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Biomaterials for tissue regeneration must mimic the biophysical properties of the native physiological environment. A protein engineering approach allows the generation of protein hydrogels with specific and customised biophysical properties designed to suit a particular physiological environment. Herein, repetitive engineered proteins were successfully designed to form covalent molecular networks with defined physical characteristics able to sustain cell phenotype. Our hydrogel design was made possible by the incorporation of the SpyTag (ST) peptide and multiple repetitive units of the SpyCatcher (SC) protein that spontaneously formed covalent crosslinks upon mixing. Changing the ratios of the protein building blocks (ST:SC), allowed the viscoelastic properties and gelation speeds of the hydrogels to be altered and controlled. The physical properties of the hydrogels could readily be altered further to suit different environments by tuning the key features in the repetitive protein sequence. The resulting hydrogels were designed with a view to allow cell attachment and encapsulation of liver derived cells. Biocompatibility of the hydrogels was assayed using a HepG2 cell line constitutively expressing GFP. The cells remained viable and continued to express GFP whilst attached or encapsulated within the hydrogel. Our results demonstrate how this genetically encoded approach using repetitive proteins could be applied to bridge engineering biology with nanotechnology creating a level of biomaterial customisation previously inaccessible.

ChatGPT, a language-learning model chatbot, has garnered considerable attention for its ability to respond to users’ questions. Using data from 14 countries and 186 institutions, we compare ChatGPT and student performance for 28,085 questions from accounting assessments and textbook test banks. As of January 2023, ChatGPT provides correct answers for 56.5 percent of questions and partially correct answers for an additional 9.4 percent of questions. When considering point values for questions, students significantly outperform ChatGPT with a 76.7 percent average on assessments compared to 47.5 percent for ChatGPT if no partial credit is awarded and 56.5 percent if partial credit is awarded. Still, ChatGPT performs better than the student average for 15.8 percent of assessments when we include partial credit. We provide evidence of how ChatGPT performs on different question types, accounting topics, class levels, open/closed assessments, and test bank questions. We also discuss implications for accounting education and research.

Purpose The initial rationale for developing integrated reporting included addressing the failures of traditional reporting to address sustainability issues. Subsequently, the International Integrated Reporting Council (IIRC) modified its stated objectives to emphasise integrated thinking and value creation. There has been debate on whether the IIRC’s process for developing its integrated reporting framework was subject to regulatory capture by the accounting profession (Flower, 2015; Adams, 2015; Thomson, 2015). This paper aims to provide additional evidence on the extent to which this regulatory capture occurred, with an update on current developments. Design/methodology/approach Data from interviews with key participants in the integrated reporting framework’s development and the IIRC’s Council and Working Group meeting minutes were analysed to identify to what extent the change in the IIRC’s focus can be explained by regulatory capture theory. Findings The findings show that the integrated reporting framework’s development was subject to regulatory capture by accountants. However, the extent of capture was mitigated to some extent by processes adopted in its development. This is consistent with regulatory capture theory. Originality/value This paper critically examines the debate on the extent to which the sustainability message has been lost as a result of regulatory capture. It provides an in-depth analysis of the IIRC’s treatment of sustainability which explores the application of regulatory capture theory and examines evidence not considered in previous studies.

Purpose The purpose of this study is to examine the relationship between going-concern (GC) opinions issued by the Big 4 audit firms and adverse credit ratings from the two largest credit rating agencies (CRAs) – Standard & Poor’s (S&P) and Moody’s. This question is relevant because there have been suggestions that auditors and CRAs should become more similar to each other, and because the two largest CRAs have different ownership structures that could affect their ratings. Design/methodology/approach Univariate and multivariate analyses are performed using a sample of firms that filed for bankruptcy between January 1, 2002 and December 31, 2013 that also had an audit opinion signed during the 12 months prior to bankruptcy, along with a credit rating issued by either or both S&P and Moody’s. Both influence each other. The likelihood of an auditor issuing a GC opinion is related to the credit rating issued by both S&P and Moody’s in the month prior to the audit report signing. The results also show differences between the CRAs. S&P reacted in the month after an auditor issued a GC opinion by downgrading its ratings 68% of the time. However, Moody’s did not react as strongly as S&P, downgrading its ratings only 24% of the time. Findings Both audit reports and credit ratings influence each other. The likelihood of an auditor issuing a GC opinion is related to the credit rating issued by both S&P and Moody’s in the month prior to the audit report signing. The results also show differences between the CRAs. S&P reacted in the month after an auditor issued a GC opinion by downgrading its ratings 68% of the time. However, Moody’s did not react as strongly as S&P, downgrading its ratings only 24% of the time. Originality/value Auditors are more likely to issue GC opinions when there is a downgrade to the credit rating, and CRAs are more likely to downgrade their ratings when there is a GC opinion. The study highlights that CRAs with different ownership structures provide different credit rating outcomes.

Regenerative medicine aims to replace damaged tissues by stimulating endogenous tissue repair or by transplanting autologous or allogeneic cells. Due to their capacity to produce unlimited numbers of cells of a given cell type, pluripotent stem cells, whether of embryonic origin or induced via the reprogramming of somatic cells, are of considerable therapeutic interest in the regenerative medicine field. However, regardless of the cell type, host immune responses present a barrier to success. The aim of this study was to investigate in vitro the immunological properties of human pluripotent stem cell (PSC)-derived hepatocyte-like cells (HLCs). These cells expressed MHC class I molecules while they lacked MHC class II and co-stimulatory molecules, such as CD80 and CD86. Following stimulation with IFN-γ, HLCs upregulated CD40, PD-L1 and MHC class I molecules. When co-cultured with allogeneic T cells, HLCs did not induce T cell proliferation; furthermore, when T cells were stimulated via αCD3/CD28 beads, HLCs inhibited their proliferation via IDO1 and tryptophan deprivation. These results demonstrate that PSC-derived HLCs possess immunoregulatory functions, at least in vitro.

BACKGROUNDAnalgesia during pregnancy is often necessary. Due to their widespread availability, many mothers opt to use over-the-counter (OTC) analgesics. Those analgesic compounds and their metabolites can readily cross the placenta and reach the developing foetus. Evidence for safety or associations with adverse health outcomes is conflicting, limiting definitive decision-making for healthcare professionals.OBJECTIVE AND RATIONALEThis review provides a detailed and objective overview of research in this field. We consider the global prevalence of OTC analgesia during pregnancy, explain the current mechanistic understanding of how analgesic compounds cross the placenta and reach the foetus, and review current research on exposure associations with offspring health outcomes.SEARCH METHODSA comprehensive English language literature search was conducted using PubMed and Scopus databases. Different combinations of key search terms were used including ‘over-the-counter/non-prescription analgesics’, ‘pregnancy’, ‘self-medication’, ‘paracetamol’, ‘acetaminophen’, ‘diclofenac’, ‘aspirin’, ‘ibuprofen’, ‘in utero exposure’, ‘placenta drug transport’, ‘placental transporters’, ‘placenta drug metabolism’ and ‘offspring outcomes’.OUTCOMESThis article examines the evidence of foetal exposure to OTC analgesia, starting from different routes of exposure to evidence, or the lack thereof, linking maternal consumption to offspring ill health. There is a very high prevalence of maternal consumption of OTC analgesics globally, which is increasing sharply. The choice of analgesia selected by pregnant women differs across populations. Location was also observed to have an effect on prevalence of use, with more developed countries reporting the highest consumption rates. Some of the literature focuses on the association of in utero exposure at different pregnancy trimesters and the development of neurodevelopmental, cardiovascular, respiratory and reproductive defects. This is in contrast to other studies which report no associations.WIDER IMPLICATIONSThe high prevalence and the challenges of reporting exact consumption rates make OTC analgesia during pregnancy a pressing reproductive health issue globally. Even though some healthcare policy-making authorities have declared the consumption of some OTC analgesics for most stages of pregnancy to be safe, such decisions are often based on partial review of literature. Our comprehensive review of current evidence highlights that important knowledge gaps still exist. Those areas require further research in order to provide pregnant mothers with clear guidance with regard to OTC analgesic use during pregnancy.

Inflammation has been recognized as essential for restorative regeneration. Here, we analyzed the sequential processes during onset of liver injury and subsequent regeneration based on time-resolved transcriptional regulatory networks (TRNs) to understand the relationship between inflammation, mature organ function, and regeneration. Genome-wide expression and TRN analysis were performed time dependently in mouse liver after acute injury by CCl4 (2 h, 8 h, 1, 2, 4, 6, 8, 16 days), as well as lipopolysaccharide (LPS, 24 h) and compared to publicly available data after tunicamycin exposure (mouse, 6 h), hepatocellular carcinoma (HCC, mouse), and human chronic liver disease (non-alcoholic fatty liver, HBV infection and HCC). Spatiotemporal investigation differentiated lobular zones for signaling and transcription factor expression. Acute CCl4 intoxication induced expression of gene clusters enriched for inflammation and stress signaling that peaked between 2 and 24 h, accompanied by a decrease of mature liver functions, particularly metabolic genes. Metabolism decreased not only in pericentral hepatocytes that underwent CCl4-induced necrosis, but extended to the surviving periportal hepatocytes. Proliferation and tissue restorative TRNs occurred only later reaching a maximum at 48 h. The same upstream regulators (e.g. inhibited RXR function) were implicated in increased inflammation and suppressed metabolism. The concomitant inflammation/metabolism TRN occurred similarly after acute LPS and tunicamycin challenges, in chronic mouse models and also in human liver diseases. Downregulation of metabolic genes occurs concomitantly to induce inflammation-associated genes as an early response and appears to be initiated by similar upstream regulators in acute and chronic liver diseases in humans and mice. In the acute setting, proliferation and restorative regeneration associated TRNs peak only later when metabolism is already suppressed. ispartof: ARCHIVES OF TOXICOLOGY vol:94 issue:1 pages:205-217 ispartof: location:Germany status: published

BACKGROUND & AIMS: Pluripotent stem cell (PSC)-derived hepatocyte-like cells (HLC) have enormous potential as a replacement for primary hepatocytes in drug screening, toxicology and cell replacement therapy, but their genome-wide expression patterns differ strongly from primary human hepatocytes (PHH). METHODS: We differentiated human induced pluripotent stem cells (hiPSC) via definitive endoderm to HLC and characterized the cells by single-cell and bulk RNA-seq, with complementary epigenetic analyses. We then compared HLC to PHH and publicly available data on human fetal hepatocytes (FH) ex vivo; we performed bioinformatics-guided interventions to improve HLC differentiation via lentiviral transduction of the nuclear receptor FXR and agonist exposure. RESULTS: Single-cell RNA-seq revealed that transcriptomes of individual HLC display a hybrid state, where hepatocyte-associated genes are expressed in concert with genes that are not expressed in PHH – mostly intestinal genes – within the same cell. Bulk-level overrepresentation analysis, as well as regulon analysis at the single-cell level, identified sets of regulatory factors discriminating HLC, FH, and PHH, hinting at a central role for the nuclear receptor FXR in the functional maturation of HLC. Combined FXR expression plus agonist exposure enhanced the expression of hepatocyte-associated genes and increased the ability of bile canalicular secretion as well as lipid droplet formation, thereby increasing HLCs’ similarity to PHH. The undesired non-liver gene expression was reproducibly decreased, although only by a moderate degree. CONCLUSION: In contrast to physiological hepatocyte precursor cells and mature hepatocytes, HLC co-express liver and hybrid genes in the same cell. Targeted modification of the FXR gene regulatory network improves their differentiation by suppressing intestinal traits whilst inducing hepatocyte features. LAY SUMMARY: Generation of human hepatocytes from stem cells represents an active research field but its success is hampered by the fact that the stem cell-derived ‘hepatocytes’ still show major differences to hepatocytes obtained from a liver. Here, we identified an important reason for the difference, specifically that the stem cell-derived ‘hepatocyte’ represents a hybrid cell with features of hepatocytes and intestinal cells. We show that a specific protein (FXR) suppresses intestinal and induces liver features, thus bringing the stem cell-derived cells closer to hepatocytes derived from human livers.

Developing renewable human liver tissue from stem cells has been pursued as a potential source of biological material for pharmaceutical and clinical endeavors. At present, two-dimensional differentiation procedures deliver tissue lacking long-term phenotypic and functional stability. Efforts to overcome these limiting factors have led to the development of protocols to generate three-dimensional cellular aggregates. Here we describe a methodology to generate 3D hepatospheres from human pluripotent stem cells using defined and commercially available reagents.

Study question Is in utero exposure to five over-the-counter (non-prescription) analgesics (paracetamol, ibuprofen, aspirin, diclofenac, naproxen) associated with offspring health outcomes? Summary answer Consumption of over-the-counter analgesics during pregnancy, either as single compounds or in combinations, is significantly associated with a variety of adverse offspring health outcomes. What is known already A high percentage of pregnant women use over-the-counter analgesics during pregnancy globally. Some of these compounds such as paracetamol are considered safe to use, while contraindications exist for others, such as NSAIDs use beyond gestational week 30. Current evidence regarding the safety of use during pregnancy in humans is largely conflicting. Results from many published human studies on the topic suffer from limitations including use of small cohorts, short study time or failure to adjust for important confounders. These may explain conflicting results that cause significant concern regarding evidence-based prenatal guidance on use during pregnancy. Study design, size, duration Retrospective cohort study using the Aberdeen Maternity and Neonatal Databank. Data from 151,141 singleton pregnancies over 30 years (between 1985 and 2015) were used. Consumption of paracetamol, ibuprofen, aspirin, diclofenac and naproxen during pregnancy was recorded in medical notes of each woman. In our analysis, the control group was pregnancies where no analgesic was consumed, and the exposure groups included pregnancies with over-the-counter analgesic consumption either in combinations or as single compound use. Participants/materials, setting, methods Maternal baseline characteristics were compared using χ2 tests for categorical variables and Mann-Whitney for continuous variables (significance at Main results and the role of chance The overall prevalence of over-the-counter analgesics use during pregnancy was 29.1%, increasing over the 30-year study period, to over 60% of women in the last seven years of the study. 83.7% of those women reported first trimester use when specifically asked at their first antenatal clinic visit. Pregnancies exposed to at least one of the five analgesics were independently associated with increased risks for premature delivery 4,000g (aOR=1.09, 95%CI 1.05–1.13), admission to neonatal unit (aOR=1.57, 95%CI 1.51–1.64), APGAR score Limitations, reasons for caution Our data were based on medical notes; however, consumption is self-reported, and details on the timing, dosage, product type (single-ingredient vs combination) and administration type were not available in the database. Our study only considered neonatal health outcomes and longer-term follow-up of the offspring was not available at this time. Wider implications of the findings: This is one of the largest and most comprehensive studies into analgesic use in pregnancy. The increased risks of adverse neonatal outcomes associated with non-prescribed, over-the-counter, analgesics use during pregnancy indicate that healthcare guidance for pregnant women regarding analgesic use should be re-assessed. Trial registration number N/A

Summary Liver disease is a major cause of premature death. Oxidative stress in the liver represents a key disease driver. Compounds, such as dimethyl fumarate (DMF), can activate the antioxidant response and are used clinically to treat disease. In this study, we tested the protective properties of DMF before or after paracetamol exposure. Following DMF administration, Nrf2 nuclear translocation was tracked at the single-cell level and target gene transactivation confirmed. Next, the protective properties of DMF were examined following paracetamol exposure. Transcriptomic and biochemical analysis revealed that DMF rescue was underpinned by reduced Nf-kB and TGF-β signaling and cell senescence. Following on from these studies, we employed a Zebrafish model to study paracetamol exposure in vivo. We combined a genetically modified Zebrafish model, expressing green fluorescent protein exclusively in the liver, with automated microscopy. Pre-treatment with DMF, prior to paracetamol exposure, led to reduced liver damage in Zebrafish demonstrating protective properties., Graphical abstract, Highlights • Dimethyl fumarate protects hepatocyte-like cells from paracetamol-induced stress • Nrf2 activation and TGF-β inhibition are main drivers of cell protection in vitro • DMF pre-treatment of zebrafish prevents paracetamol-induced liver injury in vivo, Molecular biology; Toxicology ; Cell biology; Transcriptomics.

Summary During mammalian development, liver differentiation is driven by signals that converge on multiple transcription factor networks. The hepatocyte nuclear factor signaling network is known to be essential for hepatocyte specification and maintenance. In this study, we have generated deletion and point mutants of hepatocyte nuclear factor-4alpha (HNF4α) to precisely evaluate the function of protein domains during hepatocyte specification from human pluripotent stem cells. We demonstrate that nuclear HNF4α is essential for hepatic progenitor specification, and the introduction of point mutations in HNF4α′s Small Ubiquitin-like Modifier (SUMO) consensus motif leads to disrupted hepatocyte differentiation. Taking a multiomics approach, we identified key deficiencies in cell biology, which included dysfunctional metabolism, substrate adhesion, tricarboxylic acid cycle flux, microRNA transport, and mRNA processing. In summary, the combination of genome editing and multiomics analyses has provided valuable insight into the diverse functions of HNF4α during pluripotent stem cell entry into the hepatic lineage and during hepatocellular differentiation., Graphical Abstract, Highlights • Deletion of HNF4α's DNA-binding domain blocks hepatic progenitor formation • HNF4α′s C-terminal SUMO consensus motif plays roles in hepatocyte specification • Multiomics analyses reveal various processes regulated by HNF4α during differentiation, Biological Sciences; Cell Biology; Developmental Biology; Stem Cells Research

Tissue engineering of a transplantable liver could provide an alternative to donor livers for transplant, solving the problem of escalating donor shortages. One of the challenges for tissue engineers is the extracellular matrix (ECM); a finely controlled in vivo niche which supports hepatocytes. Polymers and decellularized tissue scaffolds each provide some of the necessary biological cues for hepatocytes, however, neither alone has proved sufficient. Enhancing microenvironments using bioactive molecules allows researchers to create more appropriate niches for hepatocytes. We combined decellularized human liver tissue with electrospun polymers to produce a niche for hepatocytes and compared the human liver ECM to its individual components; Collagen I, Laminin-521 and Fibronectin. The resulting scaffolds were validated using THLE-3 hepatocytes. Immunohistochemistry confirmed retention of proteins in the scaffolds. Mechanical testing demonstrated significant increases in the Young’s Modulus of the decellularized ECM scaffold; providing significantly stiffer environments for hepatocytes. Each scaffold maintained hepatocyte growth, albumin production and influenced expression of key hepatic genes, with the decellularized ECM scaffolds exerting an influence which is not recapitulated by individual ECM components. Blended protein:polymer scaffolds provide a viable, translatable niche for hepatocytes and offers a solution to current obstacles in disease modelling and liver tissue engineering.

Human pluripotent stem cells (hPSCs) have the potential to transform medicine. However, hurdles remain to ensure safety for such cellular products. Science-based understanding of the requirements for source materials is required as are appropriate materials. Leaders in hPSC biology, clinical translation, biomanufacturing and regulatory issues were brought together to define requirements for source materials for the production of hPSC-derived therapies and to identify other key issues for the safety of cell therapy products. While the focus of this meeting was on hPSC-derived cell therapies, many of the issues are generic to all cell-based medicines. The intent of this report is to summarize the key issues discussed and record the consensus reached on each of these by the expert delegates.

Summary This protocol describes how to produce human liver spheres from pluripotent stem cell-derived hepatic progenitors, endothelial cells, and hepatic stellate cells. Liver spheres form by self-assembly in microwells, generating up to 73 spheres per well of a 96-well plate. This process was automated using liquid handling and pipetting systems, permitting cost-effective scale-up and reducing sphere variability. In its current form, this system provides a powerful tool to generate human liver tissue for disease modeling and drug screening. For complete details on the use and execution of this protocol, please refer to Lucendo-Villarin et al. (2020) ( https://doi.org/10.1088/1758-5090/abbdb2 ).

Summary This protocol describes the production of hepatocyte-like cells (HLCs) from human pluripotent stem cells and how to induce hepatic steatosis, a condition characterized by intracellular lipid accumulation. Following differentiation to an HLC phenotype, intracellular lipid accumulation is induced with a steatosis induction cocktail, allowing the user to examine the cellular processes that underpin hepatic steatosis. Furthermore, the renewable nature of our system, on a defined genetic background, permits in-depth mechanistic analysis, which may facilitate therapeutic target identification in the future. For complete details on the use and execution of this protocol, please refer to Sinton et al. (2021)., Graphical abstract, Highlights • A detailed protocol to produce stem cell-derived hepatocyte-like cells • Lactate, pyruvate, and octanoate treatment induces steatosis in hepatocyte-like cells • A reliable tool for examining the processes that underpin hepatic steatosis, This protocol describes the production of hepatocyte-like cells (HLCs) from human pluripotent stem cells and how to induce hepatic steatosis, a condition characterized by intracellular lipid accumulation. Following differentiation to an HLC phenotype, intracellular lipid accumulation is induced with a steatosis induction cocktail, allowing the user to examine the cellular processes that underpin hepatic steatosis. Furthermore, the renewable nature of our system, on a defined genetic background, permits in-depth mechanistic analysis, which may facilitate therapeutic target identification in the future.

Biliary diseases can cause inflammation, fibrosis, bile duct destruction, and eventually liver failure. There are no curative treatments for biliary disease except for liver transplantation. New therapies are urgently required. We have therefore purified human biliary epithelial cells (hBECs) from human livers that were not used for liver transplantation. hBECs were tested as a cell therapy in a mouse model of biliary disease in which the conditional deletion of Mdm2 in cholangiocytes causes senescence, biliary strictures, and fibrosis. hBECs are expandable and phenotypically stable and help restore biliary structure and function, highlighting their regenerative capacity and a potential alternative to liver transplantation for biliary disease.

Summary Nonalcoholic fatty liver disease (NAFLD) is currently the most prevalent form of liver disease worldwide. This term encompasses a spectrum of pathologies, from benign hepatic steatosis to non-alcoholic steatohepatitis, which have, to date, been challenging to model in the laboratory setting. Here, we present a human pluripotent stem cell (hPSC)-derived model of hepatic steatosis, which overcomes inherent challenges of current models and provides insights into the metabolic rewiring associated with steatosis. Following induction of macrovesicular steatosis in hepatocyte-like cells using lactate, pyruvate, and octanoate (LPO), respirometry and transcriptomic analyses revealed compromised electron transport chain activity. 13C isotopic tracing studies revealed enhanced TCA cycle anaplerosis, with concomitant development of a compensatory purine nucleotide cycle shunt leading to excess generation of fumarate. This model of hepatic steatosis is reproducible, scalable, and overcomes the challenges of studying mitochondrial metabolism in currently available models., Graphical Abstract, Highlights • LPO-exposed hPSC-derived hepatocyte-like cells resemble human hepatic steatosis • Steatosis is associated with decreased mitochondrial maximal respiration • Purine nucleotide cycle activity increases in steatotic hepatocytes • Excess fumarate production is associated with induction of macrovesicular steatosis, Endocrine System Physiology; Stem Cells Research; Transcriptomics

Developing renewable human liver tissue from stem cells has been pursued as a potential source of biological material for pharmaceutical and clinical endeavors. At present, two-dimensional differentiation procedures deliver tissue lacking long-term phenotypic and functional stability. Efforts to overcome these limiting factors have led to the development of protocols to generate three-dimensional cellular aggregates. Here we describe a methodology to generate 3D hepatospheres from human pluripotent stem cells using defined and commercially available reagents.

ObjectivesTo identify any associations between in utero exposure to five over-the-counter (non-prescription) analgesics (paracetamol, ibuprofen, aspirin, diclofenac, naproxen) and adverse neonatal outcomes.DesignRetrospective cohort study using the Aberdeen Maternity and Neonatal Databank.Participants151 141 singleton pregnancies between 1985 and 2015.Main outcome measuresPremature delivery (Results83.7% of women taking over-the-counter analgesics reported first trimester use when specifically asked about use at their first antenatal clinic visit. Pregnancies exposed to at least one of the five analgesics were significantly independently associated with increased risks for premature delivery 4000 g (aOR=1.09, 95% CI 1.05 to 1.13), admission to neonatal unit (aOR=1.57, 95% CI 1.51 to 1.64), APGAR score ConclusionsOver-the-counter (non-prescription) analgesics consumption during pregnancy was associated with a substantially higher risk for adverse perinatal health outcomes in the offspring. The use of paracetamol in combination with other non-steroidal anti-inflammatory drugs conferred the highest risk. The increased risks of adverse neonatal outcomes associated with non-prescribed, over-the-counter, analgesics use during pregnancy indicate that healthcare guidance for pregnant women regarding analgesic use need urgent updating.

An exponential increase in liver disease is driving a critical shortage of donor livers for patient transplant. In the UK alone, 58 people died in 2019 while waiting for a donor organ. A solution is sought in the form of tissue-engineered devices which support the survival and function of primary human hepatocytes. Previous work has shown that biofunctionalization of electrospun scaffolds influences hepatocytes. This study assesses the impact of drug-derived ECM on primary human hepatocytes (PHHs); a gold standard research resource. Hepatocytes seeded onto electrospun PLA scaffolds were subjected to drug treatment using histone deacetylase inhibitors. These cells were stripped from the scaffolds to leave behind their ECM. The resulting ECM-PLA scaffolds were seeded with PHHs and cultured for 24/72/120 hours. Scanning electron microscopy (SEM), mechanical and biochemical quantification, histology, and gene expression analyses were performed on the scaffolds. Results demonstrate PHHs are significantly influenced by the drug derived ECM:PLA scaffolds, with alterations in albumin production and gene expression demonstrated. Creating multidimensional scaffolds like these provides a method of creating tailored environments for liver bioengineering and the investigation of cell matrix interactions and is a step on the path to providing lab grown organoids for patient transplant.

ObjectiveTo identify associations between in utero exposure to 5 over-the-counter (OTC) analgesics and adverse neonatal outcomes.DesignRetrospective cohort studySettingAberdeen UKPopulation151,141 singleton deliveries, 1985 to 2015MethodsSelf-reported, non-prescription, consumption of paracetamol, aspirin, ibuprofen, diclofenac and naproxen during pregnancy and neonatal outcomes were obtained from the Aberdeen Maternity and Neonatal Databank (AMND). Univariable and multivariable regression analyses were performed to investigate associations between analgesic use and offspring neonatal outcomes. Crude (cORs) and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were reported, indicating the strength of association.Main Outcome MeasuresPremature delivery (ResultsPregnancies exposed to at least one of the 5 analgesics were significantly independently associated with increased odds for premature delivery 4000g (aOR=1.09, 95%CI 1.05-1.13), admission to neonatal unit (aOR=1.57, 95%CI 1.51-1.64), APGAR score ConclusionsThere was a high prevalence of OTC analgesics use during pregnancy, which steeply increased during the 30-year study period. Analgesic consumption was independently associated with multiple adverse neonatal offspring outcomes. The use of paracetamol in combination with other NSAIDs conferred the highest risk.FundingBiotechnology and Biological Sciences Research council (BBSRC) funding under the EASTBIO doctoral training programme.

A major bottleneck in the study of human liver physiology is the provision of stable liver tissue in sufficient quantity. As a result, current approaches to modelling human drug efficacy and toxicity rely heavily on immortalized human and animal cell lines. These models are informative but do possess significant drawbacks. To address the issues presented by those models, researchers have turned to pluripotent stem cells (PSCs). PSCs can be generated from defined genetic backgrounds, are scalable, and capable of differentiation to all the cell types found in the human body, representing an attractive source of somatic cells for in vitro and in vivo endeavours. Although unlimited numbers of somatic cell types can be generated in vitro, their maturation still remains problematic. In order to develop high fidelity PSC-derived liver tissue, it is necessary to better understand the cell microenvironment in vitro including key elements of liver physiology. In vivo a major driver of zonated liver function is the oxygen gradient that exists from periportal to pericentral regions. In this paper, we demonstrate how cell culture conditions for PSC-derived liver sphere systems can be optimised to recapitulate physiologically relevant oxygen gradients by using mathematical modelling. The mathematical model incorporates some often-understated features and mechanisms of traditional spheroid systems such as cell-specific oxygen uptake, media volume, spheroid size, and well dimensions that can lead to a spatially heterogeneous distribution of oxygen. This mathematical modelling approach allows for the calibration and identification of culture conditions required to generate physiologically realistic function within the microtissue through recapitulation of the in vivo microenvironment.

Liver disease represents an increasing cause of global morbidity and mortality. Currently, liver transplant is the only treatment curative for end stage liver disease. Donor organs cannot meet the demand and therefore scalable treatments and new disease models are required to improve clinical intervention. Pluripotent stem cells represent a renewable source of human tissue. Recent advances in three-dimensional cell culture have provided the field with more complex systems that better mimic liver physiology and function. Despite these improvements, current cell based models are highly variable in performance and expensive to manufacture at scale. This is due, in part, to the use of poorly defined or cross-species materials within the process, severely affecting technology translation. To address this issue, we have developed an automated and economical platform to produce liver tissue at scale for modelling disease and small molecule screening. Stem cell derived liver spheres were formed by combining hepatic progenitors with endothelial cells and stellate cells, in the ratios found within the liver. The resulting tissue permitted the study of human liver biology ‘in the dish ‘and could be scaled for screening. In summary, we have developed an automated differentiation system that permits reliable self-assembly of human liver tissue for biomedical application. Going forward we believe that this resource will not only serve as an in vitro resource and may have an important role to play in supporting failing liver function in humans.

SummaryNonalcoholic fatty liver disease (NAFLD) affects ~88% of obese individuals and is characterised by hepatic lipid accumulation. Mitochondrial metabolic dysfunction is a feature of NAFLD. We used a human pluripotent stem cell-based system to determine how mitochondrial dysfunction is linked to hepatic lipid accumulation. We induced lipid accumulation in hepatocyte-like cells (HLCs) using lactate, pyruvate and octanoate (LPO). Transcriptomic analysis revealed perturbation of mitochondrial respiratory pathways in LPO exposed cells. Using13C isotopic tracing, we identified truncation of the TCA cycle in steatotic HLCs. We show that increased purine nucleotide cycle (PNC) activity fuels fumarate accumulation and drives lipid accumulation in steatotic cells. These findings provide new insights into the pathogenesis of hepatic steatosis and may lead to an improved understanding of the metabolic and transcriptional rewiring associated with NAFLD.

Custom designed endonucleases, such as RNA-guided Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9, enable efficient genome editing in mammalian cells. Here we describe detailed procedures to seamlessly genome edit the hepatocyte nuclear factor 4 alpha (HNF4α) locus as an example in human pluripotent stem cells. Combining a piggyBac-based donor plasmid and the CRISPR-Cas9 nickase mutant in a two-step genetic selection, we demonstrate correct and efficient targeting of the HNF4α locus.