Azathioprine hepatotoxicity after liver transplantation

Early-onset hepatic veno-occlusive disease after liver transplantation: an institutional experience and analysis of a literature-based cohort

PURPOSE

Hepatic veno-occlusive disease (HVOD) after liver transplantation (LT) is almost always a fatal complication. We assessed the outcomes of HVOD in a single institute and analyzed a literature-based cohort.

METHODS

We reviewed the medical records of recipients of LT performed between 1995 and 2020 at our institute and the literature on HVOD after LT. We then analyzed the clinical features based on a "pooled" cohort of cases identified in our institute and reported in the literature.

RESULTS

HVOD was diagnosed in 3 of 331 LT recipients, all of whom died in hospital, on days 164, 12, and 13, respectively. Our comprehensive review of the literature, as well as our cases, identified eight cases of HVOD that developed within 14 days after LT (early-onset type). Early-onset HVOD had a significantly worse prognosis than HVOD that developed beyond 2 weeks after LT (non-early-onset type), which was identified in 22 cases (25.0% vs. 86.1% of the 3-month graft survival rate). The most common causes of early-onset and non-early-onset types were acute cellular rejection (50%) and drug-induced disease (50%), respectively.

CONCLUSION

Early-onset HVOD developing within 14 days after LT has a poor prognosis.

Management of long-term complications from immunosuppression

This review discusses long-term complications from immunosuppressants after liver transplantation and the management of these complications. Common complications of calcineurin inhibitors include nephrotoxicity and metabolic diseases. Nephrotoxicity can be managed by targeting a lower drug level and/or adding an immunosuppressant of a different class. Metabolic disorders can be managed by treating the underlying condition and targeting a lower drug level. Gastrointestinal adverse effects and myelosuppression are common complications of antimetabolites that are initially managed with dose reduction or discontinuation if adverse events persist. Mammalian targets of rapamycin inhibitors are associated with myelosuppression, proteinuria, impaired wound healing, and stomatitis, which may require dose reduction or discontinuation. Induction agents and agents used for steroid-refractory rejection or antibody-mediated rejection are reviewed. Other rare complications of immunosuppressants are discussed as well.

Spectrum of drug-induced liver injury in a tertiary hospital in southern India

Background

Anti-tuberculosis drugs are thought to account for about 50% of drugs that cause liver injury in India. We show that the spectrum of drugs is much wider than previously reported.

Methods

We evaluated all patients with unexplained acute liver injury presenting during 2006–2016 using a structured proforma for drug-induced liver injury (DILI). The Roussel Uclaf Causality Assessment Method was used to assess causality.

Results

DILI was found in 143 of 2534 patients with acute liver injury. Nineteen patients had probable ayurvedic DILI. The other common causes of DILI were statins (16 patients) and anti-tuberculosis drugs (11 patients). Eight patients had DILI post-liver transplant. Fluconazole was the most common cause of post-liver transplant DILI. Chronic DILI (abnormal liver function test after 12 months of stopping the suspected drug) was found in 2 patients.

Conclusion

In otherwise unexplained acute liver injury, DILI due to ayurvedic drugs should be sought. DILI should be considered in post-liver transplant patients. Patients with DILI should be monitored for at least 12 months to exclude progression to chronic DILI.

Prevalence and outcomes of patients with sinusoidal obstruction syndrome after liver transplantation: A ten year's experience of a third-level Centre in Japan

BACKGROUND

Sinusoidal obstruction syndrome (SOS) after liver transplantation (LT) is a rare and potentially lethal complication. We retrospectively reviewed the outcomes of patients with post-transplant SOS.

METHODS

Between May 2001 and December 2019, of 332 patients who underwent LT, 5 (1.5%) developed SOS. The median age at LT was 1.7 years (range 0.1-66.5). SOS was histopathologically diagnosed and classified as early-onset (<1 month) or late-onset.

RESULTS

The median time to diagnosis of SOS was one month after LT. All patients developed acute cellular rejection before SOS, and the cause of SOS was acute cellular rejection in four patients and unknown in one. The treatment of SOS included conversion to tacrolimus from cyclosporine, intrahepatic hepatic vein stent placement, strengthening of immunosuppression, and plasma exchange. The 5-year graft survival rates in patients with and without SOS were 53.0% and 92.5%, respectively (p < 0.001). Of three patients with early-onset SOS, two patients improved and are doing well, and one patient died of graft failure four months after LT.

CONCLUSIONS

The cause and treatment of post-transplant SOS are not yet defined. The poor outcomes in patients with early-onset SOS may be improved by strengthening of immunosuppression. Patients with late-onset SOS are ultimately treated by repeat LT.

Sinusoidal dilatation and congestion in post-transplant liver biopsies from patients presenting with transaminitis

AIMS

Sinusoidal dilatation and congestion (SDC) in liver biopsy may be obstructive (due to venous outflow impairment) or non-obstructive in nature. The significance of this finding in the post-liver transplant setting remains unexplored.

METHODS

We herein retrospectively analysed all post-transplant liver biopsies showing SDC and examined histopathological features in detail. Association with transaminitis and concurrent graft rejection was assessed.

RESULTS

A total of 30 post-transplant liver biopsies from 27 patients showed SDC with atrophy of hepatocyte cords (SDC; incidence 7.4%). All patients had transaminitis. Most patients (n=22; 81.5%) were asymptomatic with deranged liver function tests (LFTs) detected during routine follow-up, raising clinical suspicion of graft rejection. SDC was non-obstructive in 19 (70.4%) and obstructive (due to sinusoidal obstruction syndrome (SOS)) in 8 (29.6%) cases. The incidence of SOS was 2%. SDC was mild, moderate and severe in 18 (66.7%), 7 (25.9%) and 2 (7.4%) cases, respectively. Perivenular and centrilobular sinusoidal fibrosis was seen in the obstructive SDC group (n=3, 11.1%). Concurrent graft rejection was present in 7 (25.9%) cases, of which acute cellular rejection comprised 5 (18.5%), and late acute rejection accounted for 2 cases (7.4%). Serum tacrolimus levels ranged from normal (n=14) to below and above normal (n=5 each). Modulation of immunosuppressive therapy led to normalisation of LFTs in one patient.

CONCLUSION

Obstructive and non-obstructive SDC in post-liver transplant patients presenting with transaminitis mimics graft rejection clinically and may represent a form of drug-induced liver injury. Liver biopsy plays a crucial role in the diagnosis.

Clinical characteristics and outcomes of patients with hepatic veno-occlusive disease induced by Gynura segetum: A retrospective study

OBJECTIVE

Hepatic veno-occlusive disease (HVOD) has attracted increasing attention in recent years due to its relationship with ingestion of Gynura segetum. The mortality of severe HVOD remains high due to the lack of specific therapies. The aim of the study was to delineate the clinical characteristics and outcomes and explore the potential prognostic factors of HVOD.

METHODS

This was a single-center retrospective study. Eighty-nine HVOD patients were screened from the First Affiliated Hospital of Zhejiang University with an ingestion history of G. segetum before developing symptoms from January 2009 to May 2018. The enrolled patients were divided into the survivor and death groups according to the clinical follow-up that ended on September 1, 2019. The demographic variables and clinical data of the patients were recorded. A binary logistic regression analysis and receiver operating characteristic curve were conducted to identify the prognostic factors and assess the prognostic value for predicting death, and a survival analysis was performed to evaluate the clinical outcomes.

RESULTS

Sixty-four patients were eligible for further analysis. Most patients showed abdominal distension and were positive for migrating dullness in the abdomen (P = 0.740 and P = 0.732, respectively). The patients who died had higher levels of model for end-stage liver disease score, and higher prothrombin time than those who survived (both P < 0.001). All HVOD patients in both the survival and death groups showed ascites with abnormal imaging presentations of the liver parenchyma and hepatic blood vessels. Unexpectedly, we found that hydrothorax was detected in 21 (65.63%) patients in the death group and 19 (59.38%) patients in the survivor group during hospitalization, which was rarely mentioned in previous studies. Furthermore, international normalized ratio (INR) and creatinine are found to be potential independent prognostic factors for predicting death. Six severe patients achieved clinical improvements and survived after liver transplantation.

CONCLUSION

HVOD can be induced by the ingestion of G. segetum, and INR combined with creatinine has prognostic value for predicting death. Liver transplantation may be an effective treatment option for severe HVOD patients.

Endovascular stent placement for venous complications following pediatric liver transplantation: outcomes and indications

PURPOSE

Advances in interventional radiology (IVR) treatment have notably improved the prognosis of hepatic vein (HV) and portal vein (PV) complications following pediatric living donor liver transplantation (LDLT); however, graft failure may develop in refractory cases. Although endovascular stent placement is considered for recurrent stenosis, its indications are controversial.

METHODS

We enrolled 282 patients who underwent pediatric LDLT in our department from May 2001 to September 2016.

RESULTS

22 (7.8%) HV complications occurred after LDLT. Recurrence was observed in 45.5% of the patients after the initial treatment, and 2 patients (9.1%) underwent endovascular stent placement. The stents were inserted at 8 months and 3.8 years following LDLT, respectively. After stent placement, both patients developed thrombotic obstruction and are currently being considered for re-transplantation. 40 (14.2%) PV complications occurred after LDLT. Recurrence occurred in 27.5% of the patients after the initial treatment, and 4 patients (10.0%) underwent endovascular stent treatment. The stents of all the patients remained patent, with an average patency duration of 41 months.

CONCLUSION

Endovascular stent placement is an effective treatment for intractable PV complications following pediatric LDLT. However, endovascular stent placement for HV complications should be carefully performed because of the risk of intrastent thrombotic occlusion and the possibility of immunological venous injury.

Estrogen-Estrogen Receptor α Signaling Facilitates Bilirubin Metabolism in Regenerating Liver Through Regulating Cytochrome P450 2A6 Expression

BACKGROUND

After living donor liver transplantation (LDLT), rising serum bilirubin levels commonly indicate insufficient numbers of hepatocytes are available to metabolize bilirubin into biliverdin. Recovery of bilirubin levels is an important marker of hepatocyte repopulation after LDLT. Cytochrome P450 (CYP) 2A6 in humans (or cyp2a4 in rodents) can function as "bilirubin oxidase." Functional hepatocytes contain abundant CYP2A6, which is considered a marker for hepatocyte function recovery. The aim of our study was to determine the impact of estradiol/estrogen receptor signaling on bilirubin levels during liver function recovery.

METHODS

We conducted a hospital-based cohort study of bilirubin levels after LDLT surgery in both liver graft donors and recipients, performed a transcriptome comparison of wild-type versus estrogen receptor (ER)α knockout mice and a bioinformatics analysis of transcriptome changes in their regenerating liver after two-third partial hepatectomy (PHx), and assayed in vitro expression of cytochrome (CYP2A6) in human hepatic progenitor cells (HepRG) treated with 17β-estradiol (E2).

RESULTS

The latency of bilirubin level reduction was shorter in women than in men, suggesting that a female factor promotes bilirubin recovery after liver transplantation surgery. In the PHx mouse model, the expression of the cyp2a4 gene was significantly lower in livers from the knockout ERα mice than in livers from their wild-type littermates; but the expression of other bilirubin metabolism-related genes were similar between these groups. Moreover, E2 or bilirubin treatments significantly promoted CYP2A6 expression in hepatocyte progenitor cells (HepRG cells). Sequence analysis revealed similar levels of aryl hydrocarbon receptor (AhR; bilirubin responsive nuclear receptor) and ESR1 binding to the promoter region of CYP2A6.

CONCLUSIONS

This is the first report to demonstrate, on a molecular level, that E2/ERα signaling facilitates bilirubin metabolism in regenerating liver. Our findings contribute new knowledge to our understanding of why the latency of improved bilirubin metabolism and thereby liver function recovery is shorter in females than in males.

Management of hepatic vein occlusive disease after liver transplantation: A case report with literature review

RATIONALE

Hepatic vein occlusive disease (HVOD) is a rare complication after liver transplantation, which is characterized by nonthrombotic, fibrous obliteration of the small centrilobular hepatic veins by connective tissue and centrilobular necrosis in zone 3 of the acini. HVOD after solid organ transplantation has been reported; recently, most of these reports with limited cases have documented that acute cell rejection and immunosuppressive agents are the major causative factors. HVOD is relatively a rare complication of liver transplantation with the incidence of approximately 2%.

PATIENT CONCERNS

A 59-year-old male patient with alcoholic liver cirrhosis underwent liver transplantation in our center. He suffered ascites, renal impairment 3 months after the surgery while liver enzymes were in normal range.

DIAGNOSES

Imagining and pathology showed no evidence of rejection or vessels complications. HVOD was diagnosed with pathology biopsy.

INTERVENTIONS

Tacrolimus was withdrawn and the progression of HVOD was reversed.

OUTCOMES

Now, this patient has been followed up for 6 months after discharge with normal liver graft function.

LESSONS

The use of tacrolimus in patients after liver transplantation may cause HVOD. Patients with jaundice, body weight gain, and refractory ascites should be strongly suspected of tacrolimus related HVOD.

Azathioprine and 6-Mercaptopurine-induced Liver Injury: Clinical Features and Outcomes

OBJECTIVE

The objective of the study was to define the clinical, biochemical, and histologic features of liver injury from thiopurines.

BACKGROUND

Azathioprine (Aza) and 6-mercaptopurine (6-MP) can cause liver injury, but no large series exist.

METHODS

Clinical and laboratory data and 6-month outcomes of patients with thiopurine hepatotoxicity from the Drug-Induced Liver Injury Network Prospective Study were analyzed.

RESULTS

Twenty-two patients were identified, 12 due to Aza and 10 due to 6-MP, with a median age of 55 years; the majority were female (68%). Inflammatory bowel disease was the indication in 55%, and the median thiopurine dose was 150 (range, 25 to 300) mg daily. The median latency to onset was 75 (range, 3 to 2584) days. Injury first arose after a dose escalation in 59% of patients, the median latency after dose increase being 44 (range, 3 to 254) days. At onset, the median alanine aminotransferase level was 210 U/L, alkaline phosphatase was 151 U/L, and bilirubin was 7.4 mg/dL (peak, 13.4 mg/dL). There were no major differences between Aza and 6-MP cases, but anicteric cases typically had nonspecific symptoms and a hepatocellular pattern of enzyme elevations, whereas icteric cases experienced cholestatic hepatitis with modest enzyme elevations in a mixed pattern. One patient with preexisting cirrhosis required liver transplantation; all others resolved clinically. One patient still had moderate alkaline phosphatase elevations 2 years after onset.

CONCLUSIONS

Nearly three-quarters of patients with thiopurine-induced liver injury present with self-limited, cholestatic hepatitis, typically within 3 months of starting or a dose increase. The prognosis is favorable except in patients with preexisting cirrhosis.

Hepatotoxicity Secondary to Chemotherapy

The difficult problem faced by multiple generation of practicing physicians is determining the cause of abnormal liver function tests in cancer patients on chemotherapy. Hepatotoxicity from chemotherapy occurs frequently from an unpredictable or idiosyncratic reaction. Despite remarkable advances in our understanding of the mechanisms of action, pharmacodynamics, and interrelationships between the liver and chemotherapy, the underlying etiology of hepatic toxicity for various agents remains unexplained. Here, we present a concise review of the broad differential diagnosis for abnormal liver function tests (LFTs) in oncology patients.

Drug-drug interactions with oral anti-HCV agents and idiosyncratic hepatotoxicity in the liver transplant setting

Studies of boceprevir and telaprevir based antiviral therapy in liver transplant (LT) recipients with hepatitis C genotype 1 infection have demonstrated dramatic increases in tacrolimus, cyclosporine, and mTOR inhibitor exposure. In addition to empiric dose reductions, daily monitoring of immunosuppressant blood levels is required when initiating as well as discontinuing the protease inhibitors to maximize patient safety. Although improved suppression of HCV replication is anticipated, 20 to 40% of treated subjects have required early treatment discontinuation due to various adverse events including anemia (100%), infection (30%), nephrotoxicity (20%) and rejection (5 to 10%). Simeprevir and faldaprevir will likely have improved efficacy and safety profiles but potential drug interactions with other OATP1B1 substrates and unconjugated hyperbilirubinemia are expected. In contrast, sofosbuvir and daclatasvir based antiviral therapy are not expected to lead to clinically significant drug-drug interactions in LT recipients but confirmatory studies are needed. Liver transplant recipients may also be at increased risk of developing drug induced liver injury (DILI). Establishing a diagnosis of DILI in the transplant setting is very difficult with the variable latency, laboratory features and histopathological manifestations of hepatotoxicity associated with a given drug, the need to exclude competing causes of allograft injury, and the lack of an objective and verifiable confirmatory test. Nonetheless, a heightened awareness of the possibility of DILI is warranted in light of the large number of medications used in LT recipients and the potential adverse impact that DILI may have on patient outcomes.

Transjugular intrahepatic portosystemic shunts in liver transplant recipients

The insertion of a transjugular intrahepatic portosystemic shunt (TIPS) is a minimally invasive procedure used to relieve the signs and symptoms of portal hypertension in patients with liver disease. The most common indications for placement are refractory ascites and variceal hemorrhage. In properly selected candidates, TIPS placement can serve as a bridge to liver transplantation. Expertise in TIPS placement after transplantation has significantly increased, which has allowed the procedure to become a viable option for retransplant candidates suffering the consequences of recurrent portal hypertension due to portal vein thrombosis, recurrent liver disease, or hepatic venous outflow obstruction (HVOO). However, TIPSs in liver transplant recipients are associated with a lower clinical response rate and a higher rate of complications in comparison with patients with native liver disease, and they are, therefore, generally reserved for patients with a Model for End-Stage Liver Disease (MELD) score ≤ 15 and ≤ 12 in patients with HCV. The role of TIPS placement in nonliver transplant recipients has been well studied in large trials, and it translates well into clinical applicability to candidates for orthotopic liver transplantation (OLT). However, the experience with OLT recipients is heterogeneous and restricted to small series. Thus, we focus here on reviewing the current literature and discussing the proper use of TIPSs in liver transplant recipients.

Using aggregated, de-identified electronic health record data for multivariate pharmacosurveillance: a case study of azathioprine

OBJECTIVE

To demonstrate the use of aggregated and de-identified electronic health record (EHR) data for multivariate post-marketing pharmacosurveillance in a case study of azathioprine (AZA).

METHODS

Using aggregated, standardized, normalized, and de-identified, population-level data from the Explore platform (Explorys, Inc.) we searched over 10 million individuals, of which 14,580 were prescribed AZA based on RxNorm drug orders. Based on logical observation identifiers names and codes (LOINC) and vital sign data, we examined the following side effects: anemia, cell lysis, fever, hepatotoxicity, hypertension, nephrotoxicity, neutropenia, and neutrophilia. Patients prescribed AZA were compared to patients prescribed one of 11 other anti-rheumatologic drugs to determine the relative risk of side effect pairs.

RESULTS

Compared to AZA case report trends, hepatotoxicity (marked by elevated transaminases or elevated bilirubin) did not occur as an isolated event more frequently in patients prescribed AZA than other anti-rheumatic agents. While neutropenia occurred in 24% of patients (RR 1.15, 95% CI 1.07-1.23), neutrophilia was also frequent (45%) and increased in patients prescribed AZA (RR 1.28, 95% CI 1.22-1.34). After constructing a pairwise side effect network, neutropenia had no dependencies. A reduced risk of neutropenia was found in patients with co-existing elevations in total bilirubin or liver transaminases, supporting classic clinical knowledge that agranulocytosis is a largely unpredictable phenomenon. Rounding errors propagated in the statistically de-identified datasets for cohorts as small as 40 patients only contributed marginally to the calculated risk.

CONCLUSION

Our work demonstrates that aggregated, standardized, normalized and de-identified population level EHR data can provide both sufficient insight and statistical power to detect potential patterns of medication side effect associations, serving as a multivariate and generalizable approach to post-marketing drug surveillance.

Devastating outflow obstruction after pediatric split liver transplantation

HVOO is a rare complication after pediatric LT, which may lead to graft failure. There are various causes of HVOO, such as mechanical anastomotic obstruction and SOS. A 10-month-old female underwent split LT from a deceased donor for ALF. Her postoperative course was uneventful. However, her liver function suddenly deteriorated a month later. A liver biopsy revealed centrilobular injury, and D-US suggested outflow obstruction. Venography was performed to reveal hepatic venous narrowing inside the graft. She received another graft from a living donor because of progressive graft failure in spite of successful venoplasty with stent insertion. The macroscopic findings of the explanted graft did not show an anastomotic stricture of the hepatic vein, although the pathological findings revealed necrosis of the first graft due to SOS. SOS might cause severe consequences with concomitant mechanical outflow obstruction after pediatric LT.

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.

Transjugular intrahepatic portosystemic shunt for the treatment of sinusoidal obstruction syndrome in a liver transplant recipient and review of the literature

Sinusoidal obstruction syndrome (SOS) is a rare, life-threatening clinical syndrome resulting from sinusoidal congestion, and it is characterized by hepatomegaly, ascites, weight gain, and jaundice. The frequency of this condition after liver transplantation (LT) is low, but when SOS is severe and refractory to medical therapy, the ultimate solution is retransplantation. We describe a patient with SOS after LT who was successfully treated by the placement of a transjugular intrahepatic portosystemic shunt (TIPS). Although information on this approach is scarce because of the low incidence of SOS in LT patients, we review the available literature on treating this condition with a TIPS. On the basis of the reported information and our patient's outcome, we suggest that prompt TIPS placement can be considered for SOS when medical treatment fails. Nonetheless, a formal assessment and prospective studies are needed to confidently indicate TIPS placement in this situation.

Significance of isolated hepatic veno-occlusive disease/sinusoidal obstruction syndrome after liver transplantation

After liver transplantation (LT), hepatic veno-occlusive disease (VOD), which is also known as sinusoidal obstruction syndrome (SOS), has been reported initially in relation to azathioprine use and subsequently in relation to acute rejection (AR). Isolated veno-occlusive disease (iVOD)/SOS raises some questions about its significance and especially its treatment. From the post-LT biopsy samples of 1364 patients (2000-2008), 31 patients with index biopsy samples showing VOD/SOS (2.3%) were identified. After a review of the index biopsy samples and previous biopsy samples, those patients not exposed to azathioprine therapy were subdivided into 2 groups according to the absence or presence of AR. Fifteen of the 31 patients had no previous evidence of AR, whereas 16 experienced episodes of AR (before or concurrently with VOD). The 2 groups were similar in terms of demographic and clinical data and the range of histological centrilobular changes. AR episodes were characterized by an endothelial predilection. iVOD/SOS occurred later than acute rejection-related veno-occlusive disease (AR-VOD)/SOS (mean times of 65 and 4.4 months, respectively, P = 0.0098). There was a tendency for iVOD/SOS to progress less frequently to chronic rejection in comparison with AR-VOD/SOS (3/15 versus 9/15, P = 0.06). The histological resolution of iVOD/SOS was significantly more frequent in patients who benefited from increased immunosuppression in comparison with those who did not (5/7 versus 2/8, P = 0.05). When the groups were considered together, the same result was obtained (14/18 versus 4/12, P = 0.024). In conclusion, despite a constant overall prevalence of VOD/SOS, the proportion of iVOD/SOS has increased. The histological resolution of iVOD/SOS after increase in immunosuppression suggests an immune-mediated origin. Better optimization of immunosuppression may be a curative treatment.

Drug-induced liver injury following positive drug rechallenge

Drug rechallenge (or reinitiation), following an event of drug-induced liver injury, can lead to serious or fatal liver injury. A retrospective review of a large pharmaceutical safety database was conducted to assess clinical outcomes of positive drug rechallenge following possible drug-induced liver injury. Positive rechallenge with suspect drug was reported in 770 of 36,795 hepatic adverse events. A total of 88 cases met inclusion criteria for analysis. Mean age was 44 years (range 0.5-83) and 56% were male. A broad spectrum of suspect drugs were identified. Many patients exhibited hepatitis symptoms or jaundice on the initial and rechallenge liver event. Twelve patients (14%) exhibited clinically worrisome severe hepatocellular injury and jaundice on either initial or rechallenge event and two died, reflecting a 2.3% fatality rate in those with positive rechallenge. The two fatalities developed severe hepatocellular injury with jaundice only upon rechallenge. Liver injury recurred in most rechallenges. Improved identification and communication of possible drug-induced liver injury is needed to avoid potentially serious and/or fatal drug rechallenges. Clinicians should generally avoid such rechallenges.

Chronic liver allograft dysfunction

Approximately 90% of liver transplant patients are alive after 1 year and 75% after 5 years with the majority leading full and near-normal lives. However, although early mortality rates after transplantation have fallen dramatically over the last 2 decades, the rates of late graft loss and patient death have remained constant. Thus, understanding of the causes of graft and patient failure is essential to improve long-term outcomes. In the early days after liver transplantation, ischemia and reperfusion injuries predominate, with acute cellular rejection relatively common in first 3 months. Thereafter, the causes of graft dysfunction are variable with disease recurrence as a major cause of graft loss. In this review, we discuss causes of graft dysfunction after 6 months.

Intractable ascites without mechanical vascular obstruction after orthotopic liver transplantation: etiology and clinical outcome of sinusoidal obstruction syndrome

Intractable ascites after orthotopic liver transplantation (OLT) is a relatively rare complication. However, it often takes a life threatening course, which requires re-transplantation. In previous studies, several reports gave hepatic sinusoidal obstruction syndrome (SOS) as one of the causes of refractory ascites. However, the detailed etiology of SOS after OLT and its association with clinical consequences remain unclear because there have been few studies to date. We report two recent cases with rapidly progressive refractory ascites associated with SOS, following completely different clinical courses. In case 1, the first episode of acute allograft rejection triggered SOS and subsequent intractable ascites, while the second acute rejection worsened his clinical status. A transjugular intrahepatic portosystemic stent-shunt (TIPS) was placed and this procedure resulted in complete disappearance of ascites and of renal dysfunction. In contrast, refractory ascites in case 2, who had neither rejection nor mechanical outlet obstruction, worsened despite TIPS stent placement, and re-transplantation was necessary. We speculate that the pre-existing diseased liver of the cadaver donor caused this serious complication, necessitating a second graft.

Gastrointestinal complications of oncologic therapy

Gastrointestinal complications are common in patients undergoing various forms of cancer treatment, including chemotherapy, radiation therapy, and molecular-targeted therapies. Many of these complications are life-threatening and require prompt diagnosis and treatment. Complications of oncologic therapy can occur in the esophagus (esophagitis, strictures, bacterial, viral and fungal infections), upper gastrointestinal tract (mucositis, bleeding, nausea and vomiting), colon (diarrhea, graft-versus-host disease, colitis and constipation), liver (drug hepatotoxicity and graft-versus-host disease), and pancreas (pancreatitis). Treatment of the different gastrointestinal complications should be tailored to the individual patient and based on the underlying pathophysiology of the complication.

The prevalence and natural history of untreated isolated central perivenulitis in adult allograft livers

Central perivenulitis (CP) in the allograft liver can be associated with portal-based acute cellular rejection and autoimmune hepatitis or can occur in isolation (isolated CP). Although several studies have demonstrated the significance of CP, the prevalence and natural history of untreated isolated CP have not been well studied. We examined 100 adult allograft liver recipients who had long-term follow-up, had routine protocol biopsies, and received no treatment for isolated CP. Isolated CP was identified in 28 (28%) patients. It occurred late at a mean of 658 days. Interestingly, patients with late isolated CP (defined as >3 months posttransplant) usually manifested only mildly to modestly elevated liver function tests. However, late isolated CP was associated with prior and subsequent allograft complications. Nearly all (94%) cases of late isolated CP occurred in patients who had early episodes of CP and/or acute cellular rejection. Of 13 patients who developed adverse outcomes in their allografts (zone 3 fibrosis in 10, de novo autoimmune hepatitis in 3, and ductopenia in 3), all experienced episodes of prior CP, and 12 (92%) had late CP; 1 patient required retransplant for chronic rejection, but all were alive within the last year. In summary, "transplant-associated" isolated CP occurs in 28% of adult patients, early CP is predictive of late CP, and late CP (often present as isolated CP) is associated with long-term liver injury in some patients.

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.

Postoperative hyperbilirubinemia and graft outcome in living donor liver transplantation

Little information is available on the characteristics and clinical significance of serum bilirubin level early after liver transplantation. The aim of this study was to clarify the risk factors for early graft loss and to assess the significance of postoperative hyperbilirubinemia as a predictor of graft outcome in living donor liver transplantation (LDLT). We retrospectively analyzed perioperative parameters in 68 patients who underwent LDLT. Graft loss within 1 year post-LDLT was confirmed in 9 patients (13.4%). Univariate analysis of risk factors showed that preoperative Model for End-Stage Liver Disease score, donor age, postoperative peak serum bilirubin level (p-BIL) within 28 days after LDLT, and surgical complications were significant determinants of early graft loss (<1 year post-transplant). Multivariate analysis identified p-BIL (odds ratio = 1.170, 95% confidence interval = 1.030-1.329, P = 0.016) as the only independent predictor of early graft loss. The incidence of such loss was high in patients with p-BIL over 27.0 mg/dL (area under the receiver operating characteristic curve = 0.988). In conclusion, serum bilirubin level is a useful predictor of short-term (<1 year) graft outcome and for considering retransplantation in a timely fashion.

General aspects and pitfalls in liver transplant pathology

Pathology in a liver transplant setting addresses four different topics: establishment of a definite diagnosis of the liver disease before listing for transplantation, evaluation of the donor liver with regard to pre-existing diseases, in particular macrovesicular steatosis and fibrosis, assessment of the hepatectomy specimen, and post-transplant biopsy evaluation. Of these, post-transplant biopsy evaluation is the most challenging and clinically the most relevant issue. It requires fast diagnoses to facilitate specific treatment and it has to incorporate a broad spectrum of differential diagnoses. Precise knowledge about rejection, post-transplant therapy, pathology of immunosuppression, and recurrence of the initially underlying liver disease including the characteristic time peaks and atypical histological presentations (e.g., fibrosing cholestatic hepatitis) is needed to evaluate specific and combined histological pictures of liver damage. For adequate interpretation of post-transplant biopsies the hepatopathologist has to be informed about the essential clinico-anamnestic aspects such as time course, medication, imaging results, and serology.

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.

Review article: updates in the pathogenesis and therapy of hepatic sinusoidal obstruction syndrome

Hepatic sinusoidal obstruction syndrome is frequently linked to high-dose chemotherapy/total-body irradiation in recipients of haematopoietic stem cell transplantation, long-term use of azathioprine after organ transplantation and other chemotherapeutic agents. The incidence of hepatic sinusoidal obstruction syndrome varies from 0% to 70%, and is decreasing. Disease risk is higher in patients with malignancies, hepatitis C virus infection, those who present late, when norethisterone is used to prevent menstruation, and when broad-spectrum antibiotics and antifungals are used during and after the conditioning therapy. Hepatic sinusoidal obstruction syndrome presents with tender hepatomegaly, hyperbilirubinaemia and ascites, and diagnosis is mainly clinical (Seattle and Baltimore Criteria). Imaging excludes biliary obstruction and malignancy, but cannot establish accurate diagnosis. Hepatic sinusoidal obstruction syndrome may be prevented by avoiding the highest risk regimens, using non-myelo-ablative regimens, and reducing total-body irradiation dose. Treatment is largely symptomatic and supportive, because 70-80% of patients recover spontaneously. Tissue plasminogen activator plus heparin improves outcome in <30% of cases. Defibrotide, a polydeoxyribonucleotide, is showing encouraging results. Transjugular intrahepatic porto-systemic shunt relieves ascites, but does not improve outcome. Liver transplantation may be an option in the absence of malignancy. Prognosis is variable and depends on disease severity, aetiology and associated conditions. Death is most commonly caused by renal or cardiopulmonary failure.

Chronic allograft dysfunction: diagnosis and management. Is it always progressive?

1. There are many causes of graft dysfunction post-liver transplant, but recurrent disease remains the most common cause. 2. Viral hepatitis, nonalcoholic and alcoholic steatohepatitis, and autoimmune diseases are the most common causes of recurrent disease. 3. Graft hepatitis occurs frequently and in many cases will not progress. 4. Cirrhosis in the absence of any identifiable cause develops in a minority. 5. Treatment is of the underlying cause but some, such as recurrent and de novo autoimmune hepatitis and recurrent primary sclerosing cholangitis may not respond well, and regraft may be required.

Intrasinusoidal cytotoxic CD8+ T cells in nodular regenerative hyperplasia of the liver

Diffuse nodular regenerative hyperplasia (NRH) of the liver is an acquired architectural disturbance that can lead to portal hypertension. Although frequently associated with autoimmune or hematologic malignancies, its exact pathogenesis remains largely unknown. We observed CD8+ cytotoxic T cells in the liver sinusoids of 14 of 44 NRH patients and explored possible relationships between these lymphocytes and vascular damage. The immunophenotype of intrahepatic lymphocytes was determined using immunohistochemical analysis and endothelial injury using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling method for apoptosis combined with endothelial cell labeling. Controls for the quantitative analysis of liver-infiltrating lymphocytes consisted of patients with chronic hepatitis C or normal liver (n = 13 and n = 6, respectively). Liver specimens from the 14 patients dislayed intrasinusoidal infiltrate composed of CD3+ and CD8+ lymphocytes, located near atrophic liver cell plates. Significantly more granzyme B+ and CD57+ lymphocytes were observed in NRH than chronic hepatitis C samples with quantitatively similar CD8+ infiltrates. Double-labeling revealed apoptotic endothelial sinusoidal cells in CD8+ T-cell-infiltrated areas in all NRH samples but never in chronic hepatitis C or normal livers. T-cell receptor rearrangement or immunoscope analysis suggested liver-specific polyclonal or oligoclonal T-cell expansions. Clinical and biological characteristics of the 14 patients were similar to those observed in the 30 patients with NRH devoid of lymphocytic infiltration. We report here that CD8+ cytotoxic T cells infiltrated the liver sinusoids of a high percentage (32%) of NRH patients and suggest that some NRH cases might result from chronic, cytotoxic CD8+ T-lymphocyte targeting of sinusoidal endothelial cells.

Diagnosis of 6 mercaptopurine hepatotoxicity post liver transplantation utilizing metabolite assays

Azathioprine and 6-mercaptopurine (6 MP) are commonly used as immunosuppression postsolid organ transplantation. Recently, a better understanding of the metabolism of these drugs has developed. 6 Mercaptopurine is metabolized by thiopurine methyl transferase (TPMT) which is under the control of a common genetic polymorphism. Genetic testing and measurement of levels of 6 MP metabolites allow identification of patients at risk of toxicity. We report two cases of cholestatic hepatocellular injury associated with 6 MP toxicity occurring after orthotopic liver transplantation. Cholestasis developed after the introduction of 6 MP. Patients underwent extensive investigation and 6 MP toxicity was considered only after all other causes had been excluded. Thiopurine methyl transferase alleles identified on genetic testing were normal as were the 6 thioguanine levels. However, 6-methyl mercaptopurine levels were significantly elevated into the toxic range. Cholestasis resolved within a few weeks of drug withdrawal. 6 Mercaptopurine hepatotoxicity can present with a variety of clinical, biochemical and histological manifestations post OLT and should be considered as a cause of liver enzyme elevation. Monitoring of 6 MP metabolite levels in addition to TPMT allele testing is useful to prevent 6 MP toxicity and to help guide therapy.

Toxicity of low dose azathioprine and 6-mercaptopurine in rat hepatocytes. Roles of xanthine oxidase and mitochondrial injury

BACKGROUND/AIMS

To study effects of pharmacologic concentrations of azathioprine and 6-mercaptopurine (6-MP) on rat hepatocytes.

METHODS

Hepatocytes cultured on matrigel were incubated with azathioprine or 6-MP; effects of putative protective agents were studied. Viability (LDH leakage), reduced (GSH) and oxidized glutathione (GSSG), mitochondrial (mt) GSH, ATP and ultrastructural changes were determined.

RESULTS

Azathioprine and 6-MP (0.5-5 micromol/l) reduced viability 5-34% at day 1 and 42-92% by day 4. Allopurinol (20 microM) (xanthine oxidase inhibitor) and 2 mM Trolox (vitamin E analog) together provided near complete protection. During culture with azathioprine, GSSG increased before cell death and there was a disproportionate reduction of mtGSH and ATP, together with ultrastructural abnormalities in mitochondria. All changes were prevented by allopurinol and trolox. Discontinuation of 1 micromol/l azathioprine restored ATP levels and arrested cell injury, while culture in glucose-enriched media augmented ATP levels and ameliorated cell death.

CONCLUSIONS

Clinically relevant concentrations of azathioprine and 6-MP are toxic to rat hepatocyte cultures by a mechanism that involves oxidative stress, mitochondrial injury and ATP depletion. This can lead to irreversible de-energization and cell death by oncosis (necrosis).

Intrahepatic cholestasis after liver transplantation

Cholestasis is a common sequela of liver transplantation. Although the majority of cases remain subclinical, severe cholestasis may be associated with irreversible liver damage, requiring retransplantation. Therefore, it is essential that clinicians be able to identify and treat the syndromes associated with cholestasis. In this review, we consider causes of intrahepatic cholestasis. These may be categorized by time of occurrence, namely, within 6 months of liver transplantation (early) and thereafter (late), although there may be an overlap in their causes. The causes of intrahepatic cholestasis include ischemia/reperfusion injury, bacterial infection, acute cellular rejection, cytomegalovirus infection, small-for-size graft, drugs for hepatotoxicity, intrahepatic biliary strictures, chronic rejection, hepatic artery thrombosis, ABO blood group incompatibility, and recurrent disease. The mechanisms of cholestasis in each category and the clinical presentation, diagnosis, treatment, and outcome are discussed in detail.

Remission maintenance by tioguanine in chronic active Crohn's disease

BACKGROUND

Tioguanine may offer an alternative for immunosuppression in chronic active Crohn's disease. Recently, we have shown that tioguanine is effective in inducing rapid remission.

AIM

To evaluate the role of tioguanine in the maintenance of remission in chronic active Crohn's disease.

METHODS

A follow-up study was performed to investigate the long-term efficacy and safety of and tolerance to tioguanine in chronic active Crohn's disease. Sixteen patients who had successfully received 6-tioguanine for remission induction were enrolled. The reasons for immunosuppressive therapy were steroid dependence (n = 10), steroid refractoriness (n = 6) and intolerance (n = 6) or refractoriness (n = 1) to azathioprine. After remission induction therapy for 6 months, patients were treated for another 6 months with a daily dose of 20-40 mg tioguanine. Primary outcomes were remission (Crohn's disease activity index < 150) and complete steroid reduction in steroid-dependent patients at 12 months. Laboratory controls of white blood count and liver enzymes, as well as erythrocyte tioguanine nucleotide levels, were performed regularly.

RESULTS

After 12 months of treatment, 14 of 16 (88%) patients were in remission, and 12 of these were completely free of systemic steroids. Adverse events during maintenance therapy included photosensitivity (one patient), minor viral infections (one), headache (four) and mild alopecia (one). One patient developed elevated liver enzymes, splenomegaly and thrombocytopenia, indicative of nodular regenerative hyperplasia of the liver.

CONCLUSIONS

In responders to tioguanine, the drug appears to be very effective in maintaining remission of chronic active Crohn's disease. Unfortunately, long-term hepatotoxicity seems to be an unpredictable and potentially severe adverse drug reaction. Therefore, to date, tioguanine cannot be recommended for general use outside clinical trials.

Hepatic circulatory diseases associated with chronic myeloid disorders

These liver diseases are diseases of the hepatic circulation. Myeloproliferative disorders are among the most common prothrombotic disorders that lead to Budd-Chiari syndrome and PVT. SOS, previously known as hepatic veno-occlusive disease, is mainly seen in North America and Western Europe as a complication of the conditioning regimen for hematopoietic stem cell transplantation. SOS is caused by damage to SECs, and the initiating circulatory blockage occurs because of the embolism of sinusoidal lining cells. Myeloproliferative disorders are an uncommon cause of NRH, which is believed to be caused by uneven perfusion of the liver at the venous or sinusoidal level. Peliosis hepatis is believed to result from damage to SECs and is seen mainly in immunosuppressed patients, patients with a wasting illness, or patients with a drug toxicity.

Centrilobular fibrosis in long-term follow-up of pediatric liver transplant recipients

BACKGROUND

Centrilobular fibrosis after liver transplant in adults is caused mainly by viral hepatitis, chronic rejection, and azathioprine toxicity. The aim of this study was to investigate possible etiologies and the long-term outcome of this lesion in children.

METHODS

We identified centrilobular fibrosis in 12 of 117 pediatric liver transplant recipients who were investigated for persistent elevations in aminotransferases. Etiologic factors, histologic features on serial biopsies, and clinical and biochemical changes over time were noted for 8 recipients in whom a readily identifiable cause was not apparent.

RESULTS

Centrilobular fibrosis developed a mean of 1.7 years (range: 30 days-3.6 years) posttransplantation in patients receiving cyclosporine, azathioprine, and prednisone. Centrilobular fibrosis was always associated with portal fibrosis and, in six recipients, with persistent, low-grade, cellular rejection. None demonstrated chronic cholestasis, ductopenia, or identifiable vasculopathy. Ischemic, viral, and autoimmune etiologies were excluded. Discontinuing azathioprine did not lead to biochemical or histological improvement. After changing to tacrolimus, aminotransferases normalized in three recipients and repeat biopsies in six were unchanged during a further 2 years of follow-up.

CONCLUSIONS

Centrilobular fibrosis may develop in a small number of pediatric liver transplant recipients, resulting in considerable difficulties in biopsy interpretation. It is not associated with viral hepatitis nor with classical features of chronic rejection. The prognostic significance of centrilobular fibrosis is uncertain, although no child has required retransplantation in up to 12 years of follow-up. A role for a low-grade, chronic form of cellular rejection heralded by persistent, variable, and otherwise unexplained elevations in aminotransferases is suggested.

Centrilobular necrosis in children after combined liver and small bowel transplantation

BACKGROUND

Centrilobular necrosis is not an uncommon finding after isolated liver transplantation. In this study, we sought to describe hepatic centrilobular necrosis in children after combined liver and small bowel transplantation (LSBT), and to assess the predictive factors, possible causes, and prognosis.

METHODS

Six children aged 4 to 11 years, in whom liver biopsy showed centrilobular necrosis at least once, 3 weeks to 2 years after LSBT, were compared with nine children without this pathology. All six children experienced an acute complication in the few weeks preceding the finding of centrilobular necrosis. In addition, one child had an early arterial thrombosis and one, severe colitis 3 years after LSBT.

RESULTS

Centrilobular necrosis was associated with centrilobular swelling, dropout, endotheliitis, and inflammation. Fibrosis developed early and worsened on follow-up biopsy in three children. Portal symptoms of acute rejection were not constant, and there was no ductopenia. Biologic abnormalities were responsive to increased immunosuppression, including mycophenolate in four cases. However, follow-up biopsies showed persistent lesions in five patients, mildly inflammatory in four. Baseline immunosuppression had to be maintained at high levels. No viral infections, vascular compromise (except in one), and autoimmunity were found. We compared the two groups of children for initial diagnosis, age at transplantation, time receiving parenteral nutrition, ischemic time, presence of an associated transplanted colon, number of reoperations and infections, intestinal rejection, and immunosuppression, and found no differences.

CONCLUSIONS

This severe manifestation of chronic liver rejection occurred despite the heavy immunosuppression needed for LSBT. The previous acute clinical event could have triggered rejection by modifying the effective immunosuppression at the tissue level. Despite high baseline immunosuppression, histologic lesions persisted and significant fibrosis developed in half the children. We speculate that the lack of induction of tolerance in this particular setting of LSBT could be responsible for constant immune stimulation, thus chronic rejection. The optimal protocol of immunosuppression has yet to be defined to avoid this complication.

Mechanism of azathioprine-induced injury to hepatocytes: roles of glutathione depletion and mitochondrial injury

BACKGROUND/AIMS

We sought evidence that azathioprine causes cell death through reduced glutathione (GSH) depletion and mitochondrial injury.

METHODS

Studies were conducted in primary cultures of rat hepatocytes and cultured Hep G2 cells.

RESULTS

Azathioprine toxicity to rat hepatocytes was preceded by depletion of GSH. Prior GSH depletion (by treatment with buthionine sulfoximine) enhanced toxicity whilst supplemental GSH or N-acetylcysteine was protective. In hepatocytes, GSH is consumed during metabolism of azathioprine to 6-mercaptopurine. 6-Mercaptopurine was not toxic to hepatocytes, suggesting that the later steps in azathioprine metabolism were not related to the pathogenic mechanism. In Hep G2 cells, azathioprine did not alter levels of GSH and was not toxic. Ultrastructural studies showed hepatocyte mitochondrial lesions after exposure to azathioprine, but no features of apoptosis. Azathioprine produced rapid and profound depletion of adenosine 5'-triphosphate (ATP). Cyclosporin A and glycine afforded protection against azathioprine toxicity, and Trolox and high-dose allopurinol also attenuated injury.

CONCLUSIONS

The mechanism of azathioprine toxicity to hepatocytes involves depletion of GSH leading to mitochondrial injury with profound depletion of ATP and cell death by necrosis. Cell death was prevented by potent antioxidants, glycine and blocking the mitochondrial permeability transition pore.

Defibrotide for the treatment of veno-occlusive disease after liver transplantation

BACKGROUND

Veno-occlusive disease (VOD) after liver transplantation is associated with acute rejection and poor outcome. The use of antithrombotic and thrombolytic agents is limited by their toxicity. Defibrotide is a polydeoxyribonucleotide with thrombolytic and antithrombotic properties and no systemic anticoagulant effect.

METHODS

Defibrotide, 35-40 mg/kg/day, was administered intravenously for 21 days on a compassionate-use basis to two patients aged 66 and 49 years. VOD had developed 6 weeks and 4 months after orthotopic liver transplantation for hepatitis C and hepatitis B infection, respectively. VOD was diagnosed clinically by findings of weight gain (8.5% and 16%), ascites, jaundice (serum bilirubin 5.4 mg/dl and 21.7 mg/dl), and severe coagulopathy (in one patient), and histologically by the presence of hemorrhagic centrilobular necrosis and fibrous stenosis of the hepatic venules. One of the patients had received azathioprine as part of the immunosuppressive regimen. There was no evidence of acute cellular rejection histologically.

RESULTS

After 3 weeks of defibrotide administration, the first patient showed complete clinical resolution of the VOD, and serum bilirubin level normalized. He is alive 6 months after transplantation. The second patient, treated at a later stage of disease, showed marked improvement in the coagulopathic state, but there was no resolution of the VOD. He died 2 months later of multiorgan failure due to Escherichia coli sepsis. Neither patient had side effects from the drug.

CONCLUSIONS

Defibrotide is a promising drug for the treatment of VOD after liver transplantation and needs to be evaluated in large, prospective studies.

Veno-occlusive disease, nodular regenerative hyperplasia and hepatocellular carcinoma after azathioprine treatment in a patient with ulcerative colitis

We report the case of a 66-year-old male with ulcerative colitis diagnosed in 1987, who had been treated with azathioprine (AZA) for the past two years (average dose about 1.6 mg/kg/day). In May 1999 he presented with painless jaundice, fatigue and recent weight loss. Cholestatic enzymes were elevated, alpha-fetoprotein was normal and hepatitis B/C serology negative. After diagnosis of veno-occlusive disease (VOD) and hepatocellular carcinoma (HCC) via biopsy, tumour resection was performed. The histology was typical for a well-differentiated HCC with trabecular and pseudoglandular structures. Neighbouring liver tissue was atrophic, with nodular regenerative hyperplasia (NRH), peliosis-like sinusoidal ectasias and intra-sinusoidal accumulation of blood, associated with peri-sinusoidal fibrosis. Although none of the well-established risk factors for HCC such as cirrhosis, hepatitis B/C, metabolic liver disease or toxins were present, this patient developed HCC. This and previous reports suggest that NRH and/or VOD associated with AZA represent a risk factor for HCC. AZA should therefore not only be stopped in patients with NRH/VOD but patients should also be screened for HCC.

[Liver transplantation with a graft taken from a heart transplant patient who was brain-dead]

The shortage of organ donors has led to progressive softening of selection criteria for organ donation. We report on hepatic transplantation in a 55-year-old woman with primary biliary cirrhosis, whose donor was a 50-year-old heart transplant recipient who became brain stem dead, due to cerebral bleeding 8 months after transplantation. An orthotopic liver transplantation was performed. The postoperative course was uneventful and the recipient was alive and had normal liver function after a 42-month follow-up. Analysis of the literature included ethical consideration, potential hepatotoxic effects of immunosuppressive drugs and modification of the graft immunogenicity. It confirms that transplanted patients should not be a priori excluded from organ donation.

"Silent" presentation of veno-occlusive disease after liver transplantation as part of the process of cellular rejection with endothelial predilection

Hemorrhagic centrilobular necrosis and fibrous stenosis of hepatic venules, suggesting veno-occlusive disease (VOD) have rarely been observed after orthotopic liver transplantation (OLT). The aim of this study was to determine the prevalence of this syndrome after OLT in relation to the course with particular reference to acute rejection and to azathioprine administration. VOD was identified in 19 of 1,023 patients transplanted over a 9-year period. VOD occurred at a median of 30 days posttransplantation, without clear cut clinical evidence for hepatic vein outlet obstruction. Seventeen of the 19 patients had an episode of acute rejection before or at the time of VOD. These episodes were compared with that of patients without VOD. In patients with VOD, portal inflammation and endothelialitis were enhanced (P =.014 and P =.048) and endothelialitis was also higher than bile duct damage (P =.03). The incidence of a centrilobular endothelialitis for both groups was not different although an increased trend was observed in the study group (64% vs. 46%; P =.18). The incidence of persistent rejection was similar between both groups (47% vs. 41%). The incidence of chronic rejection was higher in the study group (29% vs. 10%; P =. 04). All patients with VOD received azathioprine as part of immunosuppressive regimen. Despite azathioprine withdrawal, zone 3 changes persisted in 57% of patients. In conclusion, the incidence of VOD was 1.9% after OLT. The association of prominent endothelial involvement and VOD with acute rejection in most cases suggests an immunological phenomenon.

Intrahepatic cholestasis following liver transplantation

Intrahepatic cholestasis following liver transplantation commonly occurs after liver transplantation and may be caused by infections, drugs such as cyclosporine and sulfonamides, and acute or chronic rejection. Less common causes such as fibrosing cholestatic hepatitis or recurrent primary biliary cirrhosis or primary sclerosing cholangitis may also be encountered. Biliary strictures may also be present. Although some disorders may be managed medically, others often require repeat liver transplantation. Prompt recognition and specific treatment can improve the outcome for liver transplant recipients.

Use of grafts procured from organ transplant recipients

BACKGROUND

Massive intracerebral bleeding may cause brain stem death in transplant (Tx) recipients early or late postTx. We addressed the question as to whether Tx recipients may safely be used as organ donors. In particular, it is feared that exposure to immunosuppressive drugs may render those organs unsuitable for Tx.

METHODS

We reviewed two case reports of liver grafts procured from Tx patients. In addition, we conducted a survey within United Kingdom Transplant Support Service Authority (UKTSSA) to delineate the UK experience in that area.

RESULTS

Donor 1 was an 50-year-old heart Tx recipient who became brain stem dead due to cerebral bleeding 8 months postTx. His liver was used in an 55-year-old patient with PBC who is alive and well more than 22 months postTx. Donor 2 was a 22-year-old kidney Tx patient who developed cerebral bleeding 4 years postTx. His liver was used in a 65-year-old patient with PBC who is doing well more than 27 months postTx. During the study period of 1989-1995, 13 organs (9 kidneys, 3 hearts, 1 liver) were procured from 6 brain stem dead Tx patients (3 long, 2 heart, and 1 kidney Tx patients). Seven recipients are enjoying satisfactory graft function 1 to 7 years postTx; one kidney Tx recipient was relisted 4 years postTx due to chronic rejection; five functionning grafts were lost to patient death; primary nonfunction was seen in one heart Tx recipient.

CONCLUSIONS

Tx patients can be successfully used as organ donors. In particular, chronic exposure to immunosuppression is not per se a contraindication to donation. Tx physicians confronted with the rare and tragic event of brain stem death in a Tx patient should not a priori exclude these patients from donation.

Gastrointestinal complications of immunosuppression

The gastrointestinal manifestations of drug-induced immunosuppression may result from direct drug effects, from infectious complications, or both. Graft-versus-host disease (GVHD) is a third mechanism whereby immunosuppressive agents are linked with gastrointestinal injury. This article reviews individual immuno-suppressive medications, first concentrating on their reported gastrointestinal side effects, then reviewing other gastrointestinal phenomena, which may represent side effects of immunosuppressive agents but have not been reported yet.

Prognostic implications of centrilobular necrosis in pediatric liver transplant recipients

BACKGROUND

We have observed centrilobular necrosis (CLN) in several liver allograft biopsies in our pediatric liver transplant population. The aims of this study were to describe the associated pathologic and clinical features of post-orthotopic liver transplantation CLN and determine its prognostic implications.

METHODS AND RESULTS

CLN was identified and characterized in 44 allografts from 40 patients (17 males and 23 females) among our 443 pediatric recipients. Twenty episodes were associated with cellular rejection, either in the same biopsy (n=15) or within the week prior (n=5), and five were associated with ductopenic rejection. Twelve were associated with vascular thrombosis. No clear etiology was identified in seven episodes, but two also had cholangitis lenta. Of the remaining five biopsies, three showed only centrilobular dropout, suggesting a resolution of some previous insult. The outcome of 40 patients following an initial episode of CLN was poor, with graft failure in 33, chronic poor function in 2, and normal recovery in only 5 patients. The results of retransplantation for graft failure due to CLN were equally poor, with 14 deaths, 3 patients with ductopenic rejection, and only 5 with normal recovery. CLN recurred in four grafts. Overall patient outcome was very poor: 25 deaths; 3 ductopenic rejections; 2 chronic poorly functioning livers; and 10 patients alive and well.

CONCLUSION

We conclude that CLN in pediatric orthotopic liver transplantation recipients is associated with cellular rejection, ductopenic rejection, or acute vessel thrombosis in the majority cases. The prognostic implications of CLN are grave, with high rates of graft failure requiring retransplantation and death.