Weibo Du

Bioartificial liver system based on choanoid fluidized bed bioreactor improve the survival time of fulminant hepatic failure pigs

Bioartificial liver (BAL) support system has been proposed as potential treatment method for end‐stage liver diseases. We described an improved BAL system based on a choanoid fluidized bed bioreactor containing alginate–chitosan encapsulated primary porcine hepatocytes. The feasibility, safety, and efficiency of this device were estimated using an allogeneic fulminant hepatic failure (FHF) model. FHF was induced with intravenous administration of D‐galactosamine. Thirty FHF pigs were divided into three groups: (1) an FHF group which was only given intensive care; (2) a sham BAL group which was treated with the BAL system with empty encapsulation, and (3) a BAL group which was treated with the BAL system containing encapsulated freshly isolated primary porcine hepatocytes. The survival times and biochemical parameters of these animals were measured, and properties of the encapsulations and hepatocytes before and after perfusion were also evaluated. Compared to the two control groups, the BAL‐treated group had prolonged the survival time and decreased the blood lactate levels, blood glucose, and amino acids remained stable. No obvious ruptured beads or statistical decline in viability or function of encapsulated hepatocytes were observed. This new fluidized bed BAL system is safe and efficient. It may represent a feasible alternative in the treatment of liver failure. Biotechnol. Bioeng. 2011;108:2229–2236.

A Modified MELD Model for Chinese Pre-ACLF and ACLF Patients and It Reveals Poor Prognosis in Pre-ACLF Patients

Background & Aims Acute-on-chronic liver failure (ACLF) is one of the most deadly, prevalent, and costly diseases in Asia. However, no prognostic model has been developed that is based specifically on data gathered from Asian patients with ACLF. The aim of the present study was to quantify the survival time of ACLF among Asians and to develop a prognostic model to estimate the probability of death related to ACLF. Methods We conducted a retrospective observational cohort study to analyze clinical data from 857 patients with ACLF/pre-ACLF who did not undergo liver transplantation. Kaplan–Meier and Cox proportional hazards regression model were used to estimate survival rates and survival affected factors. The area under the receiver operating characteristic curve (auROC) was used to evaluate the performance of the models for predicting early mortality. Results The mortality rates among patients with pre-ACLF at 12 weeks and 24 weeks after diagnosis were 30.5% and 33.2%, respectively. The mortality rates among patients with early-stage ACLF at 12 weeks and 24 weeks after diagnosis were 33.9% and 37.1%, respectively. The difference in survival between pre-ACLF patients and patients in the early stage of ACLF was not statistically significant. The prognostic model identified 5 independent factors significantly associated with survival among patients with ACLF and pre-ACLF: the model for end-stage liver disease (MELD) score; age, hepatic encephalopathy; triglyceride level and platelet count. Conclusion The findings of the present study suggest that the Chinese diagnostic criteria of ACLF might be broadened, thus enabling implementation of a novel model to predict ACLF-related death after comprehensive medical treatment.

Differences of YMDD mutational patterns, precore/core promoter mutations, serum HBV DNA levels in lamivudine-resistant hepatitis B genotypes B and C

Summary.  The aims of this study were to investigate the viral differences among lamivudine‐resistant hepatitis B virus (HBV) genotypes B and C in vivo. Fifty‐three patients carrying lamivudine‐resistant HBV were enrolled in this study. HBV genotypes, Levels of alanine aminotransferase (ALT), HBV DNA levels were monitored during therapy. The polymerase and precore/core promoter genes were amplified by polymerase chain reaction and their products were sequenced directly. Among 53 patients resistant HBV genotypes B and C accounted for 41.50% and 58.50%, respectively. The occurrence of reverse transcriptase rt204I mutants was lower in genotype B (36.36%) than that in genotype C (87.10%), whereas rt204V mutants was higher in genotype B (63.64%) than that in genotype C (12.90%). The occurrence of precore mutation (nt1896A) was higher in genotype B (77.27%) than that in genotype C (32.26%). Serum HBV DNA levels after emergence of lamivudine resistance were higher in genotype C (7.71 ± 0.80 Log copies/mL) compared with genotype B (6.97 ± 0.77 Log copies/mL). Multivariate analysis identified pretreatment HBV DNA levels, HBeAg status and HBV genotype as independent factors associated with a shorter time to lamivudine resistance(P = 0.035, P = 0.006 and P = 0.001, respectively). Multivariate analysis showed that HBV genotype (P = 0.004) and pretreatment ALT levels (P = 0.01) was independently associated with YMDD mutational patterns. The results showed that the YMDD mutational patterns, precore mutation and serum HBV DNA levels differ between lamivudine‐resistant HBV genotypes B and C in vivo. It is valuable for treatment of lamivudine‐resistant HBV in clinic.

Prevalence of Hepatitis B and C in HIV-infected Patients: A meta-analysis

BACKGROUND Hepatitis C virus (HCV), hepatitis B virus (HBV) and human immunodeficiency virus (HIV) share similar routes of transmission by sexual intercourse or drug use by parenteral injection, so coinfection is common. This study aimed to determine the prevalence of coinfection with either HCV or HBV in patients infected with HIV. DATA SOURCES A meta-analysis was performed to quantify HBV coinfection with HCV in HIV patients. Published studies in the English and Chinese language medical literature involving cohorts of HIV patients concomitantly infected with HBV and/or HCV were collected from the PubMed database, ISI Web of Science, the Cochrane library clinical trials registry, CNKI (China National Knowledge Infrastructure) and Google Scholar, for relevant articles before November 2009. The search was conducted with the following key words: hepatitis C, HCV, hepatitis B, HBV, human immunodeficiency virus, HIV, and coinfection. Data were extracted from relevant studies by two investigators. RevMan 5.0 software was used to perform the meta-analysis. RESULTS We identified 22 studies involving 17 664 patients. Substantial differences in the HCV rate compared to the HBV rate in HIV patients were found in the overall analysis [odds ratio (OR)=3.00; 95% confidence interval (CI) 1.90-4.73]. A subgroup analysis showed similar results in a European group, but not in Asian or African groups. However, a meta-analysis between HIV+HBV+HCV+ and HIV+HBV+HCV- patients showed no significant difference (OR=0.91; 95% CI 0.57-1.45). Although subgroup analysis still lacked essential differences, different regions seemed to have different patterns. CONCLUSIONS HCV-HIV coinfection is more frequent than HBV-HIV coinfection overall. However, HCV infection does not affect the prevalence of HBV infection in HIV-positive patients.

Establishment and Characterization of Immortalized Porcine Hepatocytes for the Study of Hepatocyte Xenotransplantation

BACKGROUND In light of the critical shortage of donor livers, xenogeneic sources offer the best alternative to human hepatocytes for the treatment of acute liver failure. This study investigated whether a combination of simian virus 40 large T antigen (SV40 LT) and human telomerase catalytic subunit (hTERT) genes could immortalize primary porcine hepatocytes that could reverse acute liver failure (ALF) in rats. METHODS We cotransfected SV40 LT and hTERT genes into primary porcine hepatocytes to examine the features of the transfected cell lines. We characterized the potentially therapeutic effect of immortalized porcine hepatocytes in a rat model of ALF induced by 90% hepatectomy. RESULTS An immortalized porcine hepatocyte cell line, HepLi, was expanded by >250 passages. HepLi cells maintained the defining characteristics of primary porcine hepatocytes, including porcine albumin secretion, urea production, and diazepam metabolism. Intrasplenic transplantation of HepLi cells significantly improved liver function, and significantly prolonging the survival of rats with ALF. CONCLUSIONS Cotransfection of SV40 LT and hTERT immortalized primary porcine hepatocytes without tumorigenicity in vitro. The Immortalized porcine hepatocytes served as a potential cell resource for xenotransplantation.

In vitro large-scale cultivation and evaluation of microencapsulated immortalized human hepatocytes (HepLL) in roller bottles.

Background/Aims Microencapsulated hepatocytes have been proposed as promising bioactive agents for packed-bed or fluidized-bed bioartificial liver assist devices (BLADs) and for hepatocyte transplantation because of the potential advantages they offer of high mass transport rate and an optimal microenvironment for hepatocyte culture. We developed a large-scale and high-production alginate-chitosan (AC) microcapsule roller bottle culture system for the encapsulation of HepLL immortalized human hepatocytes. In this study, the efficacy of upscaling encapsulated HepLL cells production with roller bottle cultivation was evaluated in vitro. Methods Microencapsulated HepLL cells were grown at high yield in large-scale roller bottles, with free cells cultured in roller bottle spinners serving as controls. The mechanical stability and the permeability of the AC microcapsules were investigated, and the growth, metabolism and functions of the encapsulated HepLL cells were evaluated as compared to free cells. Results The microcapsules withstood well the shear stress induced by high agitation rates. The microcapsules were permeable to albumin, but prevented the release of immunoglobulins. Culture in roller bottles of immortalized human hepatocytes immobilized in the AC microcapsules improved cell growth, albumin synthesis, ammonia elimination and lidocaine clearance as compared with free cells cultured in roller bottles. Conclusions Encapsulated HepLL cells may be cultured on a large scale in roller bottles. This makes them possible candidates for use in cell-based liver assist therapies.

Efficacy of coupled low-volume plasma exchange with plasma filtration adsorption in treating pigs with acute liver failure: A randomised study

BACKGROUND & AIMS Extracorporeal blood purification systems for supportive therapy of liver failure are widely used. We developed a novel blood purification system, named Lis artificial liver system (Li-ALS), which couples low-volume plasma exchange (low-volume PE) with plasma filtration adsorption (PFA). This study aims to evaluate the efficacy of our novel system in pigs with acute liver failure (ALF). METHODS Thirty-two pigs were infused with D-galactosamine (1.3g/kg) to induce ALF. All animals were equally and randomly divided into four groups: the ALF control group received intensive care, the PFA group underwent five hour plasma recycling filtration and adsorption purification, the low-volume PE group received one hour low-volume PE, and the Li-ALS group underwent one hour low-volume PE, followed by five hour PFA. Intervention was initiated 36hours after drug administration. The efficacy of each treatment was assessed by survival time and improvement in hematological, biochemical, and immunohistological parameters. RESULTS Pigs in the Li-ALS group survived longer than those in the other groups (p<0.001, ALF control: 60±2h; PFA group: 74±2h; low-volume PE group: 75±2h; and Li-ALS group: 90±3h). Liver enzyme, bilirubin, bile acid and blood ammonia levels were decreased significantly after Li-ALS treatment, and increases in inflammatory cytokines were ameliorated. A higher hepatocyte regeneration index was also observed in the Li-ALS group. CONCLUSION Our novel Li-ALS could expedite liver regeneration and improve survival time; hence, it could be promising for treating ALF.

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 Dulbeccos Modified Eagles 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.

Establishment and characterization of an immortalized human hepatic stellate cell line for applications in co-culturing with immortalized human hepatocytes.

Background and objective. The liver-specific functions of hepatocytes are improved by co-culturing hepatocytes with primary hepatic stellate cells (HSC). However, primary HSC have a short lifespan in vitro, which is considered a major limitation for their use in various applications. This study aimed to establish immortalized human HSC using the simian virus 40 large T antigen (SV40LT) for applications in co-culturing with hepatocytes and HSC in vitro. Methods. Primary human HSC were transfected with a recombinant retrovirus containing SV40LT. The immortalized human HSC were characterized by analyzing their gene expression and functional characteristics. The liver-specific functions of hepatocytes were evaluated in a co-culture system incorporating immortalized human hepatocytes with HSC-Li cells. Results. The immortalized HSC line, HSC-Li, was obtained after infection with a recombinant retrovirus containing SV40LT. The HSC-Li cells were longitudinally spindle-like and had numerous fat droplets in their cytoplasm as shown using electron microscopy. Hepatocyte growth factor (HGF), VEGF Receptor 1(Flt-1), collagen type Iα1 and Iα2 mRNA expression levels were observed in the HSC-Li cells by RT-PCR. Immunofluorescence staining showed that the HSC-Li cells were positive for α-smooth muscle actin (α-SMA), platelet-derived growth factor receptor-beta (PDGFR-β), vimentin, and SV40LT protein expression. The HSC-Li cells produced both HGF and transforming growth factor-beta1 (TGF-β1) in a time-dependent manner. Real-time PCR showed that albumin, CYP3A5, CYP2E1, and UGT2B7 mRNA expression generally increased in the co-culture system. The enzymatic activity of CYP1A2 under the co-culture conditions also generally increased as compared to the monoculture of immortalized human hepatocytes. Conclusions. We successfully established the immortalized human HSC cell line HSC-Li. It has the specific phenotypic and functional characteristics of primary human HSC, which would be a useful tool to develop anti-fibrotic therapies. Co-culturing with the HSC-Li cells improved the liver-specific functions of hepatocytes, which may be valuable and applicable for bioartificial liver systems.

Effects of plasma exchange combined with continuous renal replacement therapy on acute fatty liver of pregnancy

BACKGROUND Acute fatty liver of pregnancy (AFLP) in the third trimester or early postpartum period can lead to fatal liver damage. Its traditional therapy is not very effective in facilitating hepatic recovery. The safety and effect of plasma exchange (PE) in combination with continuous renal replacement therapy (CRRT) (PE+CRRT) for AFLP still needs evaluation. METHODS Five AFLP patients with hepatic encephalopathy and renal failure were subjected to PE+CRRT in our department from 2007 to 2012. Their symptoms, physical signs and results were observed, and all relevant laboratory tests were compared before and after PE+CRRT. RESULTS All the 5 patients were well tolerated to the therapy. Four of them responded to the treatment and showed improvement in clinical symptoms/signs and laboratory results, and they were cured and discharged home after the treatment. One patient succeeded in bridging to transplantation for slowing down hepatic failure and its complications process after 2 treatment sessions. Intensive care unit stay and hospital stay were 9.4 (range 5-18) and 25.0 days (range 11-42), respectively. CONCLUSION PE+CRRT is safe and effective and should be used immediately at the onset of hepatic encephalopathy and/or renal failure in patients with AFLP.