease, and posttransplant lymphoproliferative disorder.

Ischemic preconditioning and intermittent ischemia preserve bile flow in a rat model of ischemia/reperfusion injury

Ischemia and reperfusion (IR) injury of the liver is associated with impaired bile secretion, but the effects of ischemic preconditioning (IPC) and intermittent ischemia (INT) on bile flow are unknown. A rat model of segmental (60%-70%) hepatic ischemia and reperfusion was employed to test the effects of IPC and INT on bile flow. Continuous clamping for 45 min (CC) substantially reduced bile flow, and this did not recover after 60 min of reperfusion. IPC and INT caused a significant recovery of bile flow. The elevation in plasma liver marker enzymes induced by CC was not reduced by IPC and INT. Light microscopy showed mild hepatocyte damage in all groups. In the CC group, the amount of F-actin localized around the bile canaliculi in the ischemic lobes was less than that in the nonischemic lobes, but this difference was not observed in the IPC and INT groups. It is concluded that IPC and INT substantially alleviate the decrease in bile flow induced by ischemia. Bile flow may be useful in the assessment of IR injury.

Ischemia-reperfusion of rat livers decreases liver and increases kidney multidrug resistance associated protein 2 (Mrp2)

Hepatic ischemia-reperfusion (IR) injury during liver transplantation can lead to cholestasis and remote organ dysfunction. Multidrug resistance-associated proteins (Mrps) are efflux transporters known to transport a diverse set of substrates, such as amphipathic chemicals, organic anions, and endogenous molecules. The purpose of this study was to determine the effect of hepatic IR injury on the expression of Mrps in rat liver and kidney. Male Sprague-Dawley rats were subjected to 60 min of partial hepatic ischemia. At various times after reperfusion (0, 3, 6, 24, and 48 h), the ischemic lobes were harvested as well as kidneys. RNA and protein expression of Mrps in livers and kidneys were determined by the branched DNA method, Western blot analysis, and tissue immunofluorescence. Mrp2 mRNA and protein expression in livers decreased after IR. Conversely, Mrp2 mRNA and protein expression in kidneys increased after IR. Mrp3 mRNA expression, and Mrp4 mRNA and protein expression in kidneys transiently increased after IR. The intensity of immunofluorescent staining of Mrp2 corresponded to changes in Mrp2 expression in livers and kidneys after IR as detected by Western blot analysis and was localized to the apical membrane domain in both tissues. These results demonstrate that after hepatic IR, downregulation of hepatic Mrp2 and upregulation of renal Mrp2 occur. These decreases in hepatic Mrp2 may contribute to cholestasis, yet increases in kidney may protect from oxidative stress and/or inflammation after hepatic IR.

Predictors of graft and patient survival in hepatitis C virus (HCV) recipients: model to predict HCV cirrhosis after liver transplantation

BACKGROUND

Hepatitis C virus (HCV) recurrence after liver transplantation (LT) is almost universal, but the natural history of recurrent HCV in the allograft is highly variable. Our study had two aims: 1) to assess the impact of different pre- and postLT factors on graft and patient survival in HCV transplant recipients and 2) to create a model which may predict the patients at risk for HCV-related graft cirrhosis at 5 years postLT.

METHODS

A total of 168 LTs were considered for this study. Univariate and multivariate Cox proportional hazards regression model was used, as well as logistic regression analysis to create a model of prediction of HCV cirrhosis within 5 years after LT.

RESULTS

Predictive factors for both decreased graft and patient survival included patients recently transplanted (2000-2004), induction without azathioprine, short-term therapy with mycophenolate mofetil and prednisone (< or =6 months), presence of early cholestasis, histologically proven early recurrence of hepatitis C. Recipient human leukocyte antigen DR3 positivity, presence of early cholestasis, and donor age >50 years were identified as independent predictors of graft cirrhosis within 5 years. A predictive model was established in order to calculate at 6 months a risk score for graft HCV cirrhosis within 5 years postLT using a formula that included the identified independent predictors. The area under receiver operating characteristic curve was 0.83, indicating a good ability to predict medium-term HCV allograft cirrhosis.

CONCLUSION

This model may be a useful tool for better identifying high-risk HCV patients who should be selected for early initiation of antiviral therapy.

Ischemic preconditioning and intermittent ischemia preserve bile flow in a rat model of ischemia reperfusion injury

Ischemia and reperfusion (IR) injury of the liver is associated with impaired bile secretion, but the effects of ischemic preconditioning (IPC) and intermittent ischemia (INT) on bile flow are unknown. A rat model of segmental (60%-70%) hepatic ischemia and reperfusion was employed to test the effects of IPC and INT on bile flow. Continuous clamping for 45 min (CC) substantially reduced bile flow, and this did not recover after 60 min of reperfusion. IPC and INT caused a significant recovery of bile flow. The elevation in plasma liver marker enzymes induced by CC was not reduced by IPC and INT. Light microscopy showed mild hepatocyte damage in all groups. In the CC group, the amount of F-actin localized around the bile canaliculi in the ischemic lobes was less than that in the nonischemic lobes, but this difference was not observed in the IPC and INT groups. It is concluded that IPC and INT substantially alleviate the decrease in bile flow induced by ischemia. Bile flow may be useful in the assessment of IR injury.

Hepatic steatosis is associated with intrahepatic cholestasis and transient hyperbilirubinemia during regeneration after living donor liver transplantation

A clear understanding of the mechanisms in steatotic livers that trigger cholestasis or hyperbilirubinemia after living donor liver transplantation (LDLT) remains elusive. We hypothesized that microarchitectural disturbance might occur within regenerating steatotic livers without impairment of hepatic proliferative activity. Liver biopsy specimens from 67 LDLT recipients taken at the 10th postoperative day were scored for the numbers of portal tracts per area (nPT/A) of liver tissue and for intrahepatic cholestasis, and immunostained by proliferating cell nuclear antigen (PCNA) and Ki-67. The preoperative degree of macrovesicular steatosis (MaS) was independently associated with cholestasis after LDLT (P < 0.001). Serum total bilirubin results on the 1st, 3rd, and 7th days post-LDLT in MaS+ (5-30% of MaS; n = 37) patients were significantly higher than those in MaS- (<5% of MaS; n = 30) patients (P = 0.030, 0.042, and 0.019, respectively). Mean numbers of positively stained hepatocytes were 53.1 +/- 12.0 in patients with MaS and 48.0 +/- 17.1 in those without MaS by PCNA (P = 0.390), and 24.4 +/- 10.5 and 24.0 +/- 14.0 by Ki-67 (P = 0.940). However, a significant negative correlation was found between the degree of MaS and nPT/A (P = 0.013), and nPT/A was correlated with the grade of histological cholestasis (r = 0.350, P = 0.039). Intrahepatic cholestasis and hyperbilirubinemia after LDLT could be caused by scanty morphologic change of portal tract during steatotic liver regeneration.

Incidence and risk factors for the development of prolonged and severe intrahepatic cholestasis after liver transplantation

Predictive factors for intrahepatic cholestasis after orthotopic liver transplantation (OLT) have not yet been established. We sought to identify the incidence and risk factors associated with prolonged severe intrahepatic cholestasis (PSIC) after OLT. We assessed 428 consecutive patients undergoing their first OLT. PSIC was diagnosed if a serum bilirubin concentration was greater than 100 micromol/L and/or a 3-fold increase of alkaline phosphatase occurred within the first month after OLT and was sustained for at least 1 week in the absence of biliary complications. Multivariable logistic regression identified factors independently associated with PSIC. PSIC developed in 107 patients (25%). Independent risk factors by multivariable analysis were intraoperative transfusion of cryoprecipitate and platelets; nonidentical blood group status; suboptimal organ appearance; inpatient status before transplantation; and bacteraemia in the first month after transplantation. In contrast, acute liver failure, older age, and higher levels of serum sodium and serum potassium were all associated with a reduced likelihood of developing PSIC in the first month. There were 47 deaths in the PSIC group (44%) as opposed to 65 deaths in the non-PSIC group (20%) after OLT. A poor preoperative clinical status in conjunction with a suboptimal graft was associated with PSIC after OLT. Avoidance of suboptimal livers and ABO nonidentical grafts for young patients with poor synthetic function and for pretransplant inpatients may lessen this complication and reduce the associated early mortality.

Pathophysiologic observations and histopathologic recognition of the portal hyperperfusion or small-for-size syndrome

In an attempt to more completely define the histopathologic features of the portal vein hyperperfusion or small-for-size syndrome (PHP/SFSS), we strictly identified 5 PHP/SFSS cases among 39 (5/39; 13%) adult living donor liver transplants (ALDLT) completed between 11/01 and 09/03. Living donor segments consisting of 3 right lobes, 1 left lobe, and 1 left lateral segment, with a mean allograft-to-recipient weight ratio (GRWR) of 1.0 +/- 0.3 (range 0.6 to 1.4), were transplanted without complications, initially, into 6 relatively healthy 25 to 63-year-old recipients. However, all recipients developed otherwise unexplained jaundice, coagulopathy, and ascites within 5 days after transplantation. Examination of sequential posttransplant biopsies and 3 failed allografts with clinicopathologic correlation was used in an attempt to reconstruct the sequence of events. Early findings included: (1) portal hyperperfusion resulting in portal vein and periportal sinusoidal endothelial denudation and focal hemorrhage into the portal tract connective tissue, which dissected into the periportal hepatic parenchyma when severe; and (2) poor hepatic arterial flow and vasospasm, which in severe cases, led to functional dearterialization, ischemic cholangitis, and parenchymal infarcts. Late sequelae in grafts surviving the initial events included small portal vein branch thrombosis with occasional luminal obliteration or recanalization, nodular regenerative hyperplasia, and biliary strictures. These findings suggest that portal hyperperfusion, venous pathology, and the arterial buffer response importantly contribute to early and late clinical and histopathologic manifestations of the small-for-size syndrome.

Hypoattenuation in unenhanced CT reflects histological graft dysfunction and predicts 1-year mortality after living donor liver transplantation

Early postoperative graft function assessments are essential after living donor liver transplantation (LDLT) to predict patient and graft outcome. Computed tomography (CT) is usually used to evaluate various complications and parenchymal abnormalities after LDLT. Here, we attempted to determine the prognostic values of CT attenuation changes of grafts for predicting 1-year patient survival. Liver attenuation indices (LAIs), derived from differences between hepatic and splenic attenuations, were calculated on unenhanced CT images obtained 10 days after LDLT in 62 adult LDLT recipients between September 2002 and August 2004. Patients were assigned to 1 of 2 groups according to LAI value on the 10th postoperative day, as follows: group L (LAI < or = 5, n = 14) or group H (LAI > 5, n = 48). Parenchymal dysfunction scores, summed parameters for histological dysfunction including both portal tract and centrilobular features, were also assessed on the 10th postoperative day using liver biopsy specimens. Histological parenchymal dysfunction, especially in the centrilobular area, in terms of cholestasis, centrilobular necroinflammation, central vein fibrosis, steatosis, mononuclear infiltrates, and hepatocyte ballooning, was more prominent in group L than in group H, while that in the portal area was similar between the 2 study groups. Significant negative linear correlations were observed between LAI and parenchymal dysfunction scores (r = 0.486, P < 0.001). Group L patients showed lower 1-year survival (69.7%) than group H patients (95.8%; P = 0.0002). Moreover, group H patients died with a functioning graft (n = 3), whereas group L patients died of graft failure (n = 6). After multivariate analysis, LAI alone remained independently associated with 1-year mortality (P = 0.014; odds ratio = 0.845; 95% confidence interval, 0.739-0.967). The sensitivity and specificity of LAI were 84.6% and 75%, respectively, and LAI outperformed MELD score as a predictor of 1-year mortality after LDLT by receiver operating characteristic curve analysis. In conclusion, LAI, as determined by unenhanced CT 10 days after LDLT, well predicts 1-year patient survival after LDLT.

Administration of r-VEGF-A prevents hepatic artery ligation-induced bile duct damage in bile duct ligated rats

The hepatic artery, through the peribiliary plexus, nourishes the intrahepatic biliary tree. During obstructive cholestasis, the nutritional demands of intrahepatic bile ducts are increased as a consequence of enhanced proliferation; in fact, the peribiliary plexus (PBP) displays adaptive expansion. The effects of hepatic artery ligation (HAL) on cholangiocyte functions during cholestasis are unknown, although ischemic lesions of the biliary tree complicate the course of transplanted livers and are encountered in cholangiopathies. We evaluated the effects of HAL on cholangiocyte functions in experimental cholestasis induced by bile duct ligation (BDL). By using BDL and BDL + HAL rats or BDL + HAL rats treated with recombinant-vascular endothelial growth factor-A (r-VEGF-A) for 1 wk, we evaluated liver morphology, the degree of portal inflammation and periductular fibrosis, microcirculation, cholangiocyte apoptosis, proliferation, and secretion. Microcirculation was evaluated using a scanning electron microscopy vascular corrosion cast technique. HAL induced in BDL rats 1) the disappearance of the PBP, 2) increased apoptosis and impaired cholangiocyte proliferation and secretin-stimulated ductal secretion, and 3) decreased cholangiocyte VEGF secretion. The effects of HAL on the PBP and cholangiocyte functions were prevented by r-VEGF-A, which, by maintaining the integrity of the PBP and cholangiocyte proliferation, prevents damage of bile ducts following ischemic injury.

Molecular adsorbent recirculating system treatment for patients with liver failure: the Hong Kong experience

BACKGROUND

The molecular adsorbent recirculating system (MARS) is an extracorporeal liver dialysis system that allows selective removal of bilirubin and other albumin-bound toxins. We reported here our experience with the use of this technique for management of liver failure at Queen Mary Hospital, Hong Kong.

METHODS

From December 2002 to 2004, a total of 74 MARS sessions were performed on 22 patients. The cause of liver failure included acute liver failure (n = 2), acute on chronic liver failure (n = 12), posthepatectomy liver failure (n = 4), and posttransplantation allograft failure (n = 4).

RESULTS

MARS treatment showed significant reduction in total bilirubin level, serum ammonia level and blood urea, and nitrogen (P < 0.001 for all three parameters). Five patients (22.7%) were able to bridge to transplantation and one patient (4.5%) made a spontaneous recovery. The 30-day mortality rate was 72.7%.

CONCLUSIONS

Our results indicated that MARS can effectively improve serum biochemistry and is suitable for temporarily supporting patients with liver failure where transplantation is not immediately available. There is, however, no clear evidence showing that MARS can increase survival, improve the chance of transplantation or assist liver regeneration. Future studies in the form of randomized-controlled trials are crucial to characterize the true potential of this treatment.

Proteomic analysis of ischemia-reperfusion injury upon human liver transplantation reveals the protective role of IQGAP1

Ischemia-reperfusion injury (IRI) represents a major determinant of liver transplantation. IRI-induced graft dysfunction is related to biliary damage, partly due to a loss of bile canaliculi (BC) integrity associated with a dramatic remodeling of actin cytoskeleton. However, the molecular mechanisms associated with these events remain poorly characterized. Using liver biopsies collected during the early phases of organ procurement (ischemia) and transplantation (reperfusion), we characterized the global patterns of expression and phosphorylation of cytoskeleton-related proteins during hepatic IRI. This targeted functional proteomic approach, which combined protein expression pattern profiling and phosphoprotein enrichment followed by mass spectrometry analysis, allowed us to identify IQGAP1, a Cdc42/Rac1 effector, as a potential regulator of actin cytoskeleton remodeling and maintenance of BC integrity. Cell fractionation and immunohistochemistry revealed that IQGAP1 expression and localization were affected upon IRI and related to actin reorganization. Furthermore using an IRI model in human hepatoma cells, we demonstrated that IQGAP1 silencing decreased the basal level of actin polymerization at BC periphery, reflecting a defect in BC structure coincident with reduced cellular resistance to IRI. In summary, this study uncovered new mechanistic insights into the global regulation of IRI-induced cytoskeleton remodeling and led to the identification of IQGAP1 as a regulator of BC structure. IQGAP1 therefore represents a potential target for the design of new organ preservation strategies to improve transplantation outcome.

Cadaveric full-size liver transplantation and the graft alternatives in adults: a comparative study from a single centre

BACKGROUND/AIMS

This study aims to compare the results of living donor (LDLT), cadaveric split (SLT) and domino (DO) liver transplantation which are currently available alternatives to the conventional cadaveric full-size liver transplantation (CAD).

METHODS

Immunologic, vascular and biliary complications (BC) were evaluated in 38 LDLT, 20 SLT, 17 DO and 38 CAD recipients.

RESULTS

The incidence of acute rejection (AR) was similar between groups, and between blood-related and blood-unrelated patients. AR was more severe in the SLT group according to the Banff scores (P=0.03, P<0.001, P<0.001). The evolution of AR was similar between the groups, in terms of development of chronic rejection. No venous complications occurred in the overall population. The rate of arterial thrombosis (10.5, 10, 0 and 3%, respectively) was statistically similar between groups. The rate of BC (26, 40, 12, and 8%, respectively) was higher in the partial grafts than in the whole grafts (P=0.006), but was not significantly different within each group. There was an association between the severity of preservation injury and occurrence of AR (P=0.01) and arterial thrombosis (P=0.016), but not BC. One- and 2-year graft and patient survival rates were similar between groups.

CONCLUSIONS

None of the graft types seemed to confer immunological advantage. BC remained problematic in the partial grafts, independently from ischemia time.

Pathomorphological Features of Acute Rejection in Patients After Orthotopic Liver Transplantation: Own Experience

INTRODUCTION

Acute hepatic allograft rejection remains an important problem following liver transplantation. Liver biopsy specimens show a combination of characteristic changes, first observed by Snover as a diagnostic triad: portal inflammation, bile duct damage, and central or portal vein endothelial inflammation (endothelitis or endothelialitis). The aim of this study was to describe our histopathological assessment of liver transplants.

MATERIALS AND METHODS

In the period between September 2000 and June 2004, we evaluated 150 liver biopsy specimens from 105 liver recipients.

RESULTS

Acute rejection was diagnosed in 26.6% of liver biopsies taken from 31.4% patients who demonstrated clinical symptoms of liver damage. In 90% of cases the rejection was described as minimal or mild, and in 10% as moderate. There was no episode of severe acute rejection. Only four biopsies (10%) showed nothing but Snover triad changes. In 9 (22.5%) cases only acute rejection was diagnosed; the remaining showed in addition to acute rejection the possibility of other concomitant pathologies: viral infection in 15 cases (37.5%), biliary flow obstruction in 11 cases (28.5%), functional cholestasis in two cases (5%), and ischemic complications in three cases (7.5%).

CONCLUSIONS

Histologically confirmed acute rejection episodes were diagnosed in 14.9% liver recipients. Liver biopsy specimens, aside from Snover triad features, often showed other unspecific morphological changes. Differentiation of acute rejection from other accompanying diseases is sometimes difficult, requiring precise clinical data and pathologist experience.