Kidney Transplantation From Hepatitis-C Viraemic Donors:Considerations for Practice in the United Kingdom.

Background: Donor hepatitis-C (HCV) infection has historically represented a barrier to kidney transplantation (KT). However, direct-acting antiviral (DAA) medications have revolutionised treatment of chronic HCV infection. Recent American studies have demonstrated that DAA regimes can be used safely peri-operatively in KT to mitigate HCV transmission risk. Methods: To formulate this narrative review, a comprehensive literature search was performed to analyse results of existing clinical trials examining KT from HCV-positive donors to HCV-negative recipients with peri-operative DAA regimes. Results: 13 studies were reviewed (11 single centre, four retrospective). Outcomes for 315 recipients were available across these studies. A sustained virological response at 12 weeks (SVR12) of 100% was achieved in 11 studies. One study employed an ultra-short DAA regime and achieved an SVR12 of 98%, while another achieved SVR12 of 96% due to treatment of a missed mixed genotype. Conclusion: HCV+ KT is safe and may allow increased utilisation of organs for transplantation from HCV+ donors, who often have other favourable characteristics for successful donation. Findings from US clinical trials can be applied to the United Kingdom transplant framework to improve organ utilisation as suggested by the NHSBT vision strategy "Organ Donation and Transplantation 2030: meeting the need".

Genetic Contribution to Non-alcoholic Fatty Liver Disease and Prognostic Implications.

PURPOSE OF REVIEW: Non-alcoholic fatty liver disease (NAFLD) is a major and increasing health burden, with the potential to overwhelm hepatology services. However, only a minority of patients develop advanced liver disease. The challenge is early identification of patients at risk of progression. This review aims to summarize current knowledge on the genetic predisposition to NAFLD, and its implications for prognostication and risk stratification. RECENT FINDINGS: PNPLA3-I148M is the most robustly associated genetic variant with NAFLD. Recently, variants in TM6SF2, MBOAT7, GCKR and HSD17B13 have also been implicated. NAFLD is a complex disease, and any one genetic variant alone is insufficient for risk stratification, but combining multiple genetic variants with other parameters is a promising strategy. It is anticipated that, in the near future, analysis of data from large-scale prospective cohorts will reveal NAFLD subtypes and enable the development of prognostic models. This will facilitate risk stratification of patients, enabling optimisation of resources to effectively manage the NAFLD epidemic.

Emerging clinical perspectives in cystic fibrosis liver disease.

PURPOSE OF REVIEW: Liver disease (CFLD) as a complication of cystic fibrosis is recognized as a more severe disease phenotype in both children and adults. We review recent advances in understanding the disease mechanism and consider the implications of new strategies for the diagnosis and management of cystic fibrosis in those with evidence of clinically significant liver disease. RECENT FINDINGS: Evidence suggests that the prevalence of CFLD has not declined with the introduction of newborn screening. Furthermore, children with CFLD, who have been diagnosed with cystic fibrosis following newborn screening continue to have a much higher mortality rate compared with those with no liver disease. There is further data suggesting noncirrhotic obliterative portal venopathy as the predominant pathological mechanism in the majority of children and young adults receiving a liver transplantation. Little progress has been made in developing an accurate noninvasive test for early diagnosis or monitoring disease progression in CFLD. The benefit of new modulator therapies is not well understood in those with established CFLD, whereas the risk of hepatotoxicity as a complication of treatment must be carefully monitored. SUMMARY: Better understanding of the pathophysiology of CFLD would allow a standardized approach to diagnosis, with the potential to improve outcomes for those with CFLD.

Scaling Factors for Clearance in Adult Liver Cirrhosis.

In vitro to in vivo extrapolation (IVIVE) enables prediction of in vivo clinical outcomes related to drug exposure in various populations from in vitro data. Prudent IVIVE requires scalars specific to the biologic characteristics of the system in each population. This study determined experimentally for the first time scalars in liver samples from patients with varying degrees of cirrhosis. Microsomal and cytosolic fractions were extracted from 13 noncirrhotic and 32 cirrhotic livers (six mild, 13 moderate, and 13 severe, based on Child-Pugh score). Fractional protein content was determined, and cytochrome P450 reductase activity was used to correct for microsomal protein loss. Although the median microsomal protein per gram liver (MPPGL) in mild, moderate, and severe cirrhosis (26.2, 32.4, and 30.8 mg⋅g-1, respectively) seemed lower than control livers (36.6 mg⋅g-1), differences were not statistically significant (Kruskal-Wallis test, P > 0.05). Corresponding values for cytosolic protein per gram liver were 88.2, 67.9, 62.2, and 75.4 (mg⋅g-1) for mild, moderate, and severe cirrhosis and control livers, respectively, with statistically lower values for severe versus controls (Mann-Whitney P = 0.006). Cirrhosis associated with cancer showed lower MPPGL (24.8 mg⋅g-1) than cirrhosis associated with cholestasis (38.3 mg⋅g-1, P = 0.003). Physiologically based pharmacokinetic simulations with disease-specific scalars captured cirrhosis impact on exposure to alfentanil, metoprolol, midazolam, and ethinylestradiol. These experimentally-determined scalars should alleviate the need for indirect scaling using functional liver volume. Scaling factors in cirrhosis might be a reflection of the etiology rather than the disease severity. Hence, bundling various cirrhotic conditions under the same umbrella when predicting hepatic impairment impact should be revisited. SIGNIFICANCE STATEMENT: Cirrhosis-specific scalars required for extrapolation from microsomal or cytosolic in vitro systems to liver tissue are lacking. These scalars can help in predicting drug clearance and selection of dosage regimens for cirrhosis populations. Attempts to consider potential changes have been empirical and ignored the potential impact of the cause of cirrhosis. We obtained experimental values for these scalars for the first time and assessed their impact on predicted exposure to various substrate drugs using physiologically-based pharmacokinetics simulations.

Osteopontin is a novel downstream target of SOX9 with diagnostic implications for progression of liver fibrosis in humans.

UNLABELLED: Osteopontin (OPN) is an important component of the extracellular matrix (ECM), which promotes liver fibrosis and has been described as a biomarker for its severity. Previously, we have demonstrated that Sex-determining region Y-box 9 (SOX9) is ectopically expressed during activation of hepatic stellate cells (HSC) when it is responsible for the production of type 1 collagen, which causes scar formation in liver fibrosis. Here, we demonstrate that SOX9 regulates OPN. During normal development and in the mature liver, SOX9 and OPN are coexpressed in the biliary duct. In rodent and human models of fibrosis, both proteins were increased and colocalized to fibrotic regions in vivo and in culture-activated HSCs. SOX9 bound a conserved upstream region of the OPN gene, and abrogation of Sox9 in HSCs significantly decreased OPN production. Hedgehog (Hh) signaling has previously been shown to regulate OPN expression directly by glioblastoma (GLI) 1. Our data indicate that in models of liver fibrosis, Hh signaling more likely acts through SOX9 to modulate OPN. In contrast to Gli2 and Gli3, Gli1 is sparse in HSCs and is not increased upon activation. Furthermore, reduction of GLI2, but not GLI3, decreased the expression of both SOX9 and OPN, whereas overexpressing SOX9 or constitutively active GLI2 could rescue the antagonistic effects of cyclopamine on OPN expression. CONCLUSION: These data reinforce SOX9, downstream of Hh signaling, as a core factor mediating the expression of ECM components involved in liver fibrosis. Understanding the role and regulation of SOX9 during liver fibrosis will provide insight into its potential modulation as an antifibrotic therapy or as a means of identifying potential ECM targets, similar to OPN, as biomarkers of fibrosis.

Longitudinal effects of elexacaftor/tezacaftor/ivacaftor on liver tests at a large single adult cystic fibrosis centre.

BACKGROUND: Elexacaftor/tezacaftor/ivacaftor (E/T/I) therapy has resulted in substantial improvements in health status for many with cystic fibrosis. Monitoring of liver tests is recommended due to observed rises in transaminases in trials and cases of hepatotoxicity. Comprehensive data in large populations of unselected individuals and those with established CF related liver disease (CFLD) is lacking. METHODS: Patients prescribed E/T/I at a large, adult centre had liver tests monitored at least 3 monthly for 12 months. Changes in individual liver tests were analysed and abnormalities were compared in those with and without CFLD. RESULTS: 255 of 267 eligible patients were included. Mild rises in median ALT, AST and bilirubin from baseline to 3 months (all p < 0.001) within normal limits were noted which were sustained. There were no differences in changes in liver tests between those with or without CFLD. There was a significant difference in alkaline phosphatase for those with raised levels at baseline versus those with normal baseline level (-18.5 vs +2.0 IU/L, p = 0.002). Clinically significant rises in ALT and AST occurred in 8 (3.1%) and 6 (2.4%) cases respectively, with derangements in 2 individuals attributed to therapy. CONCLUSIONS: E/T/I leads to a mild, likely clinically insignificant increase in ALT, AST and bilirubin after 3 months which is sustained but does not appear to increase further in the vast majority. Underlying CFLD should not be a barrier to treatment. Although there was a reduction in ALP when elevated at baseline, this was not unique to those with pre-existing CFLD.

The prevalence and burden of Rome IV bowel disorders of gut brain interaction in patients with non-alcoholic fatty liver disease: a cross-sectional study.

Rome IV bowel disorders of gut brain interaction (DGBI) and non-alcoholic fatty liver disease (NAFLD) are highly prevalent entities with overlapping pathophysiology and risk factors. We aimed to evaluate the prevalence and burden of Rome IV irritable bowel syndrome (IBS) in patients with NAFLD. Patients diagnosed with NAFLD were recruited from a specialist liver clinic. All participants completed assessments to determine liver fibrosis severity, including liver stiffness measurement (LSM), completed the Rome IV diagnostic questionnaire for bowel disorders of gut brain interaction, the IBS symptom severity score (IBS-SSS), and the EQ-5D-5L to measure of quality-of-life (QoL). 142 patients with NAFLD (71 (50%) female, mean age 53.5 (SD ± 14.9), BMI 35.2 (SD ± 8.1) kg/M2) were recruited. 79 (55.6%) patients met criteria for a Rome IV bowel DGBI, including 50 patients (35.2%) who met the criteria for IBS (mean IBS-SSS 277.2 (SD ± 131.5)). There was no difference in liver fibrosis scores between those with and without Rome IV IBS (FIB-4 scores p = 0.14, LSM p = 0.68). Patients with NAFLD and Rome IV IBS had significantly worse QoL scores (EQ-VAS p = 0.005 and EQ-5D-5L index p = 0.0007), impairment of usual activities of daily living (p = 0.012) and were more likely to report anxiety or depression (p = 0.038). Rome IV bowel DGBI such as IBS are highly prevalent in patients with NAFLD attending liver clinics and are associated with impaired QoL and psychosocial distress.

Aetiology of Significant Liver Test Abnormalities in a Single-Centre Cohort of People with Cystic Fibrosis Exposed to Elexacaftor/Tezacaftor/Ivacaftor, Utilizing the Updated RUCAM.

BACKGROUND: The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulator elexacaftor/tezacaftor/ivacaftor (E/T/I) has been associated with substantial multisystem benefits for people with CF eligible for therapy. In a minority, tolerance has been limited by hepatic toxicity. It is unknown whether there may be particular risk factors for significant drug-induced elevation in transaminases. OBJECTIVE: We aimed to determine the cause of raised transaminases following the introduction of E/T/I, and whether E/T/I can safely be continued in some individuals with elevated transaminases. METHODS: At a large, single, adult CF centre, individuals with transaminases >3 × the upper limit of normal (ULN) since commencing E/T/I underwent clinical assessment to exclude known causes of raised transaminases. Where an alternative cause could not be identified, individuals were discussed with hepatology to advise on further investigations to establish aetiology in addition to calculation of the updated Roussel Uclaf Causality Assessment Method (RUCAM) score to assess causality grading of drug-induced liver injury (DILI) due to E/T/I, and to guide management of ongoing CFTR modulator therapy. RESULTS: Of 337 adults taking E/T/I for a median of 27 months, 19 (5.6%) had transaminases >3 × ULN. In 12 individuals, there was clear evidence of an aetiology unrelated to E/T/I (RUCAM scores -2 to 1 [excluded-unlikely]). Of the remaining cases, two had RUCAM scores in the 'possible' range and one had a RUCAM score in the 'probable' range. Liver biopsy was performed in four individuals, showing hepatic steatosis in one individual, normal histology in one individual, and hepatocyte necrosis suggestive of DILI in two individuals. E/T/I was suspended in those with hepatocyte necrosis, with one permanent discontinuation due to synthetic dysfunction. One individual with hepatocyte necrosis on histology was successfully re-established on E/T/I therapy. CONCLUSIONS: Alternative causes were identified in the majority of patients with clinically significant increases in transaminases following E/T/I, highlighting the importance of thorough investigation. Multidisciplinary assessment involving an experienced hepatologist is crucial in cases of diagnostic uncertainty or suggestion of significant DILI, as discontinuation of therapy can have significant consequences for individuals.

Effects of elexacaftor/tezacaftor/ivacaftor on liver fibrosis markers in adults with cystic fibrosis.

BACKGROUND: There are limited studies to date on the effects of elexacaftor/tezacaftor/ivacaftor (E/T/I) on markers of liver fibrosis in adults with cystic fibrosis (CF). This study aims to analyse changes in makers of liver fibrosis before and after initiation of E/T/I in CF adults. METHODS: Outcome measures of liver fibrosis, including liver stiffness measurement (LSM) using FibroScan, AST-to-platelet-ratio index (APRI) and gamma-GT-to-platelet-ratio (GPR) were available in 74 CF adults following initiation of E/T/I. This was compared to historical data collected in 2018 prior to UK availability of E/T/I. RESULTS: The median duration of E/T/I therapy at the time liver fibrosis markers were repeated was 21 (IQR: 17-25) months. There was an increase in APRI from historical measurement to follow-up but no change in LSM or GPR. There were no differences in change in fibrosis markers according to CF liver disease (CFLD) status, although those with a raised LSM at baseline (>6.8 kPa) (n = 14) had a significant reduction in LSM from historical measurement to follow-up versus those with a normal historical value (-3.3 kPa vs 0.25 kPa, p < 0.01). CONCLUSIONS: Apart from APRI, we found no changes in liver fibrosis outcomes after initiation of E/T/I in adults with CF. Those with a historical diagnosis of CFLD had no significant worsening or improvement of liver fibrosis markers. We did observe a reduction in LSM in those with liver nodularity, with an initial highest result suggesting a potential positive treatment effect of E/T/I in this category of those with severe CFLD.

Improving detection of cystic fibrosis related liver disease using liver fibrosis assessment tools.

Background & aims: Cystic Fibrosis related liver disease (CFLD) is the 3rd largest cause of death in Cystic Fibrosis (CF). As advances in pulmonary therapies have increased life-expectancy, CFLD has become more prevalent. Current guidelines may underdiagnose liver fibrosis, particularly in its early stages. Newer modalities for the assessment of fibrosis may provide a more accurate assessment. FibroScan is validated in assessing fibrosis for several aetiologies including alcohol and fatty liver, the CFLD cohort have an entirely different phenotype so the cut off values are not transferrable. We appraised fibrosis assessment tools to improve diagnosis of CFLD. Methods: A prospective cohort (n = 114) of patients from the Manchester Adult Cystic Fibrosis Centre, UK were identified at annual assessment. Demographic data including co-morbidity, CFTR genotyping, biochemistry and imaging were used alongside current guidelines to group into CFLD and CF without evidence of liver disease. All patients underwent liver stiffness measurement (LSM) and assessment of serum-based fibrosis biomarker panels. A new diagnostic criterion was created and validated in a second, independent cohort. Results: 12 of 114 patient classified as CFLD according to the European Cystic Fibrosis Society best practice guidelines. No specific risk factors for development of CFLD were identified. Liver enzymes were elevated in patients with CFLD. Serum biomarker panels did not improve diagnostic criteria. LSM accurately predicted CFLD. A new diagnostic criterion was proposed and validated in a separate cohort, accurately predicating CFLD in 10 of 32 patients (31 %). Conclusion: We present a cohort of patients with CF assessed for the presence of liver fibrosis using blood biomarkers and LSM based platforms. We propose a new, simplified diagnostic criteria, capable of accurately predicting liver disease in patients with CF.Clinical trials number: NCT04277819.

Circadian Disruption Primes Myofibroblasts for Accelerated Activation as a Mechanism Underpinning Fibrotic Progression in Non-Alcoholic Fatty Liver Disease.

Circadian rhythm governs many aspects of liver physiology and its disruption exacerbates chronic disease. CLOCKΔ19 mice disrupted circadian rhythm and spontaneously developed obesity and metabolic syndrome, a phenotype that parallels the progression of non-alcoholic fatty liver disease (NAFLD). NAFLD represents an increasing health burden with an estimated incidence of around 25% and is associated with an increased risk of progression towards inflammation, fibrosis and carcinomas. Excessive extracellular matrix deposition (fibrosis) is the key driver of chronic disease progression. However, little attention was paid to the impact of disrupted circadian rhythm in hepatic stellate cells (HSCs) which are the primary mediator of fibrotic ECM deposition. Here, we showed in vitro and in vivo that liver fibrosis is significantly increased when circadian rhythm is disrupted by CLOCK mutation. Quiescent HSCs from CLOCKΔ19 mice showed higher expression of RhoGDI pathway components and accelerated activation. Genes altered in this primed CLOCKΔ19 qHSC state may provide biomarkers for early liver disease detection, and include AOC3, which correlated with disease severity in patient serum samples. Integration of CLOCKΔ19 microarray data with ATAC-seq data from WT qHSCs suggested a potential CLOCK regulome promoting a quiescent state and downregulating genes involved in cell projection assembly. CLOCKΔ19 mice showed higher baseline COL1 deposition and significantly worse fibrotic injury after CCl4 treatment. Our data demonstrate that disruption to circadian rhythm primes HSCs towards an accelerated fibrotic response which worsens liver disease.

PAK1-dependent mechanotransduction enables myofibroblast nuclear adaptation and chromatin organization during fibrosis.

Myofibroblasts are responsible for scarring during fibrosis. The scar propagates mechanical signals inducing a radical transformation in myofibroblast cell state and increasing profibrotic phenotype. Here, we show mechanical stress from progressive scarring induces nuclear softening and de-repression of heterochromatin. The parallel loss of H3K9Me3 enables a permissive state for distinct chromatin accessibility and profibrotic gene regulation. Integrating chromatin accessibility profiles with RNA expression provides insight into the transcription network underlying the switch in profibrotic myofibroblast states, emphasizing mechanoadaptive regulation of PAK1 as key drivers. Through genetic manipulation in liver and lung fibrosis, loss of PAK1-dependent signaling impairs the mechanoadaptive response in vitro and dramatically improves fibrosis in vivo. Moreover, we provide human validation for mechanisms underpinning PAK1-mediated mechanotransduction in liver and lung fibrosis. Collectively, these observations provide insight into the nuclear mechanics driving the profibrotic chromatin landscape in fibrosis, highlighting actomyosin-dependent mechanisms as potential therapeutic targets in fibrosis.

Review article: epidemiology, pathogenesis and management of liver disease in adults with cystic fibrosis.

BACKGROUND: Cystic fibrosis-related liver disease (CFLD) is the leading cause of death in cystic fibrosis (CF), after pulmonary disease. To improve identification and management of this condition requires an understanding of the underlying disease mechanism. AIMS: This review summarises the current understanding of CFLD epidemiology, pathology, diagnosis and management. METHODS: Relevant reports on cystic fibrosis liver disease were identified using a literature search and summarised. RESULTS: CFLD is a heterogeneous condition with several different co-existent pathologies, including environmental and genetic factors. Incidence of clinically significant CFLD continues at a linear rate into early adulthood and has been described in up to 25% of CF patients. Diagnosis strategies lack precision and patient risk stratification needs to look beyond Childs-Pugh scoring. Efficacious therapies are lacking and, at present, newer modulator therapies lack data in CFLD and carry an increased risk of hepatotoxicity. Outcomes of liver transplant are comparable to non-CF transplant indications. CONCLUSIONS: The incidence of CFLD increases with age and hence is increasingly important to adult patients with CF. Effective therapies are lacking. For progress to be made a better understanding of pathogenesis and disease detection are required.

COVID-19 and hepatorenal syndrome.

Coronavirus disease 2019 (COVID-19) is a highly infectious disease which emerged into a global pandemic. Although it primarily causes respiratory symptoms for affected patients, COVID-19 was shown to have multi-organ manifestations. Elevated liver enzymes appear to be commonly observed during the course of COVID-19, and there have been numerous reports of liver injury secondary to COVID-19 infection. It has been established that patients with pre-existing chronic liver disease (CLD) are more likely to have poorer outcomes following COVID-19 infection compared to those without CLD. Co-morbidities such as diabetes, hypertension, obesity, cardiovascular and chronic kidney disease frequently co-exist in individuals living with CLD, and a substantial population may also live with some degree of frailty. The mechanisms of how COVID-19 induces liver injury have been postulated. Hepatorenal syndrome (HRS) is the occurrence of kidney dysfunction in patients with severe CLD/fulminant liver failure in the absence of another identifiable cause, and is usually a marker of severe decompensated liver disease. Select reports of HRS following acute COVID-19 infection have been presented, although the risk factors and pathophysiological mechanisms leading to HRS in COVID-19 infection or following COVID-19 treatment remain largely unestablished due to the relative lack and novelty of published data. Evidence discussing the management of HRS in high-dependency care and intensive care contexts is only emerging. In this article, we provide an overview on the speculative pathophysiological mechanisms of COVID-19 induced HRS and propose strategies for clinical diagnosis and management to optimize outcomes in this scenario.

Health Technology Adoption in Liver Disease: Innovative Use of Data Science Solutions for Early Disease Detection.

Chronic liver disease (CLD) is an ignored epidemic. Premature mortality is considerable and in the United Kingdom (UK) liver disease is in the top three for inequitable healthcare alongside heart and respiratory disease. Fifty percentage of patients with CLD are first diagnosed with cirrhosis after an emergency presentation translating to poorer patient outcomes. Traditional models of care have been based in secondary care when the need is at community level. Investigating patients for disease based on their risk factors at a population level in the community will identify its presence early when there is potential reversibility. Innovation is needed in three broad areas to improve clinical care in this area: better access to diagnostics within the community, integrating diagnostics across primary and secondary care and utilizing digital healthcare to enhance patient care. In this article, we describe how the Integrated Diagnostics for Early Detection of Liver Disease (ID-LIVER) project, funded by UK Research and Innovation, is developing solutions in Greater Manchester to approach the issue of diagnosis of liver disease at a population level. The ambition is to build on innovative pathways previously established in Nottingham by bringing together NHS organizations, academic partners and commercial organizations. The motivation is to co-create and implement a commercial solution that integrates multimodal diagnostics via cutting edge data science to drive growth and disrupt the currently inadequate model. The ambitious vision is for this to be widely adopted for early diagnosis and stratification of liver disease at a population level within the NHS.

Non-alcoholic fatty liver disease in irritable bowel syndrome: More than a coincidence?

Irritable bowel syndrome (IBS) and non-alcoholic fatty liver disease (NAFLD) are amongst the most common gastrointestinal and liver conditions encountered in primary and secondary care. Recently, there has been interest in the apparent co-incidence of NAFLD in patients with IBS mainly driven by improved understanding of their shared risk factors and pathophysiology. In this paper we summarize the shared risk factors which include; overlapping nutritional and dietary factors as well as shared putative mechanisms of pathophysiology. These include changes in the gut microbiome, gut permeability, immunity, small bowel bacterial overgrowth and bile acid metabolism. This paper describes how these shared risk factors and etiological factors may have practical clinical implications for these highly prevalent conditions. It also highlights some of the limitations of current epidemiological data relating to estimates of the overlapping prevalence of the two conditions which have resulted in inconsistent results and, therefore the need for further research. Early recognition and management of the overlap could potentially have impacts on treatment outcomes, compliance and morbidity of both conditions. Patients with known IBS who have abnormal liver function tests or significant risk factors for NAFLD should be investigated appropriately for this possibility. Similarly, IBS should be considered in patients with NAFLD and symptoms of abdominal pain associated with defecation, an altered bowel habit and bloating.

Review article: time to revisit Child-Pugh score as the basis for predicting drug clearance in hepatic impairment.

BACKGROUND: Prescription information for many drugs entering the market lacks dosage guidance for hepatic impairment. Dedicated studies for assessing the fate of drugs in hepatic impairment commonly stratify patients using Child-Pugh score. Child-Pugh is a prognostic clinical score with limitations in reflecting the liver's metabolic capacity. AIMS: To demonstrate the need for better drug dosing approaches in hepatic impairment, summarise the current status, identify knowledge gaps related to drug kinetic parameters in hepatic impairment, propose solutions for predicting the liver disease impact on drug exposure and discuss barriers to dosing guidance in those patients. METHODS: Relevant reports on dosage adjustment in hepatic impairment were analysed concerning the prediction of the impairment impact on drug kinetics using physiologically-based pharmacokinetic (PBPK) modelling. RESULTS: PBPK models are suggested as a potential framework to understand drug clearance changes in hepatic impairment. Quantifying changes in abundance and activity of drug-metabolising enzymes and transporters, understanding the impact of shunting, and accounting for interindividual variations in drug absorption could help in extending the success of these models in hepatically-impaired populations. These variables might not correlate with Child-Pugh score as a whole. Therefore, new metabolic activity markers, imaging techniques and other scoring systems are proposed to either support or substitute Child-Pugh score. CONCLUSIONS: Many physiological changes in hepatic impairment determining the fate of drugs do not necessarily correlate with Child-Pugh score. Quantifying these changes in individual patients is essential in future hepatic impairment studies. Further studies assessing Child-Pugh alternatives are recommended to allow better prediction of drug exposure.

SOX9 is required for kidney fibrosis and activates NAV3 to drive renal myofibroblast function.

Renal fibrosis is a common end point for kidney injury and many chronic kidney diseases. Fibrogenesis depends on the sustained activation of myofibroblasts, which deposit the extracellular matrix that causes progressive scarring and organ failure. Here, we showed that the transcription factor SOX9 was associated with kidney fibrosis in humans and required for experimentally induced kidney fibrosis in mice. From genome-wide analysis, we identified Neuron navigator 3 (NAV3) as acting downstream of SOX9 in kidney fibrosis. NAV3 increased in abundance and colocalized with SOX9 after renal injury in mice, and both SOX9 and NAV3 were present in diseased human kidneys. In an in vitro model of renal pericyte transdifferentiation into myofibroblasts, we demonstrated that NAV3 was required for multiple aspects of fibrogenesis, including actin polymerization linked to cell migration and sustained activation of the mechanosensitive transcription factor YAP1. In summary, our work identifies a SOX9-NAV3-YAP1 axis involved in the progression of kidney fibrosis and points to NAV3 as a potential target for pharmacological intervention.

Publisher Correction: SOX9 regulated matrix proteins are increased in patients serum and correlate with severity of liver fibrosis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Secondary sclerosing cholangitis following extracorporeal membrane oxygenation for acute respiratory distress in polytrauma.

Secondary sclerosing cholangitis is a recently identified phenomenon affecting the biliary tree. A subtype has been described in critically ill patients (SSC-CIP). However, underlying mechanisms are unknown, and few cases have been reported following extracorporeal membrane oxygenation (ECMO). We present a 19-year-old male with SSC-CIP after ECMO following major trauma.