John M. Rabkin

Prospective, randomized, multicenter, controlled trial of a bioartificial liver in treating acute liver failure

Objective:The HepatAssist liver support system is an extracorporeal porcine hepatocyte-based bioartificial liver (BAL). The safety and efficacy of the BAL were evaluated in a prospective, randomized, controlled, multicenter trial in patients with severe acute liver failure. Summary Background Data:In experimental animals with acute liver failure, we demonstrated beneficial effects of the BAL. Similarly, Phase I trials of the BAL in acute liver failure patients yielded promising results. Methods:A total of 171 patients (86 control and 85 BAL) were enrolled. Patients with fulminant/subfulminant hepatic failure and primary nonfunction following liver transplantation were included. Data were analyzed with and without accounting for the following confounding factors: liver transplantation, time to transplant, disease etiology, disease severity, and treatment site. Results:For the entire patient population, survival at 30 days was 71% for BAL versus 62% for control (P = 0.26). After exclusion of primary nonfunction patients, survival was 73% for BAL versus 59% for control (n = 147; P = 0.12). When survival was analyzed accounting for confounding factors, in the entire patient population, there was no difference between the 2 groups (risk ratio = 0.67; P = 0.13). However, survival in fulminant/subfulminant hepatic failure patients was significantly higher in the BAL compared with the control group (risk ratio = 0.56; P = 0.048). Conclusions:This is the first prospective, randomized, controlled trial of an extracorporeal liver support system, demonstrating safety and improved survival in patients with fulminant/subfulminant hepatic failure.

Association of multispecific CD4+ response to hepatitis C and severity of recurrence after liver transplantation*

BACKGROUND & AIMS After liver transplantation for hepatitis C virus (HCV), reinfection of the allograft invariably occurs. Indirect evidence suggests that the cellular immune response may play a central role. The purpose of this analysis was to determine the correlation between HCV-specific peripheral CD4(+) T-cell responses and the severity of recurrence after liver transplantation. METHODS Fifty-eight HCV-seropositive patients, including 43 liver transplant recipients with at least 1 year of histological follow-up, were studied. Peripheral blood mononuclear cells (PBMCs) were isolated from fresh heparinized blood and stimulated with either recombinant HCV antigens (core, E2, NS3, NS4, and NS5) or control antigens. RESULTS Fourteen (40%) of 35 patients with mild or no evidence of histological recurrence within their allografts responded to at least 1 of the HCV antigens. Eleven responded to NS3, 5 to all the nonstructural antigens, and 3 to the HCV core polypeptide alone. In contrast, in the 8 patients with severe HCV recurrence, no proliferation in response to any of the HCV antigens was seen (P = 0. 03) despite responses to the control antigens. CONCLUSIONS Despite immunosuppression, HCV-specific, major histocompatibility complex class II- restricted CD4(+) T-cell responses are detectable in patients with minimal histological recurrence after liver transplantation. In contrast, PBMCs from patients with severe HCV recurrence, despite being able to proliferate in response to non-HCV antigens, fail to respond to the HCV antigens. These findings suggest that the inability to generate virus-specific T-cell responses plays a contributory role in the pathogenesis of HCV-related graft injury after liver transplantation. It is hoped that further characterization of the immunoregulatory mechanisms related to recurrent HCV will provide the rationale for novel therapeutic strategies and diminish the incidence of inevitable graft loss.

Cytomegalovirus viremia : Risk factor for allograft cirrhosis after liver transplantation for hepatitis C

BACKGROUND Despite recent advances in diagnosis and treatment, cytomegalovirus (CMV) infection continues to be a common cause of morbidity in liver transplant (LT) recipients. Because CMV infection suppresses cell-mediated immunity, which seems to be important in neutralizing hepatitis C virus (HCV) infection, we assessed the impact of CMV infection on histopathological HCV recurrence after LT. METHODS The study group was comprised of 43 consecutive LT recipients with at least 6 months of histologic follow-up. Group 1 consisted of the 8 patients who developed CMV viremia after LT; group 2 comprised the 35 patients without CMV viremia. There was no significant difference with regard to age, initial immunosuppression, incidence of rejection, distribution of HCV genotypes, or mean follow-up between the groups. Semiquantitative histopathologic assessment of allograft hepatitis was performed using the Knodells score. RESULTS The mean total Knodell score of the final allograft biopsy was significantly greater in group 1 patients (P=0.016), with most of the difference due to periportal/bridging necrosis (P=0.009) and lobular activity subitem (P=0.01) scores. Half of the CMV viremic patients eventually developed allograft cirrhosis as compared with 11% of the CMV-negative patients (P=0.027). Accordingly, the cirrhosis-free actuarial survival by Kaplan-Meier estimates was significantly diminished in the CMV viremic patients. Glycoprotein B genotype analysis of CMV isolates revealed no significant differences between patients who did and those who did not develop allograft cirrhosis. CONCLUSIONS After LT for chronic HCV, patients who develop CMV viremia incur a significantly greater risk of severe HCV recurrence.

Cytokine and T cell receptor gene expression at the site of allograft rejection

Intragraft cytokine and T cell receptor gene expression was analyzed in rejecting renal allografts by polymerase chain reaction (PCR). Message for IL-1β, IL-6, and TNF-α was detected in nephrectomy tissue with pathological evidence of acute or chronic rejection. Similarly, mRNA for both IL-6 and TNF-α was present in renal biopsies from acute rejecting kidneys. IL-2R, IL-4, and IL-5 mRNA was present in both rejecting and rejected kidney allografts, indicating that these cytokines may play a role in ongoing renal allograft rejection. Conversely, IL-2, IL-7, and IFN-γ message was detected infrequently. In order to address the diversity of T cells in rejecting kidneys, we have analyzed the clonality of the TcR present within the allograft tissue. Rearranged TcR genes were identified in all allografts examined (n=16) indicating the presence of T cells bearing the α/β TcR. We have determined that there is a heterogeneous infiltration of T cells in the rejected allograft with TcR representing x=7.47±2.4 families rearranged in samples obtained from nephrectomies, whereas x=5.33±0.58 families were detected in samples obtained from biopsy tissue. These data indicate that (1) cytokines are produced locally which may contribute to graft cell destruction, (2) the heterogeneity of intragraft T cells during kidney allograft rejection may exist because nonspecific lymphocytes have been recruited to the site by locally produced cytokines or because T cells are responding to multiple epitopes or multiple donor antigens. Detection of intragraft cytokines and TcR may prove useful in elucidating the mechanism of rejection and therefore lead to improved immunosuppression.

Timing and severity of initial hepatitis C recurrence as predictors of long-term liver allograft injury

BACKGROUND The majority of patients infected with hepatitis C virus (HCV) undergoing liver transplantation develop evidence of histologic recurrence, and multiple mechanisms are likely poised to affect long-term allograft injury. The purpose of this analysis was to study the hypothesis that histologic and biochemical features at the onset of HCV recurrence predict the long-term evolution of allograft hepatitis. METHODS We studied 34 consecutive liver transplant recipients with evidence of histologic HCV recurrence and with a minimal histologic follow-up of 1 year (up to 6.2 years; mean: 696+/-83.2 days). Two-hundred and seventy-eight serial allograft biopsies (mean: 6.85+/-0.62 per patient, range: 4-21) were analyzed. The hepatic activity index was utilized to quantitate piecemeal necrosis, intralobular degeneration, portal inflammation, and hepatic fibrosis. The presence of hepatocyte ballooning degeneration and cholestasis was also assessed. RESULTS Although there was no significant difference with regard to initial hepatic activity index scores between patients who ultimately developed allograft cirrhosis (group 1; n=8) versus those with milder hepatitis (group 2; n=26), the finding of ballooning degeneration/cholestasis was more frequent in the former group (P=0.04). The distribution of HCV genotypes, the mean follow-up after orthotopic liver transplantation, the mean number of allograft biopsy specimens per patient, basal immunosuppression, and incidence of rejection were comparable in both groups. Patients who ultimately developed allograft cirrhosis had significantly higher initial total bilirubin at the onset of histologic recurrence and peak total bilirubin (pT. Bili, the highest value in the ensuing month). Actuarial rates of moderate-to-severe allograft hepatitis were significantly greater in patients with pT. Bili > or = 3.5 mg/dl (P=0.004). Multiple regression analysis identified pT. Bili as the only independent predictor of allograft cirrhosis. CONCLUSIONS Features at the onset of histologic HCV recurrence predict the natural history of allograft injury; specifically, marked, transient hyperbilirubinemia is associated with the subsequent development of allograft cirrhosis.

Bile Duct Injury as a Major Cause of Stenosis and Occlusion in Transjugular Intrahepatic Portosystemic Shunts: Comparative Histopathologic Analysis in Humans and Swine

PURPOSE A comparative histologic analysis of human and swine transjugular intrahepatic portosystemic shunts (TIPS) was performed to investigate factors limiting TIPS patency and to further develop an animal model for TIPS. MATERIALS AND METHODS Twenty-one human and 13 porcine shunts were evaluated by means of gross inspection, histologic evaluation, and electron microscopy. RESULTS Severe stenosis (> 75% narrowing) or occlusion was detected with portal venography in nine of the 21 human shunts (48%) and in 10 of 13 porcine shunts (77%). Gross or histologic evidence of a substantial biliary fistula was observed in seven of nine porcine shunts and in seven of eight human shunts with severe parenchymal tract stenosis or occlusion. No evidence of substantial bile duct injury was identified in the 13 human shunts or two swine shunts with patent, nonstenotic parenchymal tracts (P < .01, Fisher exact). Histologic findings in porcine shunts mimicked human tissue responses, including a metaplastic proliferation of bile duct epithelium at sites of bile duct transection. CONCLUSION Bile duct transection and bile leak are significantly associated with TIPS parenchymal tract abnormalities in patients and swine. TIPS in swine created with the Wallstent faithfully reproduce gross morphologic and histologic changes observed in patients.

Late mortality after orthotopic liver transplantation

BACKGROUND Mortality within the first year after orthotopic liver transplantation (OLTx) is usually due to infection or allograft failure. Late complications leading to death after OLTx have not been extensively evaluated. The aim of this study was to determine the incidence of late mortality and to identify the most common causes and risk factors associated with late mortality after OLTx. METHODS A total of 479 OLTx were performed in 459 patients (320 males, 139 females; mean age 47 years, range 13 to 69) between September 1991 and April 2000. All patient deaths among liver transplant recipients who survived more than 1 year after transplantation (follow-up mean 3.4 years, median 3, range 1 to 8.6) were reviewed. RESULTS In all, 122 allografts (24%) were lost in 109 patients during the study period (24%). Seventy-five allografts were lost in 69 patients by 1 year (15%). Forty-seven allografts were lost in 40 patients who survived at least 1 year (9.6%). Actuarial survivals at 2 years, 5 years, and 9 years were 95%, 85%, and 80%, respectively (based on 100% survival at 1 year). The causes of the late mortality were malignancy (9 patients), disease recurrence (8), late infection (6), renal failure complications (5), cardiovascular complications (4), chronic rejection (3), gastrointestinal hemorrhage (2), medication noncompliance (1), and unknown (2). CONCLUSIONS Malignancy and disease recurrence are the major causes of late mortality among adult OLTx recipients. Pharmacologic immunosuppression is associated with many of the causes of late mortality. Advances in immunosuppression with less toxicity may improve long-term survival after OLTx.

Immunosuppression impact on long-term cardiovascular complications after liver transplantation

BACKGROUND With current early transplant patient and allograft survivals nearly optimized, long-term medical complications have become a significant focus for potential improvement in patient outcomes. Cardiovascular disease and associated risk factors have been shown in renal transplant patients to be related to the pharmacologic immunosuppression employed. OBJECTIVE The objective of this study is to investigate at 3 years postliver transplant (OLTx) the incidence of hypertension (HTN), hyperlipidemia (HLIP), diabetes mellitus (DM), nephrotoxicity (NTX), and cardiovascular disease (MI, angioplasty, CHF, CVA, and seborth) as well as rejection in two cohorts of liver transplant recipients who received either tacrolimus (FK-506) or cyclosporine (CSA) and to analyze the consequences of these complications on mortality following transplantation. METHODS Eighty-seven sequential patients (CSA: n = 50, mean age 48 years, M/F 32/18; and FK-506: n = 37, mean age 45 years, M/F 22/15) who underwent OLTx between 1994 and 1998, were >/=18 years, and had a minimum of 3 years of complete follow-up were included in the analysis. All OLTx candidates over age 50, who had a history of alcoholic cirrhosis, or had a history of cardiac conditions/events underwent complete cardiac consultation including an echocardiogram with additional cardiac investigation as indicated prior to OLTx. RESULTS At 3 years following OLTx, the incidence of acute rejection (40% versus 19%, P < 0.05), HTN (62% versus 38%, P < 0.05), HLIP (14% versus 5%, P = 0.08), and cardiovascular disease (18% versus 0%, P < 0.001), were significantly greater for the CSA patients compared with the FK-506 patients. Eight (20%) of the CSA patients who died before 3 years had their death attributed to cardiovascular events versus none in the FK-506 group. CONCLUSION Compared with CSA, FK-506 was associated with significantly less rejection and a reduced incidence of HTN and cardiovascular disease.

Association of fungal infection and increased mortality in liver transplant recipients

BACKGROUND Invasive fungal infection is associated with increased morbidity and mortality following orthotopic liver transplantation (OLTx). Understanding the risk factors associated with fungal infection may facilitate identification of high-risk patients and guide appropriate initiation of antifungal therapy. OBJECTIVES The aim of this study was to determine the incidence of fungal infections, identify the most common fungal pathogens, and determine the risk factors associated with fungal infections and mortality in OLTx recipients. METHODS Medical records from 96 consecutive OLTx in 90 American veterans (88 males, 2 females; mean age 48 years, range 32 to 67) performed from January 1994 to December 1997 were retrospectively reviewed for fungal infection in the first 120 days after transplantation. Infection was defined by positive cultures from either blood, urine (<105 CFU/mL), cerebrospinal or peritoneal fluid, and/or deep tissue specimens. Superficial fungal infection and asymptomatic colonization were excluded from study. All patients received cyclosporine, azathioprine, and prednisone as maintenance immunosuppressive therapy. Fungal prophylaxis consisted of oral clotrimazole (10 mg) troches, five times per day during the study period. RESULTS Thirty-five patients (38%) had documented infection with one or more fungal pathogens, including Candida albicans (25 of 35; 71%), C torulopsis (7 of 35; 20%), C tropicalis (2 of 35; 6%), non-C albicans (2 of 35; 6%), Aspergillus fumigatus (4 of 35; 11%), and Cryptococcus neoformans (1 of 35; 3%). The crude survival for cases with or without fungal infection was 68% and 87%, respectively (P <0.0001). The median intensive care unit stay and overall duration of hospitalization were significantly longer for patients with fungal infection (P <0.01). The mean time interval from transplantation to the development of fungal infection was 15 days (range 4 to 77) with a mean survival time from fungal infection to death of 21 days (range 3 to 64). Fungal infections occurred significantly more often in patients with renal insufficiency (serum creatinine >2.5 mg/dL), biliary/vascular complications, and retransplantation. CONCLUSIONS Fungal infections were associated with increased morbidity and mortality following OLTx, with Candida albicans being the most common pathogen. Treatment strategies involving antifungal prophylaxis for high-risk patients and earlier initiation of antifungal therapy in cases of presumed infection are warranted.

Stent-Grafts for Revision of TIPS Stenoses and Occlusions: A Clinical Pilot Study

PURPOSE To assess the clinical and technical results of stent-graft placement for revision of transjugular intrahepatic portosystemic shunt (TIPS) stenoses and occlusions. MATERIALS AND METHODS Six patients who developed recurrent TIPS stenosis or occlusion of the parenchymal tract underwent shunt revision with use of polytetrafluoroethylene (PTFE) stent-grafts anchored at both ends by Z stents and centrally supported by Wallstents. RESULTS Before graft placement, mean primary patency was 50 days (range, 9-100 days). Patients underwent one to eight revisions with angioplasty or stent placement (mean, 3.2). Three patients had biliary-TIPS fistulas documented with use of a prototype double occlusion balloon catheter. Stent-grafts were successfully placed within the obstructed shunt, creating an excellent lumen in all cases. The portosystemic gradient was decreased from a mean of 24.3 mm Hg (range, 12-35 mm Hg) to a mean of 10.3 mm Hg (range, 7-16 mm Hg). Five of six patients were asymptomatic and no complications occurred (median clinical follow-up, 331 days). One patient died of pre-existing multi-organ system failure. The duration of primary patency after stent-grafting was improved (mean, 229 days; range, 27-324 days) and the difference approached statistical significance despite the small sample size (P = .056, paired t test). Three patients remained primarily patent at a mean venographic follow-up of 315 days. One shunt occluded at 1 month from residual thrombus in the portal vein, and one stenosis occurred that was secondary to misplacement of the original stent-graft. Patency was re-established in each of these patients. CONCLUSION PTFE covered stent-grafts are effective for shunt revision in patients with tract stenosis or occlusion and appear to improve TIPS patency.