Cytoprotective influence of ZVAD-fmk and glycine on gel-entrapped rat hepatocytes in a bioartificial liver

Biocompatibility of hydroxyethyl cellulose/glycine/RuO2 composite scaffolds for neural-like cells

Fabrication of scaffolds for nerve regeneration is one of the most challenging topics in regenerative medicine at the moment, which is also interlinked with the development of biocompatible substrates for cells growth. This work is targeted towards the development of green biomaterial composite scaffolds for nerve cell culture applications. Hybrid scaffolds of hydroxyethyl cellulose/glycine (HEC/Gly) composite doped with different concentrations of green ruthenium oxide (RuO₂) were synthesized and characterized via a combination of different techniques. X-rays diffraction (XRD) and differential scanning calorimetry (DSC) analyses showed a crystalline nature for all the samples with noticeable decrease in the peak intensity of the fabricated scaffolds as compared to that for pure glycine. Fourier transform infrared spectroscopy (FTIR) tests revealed an increase in the vibrational bands of the synthesized RuO₂ containing scaffolds which are related to the functional groups of the natural plant extract (Aspalathuslinearis) used for RuO₂ nanoparticles (NPs) synthesis. Scanning electron microscopy (SEM) results revealed a 3D porous structure of the scaffolds with variant features attributed to the concentration of RuO₂ NPs in the scaffold. The compressive test results recorded an enhancement in mechanical properties of the fabricated scaffolds (up to 8.55 MPa), proportionally correlated to increasing the RuO₂ NPs concentration in HEC/Gly composite scaffold. Our biocompatibility tests revealed that the composite scaffolds doped with 1 and 2 ml of RuO₂ demonstrated the highest proliferation percentages (152.2 and 135.6%) compared to control. Finally, the SEM analyses confirmed the impressive cells attachments and differentiation onto the scaffold surfaces as evidenced by the presence of many neuron-like cells with apparent cell bodies and possessing few short neurite-like processes. The presence of RuO₂ and glycine was due to their extraordinary biocompatibility due to their cytoprotective and regenerative effects. Therefore, we conclude that these scaffolds are promising for accommodation and growth of neural-like cells.

Glycine represses endoplasmic reticulum stress-related apoptosis and improves intestinal barrier by activating mammalian target of rapamycin complex 1 signaling

Endoplasmic reticulum (ER) stress has been associated with the dysfunction of intestinal barrier in humans and animals. We have previously shown that oral administration of glycine to suckling-piglets improves ER stress-related intestinal mucosal barrier impairment and jejunal epithelial apoptosis. However, the underlying mechanism remains unknown. In this study, the protective effect and the mechanism of glycine on apoptosis and dysfunction in intestinal barrier induced by brefeldin A (BFA), an ER stress inducer, was explored in porcine intestinal epithelial cells (IPEC-1). The results showed that BFA treatment led to enhanced apoptosis and upregulation of proteins involved in ER stress signaling, including inositol-requiring enzyme 1α (IRE1α), activating transcription factor 6α (ATF6α), c-Jun N-terminal kinase (JNK), and C/EBP-homologous protein (CHOP). In addition, BFA induced a dysfunction in intestinal epithelial barrier, as evidenced by the increased paracellular permeability, decreased transepithelial electrical resistance (TEER), and reduced abundance of tight junction proteins (occludin, claudin-1, zonula occludens [ZO]-1, and ZO-2). These alterations triggered by BFA were significantly abolished by glycine treatment (P < 0.05), indicating a protective effect of glycine on barrier function impaired by ER stress. Importantly, we found that the regulatory effect of glycine on intestinal permeability, proteins implicated in ER stress and apoptosis, as well as the morphological alterations of the ER were reversed by rapamycin. In summary, our results indicated that glycine alleviates ER stress-induced apoptosis and intestinal barrier dysfunction in IPEC-1 cells in a mammalian target of rapamycin complex 1 (mTORC1)-dependent manner. The data provides in vitro evidence and a mechanism for the protective effect of glycine against the disruption of intestinal barrier integrity induced by ER stress.

Cryopreservation of Hepatocyte Microbeads for Clinical Transplantation

Intraperitoneal transplantation of hepatocyte microbeads is an attractive option for the management of acute liver failure. Encapsulation of hepatocytes in alginate microbeads supports their function and prevents immune attack of the cells. Establishment of banked cryopreserved hepatocyte microbeads is important for emergency use. The aim of this study was to develop an optimized protocol for cryopreservation of hepatocyte microbeads for clinical transplantation using modified freezing solutions. Four freezing solutions with potential for clinical application were investigated. Human and rat hepatocytes cryopreserved with University of Wisconsin (UW)/10% dimethyl sulfoxide (DMSO)/5% (300 mM) glucose and CryoStor CS10 showed better postthawing cell viability, attachment, and hepatocyte functions than with histidine-tryptophan-ketoglutarate/10% DMSO/5% glucose and Bambanker. The 2 freezing solutions that gave better results were studied with human and rat hepatocytes microbeads. Similar effects on cryopreserved microbead morphology (external and ultrastructural), viability, and hepatocyte-functions post thawing were observed over 7 d in culture. UW/DMSO/glucose, as a basal freezing medium, was used to investigate the additional effects of cytoprotectants: a pan-caspase inhibitor (benzyloxycarbonyl-Val-Ala-dl-Asp-fluoromethylketone [ZVAD]), an antioxidant (desferoxamine [DFO]), and a buffering and mechanical protectant (human serum albumin [HSA]) on RMBs. ZVAD (60 µM) had a beneficial effect on cell viability that was greater than with DFO (1 mM), HSA (2%), and basal freezing medium alone. Improvements in the ultrastructure of encapsulated hepatocytes and a lower degree of cell apoptosis were observed with all 3 cytoprotectants, with ZVAD tending to provide the greatest effect. Cytochrome P450 activity was significantly higher in the 3 cytoprotectant groups than with fresh microbeads. In conclusion, developing an optimized cryopreservation protocol by adding cytoprotectants such as ZVAD could improve the outcome of cryopreserved hepatocyte microbeads for future clinical use.

Formation of a Sheet-Shaped Organoid Using Rat Primary Hepatocytes for Long-Term Maintenance of Liver-Specific Functions

In recent years, use of hepatocyte aggregates has led to development of a hybrid artificial liver support system (HALSS) that has high performance. However, in general, their thickness is 100 μm or more, and generation of a dead cell layer due to oxygen exhaustion inside the aggregates has been a universal problem. The present study proposes a novel organoid culture method with better performance than previous organoid culture methods by forming a sheet-shaped organoid (organoid-sheet) with a thickness of approximately 100 μm. The cell number of the organoid-sheet was maintained at approximately 75% of the initial number at 4 days of culture. On the other hand, that of a cylindrical organoid (cylindroid), which formed inside of a plasma separation hollow fiber with 285 μm inner diameter in our previous study, decreased to approximately 50% within 2 days. The ammonia removal rate of the cells in the organoid-sheet was higher than that of the cells in the cylindroid on the first day, but it decreased during the culture time. At day 15, the rate was reduced by almost 50% with respect to the value on the first day. The cells in the cylindroid displayed a lower ammonia removal rate. A significant difference was not observed between the albumin synthesis rates of the two cultures on the first day. However, over a period of time the cells in the organoid-sheet showed a higher albumin synthesis rate than cells in the cylindroid. As this novel organoid maintains these functions for at least 1 month, it is expected to be applied for the development of a HALSS with higher performance.

Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review

Glycine is most important and simple, nonessential amino acid in humans, animals, and many mammals. Generally, glycine is synthesized from choline, serine, hydroxyproline, and threonine through interorgan metabolism in which kidneys and liver are the primarily involved. Generally in common feeding conditions, glycine is not sufficiently synthesized in humans, animals, and birds. Glycine acts as precursor for several key metabolites of low molecular weight such as creatine, glutathione, haem, purines, and porphyrins. Glycine is very effective in improving the health and supports the growth and well-being of humans and animals. There are overwhelming reports supporting the role of supplementary glycine in prevention of many diseases and disorders including cancer. Dietary supplementation of proper dose of glycine is effectual in treating metabolic disorders in patients with cardiovascular diseases, several inflammatory diseases, obesity, cancers, and diabetes. Glycine also has the property to enhance the quality of sleep and neurological functions. In this review we will focus on the metabolism of glycine in humans and animals and the recent findings and advances about the beneficial effects and protection of glycine in different disease states.

The role of glycine in regulated cell death

The cytoprotective effects of glycine against cell death have been recognized for over 28 years. They are expressed in multiple cell types and injury settings that lead to necrosis, but are still not widely appreciated or considered in the conceptualization of cell death pathways. In this paper, we review the available data on the expression of this phenomenon, its relationship to major pathophysiologic pathways that lead to cell death and immunomodulatory effects, the hypothesis that it involves suppression by glycine of the development of a hydrophilic death channel of molecular dimensions in the plasma membrane, and evidence for its impact on disease processes in vivo.

Preservation of stem cells

Adult stem cells (hematopoietic and mesenchymal) have demonstrated tremendous human therapeutic potential. Currently, human embryonic stem cells are used principally for understanding development and disease progression but also hold tremendous therapeutic potential. The ability to preserve stem cells is critical for their use in clinical and research applications. Preservation of cells permits the transportation of cells between sites, as well as completion of safety and quality control testing. Preservation also permits the development of a 'manufacturing paradigm' for cell therapies, thereby maximizing the number of products that can be produced at a given facility. in this article, we will review modes of preservation and the current status of preservation of hematopoietic, mesenchymal and human embryonic stem cells. Current and emerging issues in the area of stem cell preservation will also be described.

Effects of glycine supplementation on myocardial damage and cardiac function after severe burn

BACKGROUND

Glycine has been shown to participate in protection from hypoxia/reoxygenation injury. However, the cardioprotective effect of glycine after burn remains unclear. This study aimed to explore the protective effect of glycine on myocardial damage in severely burned rats.

METHODS

Seventy-two Wistar rats were randomly divided into three groups: normal controls (C), burned controls (B), and glycine-treated (G). Groups B and G were given a 30% total body surface area full-thickness burn. Group G was administered 1.5 g/(kg d) glycine and group B was given the same dose of alanine via intragastric administration for 3d. Serum creatine kinase (CK), lactate dehydrogenase (LDH), aspartate transaminase (AST), and blood lactate, as well as myocardial ATP and glutathione (GSH) content, were measured. Cardiac contractile function and histopathological changes were analyzed at 12, 24, 48, and 72 hours.

RESULTS

Serum CK, LDH, AST, and blood lactate increased, while myocardial ATP and GSH content decreased in both burned groups. Compared with group B, the levels of CK, LDH, and AST significantly decreased, whereas blood lactate as well as myocardial ATP and GSH content increased in group G. Moreover, cardiac contractile function inhibition and myocardial histopathological damage in group G significantly decreased compared with group B.

CONCLUSION

Myocardial histological structure and function were damaged significantly after burn. Glycine is beneficial to myocardial preservation by improving cardiomyocyte energy metabolism and increasing ATP and GSH abundance.

Frontiers in biotransport: water transport and hydration

Biotransport, by its nature, is concerned with the motions of molecules in biological systems while water remains as the most important and the most commonly studied molecule across all disciplines. In this review, we focus on biopreservation and thermal therapies from the perspective of water, exploring how its molecular motions, properties, kinetic, and thermodynamic transitions govern biotransport phenomena and enable preservation or controlled destruction of biological systems.

Frontiers in Biotransport: Water Transport and Hydration

Biotransport, by its nature, is concerned with the motions of molecules in biological systems while water remains as the most important and the most commonly studied molecule across all disciplines. In this review, we focus on biopreservation and thermal therapies from the perspective of water, exploring how its molecular motions, properties, kinetic, and thermodynamic transitions govern biotransport phenomena and enable preservation or controlled destruction of biological systems.

Hepatocyte organoid culture in elliptic hollow fibers to develop a hybrid artificial liver

A novel organoid culture was developed in which hepatocytes maintain high liver functions for more than several weeks in vitro. The main disadvantage of tissue-engineered organoids is the lack of a blood vessel structure between the aggregated cells. Because of depletion of oxygen, the thickness from the surface of an organoid at which hepatocytes can survive is limited. This study showed that a rat hepatocyte organoid that forms by using centrifugal force in a hollow fiber (HF) had a survival limit thickness of about 80 - 100 microm from the surface of the organoid. Based on the value, we designed an elliptic HF having less than 150 microm minor diameter by using a simple annealing method. All hepatocytes were supplied with oxygen and formed an organoid without a dead cell layer in this HF A hepatocyte organoid in an elliptic HF maintained ammonia removal activity twice as high as in the original HF for at least one month during culture. Albumin secretion activity of an organoid in an elliptic HF was also maintained for at least one month and was the same level as that of liver in a living body. In conclusion, organoid culture by using an elliptic HF seems to be a promising technique to develop a hybrid artificial liver.

Hepatic tissue engineering for adjunct and temporary liver support: critical technologies

The severe donor liver shortage, high cost, and complexity of orthotopic liver transplantation have prompted the search for alternative treatment strategies for end-stage liver disease, which would require less donor material, be cheaper, and less invasive. Hepatic tissue engineering encompasses several approaches to develop adjunct internal liver support methods, such as hepatocyte transplantation and implantable hepatocyte-based devices, as well as temporary extracorporeal liver support techniques, such as bioartificial liver assist devices. Many tissue engineered liver support systems have passed the "proof of principle" test in preclinical and clinical studies; however, they have not yet been found sufficiently reliably effective for routine clinical use. In this review we describe, from an engineering perspective, the progress and remaining challenges that must be resolved in order to develop the next generation of implantable and extracorporeal devices for adjunct or temporary liver assist.

Apoptotic cell death and function of cryopreserved porcine hepatocytes in a bioartificial liver

We have previously shown that cryopreservation leads to increased apoptotic death of porcine hepatocytes intended for use in a bioartificial liver (BAL). This study was designed to determine if a broad-spectrum caspase inhibitor, IDN-1965, reduced apoptosis and increased function of cryopreserved porcine hepatocytes in static culture or in a BAL. Porcine hepatocytes were studied immediately after isolation and after 2 weeks of cryopreservation in liquid nitrogen using medium supplemented with 25 micromol/L IDN-1965 or vehicle. Both apoptotic and necrotic cells were observed in cultures of fresh and cryopreserved hepatocytes, but the percentage of apoptotic cells increased after cryopreservation. Cryopreservation in IDN-1965 improved hepatocyte viability and reduced apoptotic cell death determined by TUNEL assay. Cryopreservation of hepatocytes in IDN-1965 was also associated with reduced caspase 3-like activity, decreased release of cytochrome c from mitochondria, and a slower decline in mitochondrial membrane potential after thawing. These markers of apoptosis were lowest after cryopreservation when IDN-1965 was added to both the culture and cryopreservation medium. Functional markers of hepatocyte activity (albumin production, diazepam metabolism, urea production) were also increased after cryopreservation and culture of hepatocytes in medium supplemented with 25 micromol/L IDN-1965. Cryopreservation of porcine hepatocytes in the presence of caspase inhibitor IDN-1965 was associated with reduced apoptosis and improved function of porcine hepatocytes in both static culture and a perfused BAL. These data demonstrate that inhibition of apoptosis also preserves cell function.

Induction of necrosis and DNA fragmentation during hypothermic preservation of hepatocytes in UW, HTK, and Celsior solutions

Donor cells can be preserved in University of Wisconsin (UW), histidine-tryptophan-ketoglutarate (HTK), or Celsior solution. However, differences in efficacy and mode of action in preventing hypothermia-induced cell injury have not been unequivocally clarified. Therefore, we investigated and compared necrotic and apoptotic cell death of freshly isolated primary porcine hepatocytes after hypothermic preservation in UW, HTK, and Celsior solutions and subsequent normothermic culturing. Hepatocytes were isolated from porcine livers, divided in fractions, and hypothermically (4 degrees C) stored in phosphate-buffered saline (PBS), UW, HTK, or Celsior solution. Cell necrosis and apoptosis were assessed after 24- and 48-h hypothermic storage and after 24-h normothermic culturing following the hypothermic preservation periods. Necrosis was assessed by trypan blue exclusion, lactate dehydrogenase (LDH) release, and mitochondrial 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) reduction. Apoptosis was assessed by the induction of histone-associated DNA fragments and cellular caspase-3 activity. Trypan blue exclusion, LDH release, and MTT reduction of hypothermically preserved hepatocytes showed a decrease in cell viability of more than 50% during the first 24 h of hypothermic preservation. Cell viability was further decreased after 48-h preservation. DNA fragmentation was slightly enhanced in hepatocytes after preservation in all solutions, but caspase-3 activity was not significantly increased in these cells. Normothermic culturing of hypothermically preserved cells further decreased cell viability as assessed by LDH release and MTT reduction. Normothermic culturing of hypothermically preserved hepatocytes induced DNA fragmentation, but caspase-3 activity was not hanced in these cells. Trypan blue exclusion, LDH leakage, and MTT reduction demonstrated the highest cell viability after storage in Celsior, and DNA fragmentation was the lowest in cells that had been stored in PBS and UW solutions. None of the preservation solutions tested in this study was capable of adequately preventing cell death of isolated porcine hepatocytes after 24-h hypothermic preservation and subsequent 24-h normothermic culturing. Culturing of isolated and hypothermically preserved hepatocytes induces DNA fragmentation, but does not lead to caspase-3 activation. With respect to necrosis and DNA fragmentation of hypothermically preserved cells, UW and Celsior were superior to PBS and HTK solutions in this model of isolated porcine hepatocyte preservation.

Maintenance of integrity and function of isolated hepatocytes during extended suspension culture at 25 degrees C

Isolated hepatocytes in suspension provide a number of advantages for use in bioartificial liver device, however, poor stability of this cell preparation at physiological temperatures is an apparent barrier preventing their use. We therefore investigated the integrity and differentiated function of isolated rat hepatocytes under conditions of mild hypothermia. Isolated hepatocytes were suspended in a bicarbonate buffered saline medium, supplemented with glucose and bovine serum albumin (BSA), and maintained for 48 h at 25 degrees C on a rotary shaker under an atmosphere of 95% O2 and 5% CO2. Under these conditions there was no significant decline in cell viability and good preservation of cellular morphology on transmission electron microscopy for at least 24 h. Isolated hepatocytes in suspension at 25 degrees C were also able to maintain normal Na+ and K+ ion gradients. The cellular energy status ([ATP], ATP/ADP ratio, cytoplasmic and mitochondrial redox potentials), metabolic function (urea synthesis and ammonia removal), albumin synthesis and phase I and phase II drug detoxification activity of these cells were also maintained for at least 24 h post isolation. These observations demonstrate the robust nature of mildly hypothermic isolated hepatocytes in suspension and encourage further studies re-examining the feasibility of using this cell preparation in bioartificial livers.

L-Glycine: a novel antiinflammatory, immunomodulatory, and cytoprotective agent

PURPOSE OF REVIEW

In recent years, evidence has mounted in favor of the antiinflammatory, immunomodulatory and cytoprotective effects of the simplest amino acid L-glycine. This article will focus on the recent findings about the responsible mechanisms of protection and review the beneficial effects of glycine in different disease states.

RECENT FINDINGS

Glycine protects against shock caused by hemorrhage, endotoxin and sepsis, prevents ischemia/reperfusion and cold storage/reperfusion injury to a variety of tissues and organs including liver, kidney, heart, intestine and skeletal muscle, and diminishes liver and renal injury caused by hepatic and renal toxicants and drugs. Glycine also protects against peptidoglycan polysaccharide-induced arthritis and inhibits gastric secretion and protects the gastric mucosa against chemically and stress-induced ulcers. Glycine appears to exert several protective effects, including antiinflammatory, immunomodulatory and direct cytoprotective actions. Glycine acts on inflammatory cells such as macrophages to suppress activation of transcription factors and the formation of free radicals and inflammatory cytokines. In the plasma membrane, glycine appears to activate a chloride channel that stabilizes or hyperpolarizes the plasma membrane potential. As a consequence, agonist-induced opening of L-type voltage-dependent calcium channels and the resulting increases in intracellular calcium ions are suppressed, which may account for the immunomodulatory and antiinflammatory effects of glycine. Lastly, glycine blocks the opening of relatively non-specific pores in the plasma membrane that occurs as the penultimate event leading to necrotic cell death.

SUMMARY

Multiple protective effects make glycine a promising treatment strategy for inflammatory diseases.

Membrane barrier of a porcine hepatocyte bioartificial liver

Pores in the membrane of a bioartificial liver (BAL) allow it to function as a semipermeable barrier between its contents (i.e., liver cells) and components of the recipient's immune system. This study is designed to assess the influence of pore size on immune response to a BAL containing porcine hepatocytes. Sixteen healthy dogs were divided into four groups (four dogs per group) based on pore size of the BAL membrane and level of exposure to porcine hepatocytes. Group 1 dogs were administered porcine hepatocytes by intraperitoneal injection and served as positive controls. Group 2 dogs were exposed to porcine hepatocytes in a large-pore (200-nm) BAL, and group 3 dogs were exposed to porcine hepatocytes in a small-pore (10-nm) BAL. Group 4 dogs were exposed to a no-cell (unloaded) BAL and served as negative controls. Intraperitoneal injection of hepatocytes or 3 hours of BAL hemoperfusion was performed day 0 and 3 weeks later on day 21. Biochemical, humoral, and cellular measures of immune response were collected until day 44. The initiation of BAL hemoperfusion was associated with a rapid decline in CH(50) levels of complement and transient neutropenia and thrombocytopenia during all BAL exposures. Xenoreactive antibody response to BAL was increased by use of membranes with large pores and secondary exposures. Skin testing on day 42 showed a delayed-type hypersensitivity response to porcine hepatocytes that also correlated with level of previous antigen exposure. BAL treatment was associated with both immediate and elicited immunologic responses. The immediate response was transient and not influenced by membrane pore size, whereas elicited responses were influenced by pore size of the BAL during previous exposures.

Modulation of pro-apoptotic (Bax) and anti-apoptotic (Bcl-2) gene expression in isolated porcine hepatocytes perfused within a radial-flow bioreactor after low-temperature storing

Due to the scarcity of available human livers, porcine hepatocytes are currently being evaluated as a xenogeneic cell source for extracorporeal bioartificial liver (BAL). Hypothermic storage of isolated porcine hepatocytes could support stocking of cell-loaded bioreactors for BAL use and may provide bioreactors ready to be used at the patient's bedside. For the development of this technology, it is of utmost importance to ensure cell viability and differentiated functions after low-temperature storage and following warm reperfusion. We compared cell viability, functional activity and apoptosis in isolated porcine hepatocytes which were perfused within a radial-flow bioreactor (RFB), stored at 4 degrees C and then reperfused at 37 degrees C. RFBs were loaded with 8 x 10(9), > or = 90% viable hepatocytes at 37 degrees C for 3 h. RFBs were then flushed with 4 degrees C University of Wisconsin solution (UW) and subsequently stored for 24 h or 48 h. RFBs were then reperfused for 8 h with recirculating medium plus serum at 37 degrees C . Cytochrome P450 (CYP) activity was studied before and after cold storage by means of monoethylglycinexylide (MEGX) detection in the effluent medium, after repeated lidocaine injections. After reperfusion experiments, hepatocytes were harvested for total RNA isolation. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used in order to amplify specific mRNAs for Bcl-2 and Bax genes, by using appropriate primers; beta-actin primers were used as control. Total RNA was extracted by northern blotting analysis and for Bcl-2, Bax and beta-actin RNA messenger detection, RT-PCR amplification was used. Freshly isolated hepatocytes perfused into the RFB showed a progressive increase of MEGX while a loss in Bax expression was paralleled by an increase in Bcl-2 expression, in comparison to starting hepatocytes. After 4 degrees C storage and warm reperfusion, MEGX production was preserved in 24 h- and 48 h-stored bioreactors as well as a sharp increase of Bcl-2 and a decrease of Bax mRNAs. Our study suggests that refrigeration of hepatocyte-bioreactors is a suitable strategy to maintain both viability and function of isolated hepatocytes, for up to 48 h a time-length that is compatible with long-distance delivery of ready-to-use bioreactors.

Treatment of acute liver failure in pigs reduces hepatocyte function in a bioartificial liver support system

Several different types of bioartificial liver (BAL) support systems have been developed to bridge patients suffering from acute liver failure (ALF) to transplantation or liver regeneration. In this study we assessed the effects of ALF plasma on hepatocyte function in the BAL system that has been developed in our center. Pigs (40-60 kg) were anaesthetised and a total hepatectomy was performed. Cells were isolated from the resected livers and were transferred to the bioreactor of the BAL system. Twenty hours after cell isolation, hepatocytes in the BAL were tested for cell viability and functional activity by using a recirculating test medium in which assessment of LDH leakage, ammonia clearance, urea synthesis, 7-ethoxycoumarin O-deethylase (ECOD) activity and pseudocholine esterase production was performed. Subsequently, two groups were studied. In one group (I, n=5), the cell-loaded bioreactor was used to treat the donor pig, rendered anhepatic, for 24 hours. In the second group (II, n=5) the bioreactor was cultured for 24 h and served as a control. After 24 hours treatment or culturing, the cell viability count and functional activity tests were repeated. The results show that hepatocytes in the BAL remained viable after 24 h treatment of anhepatic pigs, as shown by the LDH release and pseudocholine esterase production. However, metabolic functions such as ammonia clearance, ECOD and urea synthesis were reduced after 24 h exposure of hepatocytes to autologous ALF plasma, whereas these functions were unaltered after 24 h culturing of the cells in the bioreactor.