Isolation, characterization, and transplantation of bone marrow-derived hepatocyte stem cells.

Recently it was shown that a population of cells in the bone marrow-expressing hematopoietic stem cell antigens could differentiate into hepatocytes. However, explicitly committed hepatocyte progenitors, which exhibit highly differentiated liver functions, immediately upon isolation, have not yet been isolated from bone marrow. After studying common antigens on blast-like cells in fetal and adult regenerating cholestatic rat livers and human regenerating and malignant livers, we hypothesized that beta-2-microglobulin-negative (beta(2)m(-)) cells might represent dedifferentiated hepatocytes and/or their progenitors. Utilizing a two-step magnetic bead cell-sorting procedure, we show that in bone marrow from rat and human, beta(2)m(-)/Thy-1(+) cells consistently express liver-specific genes and functions. After intraportal infusion into rat livers, bone marrow-derived hepatocyte stem cells (BDHSC) integrated with hepatic cell plates and differentiated into mature hepatocytes. In a culture system simulating liver regeneration and containing cholestatic serum, these cells differentiated into mature hepatocytes and metabolized ammonia into urea. This differentiation was dependent on a yet nondescript humoral signal existing in the cholestatic serum. Transmission electron microscopy and three-dimensional digital reconstruction confirmed hepatocyte ultrastructure of cultured BDHSC.

Transmission of hepatitis B infection from hepatitis B core antibody--positive liver allografts is prevented by lamivudine therapy.

Donor shortage has led to the use of hepatitis B core antibody (anti-HBc)--positive (anti-HBc(+)) liver allografts for patients in need of relatively urgent orthotopic liver transplantation (OLT). Because anti-HBc(+) allografts transmit hepatitis B virus (HBV) infection at a high rate, effective prophylaxis is required. We assessed the effectiveness of lamivudine in preventing HBV transmission by anti-HBc(+) allografts. Between March 1996 and March 2000 at Cedars-Sinai Medical Center (Los Angeles, CA), 15 of 169 patients (8.9%) received liver allografts from anti-HBc(+) donors. Six patients were hepatitis B surface antigen (HBsAg)(+) (group 1), and 9 patients were HBsAg negative (HBsAg(-); group 2) before OLT. All patients were administered lamivudine, 100 or 150 mg/d, orally after OLT. Patients who were HBsAg(+) before OLT also were administered hepatitis B immunoglobulin (HBIG) prophylaxis. Hepatitis B serological tests were performed on all patients, and HBV DNA was determined in liver tissues in 10 patients. All 15 patients remained HBsAg(-) at their last follow-up 2 to 40 months (mean, 17 months) post-OLT. All patients in group 1 had antibody to HBsAg (anti-HBs) titers greater than 250 mIU/mL post-OLT (mean follow-up, 20 months; range, 7 to 40 months). Of the 2 patients in group 1 who underwent liver biopsy after OLT, 1 patient had detectable hepatic HBV DNA despite being anti-HBs(+) and HBsAg(-). Among the patients in group 2, none acquired anti-HBc or HBsAg. Hepatic HBV DNA was undetectable in the 7 patients in group 2 who underwent liver biopsy after OLT. Anti-HBc(+) allografts can be safely used in patients who undergo OLT for chronic hepatitis B and susceptible transplant recipients if prophylaxis with combination HBIG and lamivudine or lamividine alone is administered after OLT, respectively. However, more data are needed to determine the efficacy of lamivudine monotherapy in preventing transmission of HBV infection from anti-HBc(+) liver allografts to susceptible recipients.

Radiographic findings of ischemic hepatitis in a cirrhotic patient.

We report the radiographic findings of ischemic hepatitis in a patient with cirrhosis. The abdominal ultrasound exam showed multiple hypoechoic nodules in the liver measuring up to 2 cm, suggestive of diffuse metastatic disease. Abdominal computed tomography (CT) scan revealed multiple hypodense masses throughout the liver with no enhancement. Liver biopsy revealed coagulative hepatocyte necrosis at the center of the regenerative nodules. Repeat CT scan obtained 5 months later showed complete resolution of the hypodense nodules. Ischemic necrosis of regenerative nodules should be differentiated from diffuse hepatic metastatic disease in the setting of ischemic hepatitis in cirrhotic patients.

Orthotopic liver transplantation for primary sclerosing cholangitis. A 12-year single center experience.

OBJECTIVE: The purpose of this study was to analyze a single center's 12-year experience with 127 orthotopic liver transplantations (OLT) for primary sclerosing cholangitis (PSC). SUMMARY BACKGROUND DATA: Primary sclerosing cholangitis is a chronic cholestatic liver disease of unknown origin that occurs most commonly in young men and is associated frequently (70-80%) with inflammatory bowel disease (IBD). Patients with PSC also are at risk for the development of cholangiocarcinoma (CCA) and those with IBD for colon carcinoma. Although the course of PSC is variable, it frequently is progressive, leading to cirrhosis and requirement for OLT. METHODS: The medical records of 127 consecutive patients undergoing OLT for PSC from July 1, 1984, to May 30, 1996, were reviewed. Actuarial patient and graft survival was determined at 1,2, and 5 years. The incidence and outcome of patients with CCA, recurrent sclerosing cholangitis, and post-transplant colon carcinoma was determined. Results were analyzed by way of stepwise Cox regression to determine the statistical strength of independent associations between pretransplant covariates and patient survival. The median follow-up period was 3.01 years. Incidental cholangiocarcinoma (ICCA) was defined as a tumor < 1 cm in size that was discovered at the time of pathologic sectioning of the explanted liver. RESULTS: Ninety-two patients (72%) had associated IBD. Seventy-nine (62%) had undergone previous biliary tract surgery. One hundred seven patients (84%) received a single graft, whereas 20 patients (16%) required 22 retransplants. Patients received either cyclosporine- (n = 76) or tacrolimus- (n = 51) based immunosuppression. The 1-, 2-, and 5-year actuarial patient survivals were 90%, 86%, and 85%, respectively, whereas graft survival was 82%, 77%, and 72%, respectively. The presence of previous biliary surgery had no effect on patient survival. Ten patients (8%) had ICCA and their survival was not significantly different from patients without ICCA (100%, 83%, and 83% at 1, 2, and 5 years, respectively). Four patients were known to have CCA at the time of OLT, all recurred within 6 months, and had a significantly worse outcome (p < 0.0001). Recurrent sclerosing cholangitis developed in 11 patients (8.6%). The patient and graft survival in this group was not different from those in whom recurrence did not develop (patient; 100%, 90%, and 90%; graft: 80%, 70%, and 52%). Thirty patients (23%) underwent colectomy after liver transplantation for dysplasia-carcinoma or symptomatic colitis. Of the nine covariates entered into the Cox multivariate regression analysis, only common bile duct frozen section biopsy specimen showing CCA was predictive of a survival disadvantage. CONCLUSIONS: Liver transplantation provides excellent patient and graft survival rates for patients affected with PSC independent of pretransplant biliary tract surgery. Incidental cholangiocarcinoma does not affect patient survival significantly. However, known CCA or common duct frozen section biopsy specimen or both showing CCA are associated with poor recipient survival, and OLT should be proscribed in these cases. Recurrent PSC occurs in approximately 9% of cases but does not affect patient survival. Post-transplant colectomy does not affect patient survival adversely.

Use of a novel bioartificial liver in a patient with acute liver insufficiency.

We have developed a bioartificial liver support system (BAL) using porcine hepatocytes attached to microcarriers and placed on the outer surface of hollow fibers. The BAL system was attached to a plasmapheresis device that was then used to treat the plasma of a patient with acute liver failure. Our aim was to test the efficacy and safety of this system after a single short treatment period. A patient with alcohol-induced, severe, acute liver failure manifested by coagulopathy, rising plasma ammonia level, and deteriorating mental status was studied. The procedure was well tolerated by the patient, who remained hemodynamically stable throughout the treatment period. A marked increase in coagulation factor V, VII, VIII, and IX activities, a decrease in serum ammonia level (120 to 32 mumol/L), a twofold increase in all serum amino acids except for aminobutyric acid, and an improvement in mental status were noted after a 6-hour treatment period. This preliminary report of the first use of this novel BAL system in conjunction with plasmapheresis appears promising. A clinical study is now in progress to prove its efficacy.

Intraperitoneal transplantation of microcarrier-attached enterocytes in rats.

The purpose of this study was to determine whether enterocyte transplantation could be used to correct a specific genetic metabolic defect. Bilirubin uridine diphosphoglucuronyl transferase (UDPGT) activity has been demonstrated in normal rat intestinal mucosa. We hypothesized that normal rat enterocyte transplantation may restore the ability of Gunn rats, which lack bilirubin UDPGT, to conjugate bilirubin. Small intestine was resected from normal Wistar rat donors. Enterocytes were harvested and suspended in Dulbecco's modified Eagle's medium with 10 percent fetal calf serum. Isolated enterocytes were attached to collagen-coated dextran microcarriers and transplanted into congeneic Gunn rat recipients. Recipient rats underwent bile duct cannulation after transplantation, and bile was analyzed for bilirubin glucuronides by high-pressure liquid chromatography. Fifty percent of the transplanted rats showed a significant increase in the concentration of bilirubin monoglucuronide and diglucuronide in their bile 4 and 7 days posttransplantation. Recipient rats had well vascularized microcarrier-enterocyte aggregates in the peritoneal cavity. Our method for intraperitoneal transplantation of isolated enterocytes in rats could potentially be used to correct specific enzymatic and metabolic defects.