Cerebral hemodynamic and metabolic changes in patients with fulminant hepatic failure during liver transplantation

BACKGROUND: Cerebral autoregulation and metabolism may be seriously compromised in patients with fulminant hepatic failure (FHF). The mechanism responsible for the alteration in cerebral blood flow (CBF) has not been yet clearly defined; however, it is known that it does correlate with liver function. Orthotopic liver transplant (OLT) rapidly restores normal liver function, but little is known about the restoration of cerebral metabolism and hemodynamics. To investigate the relationship between liver function and CBF, we evaluated autoregulation and metabolic changes during OLT in six patients comatose due to FHF. METHODS: We evaluated autoregulation based on a linear regression analysis between mean arterial blood pressure and parallel CBF velocity (CBFV) changes using transcranial Doppler ultrasound. Cerebral metabolism rate was estimated by the arterial-jugular venous oxygen content difference (a-jDO2), while the percentile variation in cerebral metabolic rate for oxygen (CMRO2) was estimated using CBFV percentile variation rather than CBF percentile variation (eCMRO2). RESULTS: Prior to transplant autoregulation was impaired in all patients. However it markedly improved at the end of surgery (P <.05). The eCMRO2 improved as well, particularly among subjects who displayed prompt neurological recovery. In all patients the a-jDO2 was low before transplantation increasing to normal values at the end of surgery. CONCLUSIONS: A hallmark of FHF seems to be failure of autoregulation, which is linked to uncoupling between CBF and CMRO2 as attested by an a-jDO2 lower than normal in all patients (luxury perfusion). The recovery of liver function rapidly improves cerebral hemodynamics and metabolic stability. The study of autoregulation and eCMRO2 recovery using Doppler monitoring proffers the possibility to predict early graft function after liver reperfusion. In our patients eCMRO2 seemed to be associated with improved neurological outcomes.     

Effect of fulminant hepatic failure porcine plasma supplemented with essential components on encapsulated rat hepatocyte spheroids

The development of bioartificial liver (BAL) systems has required detailed information about the functional capabilities of cultured hepatocytes during blood or plasma passage. In this study we investigated the effects of porcine plasma and various supplements on the viability and function of adult rat hepatocytes in vitro. Primary rat hepatocytes cultured in porcine plasma supplemented with various substances showed albumin synthesis rates and viability equal to or higher than those of controls. Supplementation with calcium chloride, magnesium sulfate, trace elements, amino acids, insulin, and epidermal growth factor were essential to maintain viability and high albumin synthesis. Especially, trace elements showed significantly higher and longer albumin secretion.Isolated rat hepatocytes were cultured in Spinner flasks for 24 hours to form spheroids that were harvested and encapsulated with chitosan-alginate solution before transfer to the bioreactor in the BAL system. Encapsulated rat hepatocyte spheroids cultured with porcine plasma including trace elements showed higher viability (57%) than controls (40%) after 24 hours, with ammonia removal values of 30.92 μg/10⁶ cells versus the control 9.04 μg/10⁶ cells. After 24 hours of operation the urea secretion value of encapsulated rat hepatocyte spheroids cultured in porcine plasma in the presence versus absence of trace elements was 76.73 μg/10⁶ cells and 18.80 μg/10⁶ cells, respectively. We concluded that encapsulated hepatocyte spheroids in a packed-bed bioreactor operated with human plasma including trace elements enhanced cell viability and liver function as a bases for an in vivo clinical trial of the BAL system.     

High prevalence of potentially hepatotoxic herbal supplement use in patients with fulminant hepatic failure

HYPOTHESIS: The use of potentially hepatotoxic herbal and dietary supplements is highly prevalent in the fulminant hepatic failure (FHF) patient population at our institution, and this subgroup of patients has a worse prognosis. DESIGN: Retrospective case series.Settings An adult tertiary care university hospital and a Veterans Affairs hospital in Oregon. PATIENTS: All patients referred to the liver transplantation service for FHF from January 2001 through October 2002 (N = 20). We defined FHF as onset of encephalopathy within 8 weeks of onset of jaundice in the absence of preexisting liver disease. All patients underwent investigation for potential causes of liver injury. Potentially hepatotoxic supplements were defined as those with previously published reports of hepatic injury related to their use. RESULTS: Ten patients (50%) were recent or active users of potentially hepatotoxic supplements or herbs; 10 had no history of supplement use. In the supplement group, 7 patients (35%) had no other identified cause for hepatic failure. Six patients in the supplement group and 2 patients in the nonsupplement group underwent orthotopic liver transplantation. Five patients in each group died. There were no significant differences in transplantation rate (P =.07) or survival (P>.99) between groups. Supplement use alone accounted for the most cases of FHF during this period, exceeding acetaminophen toxicity and viral hepatitis. CONCLUSIONS: Herbal and dietary supplements were potential hepatotoxins in a high proportion of patients with FHF at our institution. Enhanced public awareness of the potential hepatotoxicity of these commonly used agents and increased regulatory oversight of their use is strongly urged.     

Resolution of hypophosphatemia is associated with recovery of hepatic function in children with fulminant hepatic failure

Fulminant hepatic failure (FHF) is a rare but often fatal disease in children. Clinical and laboratory predictors of liver regeneration and recovery, however, have not been well established. We hypothesized that hypophosphatemia may indicate recovery of liver synthetic function in children with FHF. We retrospectively reviewed the medical records of children with FHF who were admitted to UCLA and recovered hepatic function either spontaneously or by liver transplantation (LTx). Serum phosphate (Ph) and prothrombin time or international normalized ratio (INR) were compared over the patient's clinical course. Records of 39 children who spontaneously recovered experienced profound hypophosphatemia that resolved as liver synthetic function improved. Similar patterns were seen in the 84 children who recovered after LTx. We found that hypophosphatemia precedes the recovery of liver synthetic function in children with FHF who recovered with or without transplantation, and that Ph levels return to normal as liver synthetic function improves. These data suggest that hypophosphatemia may be a useful laboratory indicator of recovering liver function in children with FHF.     

Use of mycophenolate mofetil in the experimental allo-transplantation of hepatocytes in rats with fulminant hepatic failure

AIM: The aim of the study was to evaluate the beneficial effect of mycophenolate mofetil (MMF) as an immunosuppressive agent for experimental transplantation of hepatocytes in rats with fulminant hepatic failure (FHF). MATERIALS AND METHODS: Six Wistar rats were used as donors and 40 Lewis rats at recipients, including four groups of 10 animals each. Group A received no treatment; Group B, cyclosporine (20 mg/kg days 0-5 and 10 mg/kg days 6-15); Group C, MMF (12 mg/kg per os every day); and Group D, MMF (23 mg/kg per os every day). Hepatocytes were transplanted intrasplenically. Animals were followed for 15 days. RESULTS: The survival rates for Group A were maximum 72 h, whereas Groups B, C, and D showed 50%, 70%, and 80%, respectively. Biochemical evaluation and histology showed satisfactory function and engraftment, respectively. CONCLUSION: The use of MMF in this experimental model yielded safe, satisfactory immunosuppression especially at the dose of 23 mg/kg.     

Efficacy of a polyurethane foam/spheroid artificial liver by using human hepatoblastoma cell line (Hep G2)

We invesigated the availability of human hepatoblastoma cell line (Hep G2), compared with human primary hepatocytes (HH) and porcine primary hepatocytes (PH), as a cell source for the hybrid artificial liver support system (HALSS) by using polyurethane foam (PUF). All three kinds of hepatocytes spontaneously formed spherical multicellular aggregates (spheroids) of 100-200 microm diameter in the pores of PUF within 3 days of culture. In a PUF stationary culture, Hep G2 spheroids recovered the ammonia removal activity that was lost in monolayer culture, although the removal for each unit cell number was about one tenth that of HH spheroids and about one eighth of PH spheroids. The synthesis activities of albumin and fibrinogen of each unit cell number of Hep G2 were also upregulated by PUF spheroid culture, and were about twice as high as in monolayer culture. The albumin secretion activity of Hep G2 spheroids was almost the same as that of PH spheroids. HH scarcely secreted these proteins in this experiment, probably because they were cultured in a serum-free medium. In the PUF module in a circulation culture, HH had high ammonia removal and low synthesis activities similar to stationary culture. Hep G2 proliferated to a high cell density, such as about 4.8 x 10(7) cells/cm3-module at 10 days of culture. Although Hep G2 spheroids had low ammonia removal activity in each cell, the removal rate in the PUF module was almost the same as for PH at 7 days of culture because of the high cell density culture by cell proliferation. The albumin secretion rate by Hep G2 in the PUF module also increased with cell proliferation and was about 10 times higher than the initial for the rate for PH at 7 days of culture. These results suggest that Hep G2 is a potential cell source PUF-HALSS.     

Hepatic differentiation of mouse embryonic stem cells in a bioreactor using polyurethane/spheroid culture

BACKGROUND: We have previously developed a hybrid artificial liver (HAL) using polyurethane foam (PUF)/hepatocyte spheroid culture. The PUF-HAL has been successfully scaled up to a clinical level. However, one of the most difficult problems for clinical application of HALs is obtaining a cell source. We now focused our attention on embryonic stem (ES) cells as a potential source for HAL. In this study, we investigated the differentiation of mouse ES (mES) cells into functional hepatocytes in the PUF-HAL module. METHODS: The PUF-HAL module included a cylindrical PUF block having many capillaries for medium flow. mES cells were immobilized in the module. To induce hepatic differentiation, growth factors were added to the culture medium. We evaluated cell density, gene expression analysis, and liver-specific functions. RESULTS: mES cells spontaneously formed spherical multicellular aggregates (spheroids) in the pores of PUF. mES cells proliferated by 20 days, achieving a high cell density (about 1 x 10(8) cells/cm3 PUF). Differentiating ES cells expressed endodermal-specific genes such as alpha-fetoprotein, albumin, and tryptophan 2, 3-deoxygenase. The activity of ammonia removal of mES cells per unit volume of the module was detectable by 15 days and increased with culture time. Maximal expression levels were comparable to those of primary (porcine and human) hepatocytes. SUMMARY: mES cells immobilized in the PUF module expressed liver-specific functions at high level, because of high cell density in culture and hepatic differentiation. These results indicated that PUF module-immobilized mES cells may be useful as a biocomponent of HALs.     

Compressed spectral arrays of patients with fulminant hepatic failure in hepatic coma undergoing liver transplantation

Assessing the coma status of patients with fulminant hepatic failure (FHF) is important for determining the reversibility of brain damage and for properly timing liver transplantation. The compressed spectral array (CSA) method is a frequency analysis technique that processes electroencephalogram signals by computer to facilitate on-line interpretation. This method has been used to monitor the consciousness levels of neurointensive care unit patients. In this study, we determined whether CSA could be used to assess the coma status of patients with FHF, and whether CSA provided information that was useful in deciding when to proceed with liver transplantation. CSA recording was carried out in 17 FHF patients with encephalopathy (coma grade III-IV) who underwent living-related liver transplantation between August 1997 and May 1999. Recording was performed with a Neuromonitor OEE-72044 (NIHON KOHDEN, Osaka, Japan) every 24 h before and after transplantation, until the patients regained consciousness. The CSAs of healthy controls were distributed almost equally between 0 and 16 Hz. The CSAs of FHF patients in hepatic coma were classified into three patterns. Eight of the 17 patients showed very prominent slow waves of about 2 Hz (group A), and seven patients showed strongly suppressed rapid waves between 8 and 16 Hz (group B). The remaining two patients showed CSA patterns that were similar to those of healthy controls, even though these patients were comatose (group C). Abnormal CSA patterns were observed in 15 of the 17 patients (88%). Group B patients seemed to have higher coma grades than did group A patients. Sixteen patients underwent liver transplantation, completely recovered from hepatic encephalopathy, and subsequently showed CSA patterns similar to those of healthy controls. One patient died without regaining consciousness. These results suggest that CSA is useful in assessing the coma status of FHF patients and in evaluating electrophysiological recovery from hepatic coma after liver transplantation.     

Efficacy of a larger version of the hybrid artificial liver support system using a polyurethane foam/spheroid packed-bed module in a warm ischemic liver failure pig model for preclinical experiments

We have reported the usefulness of a polyurethane foam packed-bed culture system of hepatocyte spheroids as a hybrid artificial liver support system (PUF-HALSS). The aim of this study was to evaluate in detail the efficacy in serum parameters regarding the liver function of a larger version of the PUF-HALSS containing 2 x 10(10) porcine hepatocytes for clinical use in warm ischemic liver failure pigs. Warm ischemic liver failure pigs weighing 25 kg were divided into two groups: (1) a control group (n = 3), in which each pig was attached to a PUF-HALSS without hepatocytes, and (2) a HALSS group (n = 3), in which each pig was attached to a PUF-HALSS. In the HALSS group, the increase of blood ammonia was completely suppressed and blood lactate levels were significantly suppressed. The Fisher's ratio was better maintained, and the increase of total bile acid, glycochenodeoxycholic acid, and taurochenodeoxycholic acid was significantly suppressed in the HALSS group. Serum creatinine levels were significantly lower, and blood glucose levels were significantly higher in the HALSS group. Serum levels of tumor necrosis factor- a were not elevated in either group. In conclusion, the larger version of the PUF-HALSS demonstrated many advantages as a liver support system in warm ischemic liver failure pigs.     

Polyurethane foam/spheroid culture system using human hepatoblastoma cell line (Hep G2) as a possible new hybrid artificial liver

The risk of xenozoonosis infections poses the greatest obstacle against the clinical application of hybrid artificial liver support system (HALSS). Primary human hepatocytes are an ideal source for HALSS, but the shortage of human livers available for hepatocyte isolation limits this modality. To resolve this issue, we used human hepatocytes with replication capacity (fetal hepatocytes, Hep G2, and Huh 7) in a polyurethane foam (PUF)/spheroid culture system in vitro, and analyzed liver functions such as ammonia removal and albumin synthesis capacity; results were compared to those of porcine hepatocytes. Human fetal hepatocytes, Hep G2, and Huh 7 formed spheroids spontaneously within 24 h in a PUF/spheroid culture system; ammonia removal activity (micromol/10(6) nuclei/h) was upregulated, as was albumin synthesis activity (microg/10(6) nuclei/day). In particular, Hep G2 spheroids demonstrated high ammonia removal and albumin synthesis activities: 85% of the ammonia removal activity and 171.7% of the albumin synthesis activity of porcine hepatocytes in the monolayer culture. These results indicate the possibility of the development of a multicapillary PUF (MC-PUF) packed-bed culture system of hepatocyte spheroids as a HALSS using Hep G2.     

Evaluation of a hybrid artificial liver using a polyurethane foam packed-Bed culture system in dogs

BACKGROUND AND AIMS. We developed a polyurethane foam packed-bed culture system of hepatocyte spheroids as a hybrid artificial liver (PUF-HAL), which was effective for recovery from liver failure in rat experiments. In this report, the design of a scaled-up PUF-HAL for dogs is described and evaluated using a dog acute liver failure model. METHODS. Warm ischemic liver failure was induced with a portocaval shunt in each dog. The dogs were divided into two groups: (1) a control group (N = 4), in which each dog was attached to a PUF-HAL without hepatocytes for 9 h, and (2) a HAL group (N = 5), in which each dog was attached to a PUF-HAL with hepatocytes. Blood pressure, blood ammonia, blood glucose, serum creatinine, and other parameters related to liver function were compared between the two groups. RESULTS. In the HAL group, blood ammonia and serum creatinine levels were significantly lower, and blood pressure and blood glucose levels significantly higher, than those in the control group. CONCLUSIONS. The scaled-up PUF-HAL developed for large animals is useful as a liver support system in the dog acute liver failure model.     

Efficacy of double-filtration plasmapheretic cross-circulation with a high-permeability membrane using canine harvested liver in porcine fulminant hepatic failure model

INTRODUCTION: The use of bioartificial liver devices requires. A sufficient liver cell mass to provide adequate metabolic support, reduction of xenogeneic immune reactions, and avoidance of viral transmission. We have developed a plasmapheresis system using a semipermeable membrane combined with canine whole liver perfusion (PMCWLP). In this study, we investigated the efficacy of our system in a porcine fulminant hepatic failure (FHF) model. METHODS: The porcine FHF model was established by intraportal administration of alpha-amanitin (0.1 mg/kg) and lipopolysaccharide (1 microg/kg). Nine hours after drug injection, xenogenic perfusion treatment was performed twice within 6 hours (n = 5). As the plasmapheresis device, we used a hollow-fiber module with cellulose diacetate porous fibers (pore size, 0.05 microm, surface area, 2 m2). The canine whole liver was perfused with modified Krebs solution, which is commonly used in many laboratories, containing albumin (2 g/dL) and glucose (300 mg/dL). Control pigs (n = 10), had the circuit not connected to the whole canine liver. RESULTS: The survival of FHF pigs was significantly increased by the treatment (58.9 +/- 21.8 hour) compared with the controls (22.3 +/- 8.1 hour). Mean blood ammonia levels and intracranial pressure during treatment were significantly lower compared with control groups. CONCLUSION: Treatment of FHF pigs with the system significantly increased survival time, suggesting that this method may have applications as a clinical liver assist device.     

Anesthetic management of liver transplantation in patients with fulminant hepatic failure: case reports

Fulminant hepatic failure (FHF), although not frequent, produces a high mortality rate of 70% to 90%. This study describes the management of FHF patients without the use of any intracranial pressure monitoring device.     

Initial experience with the modified extracorporeal liver-assist device for patients with fulminant hepatic failure: system modifications and clinical impact

BACKGROUND: The need to find a safe, effective liver support system for patients with fulminant hepatic failure (FHF) continues to be unmet. A system using immortalized human hepatocytes was originally developed in the early 1990s. A modified version of the initial extracorporeal liver-assist device (ELAD) was recently placed into an initial clinical trial at the University of Chicago. The goal of this study was to determine the safety profile of the device at one center before broadening the study to other sites. METHODS: Patients who were diagnosed with FHF and admitted to the University of Chicago were eligible for the ELAD study. Informed consent was obtained, and patients received continuous ELAD therapy until and throughout transplantation. Data were prospectively collected and subsequently analyzed. RESULTS: Five patients were treated with the device. All patients successfully underwent transplantation. Four of the five patients survived to the 30-day endpoint of the study. There were no biomechanical problems identified. The patients' hemodynamic conditions did not deteriorate during treatment. The adult patients' clinical courses appeared to stabilize while connected to the ELAD (mean arterial pressure range 80-97, mean 88.6; cerebral perfusion pressure range 62-88, mean 76.5). Patient 4 experienced remarkable improvement during ELAD therapy: elimination of phenylephrine, reduction of dopamine from 20 microg/min to 5 microg/min, and reduction of respiratory support from 100% O2, 10 cm positive end-expiratory pressure to 60% O2, and 5 cm H2O positive end-expiratory pressure. The device continued to be metabolically active throughout the study period as documented by oxygen use (mean O2 change from sampling port before cartridge to sampling port after cartridge for all patients treated = 55 mm Hg). CONCLUSIONS: The patients tolerated treatment with the ELAD well. There were no unanticipated safety issues. The cells in the cartridges were metabolically active. All patients successfully underwent transplantation. The results from this single-institution experience indicates that larger randomized multicenter trials should proceed.     

Multisorbent plasma perfusion in fulminant hepatic failure: effects of duration and frequency of treatment in rats with grade III hepatic coma

Using the model of galactosamine-induced fulminant hepatic failure in the rat, the effects of multisorbent plasma perfusion over Asahi uncoated spherical charcoal, Plasorba (BR-350) resin, and an endotoxin removing adsorbent (polymyxin B-sepharose) were determined in Grade III hepatic coma animals by studying survival as influenced by timing, duration, and frequency of treatment. The effects of treatment on liver cell proliferation and endotoxin removal also were examined. The results demonstrate that duration and frequency of treatment are major contributing factors in the successful application of nonbiological membrane-based multisorbent liver support systems. Examination of the regenerative activity in the liver indicates an enhanced proliferative response following multisorbent plasma perfusion compared with untreated fulminant hepatic failure (FHF) paired controls. Utilizing an endotoxin removal adsorbent alone, a marked reduction in systemic levels of endotoxin in FHF was demonstrated compared with nonperfused FHF paired controls. Despite current emphasis on bioartificial liver support systems, plasma purification by multisorbent systems offers a simple method for the removal of circulating toxic metabolites in general together with specific toxin removal.     

Comparative study of bioartificial liver support and plasma exchange for treatment of pigs with fulminant hepatic failure

Recently, bioartificial liver (BAL) treatment was reported to provide beneficial effects for patients with fulminant hepatic failure (FHF). Some success in experimental or clinical trials has been reported; however, the evaluation of BAL efficacy remains unclear, especially in comparison with other treatments for FHF. The purpose of this study was to compare the efficacy between BAL and plasma exchange (PE) in experimentally induced FHF in pigs. Pigs undergoing hepatic devascularization (HD) were placed into the following groups: no treatment (control; n = 6), BAL treatment (BAL; n = 5), and plasma exchange (PE; n = 5). Each treatment was initiated 6 h after HD and lasted for 4 h. BAL treatment significantly improved liver functions in FHF pigs. The decrease in cerebral perfusion pressure was also significantly suppressed in the pigs with BAL, and their survival time was prolonged compared with the results in pigs with PE. The effects of BAL outperform those of PE in the treatment of experimental FHF model.