From the Department of Surgery and the Liver Support Unit, Cedars-Sinai Medical Center,. Los Angeles, Califomia. Objective. To test the safety and efficacy of a ...
ANNALS OF SURGERY Vol. 219, No. 5, 538-546 © 1994 J. B. Lippincott Company
A Bioartificial Liver to Treat Severe Acute Liver Failure Jacek Rozga, M.D., Ph.D., Luis Podesta, M.D., Elaine LePage, R.N., M.S.N., Eugenio Morsiani, M.D., Albert D. Moscioni, Ph.D., Allen Hoffman, M.D., Linda Sher, M.D., Federico Villamil, M.D., Graham Woolf, M.D., Michael McGrath, M.D., Lawrence Kong, M.D., Hugo Rosen, M.D., Todd Lanman, M.D., John Vierling, M.D., Leonard Makowka, M.D., Ph.D., and Achilles A. Demetriou, M.D., Ph.D. From the Department of Surgery and the Liver Support Unit, Cedars-Sinai Medical Center, Los Angeles, Califomia
Objective To test the safety and efficacy of a bioartificial liver support system in patients with severe acute liver failure.
Summary Background Data The authors developed a bioartificial liver using porcine hepatocytes. The system was tested in vitro and shown to have differentiated liver functions (cytochrome P450 activity, synthesis of liverspecific proteins, bilirubin synthesis, and conjugation). When tested in vivo in experimental animals with liver failure, it gave substantial metabolic and hemodynamic support.
Methods Seven patients with severe acute liver failure received a double lumen catheter in the saphenous vein; blood was removed, plasma was separated and perfused through a cartridge containing 4 to 6 X 109 porcine hepatocytes, and plasma and blood cells were reconstituted and reinfused. Each treatment lasted 6 to 7 hours.
Results All patients tolerated the procedure(s) well, with neurologic improvement, decreased intracranial pressure (23.0 ± 2.3 to 7.8 ± 1.7 mm Hg; p < 0.005) associated with an increase in cerebral perfusion pressure, decreased plasma ammonia (163.3 ± 21.3 to 1 12.2 ± 9.8 ,uMoles/L; p < 0.01), and increased encephalopathy index (0.60 ± 0.17 to 1.24 ± 0.22; p < 0.03). All patients survived, had a liver transplant, and were discharged from the hospital.
Conclusions This bioartificial liver is safe and serves as an effective "bridge" to liver transplant in some patients.
The only clinically proven effective treatment of severe acute liver failure is orthotopic liver transplant.1 However many patients die before an organ becomes
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available.' 2 Thus these patients need a liver support system to help keep them alive and maintain neurologic function until an organ is procured. We developed a bi-
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Table 1. PATIENT DEMOGRAPHICS, CAUSES OF LIVER FAILURE, AND OUTCOMES Age
Patient
(yrs)
1 2 3 4 5 6 7
58 35 10 18 34 24
50
BAL
Sex M F M F M M F
Liver Failure Etiology
Treatment
OLT
Outcome
Primary graft non-function Viral hepatitis C Indeterminate Acetaminophen overdose Indeterminate Indeterminate Acetaminophen overdose
1 1 1 3 1 2 2
Y Y Y Y Y Y Y
Recovered Recovered Recovered Recovered Recovered Recovered Recovered
BAL = Bioartificial liver; OLT = Orthotopic liver transplantation.
oartificial liver (BAL) based on plasma perfusion through a circuit of a hollow-fiber cartridge seeded with matrix-anchored porcine hepatocytes3-6 to treat patients with severe acute liver failure. All patients were initially treated with standard supportive measures. The BAL was subsequently used as a "bridge" while patients waited for an organ to become available for transplant. This report summarizes our preliminary clinical experience with 11 bridge treatments in 7 patients with severe acute liver failure.
METHODS Patients Seven patients were studied. All procedures were in accord with the ethical standards of the institutional committee on human experimentation and with the Declaration of Helsinki of 1975. Patients were treated by a multidisciplinary Liver Support Unit team that included transplant surgeons and hepatologists, registered nurses, critical care specialists, anesthesiologists, neurosurgeons, infectious disease specialists, and nephrologists in a specialized intensive care unit equipped with a computerized, on-line clinical data collection system. The following parameters were continuously monitored: vital signs, urinary output, hemodynamics (heart rate, arterial, central venous and pulmonary artery pressures, and cardiac output), neurologic status, intracranial presPresented at the 105th Annual Scientific Session ofthe Southern Surgical Association, December 5-8, 1993. Supported by institutional grants and a grant from the National Institutes of Health (NIDDK; DK38763-09). Address reprint requests to A. A. Demetriou, Cedars-Sinai Medical Center, Liver Support Unit, Suite 8215, 8700 Beverly Boulevard, Los Angeles, CA 90048. Accepted for publication January 4, 1994.
sure and cerebral perfusion pressure (if indicated), hourly arterial blood gases, liver biochemistry (bilirubin, transaminases, alkaline phosphatase, and lactate dehydrogenase), prothrombin time, partial thromboplastin time, coagulation factor activity, complete blood cell count, serum electrolytes, ammonia, lactate, amino acids, and creatinine and blood urea nitrogen levels. Blood samples were obtained serially at the start, during, and after each BAL treatment. Patient demographic characteristics, number of BAL treatments, and underlying cause of liver failure are summarized in Table 1. All patients had extensive diagnostic workup to determine the cause of liver failure, including toxicologic and viral screening and light and electron microscopic examination oftheir explanted livers. No clear diagnosis could be made in some patients. Immediately at admission, patients were evaluated and treatment was initiated to correct electrolyte, metabolic, respiratory, coagulation, and hemodynamic abnormalities. Except for patient 2, who had stage 11/111 encephalopathy, all other patients were in deep stage IV coma.7 Five patients (patients 3 to 7) had cerebral edema documented by computed tomography scan and showed signs of severe neurologic dysfunction: unequal or abnormally reactive pupils, dysconjugate gaze, decerebrate posturing, generalized rigidity, and lack of response to external stimulation. An intracranial pressure monitor was placed at the bedside of these patients. In four patients a subdural fiber optic probe was used, whereas in one case the probe was placed in the arachnoid space (Camino Laboratories, San Diego, CA). Bioartifical liver support treatment was instituted in all patients, because they did not respond to standard measures (hyperventilation, mannitol and lactulose administration, metabolic and hemodynamic support). Barbiturate coma was not used to treat any of them.
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Rozga and Others
Ann. Surg. * May 1994
Bioartificial Liver The BAL system consisted of a plasma separation unit (COBE Spectra, Lakewood, CO) and a hollow-fiber bioreactor (Microgon Inc., Laguna Hills, CA; pore size, 0.2 ,um; total fiber internal surface area, -6,000 cm2; external surface area, -7,000 cm2; wall thickness, 62 ,um; extrafiber volume, 200 mL) loaded with isolated hepatocytes (4 to 6 X 109) attached to collagen-coated dextran microcarriers (Cytodex 3; Pharmacia, Sweden; 1.6 g dry weight per X 109 cells). Methods of hepatocyte isolation, enrichment, attachment to collagen-coated microcarriers, and storage are described in detail elsewhere.36 In patients 4 to 7, a column containing 300 g of cellulosecoated activated charcoal (Adsorba 300C; Gambro, Germany) was included in the BAL circuit in front of the hepatocyte-containing module (Fig. 1). A double lumen catheter was placed in the superficial femoral vein, blood was removed, and plasma was separated using the -
plasma separation system and perfused through the system. In patients 1 and 2, the hepatocyte module was put on-line in the plasma separation system; that is, it was perfused at a plasma flow rate of 80 to 105 mL/min. In the remaining four patients, a transmission reservoir was used in a second loop, where the plasma recirculated through the hepatocyte (and charcoal) module at a rate of 220 to 400 mL/min (Fig. 1). The charcoal column was saturated with 5% dextrose before use and was replaced after 3.5 hours by a new one. Each treatment lasted 6 or 7 hours. Sodium citrate was used as an anticoagulant. Blood calcium levels were closely monitored and hypocalcemia was prevented by a continuous infusion of calcium chloride. At the end of each BAL treatment, a sample of microcarrier-attached hepatocytes was taken from the cartridge for direct light microscopic examination and assessment of cell viability using the trypan blue exclusion test.
466 =I/mAa -'*+
hollow-fiber bioreactor loaded with porcine liver cells attached to dextran microcarriers
PATIENT Figure 1. The bioartificial liver (BAL) circuit using both a hollow-fiber module inoculated with microcarrierattached hepatocytes and a coated charcoal column.
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Table 2. BLOOD TESTS OF LIVER FUNCTION
Prothrombin time (Sec) Fibrinogen (mg/dL) Total bilirubin (mg/dL) Direct bilirubin (mg/dL) Aspartate serum transferase (U/L) Alanine serum transferase (U/L)
Pre-BAL
Post-BAL
p Value
25 ± 2.7 142 ± 12 14.9 ± 3.8 6.9 ± 1.9
23 ± 1.7 102 ± 14 13.3 ± 3.2 6.0 ± 1.6
