Availability, Functionality, and Safety as well as Quality Control of Hepatocytes as Seeding Cells in Liver Regenerative Medicine: State of the Art and Challenges.

Hepatic disease is one of the most common causes of death worldwide and has become a global health problem. Liver transplantation is the only effective treatment strategy for patients with hepatic function failure, but the insufficient number of donated healthy livers is the main obstacle limiting this process. To alleviate the demand for donor's livers, alternative approaches are being actively explored using liver tissue engineering principles. Liver tissue engineering consists of three elements, including seeding cells, extracellular matrix, and bioreactors. Among them, seeding cell is the most key factor. In this regard, hepatocyte-based tissue engineering can overcome the above shortages for tissue repair and regeneration in hepatic disorders. Primary human hepatocytes in liver regenerative medicine are the most preferred seeding cells, although limited access to a sufficient number of functional hepatocytes are a major issue due to the difficulties in long-term function maintenance of hepatocyte as well as the lack of availability of healthy donors. Hepatocyte-like cells (HLCs), derived from various stem cells, including non-liver-derived stem cells and liver-derived stem cells, as well as trans-differentiation of other cell types, may provide adequate cell sources and could replace primary human hepatocytes as seeding cells. However, it is still a great difficulty that HLCs generated by stem cell differentiation meet the quality required for clinical therapy. Furthermore, none of the standardized protocols to generate high-quality HLCs is available. Whether primary hepatocytes or HLCs are from various sources, preventing the functional deterioration of hepatocytes or generating fully functional hepatocytes is also a big challenge, respectively. In addition, the adoptions of three-dimensional co-culture systems and some small-molecule compounds contribute to maintaining the hepatic functionality of primary hepatocytes and enhancing the liver-specific functions of HLCs. In short, hepatocyte-based liver regenerative medicine is an attractive alternative strategy for liver diseases, notwithstanding some challenges still exist from bench to bedside. This review summarizes the current status, issues, and challenges in availability, functionality, and safety, as well as quality control of seeding hepatocytes with regard to liver tissue engineering in regenerative medicine for the treatment of liver disorders.

Carcinogenicity risk associated with tacrolimus use in kidney transplant recipients: a systematic review and meta-analysis.

Background: Currently, tacrolimus is the preferred anti-rejection therapy for kidney transplant recipients due to its greater protection against acute rejections compared to cyclosporin A (CsA). Despite the advantages of kidney transplantation, it has been associated with an increased incidence of de novo malignancies. Furthermore, a systematic review in 2005 revealed no statistical difference in tumorigenicity between tacrolimus and CsA. This report provides an up to date systematic review and evaluation of all relevant studies in the literature to determine the risk of malignancy in kidney transplant recipients exposed to tacrolimus. Methods: A systematic literature search was performed using the Medline (PubMed and Ovid), Embase, Clinical Trials, and Cochrane databases (from creation to May 2021). We performed a meta-analysis of 11 studies with 36,985 kidney transplant recipients that compared the tacrolimus group with the control group. Outcomes of this study were incidence of malignancies and skin cancer risk. Risk of Bias was assessed in terms of whether there was random sequence generation, allocation concealment, blinding, completeness of results, selective reporting, etc. This meta-analysis was performed in accordance with PRISMA guidelines. Results: Of the 11 included studies, 8 were high quality studies, 1 was assessed as medium quality, and 2 were low quality studies. The results showed a significantly increased risk of overall malignancy associated with tacrolimus exposure compared to non-tacrolimus therapy [risk ratio (RR) =1.59; 95% confidence interval (CI): 1.19-2.11; P=0.002], and especially with sirolimus (SRL) (RR =2.58; 95% CI: 1.62-4.09; P<0.0001). The incidence of skin cancer was consistent with the overall study (RR =2.03; 95% CI: 1.25-3.28; P=0.004). However, there was no significant difference in the incidence of tumors between tacrolimus and cyclosporine A treatment (RR =1.12; 95% CI: 0.80-1.56; P=0.52), even in studies with long follow-up periods of more than 3 years. Discussion: The data demonstrated that patients treated with tacrolimus had a higher risk of carcinogenicity compared to patients treated with SRL. However, patients treated with tacrolimus had a similar incidence of carcinogenicity compared to patients treated with CsA. Further clinical studies are warranted to confirm these findings.

Population pharmacokinetics of polymyxin B: a systematic review.

Background: Polymyxin B (PMB) is a basic cyclic polypeptide antibiotic produced by Bacillus polymyxa, and is one of the last options for treating multi-drug-resistant negative bacterial infections in clinical practice. In recent years, many population pharmacokinetic studies of PMB have been conducted. This paper sought to comprehensively summarize the characteristics of population pharmacokinetic models of PMB and provide a theoretical basis for the individualized use of PMB. Methods: In this review, we systematically searched the PubMed and Embase databases to find articles on population pharmacokinetic models published from database establishment to August 2021. Results: A total of 10 studies were included in this review, including studies on various types of severe infections caused by multi-drug-resistant bacteria, hospital-acquired infections with fibrosis and other male and female populations, and a study of 2 continuous renal replacement therapy (CRRT) patients, aged 16-94 years, who received PMB doses of 10-360 mg/day (0.13-3.45 mg/kg/day), at an administration time of 0.5-6 hours. First-order linear elimination was used in all the studies; a 1-compartment model was used in 5 studies, and a 2-compartment model was used in 5 studies. The most common covariates were creatinine clearance (CrCL) and body weight. Discussion: Although these studies included several covariates and total clearance (CL) was close, but the external validation of some models was poorly correlated between the actual and predicted value. Novel or potential covariates represent important directions for further study.

Cost-effectiveness of rivaroxaban versus warfarin in non-valvular atrial fibrillation patients with chronic kidney disease in China.

WHAT IS KNOWN AND OBJECTIVE: In non-valvular atrial fibrillation (NVAF) patients with chronic kidney disease (CKD), rivaroxaban was not inferior to warfarin in preventing stroke and systemic embolism. However, a comparative evaluation of the cost-effectiveness of rivaroxaban and warfarin therapies for NVAF patients at different renal function levels has not yet been reported, and this study aimed to estimate the cost-effectiveness of rivaroxaban compared with warfarin in Chinese NVAF patients with CKD. METHODS: A Markov model was constructed to estimate quality-adjusted life years (QALYs) and lifetime costs associated with the use of rivaroxaban relative to warfarin in patients with NVAF at different estimated glomerular filtration rate (eGFR) levels as follows: 30 to <50, 50 to <80 and ≥80 mL/min. Input parameters were sourced from the clinical literature. Probabilistic sensitivity analyses were performed to assess model uncertainty. RESULTS AND DISCUSSION: The incrementalQALYs with rivaroxaban was slightly increased by approximately 0.3 QALY as compared with that with warfarin in all the subgroups, resulting in an ICER of $9,736/QALY (eGFR, 30 to <50 mL/min), $9,758/QALY (50 to <80 mL/min) and $9,969/QALY (≥80 mL/min). The probabilistic sensitivity analysis suggested a chance of >80% that the ICER would be lower than the willingness-to-pay threshold of three times the GDP of China in 2019 in all the subgroups. Results were consistent even under the assumption of anticoagulant discontinuation after major bleeding events. The model was most sensitive to event-free-related utility and survival rates. WHAT IS NEW AND CONCLUSION: The existing evidence supports the cost-effectiveness of rivaroxaban therapy as an alternative anticoagulant to warfarin for patients with NVAF at different renal function levels.

NLRC4 inflammasome activation regulated by TNF-α promotes inflammatory responses in nonalcoholic fatty liver disease.

The prevalence of nonalcoholic fatty liver disease (NAFLD) is high and increasing throughout the world. The intense sterile inflammation stemming from steatosis plays a significant role in the development of NAFLD, but the mechanism is unclear. We found that the NLRC4 inflammasome was activated in an in vitro cell model of NAFLD, and that the secretion of inflammatory factors IL-18, IL-1ß, and tumor necrosis factor α (TNF-α) increased during this process and pyroptosis is triggered. In this study, we used NLRC4-targeting siRNA and an NLRC4-encoding plasmid to demonstrate that the increases in IL-18 and IL-1ß are mainly attributable to the activation of the NLR family CARD domain-containing protein 4 (NLRC4) inflammasome, which stimulates cellular pyroptosis. NLRC4 inflammasome activation is regulated by TNF-α and accompanies the translocation of NLRC4 from the cytoplasm into the mitochondria, but the specific mechanism is unclear. In summary, the increase in TNF-α during NAFLD promotes the activation of the NLRC4 inflammasome, which increases the production of IL-18 and IL-1ß and triggers pyroptosis. These exacerbate inflammation and promote disease development.

Inhibition of 5-lipoxygenase inhibitor zileuton in high-fat diet-induced nonalcoholic fatty liver disease progression model.

OBJECTIVES: Arachidonic Acid/5-lipoxygenase (AA/5-LOX) pathway connects lipid metabolism and proinflammatory cytokine, which are both related to the development and progression of nonalcoholic fatty liver disease (NAFLD). Therefore, the present study was designed to investigate the role of AA/5-LOX pathway in progression of NAFLD, and the effect of zileuton, an inhibitor of 5-LOX, in this model. MATERIALS AND METHODS: Animal model for progression of NAFLD was established via feeding high saturated fat diet (HFD). Liver function, HE staining, NAFLD activity score (NAS) were used to evaluate NAFLD progression. We detected the lipid metabolism substrates: free fatty acids (FFA) and AA, products: cysteinyl-leukotrienes (CysLTs), and changes in gene and protein level of key enzyme in AA/5-LOX pathway including PLA2 and 5-LOX. Furthermore, we determined whether NAFLD progression pathway was delayed or reversed when zileuton (1-[1-(1-benzothiophen-2-yl)ethyl]-1-hydroxyurea) was administrated. RESULTS: Rat model for progression of NAFLD was well established as analyzed by liver transaminase activities, hematoxylin-eosin (HE) staining and NAS. The concentrations of substrates and products in AA/5-LOX pathway were increased with the progression of NAFLD. mRNA and protein expression of PLA2 and 5-LOX were all enhanced. Moreover, administration of zileuton inhibited AA/5-LOX pathway and reversed the increased transamine activities and NAS. CONCLUSION: AA/5-LOX pathway promotes the progression of NAFLD, which can be reversed by zileuton.

Helicobacter pylori and Crohn's disease: a retrospective single-center study from China.

AIM: To investigate the association between Helicobacter pylori (H. pylori) infection and the prevalence of Crohn's disease (CD). METHODS: Subjects were selected from patients admitted the gastrointestinal (GI) department at The First Affiliated Hospital School of Medicine (Zhejiang University) for abdominal pain, hematochezia, diarrhea and other GI symptoms between January 2008 and September 2012. CD was diagnosed by endoscopy and biopsy. H. pylori infection was detected by a (14)C-urea breath test and culturing of the biopsy sample. Demographic, anthropometric and serologic data were collected for each patient. H. pylori infection rate was compared between CD and control groups, followed by a subgroup analysis based on extent and severity of CD. Student's t, Mann-Whiney U, and χ(2) tests were used to analyze the data. RESULTS: A total of 447 patients were analyzed, including 229 in the CD group and 248 in the control group. There were no significant differences in age, sex, and rates of hypertension or diabetes. However, the CD group showed significantly higher rates of smoking history (34.9% vs 18.1%), alcohol intake (17.4% vs 8.1%), white blood cell count (9.7 ± 2.9 × 10(9)/L vs 4.3 ± 0.9 × 10(9)/L), and C-reactive protein (36.3 ± 20.8 mg/L vs 5.5 ± 2.3 mg/L) but lower body mass index (24.5 ± 2.0 kg/m(2) vs 26.0 ± 2.2 kg/m(2)) than the control group. The H. pylori infection rate in the CD group was 27.1%, significantly lower than that of 47.9% in the control group. Furthermore, the H. pylori infection rates in patients with colonic, small intestine, ileocolonic and extensive CD were 31.1%, 28.9%, 26.8% and 25.9% respectively, all of which were significantly lower than in the control group. Finally, the H. pylori infection rates in patients with remission, moderate and severe CD were 34.3%, 30.7% and 22.0% respectively, which were also significantly lower than in the control group. CONCLUSION: Lower H. pylori infection in CD patients suggests a correlation between bacterial infection and CD, suggesting caution when considering H. pylori eradication in CD patients.

MAPEG expression in mouse embryonic stem cell-derived hepatic tissue system.

The expressions of membrane-associated proteins in eicosanoid and glutathione metabolism (MAPEG), a superfamily involved in both inflammation and cell protection, were investigated in an in vitro system of mouse embryonic stem (ES) cell-derived hepatic tissue. Gene expressions of all MAPEG members were demonstrated in a developmental-dependent manner in the derived hepatic tissue. The protein expression of microsomal glutathione S-transferase 1 (MGST1) was not detected until differentiating day 14. It gradually increased by maturation of hepatic tissue. The microsomes of ES cell-derived hepatic tissue possessed the MGST1-like catalytic activity. However, MGST1 from the microsome preparation could not form dimers as usual when exposed to reactive nitrogen species ONOO. Among the other members in MAPEG, weak expressions of leukotriene C(4) synthase (LTC(4)S) and microsomal prostaglandin E synthase 1 (mPGES-1) were observed. A stable expression of 5-Lipoxygenase activating protein (FLAP) appeared during the entire course of differentiation. MGST2 and MGST3 failed to express in the derived hepatic tissue, although mRNA of them do existed. In conclusion, ES cell-derived hepatic tissue possess MAPEG gene expression features, but not all protein expression could be detected, which helps to understand not only the nature of the tissue derived, but also the fate of bioartificial liver system, and may as well provide a valuable in vitro model for research in both inflammation process and toxic events in hepatological fields.

Enhanced expressions and activations of leukotriene C4 synthesis enzymes in D-galactosamine/lipopolysaccharide-induced rat fulminant hepatic failure model.

AIM: To investigate the expression and activity of leukotriene C4 (LTC4) synthesis enzymes and their underlying relationship with cysteinyl leukotriene (cys-LT) generation in a rat fulminant hepatic failure (FHF) model induced by D-galactosamine/lipopolysaccharide (D-GalN/ LPS). METHODS: Rats were treated with D-GalN (300 mg/kg) plus LPS (0.1 mg/kg) for 1, 3, 6, and 12 h. Enzyme immunoassay was used to determine the hepatic cys-LT content. Reverse transcription-polymerase chain reaction (RT-PCR), Western blot or immunohistochemical assay were employed to assess the expression or location of LTC4 synthesis enzymes, which belong to membrane associated proteins in eicosanoid and glutathione (MAPEG) metabolism superfamily. Activity of LTC4 synthesis enzymes was evaluated by determination of the products of LTA4 after incubation with liver microsomes using high performance liquid chromatography (HPLC). RESULTS: Livers were injured after treatment with D-GalN/LPS, accompanied by cys-LT accumulation at the prophase of liver injury. Both LTC4 synthase (LTC4S) and microsomal glutathione-S-transferase (mGST) 2 were expressed in the rat liver, while the latter was specifically located in hepatocytes. Their mRNA and protein expressions were up-regulated at an earlier phase after treatment with D-GalN/LPS. Meantime, a higher activity of LTC4 synthesis enzymes was detected, although the activity of LTC4S played the main role in this case. CONCLUSION: The expression and activity of both LTC4S and mGST2 are up regulated in a rat FHF model, which are, at least, partly responsible for cys-LT hepatic accumulation.