Exploring complement biomarkers in suspected axial spondyloarthritis.

OBJECTIVES: To investigate lectin pathway proteins (LPPs) as biomarkers for axial spondyloarthritis (axSpA) in a cross-sectional cohort with a suspicion of axSpA, comprising newly diagnosed axSpA and chronic low back pain (cLBP) individuals. METHODS: Serum samples from 515 participants within the OptiRef cohort, including 151 axSpA patients and 364 cLBP patients, were measured using immunoassays for LPPs (mannan-binding lectin (MBL), collectin liver-1 (CL-L1), M-ficolin, H-ficolin and L-ficolin, MBL-associated serine proteases (MASP)-1, -2 and -3, MBL-associated proteins (MAp19 and MAp44) and the complement activation product C3dg). RESULTS: Serum levels of L-ficolin, MASP-2 and C3dg were elevated in axSpA patients, whereas levels of MASP-3 and CL-L1 were decreased, and this remained significant for C3dg and MASP-3 after adjustment for C reactive protein (CRP). A univariate regression analysis showed serum levels of CL-L1, MASP-2, MASP-3 and C3dg to predict the diagnosis of axSpA, and MASP-3 and C3dg remained significant in a multivariate logistic regression analysis. Assessment of the diagnostic potential showed that a combination of human leukocyte antigen B27 (HLA-B27) and measurements of L-ficolin, MASP-3 and C3dg increased the diagnostic specificity for axSpA, however, with a concomitant loss of sensitivity. CONCLUSIONS: Serum levels of complement activation, that is, C3dg, and MASP-3 differed significantly between axSpA and cLBP patients after adjustment for CRP. Although combining HLA-B27 with measurements of L-ficolin, MASP-3 and C3dg increased the diagnostic specificity for axSpA, this seems unjustified due to the concomitant loss of sensitivity. However, both C3dg and MASP-3 were associated with axSpA diagnosis in multivariate logistic regression, suggesting an involvement of complement in the inflammatory processes and possibly pathogenesis in axSpA.

Comparison of the effect of treatment with NSAIDs added to anti-TNF therapy versus anti-TNF therapy alone on the progression of structural damage in the spine over 2 years in patients with radiographic axial spondyloarthritis from the randomised-controlled CONSUL trial.

OBJECTIVES: The study aimed to evaluate the effect of adding a non-steroidal anti-inflammatory drug (NSAID), celecoxib (CEL), to a tumour necrosis factor inhibitor (TNFi), golimumab (GOL), compared with TNFi monotherapy on radiographic spinal progression in patients with radiographic axial spondyloarthritis (r-axSpA) over 2 years. METHODS: R-axSpA patients, having risk factors for radiographic progression (high disease activity plus C reactive protein >5 mg/L and/or ≥1 syndesmophyte(s)), underwent a 12-week run-in phase with GOL 50 mg every 4 weeks. In the core phase (96 weeks), only patients with a good clinical response at week 12 were randomised (1:1) to GOL+CEL 200 mg two times per day (combination therapy) or GOL monotherapy. The primary endpoint was radiographic progression assessed by modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) change at week 108 in the intent-to-treat population. RESULTS: A total of 128 patients were enrolled in the run-in phase; and 109 patients were randomised at week 12 to monotherapy (n=55) or combination therapy (n=54). At week 108, 97 (52 vs 45) patients completed the study. The change in mSASSS at week 108 was 1.7 (95% CI 0.8 to 2.6) in the monotherapy vs 1.1 (95% CI 0.4 to 1.8) in the combination therapy groups (p=0.79). New syndesmophytes occurred in 25% of patients in the monotherapy vs 11% of patients in the combination therapy groups (p=0.12). During the study, no significant differences in adverse events and serious adverse events were observed between the groups. CONCLUSIONS: Combination therapy with GOL+CEL did not demonstrate statistically significant superiority over GOL monotherapy in retarding radiographic spinal progression over 2 years in r-axSpA.

Successful Derivation of Hepatoblasts, Cholangiocytes and Hepatocytes from Simian Induced Pluripotent Stem Cells.

The use of primary cells in human liver therapy is limited by a lack of cells. Induced pluripotent stem cells (iPSCs) represent an alternative to primary cells as they are infinitely expandable and can be differentiated into different liver cell types. The aim of our work was to demonstrate that simian iPSCs (siPSCs) could be used as a new source of liver cells to be used as a large animal model for preclinical studies. We first differentiated siPSCs into a homogenous population of hepatoblasts (siHBs). We then separately differentiated them into hepatocytes (siHeps) and cholangiocytes (siChols) expressing respective specific markers and displaying epithelial polarity. Moreover, we showed that polarized siChols can self-organize into 3D structures. These results should facilitate the deciphering of liver development and open the way to exploring co-culture systems that could be assessed during preclinical studies, including in autologous monkey donors, for regenerative medicine purposes.

Spatial transcriptomic and single-nucleus analysis reveals heterogeneity in a gigantic single-celled syncytium.

In multicellular organisms, the specification, coordination, and compartmentalization of cell types enable the formation of complex body plans. However, some eukaryotic protists such as slime molds generate diverse and complex structures while remaining in a multinucleate syncytial state. It is unknown if different regions of these giant syncytial cells have distinct transcriptional responses to environmental encounters and if nuclei within the cell diversify into heterogeneous states. Here, we performed spatial transcriptome analysis of the slime mold Physarum polycephalum in the plasmodium state under different environmental conditions and used single-nucleus RNA-sequencing to dissect gene expression heterogeneity among nuclei. Our data identifies transcriptome regionality in the organism that associates with proliferation, syncytial substructures, and localized environmental conditions. Further, we find that nuclei are heterogenous in their transcriptional profile and may process local signals within the plasmodium to coordinate cell growth, metabolism, and reproduction. To understand how nuclei variation within the syncytium compares to heterogeneity in single-nucleus cells, we analyzed states in single Physarum amoebal cells. We observed amoebal cell states at different stages of mitosis and meiosis, and identified cytokinetic features that are specific to nuclei divisions within the syncytium. Notably, we do not find evidence for predefined transcriptomic states in the amoebae that are observed in the syncytium. Our data shows that a single-celled slime mold can control its gene expression in a region-specific manner while lacking cellular compartmentalization and suggests that nuclei are mobile processors facilitating local specialized functions. More broadly, slime molds offer the extraordinary opportunity to explore how organisms can evolve regulatory mechanisms to divide labor, specialize, balance competition with cooperation, and perform other foundational principles that govern the logic of life.

In vitro recovery of FIX clotting activity as a marker of highly functional hepatocytes in a hemophilia B iPSC model.

BACKGROUND AND AIMS: Pluripotent stem cell-derived hepatocytes differentiated in monolayer culture are known to have more fetal than adult hepatocyte characteristics. If numerous studies tend to show that this immature phenotype might not necessarily be an obstacle to their use in transplantation, other applications such as drug screening, toxicological studies, or bioartificial livers are reliant on hepatocyte functionality and require full differentiation of hepatocytes. New technologies have been used to improve the differentiation process in recent years, usually evaluated by measuring the albumin production and CYP450 activity. Here we used the complex production and most importantly the activity of the coagulation factor IX (FIX) produced by mature hepatocytes to assess the differentiation of hemophilia B (HB) patient's induced pluripotent stem cells (iPSCs) in both monolayer culture and organoids. APPROACH AND RESULTS: Indeed, HB is an X-linked monogenic disease due to an impaired activity of FIX synthesized by hepatocytes in the liver. We have developed an in vitro model of HB hepatocytes using iPSCs generated from fibroblasts of a severe HB patient. We used CRISPR/Cas9 technology to target the genomic insertion of a coagulation factor 9 minigene bearing the Padua mutation to enhance FIX activity. Noncorrected and corrected iPSCs were differentiated into hepatocytes under both two-dimensional and three-dimensional differentiation protocols and deciphered the production of active FIX in vitro. Finally, we assessed the therapeutic efficacy of this approach in vivo using a mouse model of HB. CONCLUSIONS: Functional FIX, whose post-translational modifications only occur in fully mature hepatocytes, was only produced in corrected iPSCs differentiated in organoids. Immunohistochemistry analyses of mouse livers indicated a good cell engraftment, and the FIX activity detected in the plasma of transplanted animals confirmed rescue of the bleeding phenotype.

Patient reported outcome of 33 operatively treated talar fractures.

BACKGROUND: Management of talar fractures remains to be one of the most challenging aspects in trauma surgery. Unfortunately, the evidence regarding the correct treatment of these fractures is mainly based on retrospective case series, while studies assessing the patient-reported outcome are rare. Therefore, the aim of this trial was to analyze the patient reported outcome in context of trauma mechanism and concomitant injuries following operative treatment of talar fractures. METHODS: A retrospective outcome study of patients with operatively treated talar fractures between 2003 and 2015 was conducted. The fractures were classified according to AO-/Hawkins classification system and to the Marti-Weber classification. Data was collected via patient registry, radiographs and a validated patient-reported outcome measure (PROM) for foot and ankle pathologies (Foot and Ankle Outcome Score = FOAS). An analysis regarding the functional outcome, concomitant injury and timing of surgery using the nonparametric Mann-Whitney U test and Spearman`s rank correlation was performed. RESULTS: In total the functional outcome of 32 patients suffering from fractures to the talus were analyzed. The median age of the study cohort was 35±12.2 years, including 9 female (28 %) and 23 male (72 %) patients. The median FAOS score was 72±22.7 (range 13-94). Patients with an isolated talar fracture had an FAOS of 87±20 and with concomitant injury a score of 60±23.4 (p = 0.016). Patients with a closed talar fracture without emergency operation due to dislocation or polytrauma, showed no correlation between timing of surgery and FAOS (r= -0.17, p = 0.43). 10 % of the patients developed an avascular necrosis and 25 % showed signs of a posttraumatic arthritis. The follow-up time was 41 months (range: 16-145). CONCLUSIONS: Talar fractures were typically caused by high-energy trauma often associated with additional injuries of the lower extremity. The majority of the patients showed a fair to poor functional long-term outcome. Concomitant injuries of the lower extremity led to a lower FAOS. In closed talar fractures without the necessity of an emergency surgical intervention, time to surgery did not influence the patient reported outcome. Relating to the presented data, delayed surgery after soft tissue consolidation was not associated with a higher risk of developing an avascular necrosis.

Liquid silicone embolism syndrome (SES) in lungs and liver - A case report.

Silicone embolism syndrome (SES) is a well known complication after injection of silicone gel as well as liquid silicone. Rarely, men use physiologic salt solution or liquid silicone injected into the subcutaneous tissue of the scrotum, the penis, the upper genital or the inguinal region. Those men, who call themselves "siliconers", want to get a larger penis and scrotum, also visible when wearing clothes. Injections of liquid silicone in the mentioned regions can lead to liquid silicone embolism in the lungs and also the liver, sometimes eventually leading to death via right heart failure as in the present case. Autopsy revealed "frog spawn"-like vacuoles in the subcutaneous tissue of the genital region and liquid silicone embolism in lungs and liver. Additionally, toxicological analyses revealed different liquid silicones. Smaller oligomers were transported into lung and liver, larger ones showed local enrichment at the injection site. The seized Polydimethylsiloxane (PDMS) could not be detected in abdominal fat, blood or urine, potentially due to low perfusion of fat tissue, the aqueous character of blood and urine or the time span between last injection and death.

Comparison of an online self-referral tool with a physician-based referral strategy for early recognition of patients with a high probability of axial spa.

OBJECTIVES: The diagnostic delay in axial spondyloarthritis (axial SpA) remains unacceptably high, with one of the reasons being a late referral. Structured physician-based referral programs are able to improve early diagnosis, but lack of implementation is still an issue. The objective of this study was to evaluate an online self-referral (OSR) tool for patients with back pain and to compare it to an established physician-based referral tool. METHODS: Patients with back pain were included if they either fulfilled the requirements of the OSR tool or were referred by a physician using the Berlin referral tool. Rheumatologists in the specialized center performed a structured assessment in all patients that resulted in the final diagnosis of axial SpA / no axial SpA. Furthermore, we attempted to optimize the OSR tool in terms of maximizing the specificity constrained by a sensitivity of at least 90% of the original strategy. RESULTS: 361 consecutive patients (180 via the OSR and 181 via the Berlin referral tool) were included in the study. A total of 35 patients (19.4%) in the self-referral group and 71 patients (39.2%) in the physician-referral group were finally diagnosed with axial SpA. Axial SpA patients from the OSR group were more often HLA-B27 negative, females, and were more frequently at a non-radiographic stage as compared to axial SpA patients who came via the physician-based tool. Both groups had, however, a similar disease burden. According to the pre-defined selection criterion we identified an optimized combination of ≥2 IBP parameters and ≥1 other SpA parameters (in addition to both stem parameters). CONCLUSIONS: Despite the better performance of the physician-based referral strategy, the proportion of axial SpA among self-referred patients (19.4%) was clearly higher than the assumed 5% prevalence of axial SpA in patients with chronic back pain. Based on our data driven approach the performance of the OSR strategy could be further improved if at least two IBP parameters plus one additional SpA parameter had to be present in addition to the stem parameters. The OSR tool can be used in specialized centers in addition to a physician-based referral strategy to improve early diagnosis and to increase awareness of axial SpA.

Performance of the Ankylosing Spondylitis Disease Activity Score based on a quick quantitative C-reactive protein assay in patients with axial spondyloarthritis.

OBJECTIVES: To evaluate the performance of the Ankylosing Spondylitis Disease Activity Score based on a validated quick quantitative C-reactive protein assay (ASDAS-qCRP) as compared to ASDAS based on a routine lab CRP assay (ASDAS-CRP) and ASDAS based on erythrocyte sedimentation rate (ASDAS-ESR). METHODS: Disease activity assessment was performed in 50 patients with axial spondyloarthritis (axSpA). Routine lab CRP was measured in the central lab while the quantitative quick-CRP assay and ESR measurements were performed locally. ASDAS-CRP, ASDAS-qCRP and ASDAS-ESR were subsequently calculated. RESULTS: The mean (±SD) serum level of the routine lab CRP (6.2±8.3mg/l) was lower than of the quick-CRP (7.4±8.4mg/l) (P<0.05). Whereat, there was no significant difference in the mean values of ASDAS-CRP and ASDAS-qCRP in axSpA patients (2.70±0.94 and 2.74±0.96, respectively, P=0.069), while the ASDAS-ESR (2.85±1.0) was significantly higher than ASDAS-CRP (P=0.036) and numerically higher than ASDAS-qCRP (P=0.125). In 47 of the 50 cases of axSpA (94%), patients were assigned to the same disease activity category according to ASDAS-CRP and ASDAS-qCRP. CONCLUSIONS: ASDAS-qCRP performed similarly well compared to ASDAS-CRP with the absolute agreement on the disease activity category according to the ASDAS of 94%. ASDAS-qCRP is, therefore, feasible for an immediate decision-making in clinical practice and trials aimed at treating to target.

Low-density lipoprotein receptor-deficient hepatocytes differentiated from induced pluripotent stem cells allow familial hypercholesterolemia modeling, CRISPR/Cas-mediated genetic correction, and productive hepatitis C virus infection.

BACKGROUND: Familial hypercholesterolemia type IIA (FH) is due to mutations in the low-density lipoprotein receptor (LDLR) resulting in elevated levels of low-density lipoprotein cholesterol (LDL-c) in plasma and in premature cardiovascular diseases. As hepatocytes are the only cells capable of metabolizing cholesterol, they are therefore the target cells for cell/gene therapy approaches in the treatment of lipid metabolism disorders. Furthermore, the LDLR has been reported to be involved in hepatitis C virus (HCV) entry into hepatocytes; however, its role in the virus infection cycle is still disputed. METHODS: We generated induced pluripotent stem cells (iPSCs) from a homozygous LDLR-null FH-patient (FH-iPSCs). We constructed a correction cassette bearing LDLR cDNA under the control of human hepatic apolipoprotein A2 promoter that targets the adeno-associated virus integration site AAVS1. We differentiated both FH-iPSCs and corrected FH-iPSCs (corr-FH-iPSCs) into hepatocytes to study statin-mediated regulation of genes involved in cholesterol metabolism. Upon HCV particle inoculation, viral replication and production were quantified in these cells. RESULTS: We showed that FH-iPSCs displayed the disease phenotype. Using homologous recombination mediated by the CRISPR/Cas9 system, FH-iPSCs were genetically corrected by the targeted integration of a correction cassette at the AAVS1 locus. Both FH-iPSCs and corr-FH-iPSCs were then differentiated into functional polarized hepatocytes using a stepwise differentiation approach (FH-iHeps and corr-FH-iHeps). The correct insertion and expression of the correction cassette resulted in restoration of LDLR expression and function (LDL-c uptake) in corr-FH-iHeps. We next demonstrated that pravastatin treatment increased the expression of genes involved in cholesterol metabolism in both cell models. Moreover, LDLR expression and function were also enhanced in corr-FH-iHeps after pravastatin treatment. Finally, we demonstrated that both FH-iHeps and corr-FH-iHeps were as permissive to viral infection as primary human hepatocytes but that virus production in FH-iHeps was significantly decreased compared to corr-FH-iHeps, suggesting a role of the LDLR in HCV morphogenesis. CONCLUSIONS: Our work provides the first LDLR-null FH cell model and its corrected counterpart to study the regulation of cholesterol metabolism and host determinants of HCV life cycle, and a platform to screen drugs for treating dyslipidemia and HCV infection.

Management and clinical practice of multiple face and scalp actinic keratosis in France.

Background: Actinic keratosis (AK) is characterized by the occurrence of thick and scaly skin areas caused by damage from ultraviolet radiation. The management of AK aims to reduce lesions and prevent their recurrence by regular monitoring. French guidelines, last updated in 2009, reflect European guidelines for the management of face and scalp AK. However, they do not address all current, available options. Objective: To assess the management of face and scalp AK in French clinical practice. Methods: A two-part online questionnaire comprising a survey among French dermatologists and an analysis of patient medical records was performed to describe AK patients treated with topical therapy, patients' profiles, and characteristics of the affected lesion areas. Results: Decisions for topical treatments for face and scalp AK made by dermatologists were mainly driven by the lesion size. According to the last 10 patients they have seen, dermatologists were prescribing physical therapy in 53% of the cases, a combination of topical and physical therapy in 27% and topical only in 20%. Patient records revealed the average surface area targeted for treatment was 139 ± 113cm2. Conclusions: Discrepancies between the guidelines on the treatment of face and scalp AK and clinical practice exist. Further research may help to standardize the treatment.

Interest of Using Ropivacaine for Outpatient Laparoscopic Cholecystectomy: Prospective Randomized Trial.

BACKGROUND: The objective of this study was to evaluate the interest of using ropivacaine for outpatient laparoscopic cholecystectomy. The use of local anesthesia by instillation and infiltration could reduce pain and increase the number of outpatient cholecystectomies. METHODS: A one-center randomized prospective clinical trial compared the use of ropivacaine during outpatient laparoscopic cholecystectomy to the control group of outpatients for laparoscopic cholecystectomy between April 2014 and May 2015. One hundred twenty-four were eligible, and 100 patients were randomized. Patients with outpatient cholecystectomy were randomized into 2 groups: ropivacaine group (Rop group) and control group (control group). We performed a ropivacaine intraperitoneal instillation and wound infiltration for the ropivacaine group at the end of the procedure. The primary observation was authorization for home discharge. The patient was evaluated by the surgeon using the Chung score. Secondary observations included postoperative pain at 2 h post-surgery, at 6 h post-surgery and the day following surgery. RESULTS: Ninety-eight were able to leave on the evening of surgery. At 6 h post-surgery, the Chung score was identical for both groups (p = 0.73). At 2 and 6 h post-surgery and the day following surgery, there was no significant difference in pain levels (p = 0.63; p = 0.61; p = 0.98). Analgesic consumption was no significant difference in the groups. CONCLUSIONS: The use of ropivacaine does not increase the rate of home discharge and does not change the postoperative pain of outpatient cholecystectomy.

Influence of Renal Impairment on the Pharmacokinetics of Afatinib: An Open-Label, Single-Dose Study.

BACKGROUND AND OBJECTIVE: Afatinib is an oral irreversible ErbB-Family Blocker indicated for treatment of patients with EGFR mutation positive advanced non-small cell lung cancer. This trial assessed whether renal impairment influences the pharmacokinetics and safety of afatinib. METHODS: This was an open-label, single-dose study. Pharmacokinetic parameters after afatinib 40 mg were investigated in subjects with moderate (n = 8) or severe (n = 8) renal impairment (estimated glomerular filtration rate 30-59 mL/min/1.73 m2 and 15-29 mL/min/1.73 m2, respectively) and healthy matched controls (n = 14). Plasma and urine samples were collected before and up to 14 days after dosing for pharmacokinetic and plasma protein-binding assessment. Primary endpoints were area under the plasma concentration-time curve from time zero to the last quantifiable concentration (AUClast) and maximum plasma concentration (C max) between subjects with renal impairment and healthy matched controls. RESULTS: Pharmacokinetic profiles and plasma protein binding were similar in all groups. The extent of exposure, as indicated by AUClast and C max, was generally similar between the matched treatment groups, with the exception of the geometric mean ratio of AUClast for subjects with severe renal impairment, which showed a trend towards a higher value compared with matched healthy subjects (150.0 % [90 % CI 105.3-213.7]) Inter-individual variability was moderate (geometric mean coefficient of variation 28-39 % for moderate impairment, 34-42 % for severe impairment). Afatinib was well tolerated and urinary excretion was minimal. CONCLUSION: Moderate-to-severe renal impairment had a minor influence on the pharmacokinetics of afatinib that was within the observed inter-individual variability, suggesting that afatinib treatment can be considered in this patient population. Registered at ClinicalTrials.gov as NCT02096718.

[Human pluripotent stem cells and liver disorders]. / Cellules souches pluripotentes humaines et modélisation de maladies hépatiques.

The liver is associated with many diseases including metabolic and cholestatic diseases, cirrhosis as well as chronic and acute hepatitis. However, knowledge about the mechanisms involved in the pathophysiology of these diseases remains limited due to the restricted access to liver biopsies and the lack of cellular models derived from patients. The liver is the main organ responsible for the elimination of xenobiotics and thus hepatocytes have a key role in toxicology and pharmacokinetics. The induced pluripotent stem cells generated from patients with monogenic metabolic disorders, for which the corresponding gene is identified, are relevant in vitro models for the study of the mechanisms involved in generation of pathologies and also for drug screening. Towards this aim, robust protocols for generating liver cells, such as hepatocytes and cholangiocytes, are essential. Our study focused on familial hypercholesterolemia disease modeling, as well as on establishing a protocol for generation of functional cholangiocytes from pluripotent stem cells.

The potential of induced pluripotent stem cell derived hepatocytes.

Orthotopic liver transplantation remains the only curative treatment for liver disease. However, the number of patients who die while on the waiting list (15%) has increased in recent years as a result of severe organ shortages; furthermore the incidence of liver disease is increasing worldwide. Clinical trials involving hepatocyte transplantation have provided encouraging results. However, transplanted cell function appears to often decline after several months, necessitating liver transplantation. The precise aetiology of the loss of cell function is not clear, but poor engraftment and immune-mediated loss appear to be important factors. Also, primary human hepatocytes (PHH) are not readily available, de-differentiate, and die rapidly in culture. Hepatocytes are available from other sources, such as tumour-derived human hepatocyte cell lines and immortalised human hepatocyte cell lines or porcine hepatocytes. However, all these cells suffer from various limitations such as reduced or differences in functions or risk of zoonotic infections. Due to their significant potential, one possible inexhaustible source of hepatocytes is through the directed differentiation of human induced pluripotent stem cells (hiPSCs). This review will discuss the potential applications and existing limitations of hiPSC-derived hepatocytes in regenerative medicine, drug screening, in vitro disease modelling and bioartificial livers.

[Scholars and Amateurs in Ornithology around 1800: Sharing Literature]. / Savants et amateurs ornithologues au tournant des XVIIIe et XIXe siècles: la littérature en partage?

Ornithology has emerged as a science at the turn of the 18th century. To become a self-sufficient scientific discipline, studies of birds had to distinguish themselves from luxury, trade and poetry. Scholars had to invent new ways of writing, different from the beautiful and ornamented books on birds, even if these books were often published by other scholars who had been expelled from academic institutions and therefore considered as «amateurs¼. The same scholars needed the help of «amateurs¼ in order to observe and explain bird migration. First ornithological discourses in Europe and the United States illustrate the relationships between scholars, authors and «amateurs¼ and show how these words can be used in different meanings.

Transplantation of hESC-derived hepatocytes protects mice from liver injury.

BACKGROUND: Hepatic cell therapy has become a viable alternative to liver transplantation for life-threatening liver diseases. However, the supply of human hepatocytes is limited due to the shortage of suitable donor organs required to isolate high-quality cells. Human pluripotent stem cells reflect a potential renewable source for generating functional hepatocytes. However, most differentiation protocols use undefined matrices or factors of animal origin; as such, the resulting hepatocytes are not Good Manufacturing Practice compliant. Moreover, the preclinical studies employed to assess safety and function of human embryonic stem cell (hESC)-derived hepatocytes are generally limited to immunodeficient mice. In the present study, we evaluate the generation of hepatocytes under defined conditions using a European hESC line (VAL9) which was derived under animal-free conditions. The function capacity of VAL9-derived hepatocytes was assessed by transplantation into mice with acetaminophen-induced acute liver failure, a clinically relevant model. METHODS: We developed a protocol that successfully differentiates hESCs into bipotent hepatic progenitors under defined conditions, without the use of chromatin modifiers such as dimethyl sulphoxide. These progenitors can be cryopreserved and are able to generate both committed precursors of cholangiocytes and neonate-like hepatocytes. RESULTS: Thirty days post-differentiation, hESCs expressed hepatocyte-specific markers such as asialoglycoprotein receptor and hepatic nuclear factors including HNF4α. The cells exhibited properties of mature hepatocytes such as urea secretion and UGT1A1 and cytochrome P450 activities. When transplanted into mice with acetaminophen-induced acute liver failure, a model of liver damage, the VAL9-derived hepatocytes efficiently engrafted and proliferated, repopulating up to 10 % of the liver. In these transplanted livers, we observed a significant decrease of liver transaminases and found no evidence of tumourigenicity. Thus, VAL9-derived hepatocytes were able to rescue hepatic function in acetaminophen-treated animals. CONCLUSIONS: Our study reveals an efficient protocol for differentiating VAL9 hESCs to neonatal hepatocytes which are then able to repopulate livers in vivo without tumour induction. The human hepatocytes are able to rescue liver function in mice with acetaminophen-induced acute toxicity. These results provide proof-of-concept that replacement therapies using hESC-derived hepatocytes are effective for treating liver diseases.

Improvement of hepatocyte transplantation efficiency in the mdr2-/- mouse model by glyceryl trinitrate.

INTRODUCTION: Hepatocyte transplantation could be an alternative to liver transplantation for the treatment of metabolic diseases. However, rodent models have shown that engraftment of transplanted cells in the liver is low and requires deposition of cells in hepatic sinusoids. Splanchnic vasodilatators improved hepatocyte engraftment in a rat model. Therefore, we investigated the effect of glyceryl trinitrate (GTN) on the efficacy of cell engraftment and on liver repopulation in the mdr2-knockout mouse, a model for progressive familial intrahepatic cholestasis type 3. METHODS: Congenic normal mdr2 (+/+) hepatocytes were isolated by two-step collagenase perfusion and transplanted into mdr2(-/-) mice livers through the portal vein in the presence or absence of GTN. Liver repopulation was assessed by immunohistochemistry, and transplanted hepatocyte function was assessed at different times after transplantation by measurement of biliary lipid secretion and quantification of fibrosis. RESULTS: The number of engrafted cells in GTN-treated mice was significantly higher than that in control mice, and transplanted hepatocytes were found in a greater number of distal sinusoids. Levels of phospholipid secretion were significantly higher than those in the control group 3 months after hepatocyte transplantation (18.3 ± 2.3 vs. 5.2 ± 3.9 nmol/min/100 g, P < 0.0001), and the ratio of phospholipids to bile salt was greater (6.8 ± 1.3 vs. 3.2 ± 1.6, P = 0.03). The percentage area of liver fibrosis was also significantly reduced in GTN-treated mice (5.7% ± 2.3% vs. 12.4% ± 2.9%, P = 0.016). CONCLUSION: The use of GTN improves hepatocyte engraftment and correction of metabolic disease in mdr2 (-/-) mice. This approach might be beneficial in hepatocyte transplantation for the treatment of patients with liver diseases.

Portopulmonary hypertension and hepatopulmonary syndrome.

Portopulmonary hypertension (POPH) and hepatopulmonary syndrome (HPS) are two frequent complications of liver disease, with prevalence among liver transplant candidates of 6% and 10%, respectively. Both conditions result from a lack of hepatic clearance of vasoactive substances produced in the splanchnic territory. Subsequently, these substances cause mainly pulmonary vascular remodeling and some degree of vasoconstriction in POPH with resulting elevated pulmonary pressure and right ventricular dysfunction. In HPS the vasoactive mediators cause intrapulmonary shunts with hypoxemia. Medical treatment is disappointing overall. Whereas liver transplantation (LT) results in the disappearance of HPS within six to twelve months, its effect on POPH is highly unpredictable. Modern strategies in managing HPS and POPH rely on a thorough screening and grading of the disease's severity, in order to tailor the appropriate therapy and select only the patients who will benefit from LT. The anesthesiologist plays a central role in managing these high-risk patients. Indeed, the important hemodynamic and respiratory modifications of the perioperative period must be avoided through continuation of the preoperatively initiated drugs, appropriate intraoperative monitoring and proper hemodynamic and respiratory therapies.