Clinical experience with a bioartificial liver in the treatment of severe liver failure. A phase I clinical trial

Auxiliary liver xenotransplantation technique in a transgenic pig-to-non-human primate model: A surgical approach to prolong survival

Xenotransplantation using pigs' liver offers a potentially alternative method to overcome worldwide donor shortage, or more importantly as a bridge to allotransplantation. However, it has been challenged by profound thrombocytopenia and fatal coagulopathy in non-human primate models. Here we suggest that a left auxiliary technique can be a useful method to achieve extended survival of the xenograft. Fifteen consecutive liver xenotransplants were carried out in a pig-to-cynomolgus model. Right auxiliary technique was implemented in two cases, orthotopic in eight cases, and left auxiliary in five cases. None of the right auxiliary recipients survived after surgery due to hemorrhage during complex dissection between the primate's right lobe and inferior vena cava. Orthotopic recipients survived less than 7 days secondary to profound thrombocytopenia and coagulopathy. Two out of five left auxiliary xenotransplants survived more than 3 weeks without uncontrolled thrombocytopenia or anemia, with one of them surviving 34 days, the longest graft survival reported to date. Left auxiliary xenotransplant is a feasible approach in non-human primate experiments, and the feared risk of thrombocytopenia and coagulopathy can be minimized. This may allow for longer evaluation of the xenograft and help better understand histopathological and immunological changes that occur following liver xenotransplantation.

Analysis of Risk Factors and Protective Strategies for Tube Blockage in Patients with Drug-Induced Liver Failure Based on Artificial Liver Therapy

Objective

To analyse the influencing factors of tube blockage during the treatment of artificial liver in patients with drug-induced liver failure and explore effective patient protection strategies.

Methods

In this study, 49 patients with pharmacological (antituberculosis drugs, antibiotics, proprietary Chinese medicine, gastric drugs, and antihyperthyroid drugs) liver failure admitted to our hospital from June 2015 to December 2021 were selected for prospective analysis. Clinical indicators and general data of all patients were collected and collated, risk factors leading to the obstruction of artificial liver treatment were analysed, and corresponding protective measures were proposed.

Results

The incidence of tube blockage was 5.32% (10 times) in 49 patients with pharmacological liver failure treated 188 times with artificial liver therapy. The incidence of tube blockage was significantly higher in patients in the PDF mode than in those in the PP and PE modes (P < 0.05), and there were differences in the location of blocked tubes between the treatment modes. Blocked tubes occurred more often in the venous cauldron of the circuit in the PDF mode and in the plasma separator of the circuit in the PP mode. The incidence of tube blockage was significantly lower in patients with no more than 3 treatments than in those with 3 to 5 treatments and those with more than 5 treatments (p < 0.05). The incidence of catheter blockage was higher in patients with PTA values ≤20% than in those with PTA values between 20% and 30%, and higher than in those with PTA values above 30% (P < 0.05).

Conclusion

The risk factors of tube plugging in patients with liver failure treated with artificial liver include different treatment modes, different treatment times, and different PTA values. The PDF mode has a higher rate of tube plugging than PE or PP treatment modes. The more the number of treatment times and the lower the PTA value of patients, the more tube plugging is likely to occur.

Stem Cell Based Therapy Option in COVID-19: Is It Really Promising?

The COVID-19 patients were first detected in China, in December 2019, then the novel virus with associated pneumonia and other diseases spread quickly to worldwide becoming a serious public health intimidation. Despite all the efforts, the pharmacological agents used for controlling or treating the disease, especially respiratory problems, have not been accomplished so far. Among various treatment options, mesenchymal stem cell-based cellular therapies are being investigated, because of their regeneration ability and multipotency along with other features like immunomodulation, antifibrosis and anti-inflammatory effects. This paper intends to analyze the current clinical trials on stem cell treatment of novel virus, searching and reviewing the available information and the International Clinical Trials Registry Platform (ICTRP) of World Health Organization (WHO). We concluded that the stem cell treatment of COVID-19 is found promising with pilot studies' results, but still in the early development phase. There is an urgent need for large-scale investigations to confirm and validate the safety and efficacy profile of these therapies with reliable scientific evidence.

Bioartificial liver support systems for acute liver failure: A systematic review and meta-analysis of the clinical and preclinical literature

BACKGROUND

Acute liver failure (ALF) has a high mortality varying from 80% to 85% with rapid progress in multi-organ system failure. Bioartificial liver (BAL) support systems have the potential to provide temporary support to bridge patients with ALF to liver transplantation or spontaneous recovery. In the past decades, several BAL support systems have been conducted in clinical trials. More recently, concerns have been raised on the renovation of high-quality cell sources and configuration of BAL support systems to provide more benefits to ALF models in preclinical experiments.

AIM

To investigate the characteristics of studies about BAL support systems for ALF, and to evaluate their effects on mortality.

METHODS

Eligible clinical trials and preclinical experiments on large animals were identified on Cochrane Library, PubMed, and EMbase up to March 6, 2019. Two reviewers independently extracted the necessary information, including key BAL indicators, survival and indicating outcomes, and adverse events during treatment. Descriptive analysis was used to identify the characteristics of the included studies, and a meta-analysis including only randomized controlled trial (RCT) studies was done to calculate the overall effect of BAL on mortality among humans and large animals, respectively.

RESULTS

Of the 30 selected studies, 18 were clinical trials and 12 were preclinical experiments. The meta-analysis result suggested that BAL might reduce mortality in ALF in large animals, probably due to the recent improvement of BAL, including the type, cell source, cell mass, and bioreactor, but seemed ineffective for humans [BAL vs control: relative risk (95% confidence interval), 0.27 (0.12-0.62) for animals and 0.72 (0.48-1.08) for humans]. Liver and renal functions, hematologic and coagulative parameters, encephalopathy index, and neurological indicators seemed to improve after BAL, with neither meaningful adverse events nor porcine endogenous retrovirus infection.

CONCLUSION

BAL may reduce the mortality of ALF by bridging the gap between preclinical experiments and clinical trials. Clinical trials using improved BAL must be designed scientifically and conducted in the future to provide evidence for transformation.

Future Approaches and Therapeutic Modalities for Acute Liver Failure

The current gold standard for the management of acute liver failure is liver transplantation. However, because of organ shortages, other modalities of therapy are necessary as a possible bridge. This article discusses the current modalities as well as the future management of acute liver failure. Liver assist devices, hepatocyte transplantation, stem cell transplant, organogenesis, and repopulation of decellularized organs are discussed.

Enhancing Filtration Rates by the use of Blood Flow around the Capillaries of Plasmafilters: An in Vitro Study

As the low clearance rate of plasmaseparation limits its use in the treatment of patients suffering from liver failure, sepsis or MOF, we intend to develop strategies for a plasmaseparation unit which increases plasmafiltration rates. Our first question focused on whether commercially available plasmaseparation filters, and in particular their membranes, are suitable for the inversion of blood and plasma compartments. This experimental study was performed using in vitro systems. Commercially available plasmafilters PF2000N (Gambro) and Plasmaflo (Asahi) were compared in both their normal operating mode with blood flow through the capillary lumen, and in the inverse mode. Inverse mode means that blood flows through the outer space of the capillaries while plasma was obtained from the lumen. Heparinised porcine blood (5 I.U./ml) was used in a heated, recirculating in vitro circuit. Our main results were that the normal use of both filter types Plasmaflo and PF2000N enabled maximal blood flows (Qb) of 200 ml/min and filtration rates (Qf) of 25–40 ml/min. Operating the filters in the inverse mode enabled Qb up to 500 ml/min and Qf up to 100 ml/min. Hemolysis, platelet counts and coagulation parameters did not differ significantly regardless of whether the normal or inverse mode was used. The tested plasmafiltration membranes appear to be suitable for use in inverse mode. Although in our experiments, hemocompatibility tests did not indicate severe problems induced by the module geometry, the development of a module specially constructed for blood flow outside of the hollow fibers appears to be necessary in order to minimise shunts and low perfusion areas.

Comparison of Pig, Human and Rat Hepatocytes as a Source of Liver Specific Metabolic Functions in Culture Systems - Implications for Use in Bioartificial Liver Devices

The limited availability of human hepatocytes results in the use of animal cells in most bioartificial liver support devices. In the present work, clinically relevant liver specific metabolic activities were compared in rat, pig and human hepatocytes cultured on liver-derived biomatrix to optimize the expression of differentiated functions. Pig hepatocytes showed higher rates of diazepam metabolism (2.549±0.821 μg/h/million cells vs. 0.474±0.079 μg/h/million cells rats, p<0.005, and vs. 0.704±0.171 μg/h/million cells in man, p<0.005) and of bilirubin conjugation (21.60116±8.433237 μmoles/l/24 h vs. 6.786809±2.983758 in man, p<0.001 and vs. 9.956538±1.781016 μmoles/l/24 h in rats, p<0.005). Urea synthesis was similar in pig and in human hepatocytes (150±46.3 vs. 144.8±21.46 nmoles/h/million cells) and it was lower in rats (84.38±35.2; p<0.001 vs. man, p<0.02 vs. pig). High liver specific metabolic activities in cultured pig hepatocytes further support their use as a substitue for human cells in bioartificial liver devices

Experimental Evaluation of a Cell Module for Hybrid Liver Support

Aim of the study was to evaluate a hybrid liver support system in a porcine model of acute liver failure, after hepatectomy. Pigs with a body weight of 70±18 kg underwent total hepatectomy and porto - cavo - caval shunting as well as ligation of the bile duct and the hepatic artery. Control animals were connected to the system (including capillary membrane plasma separation) containing a four compartment bioreactor with integral oxygenation and decentralized mass exchange but without liver cells. The treatment group received hybrid liver support with the same system including 370±42 g primary isolated porcine parenchymal liver cells in co-culture with hepatocyte nursing cells, tissue engineered to liver- like structures at high density. Treatment started after complete recovery from anesthesia and was performed continuously. A positive influence on peripheral vascular resistance and a reduced need of catecholamine dosage was observed in the treatment group. Hybrid liver support with a cell module upscaled for clinical application significantly prolonged survival time in animals after hepatectomy with the longest survival being 26 hours in the control group an 57 hours in the treatment group.

Mass Preparation of Primary Porcine Hepatocytes and the Design of a Hybrid Artificial Liver Module using Spheroid Culture for a Clinical Trial

To isolate a large number of porcine hepatocytes, we originally developed a mass preparation method that combined the usual collagenase perfusion method of a whole liver with a collagenase redigestion method of tissue fragments after liver perfusion. Using a pig of 10kg, collagenase perfusion only resulted in a yield of 63 ± 78 x 108 total cells with a viability of 69.2 ± 25.3 %, but our combined method had a yield of 167 ± 31 x 108 total cells with a viability of 87.9 ± 4.4 % (mean ± SD). Also, the combined method was applied to two pigs of 10kg body weight at the same time, and isolated 387 ± 89 x 108 hepatocytes with a viability of 87.1 ± 6.9 % and a purity of 93.6 ± 2.8 % in 11 experiments.

We designed a large multi-capillary polyurethane foam (MC-PUF) packed-bed module containing 1 x 1010 porcine hepatocytes on a clinical trial scale. The porcine hepatocytes in the module formed spherical multicellular aggregates (spheroids) of 200 – 500 μm diameter. Most hepatocytes forming spheroids were viable judged by fluorescein diacetate and ethidium bromide staining. The activities of ammonia removal, albumin secretion and oxygen consumption of the large MC-PUF module were the same as for a small MC-PUF module containing 2 x 108 porcine hepatocytes, and were maintained for at least 9 days of culture. These results show that a large MC-PUF module is successfully scaled up 50 times.

In conclusion, we succeeded in developing a mass preparation method of porcine hepatocytes and a large hybrid artificial liver module on a clinical trial scale.

Morphological and Functional Evaluation of Isolated Rat Hepatocytes in three Dimensional Culture Systems

Various three-dimensional configurations, such as polyester tissue and woven-nonwoven, hydrophilic polyester fabric, either collagen-coated or uncoated, were investigated as potential scaffold for hepatocyte culture, in view of their use in bioreactors for hybrid liver support systems. Attachment, morphology and ultrastructure of primary adult rat hepatocytes were evaluated, as well as urea production and ammonium detoxification during a 24h incubation period in serum-free tissue culture medium. As control, hepatocytes were also plated onto collagen-coated dextran microcarriers and on plastic petri dishes, either collagen-coated or uncoated. In all the three-dimensional cultures, hepatocytes appeared morphologically intact without any statistically significant difference in metabolic activity. Collagen-coating did not influence cell attachment to polyester substrates, whereas woven-nonwoven hydrophilic polyester fabric may offer some potential advantages as three-dimensional system for hepatocyte culture in hybrid liver support systems.

Significantly Improved Survival Time in Pigs with Complete Liver Ischemia Treated with a Novel Bioartificial Liver

Aim of the study was to evaluate treatment efficacy and safety of a scaled-up version of our porcine hepatocytes based BAL system in pigs with complete liver ischemia (LIS).

Thirty-one pigs underwent total devascularization of the liver (LIS) by termino-lateral porta-caval shunts and sutures around the bile duct, the common hepatic and gastroduodenal arteries and their accessory branches. The hepato-duodenal ligament was completely transected. Four experimental groups were studied: the first control group (LIS Control, n = 10) received glucose infusion only, the second control group (LIS Plasmapheresis, n = 8) was connected to a centrifugal plasma-separator with a bottle representing the bioreactor volume, the third control group (LIS Empty-BAL, n = 5) received BAL treatment without cells, and the treated group (LIS Cell-BAL, n = 8) was connected for a maximum period of 24 hours to our scaled-up BAL seeded with around 14 billion viable primary porcine hepatocytes.

BAL treatment significantly prolonged life in large animals (-35 kg) with complete LIS (Controls, mean ± SEM: 33.1 ± 3 h, Cell-BAL: 51.1 ± 3.4 h; p = 0.001; longest survivor 63 h). In addition, blood ammonia and total bilirubin levels decreased significantly, indicating metabolic activity of porcine hepatocytes in the bioreactor. No significant differences were noticed among the three control groups, indicating that there was no device effect and that the plasmapheresis procedure was well tolerated. No important adverse effectes were observed.

Efficacy of Nafamostat Mesilate for Improving the Performance of a Bioartificial Liver Using Porcine Hepatocytes

Our bioartificial liver (BAL) consists of porcine hepatocytes attached to beads and plasma perfused through the system. The function of our BAL lasts for approximately 7 hours. The objective of the present study was to investigate the efficacy of Nafamostat Mesilate (NM), a protease inhibitor and potent complement inhibitor, for improving the performance of the BAL. The experimental groups were divided as follows; the NM group (n=7) where the BAL had porcine hepatocytes with 3.8×10−4 M, of NM, and the control group where the BAL had no NM. Plasma obtained from patients suffering from hepatic failure was perfused through the BAL for 10 hours. The viability of the porcine hepatocytes and the levels of alanine aminotransferase (ALT) in the human plasma were measured during perfusion. After the 10-hour perfusion, another human hepatic failure plasma was perfused for an additional 1 hour and then the function of the BAL was evaluated. After the 10-hour perfusion, the viability of the hepatocytes in the NM group was 51± 7 %, whereas that in the control group was rapidly reduced by 35 ± 5 %. Although the levels of ALT in the human plasma in both groups increased with the perfusion time, those in the NM group were significantly lower than those in the control group (p < 0.05). These results suggest that NM prevented damage to the porcine hepatocytes in human hepatic failure plasma as compared to the control group. In the human hepatic failure plasma before perfusion, the partial thrombin time (PT) and the plasma ammonia (NH3) levels were 19.8 ± 12 % and 288 ± 102 μg/dl, respectively. Fischer's ratios were 0.98 ± 0.39. Even after the 10- hour perfusion, the BAL in the NM group significantly improved the levels of PT (38 ± 10 %; p < 0.05), NH3 (214 ± 34 μg/dl; p < 0.05) and Fischer's ratios (1.4 ± 0.3; p < 0.05). On the other hand, the BAL in the control group did not show any improvement in those parameters. In conclusion, NM was found to help in maintaining the viability of porcine hepatocytes in human hepatic failure plasma, thereby allowing the porcine hepatocyte-based BAL to function much better.

The Effect of Serum from Liver Cancer Patients on the Growth and Function of Primary and Immortalised Hepatocytes

A limiting factor in the efficacy of bioartificial liver (BAL) for the treatment of liver failure is the toxicity of the patients’ serum to the hepatocytes in the device. This study investigates the interaction of liver cancer patient serum with primary and immortalised rat hepatocytes. Liver cancer serum increased the growth rate of immortalised hepatocytes, without affecting reduced glutathione levels. The activities of DT-diaphorase and pi glutathione-S-transferase (GST), enzymes associated with de-differentiation, were also increased. Exposure of primary hepatocytes to liver cancer serum resulted in a decrease in cytochrome P450 (CYP) content, and in P450 dependent metabolism of testosterone. Formation of 2-alpha- and 6-beta- hydroxy testosterone was decreased. These reactions are predominantly associated with CYP 2C11 and 3A1 respectively in normal rat liver. The activity of total GST was also decreased, although that of the pi isoenzyme of GST was not affected. Our results suggest that exposure of hepatocytes in a bioreactor to liver cancer patient serum will result in overgrowth of cells, if proliferating cells are being used, and in de-differentiation. The serum may have to be pretreated with adsorbants to remove toxins prior to BAL treatment.

Characterization of the Distribution of Matter in Hybrid Liver Support Devices where Cells are Cultured in a 3-D Membrane Network or on Flat Substrata

Bioreactors for liver assist tested on small animal models are generally scaled-up to treat humans by increasing their size to host a given liver cell mass. In this process, liver cell function in different culture devices is often established based on the metabolite concentration difference between the bioreactor inlet and outlet irrespective of how matter distributes in the bioreactor.

In this paper, we report our investigation aimed at establishing whether bioreactor design and operating conditions influence the distribution of matter in two bioreactors proposed for liver assist. We investigated a clinical-scale bioreactor where liver cells are cultured around a three-dimensional network of hollow fiber membranes and a laboratory-scale bioreactor with cells adherent on collagen-coated flat substrata. The distribution of matter was characterized under different operating modes and conditions in terms of the bioreactor residence time distribution evaluated by means of tracer experiments and modeled as a cascade of N stirred tanks with the same volume. Under conditions recommended by the manufacturers, matter distributed uniformly in the clinical-scale bioreactor as a result of the intense backmixing (N=1) whereas axial mixing was negligible in the laboratory-scale bioreactor (N=8). Switching from recycle to single-pass operation definitely reduced axial mixing in the clinical-scale bioreactor (N=2). Increasing feed flow rate significantly enhanced axial mixing in the laboratory-scale bioreactor (N=4). The effects of design, operating mode and conditions on matter distribution in bioreactors for liver cell culture suggest that characterization of the distribution of matter is a necessary step in the scale-up of bioreactors for liver assist and when function of liver cells cultured in different bioreactors is evaluated and compared.

Does the Extend of the Culture Time of Primary Hepatocytes in a Bioreactor Affect the Treatment Efficacy of a Bioartificial Liver?

The purpose of this study was to investigate whether the efficacy of our novel extracorporeal bioartificial liver (BAL) to support rats with complete liver ischemia (LIS) could be improved by extending the culture time of freshly isolated porcine hepatocytes from 14 hours to 38 hours. The results showed that survival as well as porcine hepatocyte integrity improved, the onset of coma delayed, and the ammonia levels decreased in LIS rats of the 38 hour group compared to the 14 hour group, but no statistically significant differences were observed. In the 38 hour group, but not the 14 hour group, the onset of hepatic encephalopathy was significantly delayed and ammonia metabolism significantly improved compared to the LIS rats in control groups that only received a glucose infusion or were connected to a BAL without cells. In conclusion, prolonged hepatocyte recovery favoured all investigated parameters, although not all observed effects were statistically significant. More research is required to find out how long primary hepatocytes should be cultured in a bioreactor for optimal BAL support.

Biochemical Assessment and Clinical Evaluation of a Non-Ionic Adsorbent Resin in Patients with Intractable Jaundice

We investigated in vitro and in vivo the ability of a non-ionic adsorbing resin (styrenedivinylbenzene copolymer) to remove bilirubin and bile acids from human plasma. In preliminary experiments, human plasma from healthy donors, enriched in conjugated bile acids and bilirubin, and pooled plasma from jaundiced patients were recirculated through the resin column. The removal of bilirubin and bile acids was evaluated at two different flow rates (200 ml/min and 40 ml/min), and compared to an activated charcoal column. Four patients with severe jaundice were subsequently treated by 4-hour plasmaperfusion through the resin. The in vitro studies showed that after 1 hour the removal of bile acids was almost complete and bilirubin level decreased significantly, reaching a plateau after 4 hours. In the in vivo study, all treatments were well tolerated. After plasmaperfusion, serum bile acid levels decreased by 64.9–94.6% and total bilirubin by 35.3–57.7%. No clinical or biochemical side effects were observed. Our data suggest that plasmaperfusion through this resin is safe and efficient for removal of bilirubin and bile acids in jaundiced patients. Thus, it may serve as a method of artificial liver support in the treatment of cholestatic syndromes.

The Efficacy of Nafamostat Mesilate on the Performance of a Hybrid-artificial Liver using a Polyurethane foam/porcine Hepatocyte Spheroid Culture System in Human Plasma

Nafamostat mesilate (FUT) is a protease inhibitor of complement activation. The present study investigates whether FUT protects porcine hepatocytes from being injured by human plasma in a multi-capillary polyurethane foam packed-bed culture system (MC-PUF) such as the hybrid-artificial liver (PUF-HAL). Human plasmas with 1 mM of added ammonia were perfused using a small-scale PUF-HAL with porcine hepatocytes. FUT was continuously infused (10 μ g/ml, 50 μ g/ml,). The ammonia detoxification was maintained in human plasma for 24 hours and for 48 hours with FUT which suppressed the rapid increase of asparaginic acid aminotransferase (AST) and alanine aminotransferase (ALT). After 60 hours of perfusion, hepatocyte spheroids completely collapsed in the human plasma, but a small amount of hepatocyte spheroid was maintained by FUT. The effect of FUT was slightly greater at 50 μ g/ml than at 10 μ g/ml. Our results suggest that FUT has protective effects against porcine hepatocytes in human plasma, and our PUF-HAL using porcine hepatocytes can function in human plasma for about 48 hours with FUT.

Conditions Required for a Hybrid Artificial Liver Support System using a PUF/Hepatocyte-Spheroid Packed-Bed Module and it's use in Dogs with Liver Failure

We studied the effects of a hybrid artificial liver support system we developed on dogs with hepatic failure. The system consisted of a multi-channel polyurethane foam packed-bed culture module, including primary dog hepatocyte spheroids.

Blood ammonia was well metabolized by 20 g hepatocytes, but the other functions such as glucose concentration, total bile acid concentration, and survival time required 30 g hepatocytes to improve conditions. We found that we should use a culture substratum that easily forms spheroids, and that an artificial liver module should be used as soon as possible after spheroid formation by hepatocytes in the module.

A clinical-scale BioArtificial Liver, developed for GMP, improved clinical parameters of liver function in porcine liver failure

Liver failure, whether arising directly from acute liver failure or from decompensated chronic liver disease is an increasing problem worldwide and results in many deaths. In the UK only 10% of individuals requiring a liver transplant receive one. Thus the need for alternative treatments is paramount. A BioArtificial Liver machine could temporarily replace the functions of the liver, buying time for the patient's liver to repair and regenerate. We have designed, implemented and tested a clinical-scale BioArtificial Liver machine containing a biomass derived from a hepatoblastoma cell-line cultured as three dimensional organoids, using a fluidised bed bioreactor, together with single-use bioprocessing equipment, with complete control of nutrient provision with feedback BioXpert recipe processes, and yielding good phenotypic liver functions. The methodology has been designed to meet specifications for GMP production, required for manufacture of advanced therapy medicinal products (ATMPs). In a porcine model of severe liver failure, damage was assured in all animals by surgical ischaemia in pigs with human sized livers (1.2-1.6 kg liver weights). The BioArtificial liver (UCLBAL) improved important prognostic clinical liver-related parameters, eg, a significant improvement in coagulation, reduction in vasopressor requirements, improvement in blood pH and in parameters of intracranial pressure (ICP) and oxygenation.

Comparison of Porcine Hepatocytes with Human Hepatoma (C3A) Cells for Use in a Bioartificial Liver Support System

Cells from primary porcine hepatocytes (PPH) and the immortalized human hepatoma cell line C3A are both used in bioartificial liver support systems (BALSS). In this work the viability and metabolic capacity of PPH and C3A cells cultured in different media were compared. Also, because the cells come into direct or indirect contact with human blood components in BALSS, the effects of human complement on survival and functions of the cells was evaluated. For short-term culture, maintenance of PPH viability was essential for retention of P450IA1 activity ( r = 0.882, p < 0.01) and effective ammonia clearance ( r = −0.791, p < 0.01). When cell viability was below 60% P450IA1 activity could not be recorded and nitrogen elimination activity significantly diminished. In contrast to PPH, ammonia levels were markedly increased for C3A cells in all culture media tested ( p < 0.01). Ammonia increase correlated with C3A viability ( r = 0.896, p < 0.05). PPH metabolic function was superior to that of the C3A cell line when evaluated by P450IA1 activity, ammonia removal, and amino acid metabolism. When PPH were incubated in human plasma (HP) or human serum (HS) there was rapid and irreversible deterioration of viability occurring within 9 h. This toxic effect could be prevented by the inactivation of complement. When sodium citrate dissolved in dextrose was added to medium, there was considerable damage to both PPH and the C3A cell line. However, there was no demonstrable toxic effect when hepatic cells of either type were exposed to heparin. We conclude that PPH cultivated in complement-inactivated HP or HS are to be preferred to C3A for clinical application of BALSS, and that heparin should be preferred for anticoagulation in BALSS. © 1998 Elsevier Science Inc.

Transplantation of Hepatocytes for Prevention of Intracranial Hypertension in Pigs with Ischemic Liver Failure

Intracranial hypertension leading to brain stem herniation is a major cause of death in fulminant hepatic failure (FHF). Mannitol, barbiturates, and hyperventilation have been used to treat brain swelling, but most patients are either refractory to medical management or cannot be treated because of concurrent medical problems or side effects. In this study, we examined whether allogeneic hepatocellular transplantation may prevent development of intracranial hypertension in pigs with experimentally induced liver failure. Of the two preparations tested—total hepatectomy (n = 47), and liver devascularization (n = 16)—only pigs with liver ischemia developed brain edema provided, however, that animals were maintained normothermic throughout the postoperative period. This model was then used in transplantation studies, in which six pigs received intrasplenic injection of allogeneic hepatocytes (2.5 × 109 cells/pig) and 3 days later acute liver failure was induced. In both models (anhepatic state, liver devascularization), pigs allowed to become hypothermic had significantly longer survival compared to those maintained normothermic. Normothermic pigs with liver ischemia had, at all time points studied, ICP greater than 20 mmHg. Pigs that received hepatocellular transplants had ICP below 15 mmHg until death; at the same time, cerebral perfusion pressure (CPP) in transplanted pigs was consistently higher than in controls (45 ± 11 mmHg vs. 16 ± 18 mmHg; p < 0.05). Spleens of transplanted pigs contained clusters of viable hepatocytes (hematoxylin-eosin, CAM 5.2). It was concluded that removal of the liver does not result in intracranial hypertension; hypothermia prolongs survival time in both anhepatic pigs and pigs with liver devascularization, and intrasplenic transplantation of allogeneic hepatocytes prevents development of intracranial hypertension in pigs with acute ischemic liver failure.

Engineering of Human Hepatocyte Lines for Cell Therapies in Humans: Prospects and Remaining Hurdles

Hepatocyte-based biological therapies are increasingly envisioned for temporary support in acute liver failure and provision of specific-liver functions in liver-based metabolic deficiency. One of the hurdles to develop such therapies is severe shortage of human livers for hepatocyte isolation. To address the issue, we have focused on reversible immortalization of human hepatocytes. Such technology can allow rapid preparation of functional and uniform human hepatocytes. Here we present our strategy to construct transplantable human hepatocyte cell lines.

cDNA Microarray Analysis in Hepatocyte Differentiation in Huh 7 Cells

The risk of xenozoonosis infections poses the greatest obstacle against the clinical application of a 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 previously demonstrated the upregulation of hepatocyte-specific function by spheroid formation in polyurethane foam and by culturing with the histone deacetylase inhibitor, trichostatin A (TSA), in a human hepatoma cell line (Huh 7). In this article we analyze the gene expression profile using cDNA microarray (1281 genes) in spheroid formation or culturing with TSA in Huh 7 to determine the target genes in hepatocyte differentiation. In both the spheroid formation and in the culture with TSA, the Oct-3/4 transcription factor was upregulated more than twofold, while the early growth response-1 (EGR-1) transactivator was downregulated less than 0.5-fold. These results indicate that expressions of Oct-3/4 and EGR-1 may be key factors in the induction of hepatocyte differentiation in Huh 7.

High Metabolic Function of Primary Human and Porcine Hepatocytes in a Polyurethane Foam/Spheroid Culture System in Plasma from Patients with Fulminant Hepatic Failure

It has been demonstrated that plasma from patients with fulminant hepatic failure (FHF) interferes extensively with cellular function. We placed primary human and primary porcine hepatocytes in a polyurethane foam (PUF)/spheroid culture system and compared the metabolic functions in the plasma of patients with FHF in a 24-h stationary culture to those in a monolayer culture. The PUF/spheroid culture system using primary human and primary porcine hepatocytes significantly decreased ammonia content during 28-day culture. Fisher's ratio significantly increased at culture days 3 and 7. Tauroursodeoxycholic acid significantly increased and glycochenodeoxycholic acid and taurochenodeoxycholic acid decreased in the FHF patients' plasma at culture day 3. During at least a 24-h culture in the FHF patients' plasma, metabolic functions of primary human and primary porcine hepatocytes were almost identical. The present results indicate that the PUF/spheroid culture system using primary human or primary porcine hepatocytes demonstrated more advantageous metabolic functions in the plasma from patients with FHF than the monolayer culture.

Comparison of Bioenergetic Activity of Primary Porcine Hepatocytes Cultured in Four Different Media

Primary hepatocytes have extensively been used in biochemical, pharmacological, and physiological research. Recently, primary porcine hepatocytes have been regarded as the cells of choice for bioartificial liver support systems. The optimum culture medium for hepatocytes to be used in such devices has yet to be defined. In this study we investigated the effectiveness of four culture media in driving energy metabolism of primary porcine hepatocytes. The media selected were William's E medium, medium 1640, medium 199, and hepatocyte medium. Cells (3 × 1010; viability 87 ± 6%) were isolated from weanling piglets and seeded on 90-mm plates in the above media supplemented with antibiotics and hormones at a density of 8 × 106 viable cells per plate. Using 1H NMR spectroscopy we looked at indices of glycolysis, gluconeogenesis, ketogenesis, and ureagenesis on days 2, 4, and 6 of the experiments (n = 9). We also studied urea and albumin synthesis and total P450 content. The examined metabolic pathways of the hepatocytes were maintained by all media, although there were statistically significant differences between them. All media performed well in glycolysis, ureagenesis, and albumin synthesis. William's E medium and medium 199 outperformed the rest in gluconeogenesis. Medium 199 was best in ketogenesis. Overall, medium 199 was the best at driving energy metabolism from its constituent substrates and we think that it preferentially should be used in the culture of primary porcine hepatocytes.

Extracorporeal Liver Support Systems in Paediatric Liver Failure

Extracorporeal liver support systems (ELSS), encompassing artificial and bioartificial devices, have been used for decades, with the aim of supporting patients with acute liver failure and acute-on chronic liver failure, as a bridge to recovery (acute liver failure only) or liver transplantation, in an era of organ donation shortage. Although biochemical efficacy has been consistently demonstrated by these devices, translation into clinical and survival benefits has been unclear, due to study limitations and lack of reliable prognostic scoring in liver failure. Consequently, extracorporeal devices are not widely accepted as routine therapy in adult liver failure. Recent large multicentre trials using artificial liver systems have not revealed beneficial outcomes associated with albumin dialysis but plasma exchange practices have shown some potential. In paediatric liver failure, data on extracorporeal systems is scarce, comprising few reports on albumin dialysis (namely, Molecular Adsorbent Recirculating System; MARS) and plasma exchange. When extrapolating data from adult studies differences in disease presentation, aetiology, prognosis and the suitability, and safety of such devices in children must be considered. The aim of this review is to critically appraise current practices of extracorporeal liver support systems to help determine efficacy in paediatric liver failure.

Development of hepatic blocks using human adipose tissue-derived stem cells through three-dimensional cell printing techniques

Currently, most acute liver diseases are treated through liver transplantation.

New Phase of Growth for Xenogeneic-Based Bioartificial Organs

In this article, we examine the advanced clinical development of bioartificial organs and describe the challenges to implementing such systems into patient care. The case for bioartificial organs is evident: they are meant to reduce patient morbidity and mortality caused by the persistent shortage of organs available for allotransplantation. The widespread introduction and adoption of bioengineered organs, incorporating cells and tissues derived from either human or animal sources, would help address this shortage. Despite the decades of development, the variety of organs studied and bioengineered, and continuous progress in the field, only two bioengineered systems are currently commercially available: Apligraf® and Dermagraft® are both approved by the FDA to treat diabetic foot ulcers, and Apligraf® is approved to treat venous leg ulcers. Currently, no products based on xenotransplantation have been approved by the FDA. Risk factors include immunological barriers and the potential infectivity of porcine endogenous retrovirus (PERV), which is unique to xenotransplantation. Recent breakthroughs in gene editing may, however, mitigate risks related to PERV. Because of its primary role in interrupting progress in xenotransplantation, we present a risk assessment for PERV infection, and conclude that the formerly high risk has been reduced to a moderate level. Advances in gene editing, and more broadly in the field, may make it more likely than ever before that bioartificial organs will alleviate the suffering of patients with organ failure.

Three-dimensional co-culture of hepatic progenitor cells and mesenchymal stem cells in vitro and in vivo

INTRODUCTION

Here we co-cultured hepatic progenitor cells (HPCs) and mesenchymal stem cells (MSCs) to investigate whether the co-culture environments could increase hepatocytes form.

METHODS

Three-dimensional (3D) co-culture model of HPCs and MSCs was developed and morphological features of cells were continuously observed. Hepatocyte specific markers Pou5f1/Oct4, AFP, CK-18 and Alb were analyzed to confirm the differentiation of HPCs. The mRNA expression of CK-18 and Alb was analyzed by RT-PCR to investigate the influence of co-culture model to the terminal differentiation process of mature hepatocytes. The functional properties of hepatocyte-like cells were detected by continuously monitoring the albumin secretion using Gaussia luciferase assays. Scaffolds with HPCs and MSCs were implanted into nude mouse subcutaneously to set up the in vivo co-culture model.

RESULTS

Although two groups formed smooth spheroids and high expressed of CK-18 and Alb, hybrid spheroids had more regular structures and higher cell density. CK-18 and Alb mRNA were at a relatively higher expression level in co-culture system during the whole cultivation time (P < 0.05). Albumin secretion rates in the hybrid spheroids had been consistently higher than that in the mono-culture spheroids (P < 0.05). In vivo, the hepatocyte-like cells were consistent with the morphological features of mature hepatocytes and more well-differentiated hepatocyte-like cells were observed in the co-culture group.

CONCLUSIONS

HPCs and MSCs co-culture system is an efficient way to form well-differentiated hepatocyte-like cells, hence, may be helpful to the cell therapy of hepatic tissues and alleviate the problem of hepatocytes shortage.

Coculture of hepatocytes with islets

Bioartificial liver support (BAL) systems are potential new therapeutic approaches for use as liver support to prevent nutrient deficiencies, hypoxia, or ischemia before the acquisition of donated organs. To investigate whether islets are beneficial for hepatocyte function and survival, we cocultured BALB/c mouse islets with C57BL/6J hepatocytes to assess hepatocyte viability, function, and apoptosis. We observe cell viability to decrease progressively by 50% from day 0 to day 3 among isolated hepatocytes (group A) and hepatocytes cocultured with islets (group B). However, group A was prone to necrosis and reduced albumin secretion during culture. In contrast, at day 7 group B maintained albumin secretion (0.3351 ± 0.0581 vs 0.1451 ± 0.0329 μg/h/mL; P < .05). Early apoptosis was observed at day 3 among group A but at day 7 in group B. In addition, quantitative analysis of the apoptotic cells revealed group B to show a delayed phenotype of both early and late apoptosis compared with group A. Our results indicated that islets could retain hepatocyte function and delay apoptosis, suggesting that the coculture system is potentially applicable to develop a high-performance BAL.

Immortalization of Human Fetal Hepatocyte by Ectopic Expression of Human Telomerase Reverse Transcriptase, Human Papilloma Virus (E7) and Simian Virus 40 Large T (SV40 T) Antigen Towards Bioartificial Liver Support

BACKGROUND

Generation of genetically stable and non-tumoric immortalization cell line from primary cells would be enormously useful for research and therapeutic purposes, but progress towards this goal has so far been limited. It is now universal acceptance that immortalization of human fetal hepatocytes based on recent advances of telomerase biology and oncogene, lead to unlimited population doubling could be the possible source for bioartificial liver device.

METHODS

Immortalization of human fetal hepatocytes cell line by ectopic expression of human telomerase reverse transcriptase (hTERT), human papilloma virus gene (E7) and simian virus 40 large T (SV40 T) antigens is main goal of present study. We used an inducible system containing human telomerase and E7, both of which are cloned into responder constructs controlled by doxycycline transactivator. We characterized the immortalized human fetal hepatocyte cells by analysis of green fluorescent cells (GFP) positive cells using flow cytometry (FACs) cell sorting and morphology, proliferative rate and antigen expression by immunohistochemical analysis. In addition to we analysized lactate formation, glucose consumption, albumin secretion and urea production of immortalized human fetal hepatocyte cells.

RESULTS

After 25 attempts for transfection of adult primary hepatocytes by human telomerase and E7 to immortalize them, none of the transfection systems resulted in the production of a stable, proliferating cell line. Although the transfection efficiency was more than 70% on the first day, the vast majority of the transfected hepatocytes lost their signal within the first 5-7 days. The remaining transfected hepatocytes persisted for 2-4 weeks and divided one or two times without forming a clone. After 10 attempts of transfection human fetal hepatocytes using the same transfection system, we obtained one stable human fetal hepatocytes cell line which was able albumin secretion urea production and glucose consumption.

CONCLUSION

We established a conditional human fetal hepatocytes cell line with mesenchymal characteristics. Thus immortalization of human fetal hepatocytes cell line by telomerase biology offers a great challenge to examine basic biological mechanisms which are directly related to human and best cell source having unlimited population doubling for bioartificial support without any risk of replicative senescence and pathogenic risks.

Increased transfusion-free survival following auxiliary pig liver xenotransplantation

BACKGROUND

Pig to baboon liver xenotransplantation typically results in severe thrombocytopenia and coagulation disturbances, culminating in death from hemorrhage within 9 days, in spite of continuous transfusions. We studied the contribution of anticoagulant production and clotting pathway deficiencies to fatal bleeding in baboon recipients of porcine livers.

METHODS

By transplanting liver xenografts from α1,3-galactosyltransferase gene-knockout (GalT-KO) miniature swine donors into baboons as auxiliary organs, leaving the native liver in place, we provided the full spectrum of primate clotting factors and allowed in vivo mixing of porcine and primate coagulation systems.

RESULTS

Recipients of auxiliary liver xenografts develop severe thrombocytopenia, comparable to recipients of conventional orthotopic liver xenografts and consistent with hepatic xenograft sequestration. However, baboons with both pig and native livers do not exhibit clinical signs of bleeding and maintain stable blood counts without transfusion for up to 8 consecutive days post-transplantation. Instead, recipients of auxiliary liver xenografts undergo graft failure or die of sepsis, associated with thrombotic microangiopathy in the xenograft, but not the native liver.

CONCLUSION

Our data indicate that massive hemorrhage in the setting of liver xenotransplantation might be avoided by supplementation with primate clotting components. However, coagulation competent hepatic xenograft recipients may be predisposed to graft loss related to small vessel thrombosis and ischemic necrosis.

Evaluation of a novel choanoid fluidized bed bioreactor for future bioartificial livers

AIM

To construct and evaluate the functionality of a choanoid-fluidized bed bioreactor (CFBB) based on microencapsulated immortalized human hepatocytes.

METHODS

Encapsulated hepatocytes were placed in the constructed CFBB and circulated through Dulbecco's Modified Eagle's Medium (DMEM) for 12 h, and then through exchanged plasma for 6 h, and compared with encapsulated cells cultivated under static conditions in a spinner flask. Levels of alanine aminotransferase (ALT) and albumin were used to evaluate the CFBB during media circulation, whereas levels of ALT, total bilirubin (TBil), and albumin were used to evaluate it during plasma circulation. Mass transfer and hepatocyte injury were evaluated by comparing the results from the two experimental conditions. In addition, the viability and microstructure of encapsulated cells were observed in the different environments.

RESULTS

The bioartificial liver model based on a CFBB was verified by in vitro experiments. The viability of encapsulated cells accounting for 84.6% ± 3.7% in CFBB plasma perfusion was higher than the 74.8% ± 3.1% in the static culture group (P < 0.05) after 6 h. ALT release from cells was 29 ± 3.5 U/L vs 40.6 ± 3.2 U/L at 12 h (P < 0.01) in the CFBB medium circulation and static medium culture groups, respectively. Albumin secretion from cells was 234.2 ± 27.8 μg/1 × 10(7) cells vs 167.8 ± 29.3 μg/1 × 10(7) cells at 6 h (P < 0.01), 274.4 ± 34.6 μg/1 × 10(7) cells vs 208.4 ± 49.3 μg/1 × 10(7) cells (P < 0.05) at 12 h, in the two medium circulation/culture groups, respectively. Furthermore, ALT and TBil levels were 172.3 ± 24.1 U/L vs 236.3 ± 21.5 U/L (P < 0.05), 240.1 ± 23.9 μmol/L vs 241.9 ± 31.4 μmol/L (P > 0.05) at 6 h in the CFBB plasma perfusion and static plasma culture groups, respectively. There was no significant difference in albumin concentration between the two experimental plasma groups at any time point. The microstructure of the encapsulated hepatocytes remained healthier in the CFBB group compared with the static culture group after 6 h of plasma perfusion.

CONCLUSION

The CFBB can function as a bioartificial liver based on a bioreactor. The efficacy of this novel bioreactor is promising for the study of liver failure.

Effect of membranes on oxygen transfer rate and consumption within a newly developed three-compartment bioartificial liver device: Advanced experimental and theoretical studies

A mathematical model is developed to predict oxygen transfer in the fiber-in-fiber (FIF) bioartificial liver device. The model parameters are taken from the constructed and tested FIF modules. We extended the Krogh cylinder model by including one more zone for oxygen transfer. Cellular oxygen uptake was based on Michaelis-Menten kinetics. The effect of varying a number of important model parameters is investigated, including (1) oxygen partial pressure at the inlet, (2) the hydraulic permeability of compartment B (cell region), (3) the hydraulic permeability of the inner membrane, and (4) the oxygen diffusivity of the outer membrane. The mathematical model is validated by comparing its output against the experimentally acquired values of an oxygen transfer rate and the hydrostatic pressure drop. Three governing simultaneous linear differential equations are derived to predict and validate the experimental measurements, e.g., the flow rate and the hydrostatic pressure drop. The model output simulated the experimental measurements to a high degree of accuracy. The model predictions show that the cells in the annulus can be oxygenated well even at high cell density or at a low level of gas phase PG if the value of the oxygen diffusion coefficient Dm is 16 × 10(-5) . The mathematical model also shows that the performance of the FIF improves by increasing the permeability of polypropylene membrane (inner fiber). Moreover, the model predicted that 60% of plasma has access to the cells in the annulus within the first 10% of the FIF bioreactor axial length for a specific polypropylene membrane permeability and can reach 95% within the first 30% of its axial length.

Right-lobe living-donor liver transplantation in adult patients with acute liver failure

BACKGROUND

Right-lobe living-donor liver transplantation (RLDLT) is an excellent option to reduce donor shortages for adult patients with acute liver failure (ALF). The aim of this study was to evaluate the etiologies and outcomes of 30 consecutive adult patients who underwent emergency RLDLT for ALF.

METHODS

Between January 2007 and September 2011, we examined data from medical records of patients with ALF who underwent RLDLT.

RESULTS

Their mean age was 32.2 ± 13.05 years. The etiologies of ALF were acute hepatitis B (n = 11; 36.6%), hepatitis A (n = 4; 13.3%), drug intoxication (n = 4; 13.3%), pregnancy (n = 2; 6.7%), hepatitis B with pregnancy (n = 1; 3.3%), mushroom intoxication (n = 1; 3.3%), and unknown (n = 7; 23.3%). The mean hepatic coma grade (Model for End-Stage Liver Disease score) was 34.13 ± 8.72. The 43 (48.7%) postoperative complications were minor (grades I-II) and 44 (51.3%) were major (grades III-V). Reoperation was required in 14 of 30 (47%) recipients (grades IIIb-IVa). Deaths occurred owing to pulmonary (n = 2), cardiac (n = 1), septic (n = 2), or encephalopathic (n = 4) complications. The mean durations of intensive care unit stay and postoperative hospitalization were 3.2 ± 2.3 and 29.5 ± 23 days, respectively. The survival rate was 70%. The mean follow-up duration was 305 days (range, 1-1582).

CONCLUSION

Liver transplantation is potentially the only curative modality, markedly improving the prognosis of patients with ALF. The interval between ALF onset and death is short and crucial because of the rapid, progressive multiorgan failure. Thus, RLDLT should be considered to be a life-saving procedure for adult patients with ALF, requiring quicker access to a deceased-donor liver graft and a short ischemia time.

Composite nonwovens in medical applications

This chapter reviews the role of composite nonwovens in medical applications. It covers surgical gowns, clinical wearable products, wipes, wound dressings, pads, swabs, scaffolds for tissue engineering, hernia meshes, filtration materials, and incontinence products. Commercially available, innovatively designed composite nonwovens for various medical applications are improving the quality of life of many people. Specific research needs have been highlighted to further improve the effectiveness of these products. The chapter ends with some perspectives for the use of composite nonwovens in medical applications in the future.

3D co-culturing model of primary pancreatic islets and hepatocytes in hybrid spheroid to overcome pancreatic cell shortage

Here, a spheroidal 3D co-culture model of primary (rat) pancreatic islets and hepatocytes with uniform size and shape was developed using hemispheric concave microwell arrays. We conducted morphological and functional analyses of hybrid spheroids versus mono-cultures of islets or hepatocytes (controls). For the establishment of a 3D hybrid model, a broad range of cell ratios - 1:1, 1:3, 1:5, 1:7, 3:1, 5:1 and 7:1 mixture - of hepatocytes and pancreatic islets were used. As control, each hepatocyte and pancreatic islet were mono-cultured forming 3D spheroids. The transient morphology of spheroid formation in 9 culture models was observed using optical microscopy. Cell viability under these culture environments was assessed, and the morphologies of the outer and inner porous cell-spheroid structures were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and imaging of stained spheroid sections. The pancreatic islet-specific function of hybrid spheroids was evaluated by measuring insulin secretion and in vivo test by xenotransplantation of encapsulated spheroids in microfibers with a consistent maintenance of normal blood glucose levels over 4 weeks, while liver-specific functions were measured in terms of albumin secretion, urea secretion and cytochrome P450 activity. These diverse observations and evaluations validated the positive and bidirectional effects of co-cultured 3D spheroids. The proposed 3D co-culture model demonstrated that both cells appeared to support each other's functions strongly in spheroids, even though smaller proportions of each cell type was evaluated compared to mono-culture models, suggesting that the proposed model could help overcome the problem of cell shortages in clinical applications.

Adipose tissue regeneration: a state of the art

Adipose tissue pathologies and defects have always represented a reconstructive challenge for plastic surgeons. In more recent years, several allogenic and alloplastic materials have been developed and used as fillers for soft tissue defects. However, their clinical use has been limited by further documented complications, such as foreign-body reactions potentially affecting function, degradation over time, and the risk for immunogenicity. Tissue-engineering strategies are thus being investigated to develop methods for generating adipose tissue. This paper will discuss the current state of the art in adipose tissue engineering techniques, exploring the biomaterials used, stem cells application, culture strategies, and current regulatory framework that are in use are here described and discussed.

Stable overexpression of arginase I and ornithine transcarbamylase in HepG2 cells improves its ammonia detoxification

HepG2 is an immortalized human hepatoma cell line that has been used for research into bioartificial liver systems. However, a low level of ammonia detoxification is its biggest drawback. In this work, a recombinant HepG2 cell line with stable overexpression of human arginase I (hArgI) and human ornithine transcarbamylase (hOTC), HepG2/(hArgI + hOTC)4, was developed using a eukaryotic dual gene expression vector pBudCE4.1. (1) The hArgI and hOTC enzymatic activity in HepG2/(hArgI + hOTC)4 cells were higher than in the control cells. (2) The ammonia tolerance capacity of HepG2/(hArgI + hOTC)4 cells was three times that of HepG2 cells and 37.5% of that of primary human hepatocytes in cultivation. In the experiment of ammonia detoxification, HepG2/(hArgI + hOTC)4 cells produced 3.1 times more urea (at 180 mM NH(4) Cl) and 3.1 times more glutamine (at 120 mM NH(4) Cl and 15 mM glutamate) than HepG2 cells, reaching 63.1% and 36.0% that of primary human hepatocytes, respectively. (3) The hArgI and hOTC overexpression did not influence the growth of HepG2 cells and also promoted the expression of other ammonia detoxification associated proteins including glutamine synthetase (GS), arginase II (ArgII), arginosuccinate synthase (ASS) and arginosuccinate lyase (ASL) in HepG2 cells. This work illustrates that the modification reported here made significant progress in the improvement of HepG2 cell function and the HepG2/(hArgI + hOTC)4 cells will provide a better selection for the application of bioartificial liver system.

Systematic review: extracorporeal bio-artificial liver-support system for liver failure

BACKGROUND

Orthotopic liver transplantation (OLT) is the only effective long-term treatment for liver failure by now. However, it is not yet a perfect choice due to donor-organ shortage and the need of a lifelong immunosuppressive therapy. Therefore, it is necessary to find a new approach to fighting the disease. Several published clinical trials have reported the therapeutic effect of bio-artificial liver (BAL) for liver failure.

OBJECTIVE

To overview and evaluate the current clinical application and outcomes of extracorporeal BAL support system during the past 15 years.

METHODS

Relevant studies were retrieved from PubMed and Cochrane Library databases. Independent assessments and the final consensus decision were performed by three independent reviewers. Acceptable study designs included randomized controlled trials, controlled clinical trials, and case reports. A total of 31 studies were tabulated and critically appraised in terms of characteristics, methods, and outcomes.

RESULTS

There was a trend of falling into the normal ranges with the clinical and biochemical parameters after the BAL treatment. The neurological status of most patients was improved or stabilized during BAL treatment as well. No significant effect on survival could be seen after the BAL treatment.

CONCLUSIONS

Although BAL system proved to be a success in some clinical cases reported, it still needs to be improved greatly.