Background & AimsLiver regeneration requires functional liver macrophages, which provide an immune barrier that is compromised after liver injury. The numbers of liver macrophages are controlled by macrophage colony-stimulating factor (CSF1). We examined the prognostic significance of the serum level of CSF1 in patients with acute liver injury and studied its effects in mice.MethodsWe measured levels of CSF1 in serum samples collected from 55 patients who underwent partial hepatectomy at the Royal Infirmary Edinburgh between December 2012 and October 2013, as well as from 78 patients with acetaminophen-induced acute liver failure admitted to the Royal Infirmary Edinburgh or the University of Kansas Medical Centre. We studied the effects of increased levels of CSF1 in uninjured mice that express wild-type CSF1 receptor or a constitutive or inducible CSF1-receptor reporter, as well as in chemokine receptor 2 (Ccr2)-/- mice; we performed fate-tracing experiments using bone marrow chimeras. We administered CSF1-Fc (fragment, crystallizable) to mice after partial hepatectomy and acetaminophen intoxication, and measured regenerative parameters and innate immunity by clearance of fluorescent microbeads and bacterial particles.ResultsSerum levels of CSF1 increased in patients undergoing liver surgery in proportion to the extent of liver resected. In patients with acetaminophen-induced acute liver failure, a low serum level of CSF1 was associated with increased mortality. In mice, administration of CSF1-Fc promoted hepatic macrophage accumulation via proliferation of resident macrophages and recruitment of monocytes. CSF1-Fc also promoted transdifferentiation of infiltrating monocytes into cells with a hepatic macrophage phenotype. CSF1-Fc increased innate immunity in mice after partial hepatectomy or acetaminophen-induced injury, with resident hepatic macrophage as the main effector cells.ConclusionsSerum CSF1 appears to be a prognostic marker for patients with acute liver injury. CSF1 might be developed as a therapeutic agent to restore innate immune function after liver injury.

SummaryBackgroundParacetamol overdose is common but patient stratification is suboptimal. We investigated the usefulness of new biomarkers that have either enhanced liver specificity (microRNA-122 [miR-122]) or provide mechanistic insights (keratin-18 [K18], high mobility group box-1 [HMGB1], and glutamate dehydrogenase [GLDH]). The use of these biomarkers could help stratify patients for their risk of liver injury at hospital presentation.MethodsUsing data from two prospective cohort studies, we assessed the potential for biomarkers to stratify patients who overdose with paracetamol. We completed two independent prospective studies: a derivation study (MAPP) in eight UK hospitals and a validation study (BIOPAR) in ten UK hospitals. Patients in both cohorts were adults (≥18 years in England, ≥16 years in Scotland), were diagnosed with paracetamol overdose, and gave written informed consent. Patients who needed intravenous acetylcysteine treatment for paracetamol overdose had circulating biomarkers measured at hospital presentation. The primary endpoint was acute liver injury indicating need for continued acetylcysteine treatment beyond the standard course (alanine aminotransferase [ALT] activity >100 U/L). Receiver operating characteristic (ROC) curves, category-free net reclassification index (cfNRI), and integrated discrimination index (IDI) were applied to assess endpoint prediction.FindingsBetween June 2, 2010, and May 29, 2014, 1187 patients who required acetylcysteine treatment for paracetamol overdose were recruited (985 in the MAPP cohort; 202 in the BIOPAR cohort). In the derivation and validation cohorts, acute liver injury was predicted at hospital presentation by miR-122 (derivation cohort ROC–area under the curve [AUC] 0·97 [95% CI 0·95–0·98]), HMGB1 (0·95 [0·93–0·98]), and full-length K18 (0·95 [0·92–0·97]). Results were similar in the validation cohort (miR-122 AUC 0·97 [95% CI 0·95–0·99], HMGB1 0·98 [0·96–0·99], and full-length K18 0·93 [0·86–0·99]). A combined model of miR-122, HMGB1, and K18 predicted acute liver injury better than ALT alone (cfNRI 1·95 [95% CI 1·87–2·03], p<0·0001 in the MAPP cohort; 1·54 [1·08–2·00], p<0·0001 in the BIOPAR cohort).InterpretationPersonalised treatment pathways could be developed by use of miR-122, HMGB1, and full-length K18 at hospital presentation for patient stratification. This prospective study supports their use for hepatic safety assessment of new medicines.FundingEdinburgh and Lothians Health Foundation, UK Medical Research Council.

Background The Gly-to-Arg substitution at the 16 position (rs1042713) in the beta 2 adrenoceptor (ADRB2) gene is associated with enhanced down-regulation and uncoupling of beta-2 receptors. Objectives To undertake a meta-analysis to test the hypothesis that there is an interaction between the A allele of rs1042713 (Arg16 amino acid) and long acting beta agonist (LABA) exposure for asthma exacerbations in children. Methods Children with diagnosed asthma were recruited in five populations (BREATHE, GALA II, PACMAN, PAGES and PASS). A history of recent exacerbation and asthma treatment were determined from questionnaire data. DNA was extracted and the Gly16Arg genotype determined. Results Data from 4226 children of white Northern European and Latino origin were analysed and the odds ratio for exacerbation increased by 1.52 [1.17, 1.99] p=0.0021 for each copy of the A allele among the 637 children treated with inhaled corticosteroids (ICS) plus LABA but not for treatment with ICS alone (n=1758), nor ICS plus leukotriene receptor antagonist (LTRA, n=354) or ICS plus LABA plus LTRA (n=569). Conclusions The use of LABA as “add-on controller”, but not LTRA, is associated with increased risk of asthma exacerbations in children carrying one or two A alleles at rs1042713. Prospective genotype stratified clinical trials are now required to explore the potential role of rs1042713 genotyping for personalised asthma therapy in children.

SummaryBackgroundA serious adverse effect of corticosteroid therapy is adrenal suppression. Our aim was to identify genetic variants affecting susceptibility to corticosteroid-induced adrenal suppression.MethodsWe enrolled children with asthma who used inhaled corticosteroids as part of their treatment from 25 sites across the UK (discovery cohort), as part of the Pharmacogenetics of Adrenal Suppression with Inhaled Steroids (PASS) study. We included two validation cohorts, one comprising children with asthma (PASS study) and the other consisting of adults with chronic obstructive pulmonary disorder (COPD) who were recruited from two UK centres for the Pharmacogenomics of Adrenal Suppression in COPD (PASIC) study. Participants underwent a low-dose short synacthen test. Adrenal suppression was defined as peak cortisol less than 350 nmol/L (in children) and less than 500 nmol/L (in adults). A case-control genome-wide association study was done with the control subset augmented by Wellcome Trust Case Control Consortium 2 (WTCCC2) participants. Single nucleotide polymorphisms (SNPs) that fulfilled criteria to be advanced to replication were tested by a random-effects inverse variance meta-analysis. This report presents the primary analysis. The PASS study is registered in the European Genome-phenome Archive (EGA). The PASS study is complete whereas the PASIC study is ongoing.FindingsBetween November, 2008, and September, 2011, 499 children were enrolled to the discovery cohort. Between October, 2011, and December, 2012, 81 children were enrolled to the paediatric validation cohort, and from February, 2010, to June, 2015, 78 adults were enrolled to the adult validation cohort. Adrenal suppression was present in 35 (7%) children in the discovery cohort and six (7%) children and 17 (22%) adults in the validation cohorts. In the discovery cohort, 40 SNPs were found to be associated with adrenal suppression (genome-wide significance p<1 × 10−6), including an intronic SNP within the PDGFD gene locus (rs591118; odds ratio [OR] 7·32, 95% CI 3·15–16·99; p=5·8 × 10−8). This finding for rs591118 was validated successfully in both the paediatric asthma (OR 3·86, 95% CI 1·19–12·50; p=0·02) and adult COPD (2·41, 1·10–5·28; p=0·03) cohorts. The proportions of patients with adrenal suppression by rs591118 genotype were six (3%) of 214 patients with the GG genotype, 15 (6%) of 244 with the AG genotype, and 22 (25%) of 87 with the AA genotype. Meta-analysis of the paediatric cohorts (discovery and validation) and all three cohorts showed genome-wide significance of rs591118 (respectively, OR 5·89, 95% CI 2·97–11·68; p=4·3 × 10−9; and 4·05, 2·00–8·21; p=3·5 × 10−10).InterpretationOur findings suggest that genetic variation in the PDGFD gene locus increases the risk of adrenal suppression in children and adults who use corticosteroids to treat asthma and COPD, respectively.FundingDepartment of Health Chair in Pharmacogenetics.

BackgroundCurrent tests for diagnosing liver disease in dogs are sub‐optimal. MicroRNA‐122 (miR‐122) is a sensitive and specific biomarker of liver injury in humans and rodents. Circulating miR‐122 could have utility in identifying dogs with liver disease.ObjectiveEstablish the reference interval for miR‐122 in healthy dogs and determine performance in a range of dog breeds with liver disease and control animals with non‐liver disease.AnimalsStored serum from 120 healthy dogs, 100 dogs with non‐liver diseases, and 30 dogs with histologically confirmed liver disease was analyzed.MethodsRetrospective study. Medical records of dogs with liver disease, non‐liver disease and healthy dogs were reviewed. Serum miR‐122 concentrations were measured by PCR and compared with the characteristics of the dogs and their conventional clinical measurements.ResultsIn healthy dogs the 2.5th, 50th, and 97.5th quartiles of miR‐122 were 110 (90% CI 80‐114), 594 (505‐682), and 3312 (2925‐5144) copies/μL, respectively. There was no difference between healthy dogs and dogs with non‐liver disease (median ± IQR: healthy dogs 609 [327‐1014] copies/μL; non‐liver disease 607 [300‐1351] copies/μL). miR‐122 was higher in dogs with liver disease (11 332 [4418‐20 520] copies/μL, P < .001 compared to healthy dogs). miR‐122 identified dogs with liver disease with high accuracy (receiver operating characteristic area under curve for comparison with healthy dogs: 0.93 [95% CI 0.86‐0.99]). The upper limit of normal for healthy dogs (3312 copies/μL) had a sensitivity of 77% and specificity of 97% for identifying liver disease.Conclusion and Clinical ImportanceLiver disease can be sensitively and specifically diagnosed in dogs by measurement of miR‐122.