Relative contributions of osteal macrophages and osteoclasts to postnatal bone development in CSF1R-deficient rats and phenotype rescue following wild-type bone marrow cell transfer

Macrophage and osteoclast proliferation, differentiation and survival are regulated by colony-stimulating factor-1 receptor (CSF1R) signaling. Osteopetrosis associated with Csf1 and Csf1r mutations has been attributed to the loss of osteoclasts and deficiency in bone resorption. Here we demonstrate that homozygous Csf1r mutation in rat leads to delayed postnatal skeletal ossification associated with substantial loss of osteal macrophages (osteomacs) in addition to osteoclasts. Osteosclerosis and site-specific skeletal abnormalities were reversed by intraperitoneal transfer of wild-type bone marrow cells (BMT) at weaning. Following BMT, IBA1+ macrophages were detected before TRAP+ osteoclasts at sites of ossification restoration. These observations extend evidence that osteomacs independently contribute to bone anabolism and are required for normal postnatal bone growth and morphogenesis.

A convergent evolutionary pathway attenuating cellulose production drives enhanced virulence of some bacteria

Bacteria adapt to selective pressure in their immediate environment in multiple ways. One mechanism involves the acquisition of independent mutations that disable or modify a key pathway, providing a signature of adaptation via convergent evolution. Extra-intestinal pathogenic Escherichia coli (ExPEC) belonging to sequence type 95 (ST95) represent a global clone frequently associated with severe human infections including acute pyelonephritis, sepsis, and neonatal meningitis. Here, we analysed a publicly available dataset of 613 ST95 genomes and identified a series of loss-of-function mutations that disrupt cellulose production or its modification in 55.3% of strains. We show the inability to produce cellulose significantly enhances ST95 invasive infection in a rat model of neonatal meningitis, leading to the disruption of intestinal barrier integrity in newborn pups and enhanced dissemination to the liver, spleen and brain. Consistent with these observations, disruption of cellulose production in ST95 augmented innate immune signalling and tissue neutrophil infiltration in a mouse model of urinary tract infection. Mutations that disrupt cellulose production were also identified in other virulent ExPEC STs, Shigella and Salmonella, suggesting a correlative association with many Enterobacteriaceae that cause severe human infection. Together, our findings provide an explanation for the emergence of hypervirulent Enterobacteriaceae clones.

Reversible expansion of tissue macrophages in response to macrophage colony-stimulating factor (CSF1) transforms systemic lipid and carbohydrate metabolism

Macrophages regulate metabolic homeostasis in health and disease. Macrophage colony-stimulating factor (CSF1)-dependent macrophages contribute to homeostatic control of the size of the liver. This study aimed to determine the systemic metabolic consequences of elevating circulating CSF1. Acute administration of a CSF1-Fc fusion protein to mice led to monocytosis, increased resident tissue macrophages in the liver and all major organs, and liver growth. These effects were associated with increased hepatic glucose uptake and extensive mobilization of body fat. The impacts of CSF1 on macrophage abundance, liver size, and body composition were rapidly reversed to restore homeostasis. The effects of CSF1 on metabolism were independent of several known endocrine regulators and did not impact the physiological fasting response. Analysis using implantable telemetry in metabolic cages revealed progressively reduced body temperature and physical activity with no change in diurnal food intake. These results demonstrate the existence of a dynamic equilibrium between CSF1, the mononuclear phagocyte system, and control of liver-to-body weight ratio, which in turn controls systemic metabolic homeostasis. This novel macrophage regulatory axis has the potential to promote fat mobilization, without changes in appetence, which may have novel implications for managing metabolic syndrome.NEW & NOTEWORTHY CSF1 administration expands tissue macrophages, which transforms systemic metabolism. CSF1 drives fat mobilization and glucose uptake to support liver growth. The effects of CSF1 are independent of normal hormonal metabolic regulation. The effects of CSF1 are rapidly reversible, restoring homeostatic body composition. CSF1-dependent macrophages and liver size are coupled in a dynamic equilibrium.

Genetic and Immunohistochemistry Tools to Visualize Rat Macrophages In Situ

Macrophages contribute to many aspects of development and homeostasis, innate and acquired immunity, immunopathology, and tissue repair. Every tissue contains an abundant resident macrophage population. Inflammatory stimuli promote the recruitment of monocytes from the blood and their adaptation promotes the removal of the stimulus and subsequent restoration of normal tissue architecture. Dysregulation of this response leads to chronic inflammation and tissue injury. In many tissues, their differentiation and survival are dependent on the colony stimulating factor 1 receptor (CSF1R) signalling axis, which is highly conserved across all vertebrates. Complete loss of either CSF1R or its cognate ligands, colony stimulating factor 1 (CSF1), and interleukin 34 (IL-34), results in the loss of many tissue-resident macrophage populations. This provides a useful paradigm to study macrophages.There are many tools used to visualize tissue-resident macrophages and their precursors, monocytes, in mice and humans. Particularly in mice there are genetic tools available to delete, enhance and manipulate monocytes and macrophages and their gene products to gain insight into phenotype and function. The laboratory rat has many advantages as an experimental model for the understanding of human disease, but the analytical resources are currently more limited than in mice. Here, we describe available genetic models, antibodies, and immunohistochemistry (IHC) methods that may be used to visualize tissue-resident macrophages in rats.

Macrophage deficiency in CSF1R-knockout rat embryos does not compromise placental or embryo development

Macrophages are an abundant cell population in the placenta and developing embryo and appear to be involved in processes of vascularization, morphogenesis, organogenesis, and hematopoiesis. The proliferation, differentiation, and survival are dependent on signals from the macrophage colony-stimulating factor receptor, CSF1R. Aside from the role in macrophages, Csf1r mRNA is highly expressed in placental trophoblasts. To explore the function of macrophages and Csf1r in placental and embryonic development, we analyzed the impact of homozygous Csf1r null mutation (Csf1rko) in the rat. In late gestation, IBA1+ macrophages were abundant in control embryos in all tissues, including the placenta, and greatly reduced in the Csf1rko. CSF1R was also detected in stellate macrophage-like cells and in neurons using anti-CSF1R antibody but was undetectable in trophoblasts. However, the neuronal signal was not abolished in the Csf1rko. CD163 was most abundant in cells forming the center of erythroblastic islands in the liver and was also CSF1R dependent. Despite the substantial reduction in macrophage numbers, we detected no effect of the Csf1rko on development of the placenta or any organs, the relative abundance of vascular elements (CD31 staining), or cell proliferation (Ki67 staining). The loss of CD163+ erythroblastic island macrophages in the liver was not associated with anemia or any reduction in the proliferative activity in the liver, but there was a premature expansion of CD206+ cells, presumptive precursors of liver sinusoidal endothelial cells. We suggest that many functions of macrophages in development of the placenta and embryo can be provided by other cell types in their absence.

Intraperitoneal transfer of wild-type bone marrow repopulates tissue macrophages in the Csf1r knockout rat without contributing to monocytopoiesis

Homozygous null mutation of the Csf1r gene (Csf1rko) in rats leads to the loss of most tissue macrophage populations and pleiotropic impacts on postnatal growth and organ maturation, leading to early mortality. The phenotype can be reversed by intraperitoneal transfer of WT BM cells (BMT) at weaning. Here, we used a Csf1r-mApple transgenic reporter to track the fate of donor-derived cells. Following BMT into Csf1rko recipients, mApple+ve cells restored IBA1+ tissue macrophage populations in every tissue. However, monocytes, neutrophils, and B cells in the BM, blood, and lymphoid tissues remained of recipient (mApple-ve ) origin. An mApple+ve cell population expanded in the peritoneal cavity and invaded locally in the mesentery, fat pads, omentum, and diaphragm. One week after BMT, distal organs contained foci of mApple+ve , IBA1-ve immature progenitors that appeared to proliferate, migrate, and differentiate locally. We conclude that rat BM contains progenitor cells that are able to restore, replace, and maintain all tissue macrophage populations in a Csf1rko rat directly without contributing to the BM progenitor or blood monocyte populations.

Lower prevalence of elevated liver stiffness measurements in people with type 2 diabetes taking sodium-glucose co-transporter 2 inhibitors or glucagon-like peptide-1 receptor agonists

INTRODUCTION AND OBJECTIVES

Among people with type 2 diabetes (T2D), non-alcoholic fatty liver disease (NAFLD) is very common and has an increased risk of clinically significant liver disease. The use of sodium-glucose co-transporter 2 (SGLT2i) inhibitors and glucagon-like peptide-1 (GLP-1a) receptor agonists is endorsed to reduce major cardiovascular events and/or progression of chronic kidney disease. Their prevalence of use in people with T2D and co-existent NAFLD remains unclear. We sought to determine the prevalence of use of these medications at two different time periods, and their association with prevalence of clinically significant liver disease.

MATERIALS AND METHODS

Consecutive people with type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD) were recruited from diabetes clinics between Jun-2021 and Jun-2022 ('current' cohort). Liver stiffness measurements (LSM) using FibroScan were performed. Medication data were collected prospectively at recruitment and verified with the dispensing pharmacy or general practitioner medical records. Data for a historical cohort with NAFLD and T2D recruited from the same clinics during 2015-2017 ('historical' cohort) were available. Logistic regression was used to evaluate factors associated with LSM <8.0 or ≥8 kPa (clinically significant fibrosis).

RESULTS

There were 292 participants, 177 in the historical cohort and 115 in the current cohort. In the current cohort, 57.4% of patients with T2D and NAFLD were taking a GLP-1a and 42.6% were taking a SGLT2i; a 2.6 to 3.4-fold higher prevalence than in 2015-2017. A lower proportion of the current cohort (23.9% compared to 38.4%) had clinically significant fibrosis (LSM ≥8 kPa; p=0.012). When the cohorts were pooled and differences adjusted for in multivariable logistic regression analysis, patients taking a GLP-1a or a SGLT2i were 2 times more likely to have a lower LSM (<8 kPa) compared to patients not taking these drugs (OR=2.05, 95%CI 1.07-3.94, p=0.03 and OR 2.07 95%CI 1.04-4.11, p=0.04, respectively).

CONCLUSIONS

The observation of a lower LSM in people taking SGLT2i and/or GLP-1a following adjustment for other relevant clinico-demographic variables provides support for clinical trials to assess their efficacy in reducing the progression of NAFLD.

β-cell function is regulated by metabolic and epigenetic programming of islet-associated macrophages, involving Axl, Mertk, and TGFβ receptor signaling

We have exploited islet-associated macrophages (IAMs) as a model of resident macrophage function, focusing on more physiological conditions than the commonly used extremes of M1 (inflammation) versus M2 (tissue remodeling) polarization. Under steady state, murine IAMs are metabolically poised between aerobic glycolysis and oxidative phosphorylation, and thereby exert a brake on glucose-stimulated insulin secretion (GSIS). This is underpinned by epigenetic remodeling via the metabolically regulated histone demethylase Kdm5a. Conversely, GSIS is enhanced by engaging Axl receptors on IAMs, or by augmenting their oxidation of glucose. Following high-fat feeding, efferocytosis is stimulated in IAMs in conjunction with Mertk and TGFβ receptor signaling. This impairs GSIS and potentially contributes to β-cell failure in pre-diabetes. Thus, IAMs serve as relays in many more settings than currently appreciated, fine-tuning insulin secretion in response to dynamic changes in the external environment. Intervening in this nexus might represent a means of preserving β-cell function during metabolic disease.

CSF1R as a Therapeutic Target in Bone Diseases: Obvious but Not so Simple

PURPOSE OF REVIEW

The purpose of the review is to summarize the expression and function of CSF1R and its ligands in bone homeostasis and constraints on therapeutic targeting of this axis.

RECENT FINDINGS

Bone development and homeostasis depends upon interactions between mesenchymal cells and cells of the mononuclear phagocyte lineage (MPS), macrophages, and osteoclasts (OCL). The homeostatic interaction is mediated in part by the systemic and local production of growth factors, macrophage colony-stimulating factor (CSF1), and interleukin 34 (IL34) that interact with a receptor (CSF1R) expressed exclusively by MPS cells and their progenitors. Loss-of-function mutations in CSF1 or CSF1R lead to loss of OCL and macrophages and dysregulation of postnatal bone development. MPS cells continuously degrade CSF1R ligands via receptor-mediated endocytosis. As a consequence, any local or systemic increase or decrease in macrophage or OCL abundance is rapidly reversible. In principle, both CSF1R agonists and antagonists have potential in bone regenerative medicine but their evaluation in disease models and therapeutic application needs to carefully consider the intrinsic feedback control of MPS biology.

Serum CCL2 is associated with visceral adiposity but not fibrosis in patients with Non-alcoholic Fatty Liver Disease (NAFLD)

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is caused by ectopic fat accumulation in the liver as a consequence of metabolic perturbations associated with obesity, type 2 diabetes, dyslipidemia and insulin resistance. People with NAFLD may develop metabolic and cardiovascular complications, and/or liver-related complications, especially fibrosis and hepatocellular carcinoma, associated with high morbidity and mortality. Due to the high and increasing prevalence of NAFLD there is an urgent need to identify people at risk of developing liver fibrosis and complications. CC-chemokine ligand 2 (CCL2) is chemokine that attracts inflammatory monocytes to stressed or injured tissues. Infiltrating inflammatory monocytes, and CCL2, are strongly implicated in the pathogenesis of liver disease in animal models, however evidence in patient cohorts is conflicting.

METHODS

We investigated associations between circulating CCL2 and clinical parameters, including fibrosis assessed by liver stiffness measurement, in a cohort of 250 NAFLD patients. We also measured Fatty Acid Binding Protein 2 (FABP2), a putative biomarker of intestinal permeability in patients with liver disease, since pro-inflammatory gut-derived microbial products may induce inflammatory chemokines such as CCL2.

RESULTS

Serum CCL2 levels were weakly associated with liver stiffness, but the association was no longer significant after accounting for age, diabetes and BMI in a multivariable model. Consistent with this, girth and BMI were the strongest predictors of elevated circulating CCL2. Serum FABP2 was weakly, but significantly, correlated with CCL2, and negatively correlated with estimated Glomerular Filtration Rate (eGFR).

CONCLUSION

Circulating CCL2 and FABP2 are associated with NAFLD co-morbidities, but not liver disease progression in patients with NAFLD.

Epidemiology of ascites fluid infections in patients with cirrhosis in Queensland, Australia from 2008 to 2017: A population-based study

Spontaneous bacterial peritonitis (SBP), a common infection in patients with cirrhosis and ascites, is associated with high morbidity and mortality. The aim of this study was to investigate changes in the epidemiology of ascites fluid infections over time in an Australian population, including patient demographics, trends in mortality, length of hospital stay and the nature and antibiotic resistance profile of causative organisms.An observational descriptive population-based epidemiological study of patients with cirrhosis admitted to public hospitals in Queensland during 2008-2017 was performed, linking demographic/clinical and microbiology data.Among 103,165 hospital admissions of patients with cirrhosis, ascites was present in 16,550 and in 60% (9977) a sample of ascitic fluid was tested. SBP was diagnosed in 770 admissions (neutrophil count >250/ml) and bacterascites in 552 (neutrophil count <250/ml with positive culture). The number of admissions with an ascites fluid infection increased by 76% from 2008 to 2017, paralleling an 84% increase in cirrhosis admissions over the same timeframe. Patients with SBP had a longer hospital stay (median 15.7 vs 8.3 days for patients without SBP, P < .001) and higher in-hospital mortality, although this decreased from 39.5% in 2008 to 2010 to 24.8% in 2015 to 2017 (P < .001). Common Gram-positive isolates included coagulase negative staphylococci (37.9%), viridans group streptococci (12.1%), and Staphylococcus aureus (7.2%). Common Gram-negative isolates included Escherichia coli (13.0%), Klebsiella pneumoniae (3.1%) and Enterobacter cloacae (2.6%). The prevalence of resistance to any tested antibiotic was <10%.SBP remains associated with high in-hospital mortality and long hospital stay. Typical skin and bowel pathogens were common, therefore, empirical antibiotic therapy should target these pathogens. This study provides valuable evidence informing infection management strategies in this vulnerable patient population.

A kinase-dead Csf1r mutation associated with adult-onset leukoencephalopathy has a dominant inhibitory impact on CSF1R signalling

Amino acid substitutions in the kinase domain of the human CSF1R gene are associated with autosomal dominant adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP). To model the human disease, we created a disease-associated mutation (pGlu631Lys; E631K) in the mouse Csf1r locus. Homozygous mutation (Csf1rE631K/E631K) phenocopied the Csf1r knockout, with prenatal mortality or severe postnatal growth retardation and hydrocephalus. Heterozygous mutation delayed the postnatal expansion of tissue macrophage populations in most organs. Bone marrow cells from Csf1rE631K/+mice were resistant to CSF1 stimulation in vitro, and Csf1rE631K/+ mice were unresponsive to administration of a CSF1-Fc fusion protein, which expanded tissue macrophage populations in controls. In the brain, microglial cell numbers and dendritic arborisation were reduced in Csf1rE631K/+ mice, as in patients with ALSP. The microglial phenotype is the opposite of microgliosis observed in Csf1r+/- mice. However, we found no evidence of brain pathology or impacts on motor function in aged Csf1rE631K/+ mice. We conclude that heterozygous disease-associated CSF1R mutations compromise CSF1R signalling. We speculate that leukoencephalopathy associated with dominant human CSF1R mutations requires an environmental trigger and/or epistatic interaction with common neurodegenerative disease-associated alleles.

Implementing the right care in the right place at the right time for non-alcoholic fatty liver disease (NAFLD-RRR study): a study protocol for a community care pathway for people with type 2 diabetes

Background

Non-alcoholic fatty liver disease (NAFLD) is an emerging epidemic that affects approximately half of all people with type 2 diabetes. Those with type 2 diabetes are a high-risk NAFLD subgroup because of their increased risk of clinically significant liver-related outcomes from NAFLD which include hepatocellular carcinoma, cirrhosis-related complications and liver disease mortality. They may benefit from early detection of disease as this would allow at risk patients to access hepatocellular carcinoma surveillance, emerging drug trials for NAFLD and specialist hepatology care prior to emergence of liver-related complications.

Methods

This is a prospective cohort study aimed at incorporating and assessing a community care pathway for liver fibrosis screening into routine care for type 2 diabetes. Patients undergo a point of care assessment of hepatic steatosis and stiffness using FibroScan at the time of the routine diabetes appointment or when attending the clinic for blood tests in preparation for this appointment.

Discussion

We propose that implementation of a community-based NAFLD diagnosis, risk-stratification, and referral pathway for people with type 2 diabetes is feasible, will provide earlier, targeted detection of advanced fibrosis, and reduce unnecessary referrals to hepatology outpatients for fibrosis risk assessment. Our study will provide important information about the feasibility of establishing a NAFLD pathway for people with type 2 diabetes in primary care. Ultimately, our findings will help direct spending and resource allocation for NAFLD in a high-risk population. Regular evaluation by stakeholders during implementation will help to create a reliable and sustainable community care pathway and establish a perpetual cycle of learning in primary care.

Trial registration

ANZCTR, ACTRN12621000330842. Registered 23 March 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-07808-7.

Depressive symptoms in non-alcoholic fatty liver disease are identified by perturbed lipid and lipoprotein metabolism

Non-alcoholic fatty liver disease (NAFLD) and depression are common disorders and have bidirectional contributing relationships to metabolic syndrome. We aimed to determine whether a fasting serum signature of recent, self-reported depressive symptoms could be identified in a heterogeneous NAFLD cohort using nuclear magnetic resonance (NMR)-based metabolomics integrated with clinical chemistry. Serum nuclear magnetic resonance (NMR) metabolite profiles and corresponding clinical chemistry were compared between patients with depressive symptoms in the last 12-months (n = 81) and patients without recent depressive symptoms (n = 137 controls) using multivariate statistics. Orthogonal partial least squares discriminant analysis (OPLS-DA) of the biochemical and metabolomic data identified NAFLD patients with recent depression with a cross-validated accuracy of 61.5%, independent of age, sex, medication, and other comorbidities. This led to the development of a diagnostic algorithm with AUC 0.83 for future testing in larger clinical cohorts. Serum triglycerides, VLDL cholesterol, and the inflammatory biomarker GlycA were key metabolites increased in patients with recent depressive symptoms, while serum glutamine level was reduced. Here, serum NMR metabolite analysis provides a link between disturbed lipid metabolism, inflammation, and active mental health issues in NAFLD, irrespective of disease severity.

Therapeutic potential of macrophage colony-stimulating factor (CSF1) in chronic liver disease

Resident and recruited macrophages control the development and proliferation of the liver. We showed previously in multiple species that treatment with a macrophage colony stimulating factor (CSF1)-Fc fusion protein initiated hepatocyte proliferation and promoted repair in models of acute hepatic injury in mice. Here we investigated the impact of CSF1-Fc on resolution of advanced fibrosis and liver regeneration, utilizing a non-resolving toxin-induced model of chronic liver injury and fibrosis in C57BL/6J mice. Co-administration of CSF1-Fc with exposure to thioacetamide (TAA) exacerbated inflammation consistent with monocyte contributions to initiation of pathology. After removal of TAA, either acute or chronic CSF1-Fc treatment promoted liver growth, prevented progression and promoted resolution of fibrosis. Acute CSF1-Fc treatment was also anti-fibrotic and pro-regenerative in a model of partial hepatectomy in mice with established fibrosis. The beneficial impacts of CSF1-Fc treatment were associated with monocyte-macrophage recruitment and increased expression of remodeling enzymes and growth factors. These studies indicate that CSF1-dependent macrophages contribute to both initiation and resolution of fibrotic injury and that CSF1-Fc has therapeutic potential in human liver disease.

Inhibition of the master regulator of Listeria monocytogenes virulence enables bacterial clearance from spacious replication vacuoles in infected macrophages

A hallmark of Listeria (L.) monocytogenes pathogenesis is bacterial escape from maturing entry vacuoles, which is required for rapid bacterial replication in the host cell cytoplasm and cell-to-cell spread. The bacterial transcriptional activator PrfA controls expression of key virulence factors that enable exploitation of this intracellular niche. The transcriptional activity of PrfA within infected host cells is controlled by allosteric coactivation. Inhibitory occupation of the coactivator site has been shown to impair PrfA functions, but consequences of PrfA inhibition for L. monocytogenes infection and pathogenesis are unknown. Here we report the crystal structure of PrfA with a small molecule inhibitor occupying the coactivator site at 2.0 Å resolution. Using molecular imaging and infection studies in macrophages, we demonstrate that PrfA inhibition prevents the vacuolar escape of L. monocytogenes and enables extensive bacterial replication inside spacious vacuoles. In contrast to previously described spacious Listeria-containing vacuoles, which have been implicated in supporting chronic infection, PrfA inhibition facilitated progressive clearance of intracellular L. monocytogenes from spacious vacuoles through lysosomal degradation. Thus, inhibitory occupation of the PrfA coactivator site facilitates formation of a transient intravacuolar L. monocytogenes replication niche that licenses macrophages to effectively eliminate intracellular bacteria. Our findings encourage further exploration of PrfA as a potential target for antimicrobials and highlight that intra-vacuolar residence of L. monocytogenes in macrophages is not inevitably tied to bacterial persistence.

ROCK2 inhibition attenuates profibrogenic immune cell function to reverse thioacetamide-induced liver fibrosis

Background & Aims

Fibrosis, the primary cause of morbidity in chronic liver disease, is induced by pro-inflammatory cytokines, immune cell infiltrates, and tissue resident cells that drive excessive myofibroblast activation, collagen production, and tissue scarring. Rho-associated kinase 2 (ROCK2) regulates key pro-fibrotic pathways involved in both inflammatory reactions and altered extracellular matrix remodelling, implicating this pathway as a potential therapeutic target.

Methods

We used the thioacetamide-induced liver fibrosis model to examine the efficacy of administration of the selective ROCK2 inhibitor KD025 to prevent or treat liver fibrosis and its impact on immune composition and function.

Results

Prophylactic and therapeutic administration of KD025 effectively attenuated thioacetamide-induced liver fibrosis and promoted fibrotic regression. KD025 treatment inhibited liver macrophage tumour necrosis factor production and disrupted the macrophage niche within fibrotic septae. ROCK2 targeting in vitro directly regulated macrophage function through disruption of signal transducer and activator of transcription 3 (STAT3)/cofilin signalling pathways leading to the inhibition of pro-inflammatory cytokine production and macrophage migration. In vivo, KDO25 administration significantly reduced STAT3 phosphorylation and cofilin levels in the liver. Additionally, livers exhibited robust downregulation of immune cell infiltrates and diminished levels of retinoic acid receptor-related orphan receptor gamma (RORγt) and B-cell lymphoma 6 (Bcl6) transcription factors that correlated with a significant reduction in liver IL-17, splenic germinal centre numbers and serum IgG.

Conclusions

As IL-17 and IgG–Fc binding promote pathogenic macrophage differentiation, together our data demonstrate that ROCK2 inhibition prevents and reverses liver fibrosis through direct and indirect effects on macrophage function and highlight the therapeutic potential of ROCK2 inhibition in liver fibrosis.

Lay summary

By using a clinic-ready small-molecule inhibitor, we demonstrate that selective ROCK2 inhibition prevents and reverses hepatic fibrosis through its pleiotropic effects on pro-inflammatory immune cell function. We show that ROCK2 mediates increased IL-17 production, antibody production, and macrophage dysregulation, which together drive fibrogenesis in a model of chemical-induced liver fibrosis. Therefore, in this study, we not only highlight the therapeutic potential of ROCK2 targeting in chronic liver disease but also provide previously undocumented insights into our understanding of cellular and molecular pathways driving the liver fibrosis pathology.

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ROCK2 inhibition with the small-molecule inhibitor KD025 prevents and reverses hepatoxin-induced liver fibrosis.

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ROCK2 inhibition attenuates profibrogenic immune function.

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KD025 exerts direct effects on liver macrophages resulting in decreased TNF secretion and impeded migration.

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KD025 administration attenuates T cell IL-17 production and B-cell IgG production, which indirectly contributes to downregulation of profibrogenic macrophage function.

Bacteraemia, sepsis and antibiotic resistance in Australian patients with cirrhosis: a population-based study

Objective

Multiple factors predispose patients with cirrhosis to sepsis and/or bacteraemia and this has a high mortality rate. Within different geographical regions there are marked differences in the prevalence of infection with multidrug-resistant organisms (MDR). This study examined risk factors for and outcomes of sepsis/bacteraemia in public hospital admissions with cirrhosis in the state of Queensland, Australia, over the last decade, along with the bacterial pathogens responsible and their antibiotic susceptibility profiles.

Design

A population-based retrospective cohort study of public hospital admissions was conducted from 1 January 2008 to 31 December 2017. Hospital admissions for patients with a diagnosis of cirrhosis were categorised by the presence or absence of sepsis/bacteraemia. Clinical and sociodemographic information including cirrhosis aetiology, complications and comorbidities, and in-hospital mortality were examined using bivariate and multivariate analyses. In patients with bacteraemia, the type and prevalence of bacteria and antibiotic resistance was assessed.

Results

Sepsis/bacteraemia was present in 3951 of 103 165 hospital admissions with a diagnosis of cirrhosis. Factors associated with sepsis/bacteraemia included disease aetiology, particularly primary sclerosing cholangitis (adj-OR 15.09, 95% CI 12.24 to 18.60), alcohol (adj-OR 2.90, 95% CI 2.71 to 3.09), Charlson Comorbidity Index ≥3 (adj-OR 3.54, 95% CI 3.19 to 3.93) and diabetes (adj-OR 1.87, 95% CI 1.74 to 2.01). Overall case-fatality rate among admissions with sepsis/bacteraemia was 27.7% (95% CI 26.3% to 29.1%) vs 3.7% (95% CI 3.6% to 3.8%) without sepsis/bacteraemia. In-hospital death was significantly associated with sepsis/bacteraemia (adj-OR 6.50, 95% CI 5.95 to 7.11). The most common organisms identified were Escherichia coli and Staphylococcus aureus, present in 22.9% and 18.1%, respectively, of the 2265 admissions with a positive blood culture. The prevalence of MDR bacteria was low (5.6%)

Conclusion

Morbidity and mortality related to sepsis/bacteraemia in patients with cirrhosis remains a critical clinical problem.

Fragmentation of tissue-resident macrophages during isolation confounds analysis of single-cell preparations from mouse hematopoietic tissues

Mouse hematopoietic tissues contain abundant tissue-resident macrophages that support immunity, hematopoiesis, and bone homeostasis. A systematic strategy to characterize macrophage subsets in mouse bone marrow (BM), spleen, and lymph node unexpectedly reveals that macrophage surface marker staining emanates from membrane-bound subcellular remnants associated with unrelated cells. Intact macrophages are not present within these cell preparations. The macrophage remnant binding profile reflects interactions between macrophages and other cell types in vivo. Depletion of CD169⁺ macrophages in vivo eliminates F4/80⁺ remnant attachment. Remnant-restricted macrophage-specific membrane markers, cytoplasmic fluorescent reporters, and mRNA are all detected in non-macrophage cells including isolated stem and progenitor cells. Analysis of RNA sequencing (RNA-seq) data, including publicly available datasets, indicates that macrophage fragmentation is a general phenomenon that confounds bulk and single-cell analysis of disaggregated hematopoietic tissues. Hematopoietic tissue macrophage fragmentation undermines the accuracy of macrophage ex vivo molecular profiling and creates opportunity for misattribution of macrophage-expressed genes to non-macrophage cells.

Predicting Liver-Related Outcomes in People With Nonalcoholic Fatty Liver Disease: The Prognostic Value of Noninvasive Fibrosis Tests

It remains unclear whether screening for advanced fibrosis in the community can identify the subgroup of people with nonalcoholic fatty liver disease (NAFLD) at higher risk for development of liver‐related complications. We aimed to determine the prognostic value of baseline noninvasive fibrosis tests for predicting liver‐related outcomes and mortality in patients with NAFLD from type 2 diabetes (T2D) clinics or primary care. Patients (n = 243) who were screened for NAFLD with advanced fibrosis by using NAFLD fibrosis score (NFS), fibrosis 4 score (FIB‐4), enhanced liver fibrosis (ELF) test, and liver stiffness measurements (LSMs) were followed up for clinical outcomes by review of electronic medical records. During a median follow‐up of 50 months, decompensated liver disease or primary liver cancer occurred in 6 of 35 (17.1%) patients with baseline LSM > 13 kPa, 1 of 17 (5.9%) patients with LSM 9.5‐13 kPa, and in no patients with LSM < 9.5 kPa. No patient with low‐risk NFS developed liver decompensation or liver‐related mortality. Following repeat NFSs at the end of follow‐up, all patients with a liver‐related complication were in the high‐risk NFS category. Patients who developed liver‐related complications were also more likely to have baseline high‐risk FIB‐4 scores or ELF test ≥9.8 compared to patients who did not develop liver outcomes. Conclusion: Liver fibrosis risk stratification in non‐hepatology settings can identify the subset of patients at risk of liver‐related complications. Although the rate of development of a decompensation event or hepatocellular carcinoma was low (2.1% per year) in our patients with compensated cirrhosis (LSM > 13 kPa), these events are projected to lead to a substantial increase in NAFLD‐related disease burden over the next decade due to the high prevalence of NAFLD in people with obesity and T2D.

Functions of macrophage colony-stimulating factor (CSF1) in development, homeostasis, and tissue repair

Macrophage colony-stimulating factor (CSF1) is the primary growth factor required for the control of monocyte and macrophage differentiation, survival, proliferation and renewal. Although the cDNAs encoding multiple isoforms of human CSF1 were cloned in the 1980s, and recombinant proteins were available for testing in humans, CSF1 has not yet found substantial clinical application. Here we present an overview of CSF1 biology, including evolution, regulation and functions of cell surface and secreted isoforms. CSF1 is widely-expressed, primarily by cells of mesenchymal lineages, in all mouse tissues. Cell-specific deletion of a floxed Csf1 allele in mice indicates that local CSF1 production contributes to the maintenance of tissue-specific macrophage populations but is not saturating. CSF1 in the circulation is controlled primarily by receptor-mediated clearance by macrophages in liver and spleen. Administration of recombinant CSF1 to humans or animals leads to monocytosis and expansion of tissue macrophage populations and growth of the liver and spleen. In a wide variety of tissue injury models, CSF1 administration promotes monocyte infiltration, clearance of damaged cells and repair. We suggest that CSF1 has therapeutic potential in regenerative medicine.

Osteal macrophages support osteoclast-mediated resorption and contribute to bone pathology in a postmenopausal osteoporosis mouse model

Osteal macrophages (osteomacs) support osteoblast function and promote bone anabolism, but their contribution to osteoporosis has not been explored. Although mouse ovariectomy (OVX) models have been repeatedly used, variation in strain, experimental design and assessment modalities have contributed to no single model being confirmed as comprehensively replicating the full gamut of osteoporosis pathological manifestations. We validated an OVX model in adult C3H/HeJ mice and demonstrated that it presents with human postmenopausal osteoporosis features with reduced bone volume in axial and appendicular bone and bone loss in both trabecular and cortical bone including increased cortical porosity. Bone loss was associated with increased osteoclasts on trabecular and endocortical bone and decreased osteoblasts on trabecular bone. Importantly, this OVX model was characterized by delayed fracture healing. Using this validated model, we demonstrated that osteomacs are increased post-OVX on both trabecular and endocortical bone. Dual F4/80 (pan-macrophage marker) and tartrate-resistant acid phosphatase (TRAP) staining revealed osteomacs frequently located near TRAP⁺ osteoclasts and contained TRAP⁺ intracellular vesicles. Using an in vivo inducible macrophage depletion model that does not simultaneously deplete osteoclasts, we observed that osteomac loss was associated with elevated extracellular TRAP in bone marrow interstitium and increased serum TRAP. Using in vitro high-resolution confocal imaging of mixed osteoclast-macrophage cultures on bone substrate, we observed macrophages juxtaposed to osteoclast basolateral functional secretory domains scavenging degraded bone byproducts. These data demonstrate a role for osteomacs in supporting osteoclastic bone resorption through phagocytosis and sequestration of resorption byproducts. Overall, our data expose a novel role for osteomacs in supporting osteoclast function and provide the first evidence of their involvement in osteoporosis pathogenesis. © 2021 American Society for Bone and Mineral Research (ASBMR).

Towards collaborative management of nonalcoholic fatty liver disease (TCM-NAFLD): a 'real-world' pathway for fibrosis risk assessment in primary care

BACKGROUND

The optimal strategy to support primary care practitioners (PCPs) to assess fibrosis severity in nonalcoholic fatty liver disease (NAFLD) and thereby make appropriate management decisions remains unclear.

AIMS

We aimed to examine the feasibility of using a 2-step pathway that combined simple scores (NAFLD Fibrosis Score and Fibrosis-4 Index) with transient elastography (FibroScan®) to streamline NAFLD referrals from a 'routine' primary care population to specialist hepatology management clinics (HMC).

METHODS

The 2-step "Towards Collaborative Management of NAFLD" (TCM-NAFLD) fibrosis risk assessment pathway was implemented at two outer metropolitan primary healthcare practices in Brisbane. Patients aged ≥18 years with a new or established PCP-diagnosis of NAFLD were eligible for assessment. The pathway triaged patients at "high risk" of clinically significant fibrosis to HMC for specialist review, and "low risk" patients to receive ongoing management and longitudinal follow-up in primary care.

RESULTS

A total of 162 patient assessments between Jun-2019 and Dec-2020 were included. Mean age was 58.7 ± 11.7 years, 30.9% were male, 54.3% had type 2 diabetes or impaired fasting glucose, and mean body mass index was 34.2 ± 6.9 kg/m² . 122 patients were considered "low risk" for clinically significant fibrosis, two patients had incomplete assessments, and 38 (23.5%) were triaged to HMC. Among 31 completed HMC assessments to date, 45.2% were considered to have clinically significant (or more advanced) fibrosis, representing 9.2% of 153 completed assessments.

CONCLUSION

Implementation of the 2-step TCM-NAFLD pathway streamlined hepatology referrals for NAFLD and may facilitate a more cost-effective and targeted use of specialist hepatology resources. This article is protected by copyright. All rights reserved.

CSF1R-dependent macrophages control postnatal somatic growth and organ maturation

Homozygous mutation of the Csf1r locus (Csf1rko) in mice, rats and humans leads to multiple postnatal developmental abnormalities. To enable analysis of the mechanisms underlying the phenotypic impacts of Csf1r mutation, we bred a rat Csf1rko allele to the inbred dark agouti (DA) genetic background and to a Csf1r-mApple reporter transgene. The Csf1rko led to almost complete loss of embryonic macrophages and ablation of most adult tissue macrophage populations. We extended previous analysis of the Csf1rko phenotype to early postnatal development to reveal impacts on musculoskeletal development and proliferation and morphogenesis in multiple organs. Expression profiling of 3-week old wild-type (WT) and Csf1rko livers identified 2760 differentially expressed genes associated with the loss of macrophages, severe hypoplasia, delayed hepatocyte maturation, disrupted lipid metabolism and the IGF1/IGF binding protein system. Older Csf1rko rats developed severe hepatic steatosis. Consistent with the developmental delay in the liver Csf1rko rats had greatly-reduced circulating IGF1. Transfer of WT bone marrow (BM) cells at weaning without conditioning repopulated resident macrophages in all organs, including microglia in the brain, and reversed the mutant phenotypes enabling long term survival and fertility. WT BM transfer restored osteoclasts, eliminated osteopetrosis, restored bone marrow cellularity and architecture and reversed granulocytosis and B cell deficiency. Csf1rko rats had an elevated circulating CSF1 concentration which was rapidly reduced to WT levels following BM transfer. However, CD43hi non-classical monocytes, absent in the Csf1rko, were not rescued and bone marrow progenitors remained unresponsive to CSF1. The results demonstrate that the Csf1rko phenotype is autonomous to BM-derived cells and indicate that BM contains a progenitor of tissue macrophages distinct from hematopoietic stem cells. The model provides a unique system in which to define the pathways of development of resident tissue macrophages and their local and systemic roles in growth and organ maturation.

A binge high sucrose diet provokes systemic and cerebral inflammation in rats without inducing obesity

While the dire cardiometabolic consequences of the hypercaloric modern 'Western' diet are well known, there is not much information on the health impact of a high sucrose diet not inducing weight gain. Here, we tested the hypothesis that rats reared with intermittent binge access to sucrose in addition to normal chow would develop an inflammatory response in brain. To test this hypothesis, we undertook serial PET/MRI scans with the TSPO ligand [18F]DPA714 in a group of (n=9) rats at baseline and again after voluntarily consuming 5% sucrose solution three days a week for three months. Compared to a control group fed with normal chow (n=9), the sucrose rats indeed showed widespread increases in the availability of cerebral binding sites for the microglial marker, despite normal weight gain compared to the control diet group. Subsequent immunofluorescence staining of the brains confirmed the PET findings, showing a widespread 20% increase in the abundance of IBA-1-positive microglia with characteristic 'semi-activated' morphology in the binge sucrose rats, which had 23% lower density of microglial endpoints and 25% lower mean process length compared to microglia in the control rats with ordinary feeding. GFAP immunofluorescence showed no difference in astroglial coverage in the sucrose rats, except for a slight reduction in hypothalamus. The binge sucrose diet-induced neuroinflammation was associated with a significant elevation of white blood cell counts. Taking these results together, we find that long-term intake of sucrose in a binge paradigm, similar in sucrose content to the contemporary Western diet, triggered a low-grade systemic and central inflammation in non-obese rats. The molecular mechanism of this phenomenon remains to be established.

The Mononuclear Phagocyte System of the Rat

The laboratory rat continues to be the model of choice for many studies of physiology, behavior, and complex human diseases. Cells of the mononuclear phagocyte system (MPS; monocytes, macrophages, and dendritic cells) are abundant residents in every tissue in the body and regulate postnatal development, homeostasis, and innate and acquired immunity. Recruitment and proliferation of MPS cells is an essential component of both initiation and resolution of inflammation. The large majority of current knowledge of MPS biology is derived from studies of inbred mice, but advances in technology and resources have eliminated many of the advantages of the mouse as a model. In this article, we review the tools available and the current state of knowledge of development, homeostasis, regulation, and diversity within the MPS of the rat.

Serum matrix metalloproteinase 7 (MMP7) is a biomarker of fibrosis in patients with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) affects 25% of the adult population globally. Since liver fibrosis is the most important predictor of liver-related complications in patients with NAFLD, identification of patients with advanced fibrosis among at-risk individuals is an important issue in clinical practice. Transient elastography is the best evaluated non-invasive method used in referral centres to assess liver fibrosis, however serum-based tests, such as the Enhanced Liver Fibrosis (ELF) score, have a practical advantage as first-line tests due to their wider availability and lower cost. We previously identified matrix metalloproteinase 7 (MMP7) as a serum biomarker of histological advanced fibrosis in a mixed-etiology patient cohort. In this study we aimed to determine the association between MMP7 and fibrosis, assessed by transient elastography, in patients with NAFLD. Serum MMP7 levels were measured in a cohort of 228 patients with NAFLD. Associations between MMP7, liver stiffness measurement (LSM), ELF score and clinical parameters were determined using logistic regression modelling. Serum MMP7 was associated with clinically significant fibrosis (LSM ≥ 8.2), independent of age, gender, BMI and diabetes. The addition of MMP7 significantly improved the diagnostic performance of the ELF test, particularly in patients over the age of 60. Combinations of serum biomarkers have the potential to improve the sensitivity and specificity of detection of advanced fibrosis in at-risk patients with NAFLD. We have demonstrated that serum MMP7 is independently associated with clinically significant fibrosis and improves the diagnostic performance of currently available tests in older patients.

Transcriptomic Analysis of Rat Macrophages

The laboratory rat is widely used as a model for human diseases. Many of these diseases involve monocytes and tissue macrophages in different states of activation. Whilst methods for in vitro differentiation of mouse macrophages from embryonic stem cells (ESC) and bone marrow (BM) are well established, these are lacking for the rat. The gene expression profiles of rat macrophages have also not been characterised to the same extent as mouse. We have established the methodology for production of rat ESC-derived macrophages and compared their gene expression profiles to macrophages obtained from the lung and peritoneal cavity and those differentiated from BM and blood monocytes. We determined the gene signature of Kupffer cells in the liver using rats deficient in macrophage colony stimulating factor receptor (CSF1R). We also examined the response of BM-derived macrophages to lipopolysaccharide (LPS). The results indicate that many, but not all, tissue-specific adaptations observed in mice are conserved in the rat. Importantly, we show that unlike mice, rat macrophages express the CSF1R ligand, colony stimulating factor 1 (CSF1).

Analysis of homozygous and heterozygous Csf1r knockout in the rat as a model for understanding microglial function in brain development and the impacts of human CSF1R mutations

Mutations in the human CSF1R gene have been associated with dominant and recessive forms of neurodegenerative disease. Here we describe the impacts of Csf1r mutation in the rat on development of the brain. Diffusion imaging indicated small reductions in major fiber tracts that may be associated in part with ventricular enlargement. RNA-seq profiling revealed a set of 105 microglial markers depleted in all brain regions of the Csf1rko rats. There was no evidence of region or sex-specific expression of microglia-associated transcripts. Other than the microglial signature, Csf1rko had no effect on any neuronal or region-specific transcript cluster. Expression of markers of oligodendrocytes, astrocytes, dopaminergic neurons and Purkinje cells was minimally affected. However, there were defects in dendritic arborization of doublecortin-positive neurogenic precursors and expression of poly-sialylated neural cell adhesion molecule (PS-NCAM) in the dentate gyrus of the hippocampus. Heterozygous Csf1rko rats had no detectable brain phenotype. We conclude that most brain developmental processes occur normally in the absence of microglia and that CSF1R haploinsufficiency is unlikely to cause leukoencephalopathy.

Effectiveness of patient-oriented education and medication management intervention in people with decompensated cirrhosis

People with chronic disease often have poor comprehension of their disease and medications, which can negatively affect health outcomes. In a randomised-controlled trial, we found that patients with decompensated cirrhosis who received a pharmacist-led, patient-oriented education and medication management intervention (n = 57) had greater knowledge of cirrhosis and key self-care tasks compared with usual care (n = 59). Intervention patients also experienced improved quality of life. Dedicated resources are needed to support implementation of evidence-based measures at local centres to improve outcomes.

Type 2 Diabetes: A Risk Factor for Hospital Readmissions and Mortality in Australian Patients With Cirrhosis

Although there is evidence that type 2 diabetes mellitus (T2D) impacts adversely on liver‐related mortality, its influence on hospital readmissions and development of complications in patients with cirrhosis, particularly in alcohol‐related cirrhosis (the most common etiological factor among Australian hospital admissions for cirrhosis) has not been well studied. This study aimed to investigate the association between T2D and liver cirrhosis in a population‐based cohort of patients admitted for cirrhosis in the state of Queensland, Australia. A retrospective cohort analysis was conducted using data from the Queensland Hospital Admitted Patient Data Collection, which contains information on all hospital episodes of care for patients with liver cirrhosis, and the Death Registry during 2008‐2017. We used demographic, clinical data, and socioeconomic characteristics. A total of 8,631 patients were analyzed. A higher proportion of patients with T2D had cryptogenic cirrhosis (42.4% vs. 27.3%, respectively; P < 0.001) or nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (13.8% vs. 3.4%, respectively; P < 0.001) and an admission for hepatocellular carcinoma (18.0% vs. 12.2%, respectively; P < 0.001) compared to patients without T2D. Patients with liver cirrhosis with T2D compared to those without T2D had a significantly increased median length of hospital stay (6 [range, 1‐11] vs. 5 [range, 1‐11] days, respectively; P < 0.001), double the rate of noncirrhosis‐related admissions (incidence rate ratios [IRR], 2.03; 95% confidence interval [CI], 1.98‐2.07), a 1.35‐fold increased rate of cirrhosis‐related admissions (IRR, 1.35; 95% CI, 1.30‐1.41), and significantly lower survival (P < 0.001). Conclusion: Among hospitalized patients with cirrhosis, the cohort with T2D is at higher risk and may benefit from attention to comorbidities and additional support to reduce readmissions.

Hospitalisation for cirrhosis in Australia: disparities in presentation and outcomes for Indigenous Australians

Background

Indigenous Australians experience greater health disadvantage and have a higher prevalence of many chronic health conditions. Liver diseases leading to cirrhosis are among the most common contributor to the mortality gap between Indigenous and other Australian adults. However, no comparative data exist assessing differences in presentation and patient outcomes between Indigenous and non-Indigenous Australians hospitalised with cirrhosis.

Methods

Using data from the Hospital Admitted Patient Data Collection and the Death Registry, this retrospective, population-based, cohort study including all people hospitalised for cirrhosis in the state of Queensland during 2008–2017 examined rate of readmission (Poisson regression), cumulative survival (Kaplan–Meier), and assessed the differences in survival (Multivariable Cox regression) by Indigenous status. Predictor variables included demographic, health service characteristics and clinical data.

Results

We studied 779 Indigenous and 10,642 non-Indigenous patients with cirrhosis. A higher proportion of Indigenous patients were younger than 50 years (346 [44%] vs. 2063 [19%] non-Indigenous patients), lived in most disadvantaged areas (395 [51%) vs. 2728 [26%]), had alcohol-related cirrhosis (547 [70%] vs. 5041 [47%]), had ascites (314 [40%] vs. 3555 [33%), and presented to hospital via the Emergency Department (510 [68%] vs. 4790 [47%]). Indigenous patients had 3.04 times the rate of non-cirrhosis readmissions (95%CI 2.98–3.10), 1.35 times the rate of cirrhosis-related readmissions (95%CI 1.29–1.41), and lower overall survival (17% vs. 27%; unadjusted hazard ratio (HR) = 1.16 95%CI 1.06–1.27), compared to non-Indigenous patients. Most of the survival deficit was explained by Emergency Department presentation (adj-HR = 1.03 95%CI 0.93–1.13), and alcohol-related aetiology (adj-HR = 1.08 95%CI 0.99–1.19). The remaining survival deficit was influenced by the other clinico-demographic and health service factors (final adj-HR = 1.08 95%CI 0.96–1.20).

Conclusions

There was evidence of differential presentation, higher rates of readmissions, and poorer survival for Indigenous Australians with cirrhosis, compared to other Australians. The increased prevalence of Emergency Department presentation among Indigenous patients suggests missed opportunities for early intervention to prevent progressive cirrhosis complications and hospital readmissions.

Association between the fetal cerebroplacental ratio and biomarkers of hypoxia and angiogenesis in the maternal circulation at term

OBJECTIVES

A low fetal cerebroplacental ratio (CPR) in late pregnancy is a marker of a fetus that has failed to reach its growth potential and is associated with a variety of perinatal and pregnancy complications. It is not known if it is also correlated with aberrations in angiogenic, hypoxia-responsive or inflammatory cytokine levels in the maternal circulation. We investigated if there were any differences in levels of biomarkers of angiogenesis, endothelial cell dysfunction, hypoxia and/or inflammation in term pregnancies with a low fetal CPR compared to controls. We hypothesized that as the CPR is a marker of suboptimal growth, this would be reflected in a shift towards upregulation of hypoxia-responsive factors even in non-small for gestational age fetuses.

STUDY DESIGN

We used Multiplex ELISA to measure a panel of 28 candidate biomarkers of angiogenesis and/or hypoxia in pre-labour maternal plasma from 113 women at term, stratified for CPR <10th centile vs. CPR >10th centile. Plasma levels of the biomarkers were measured using 2 multiplex Luminex assays - a commercially available human angiogenesis/growth factor panel (R&D Systems®), comprising 15 analytes and an in-house custom panel of a further 13 candidate biomarkers.

RESULTS

Of the 28 candidate biomarkers investigated, we found significantly elevated levels of Carbonic Anhydrase 9 and soluble Fms-like tyrosine kinase (Vascular Endothelial Growth Factor Receptor 1), and lower levels of Placental Growth Factor in plasma from women with a low fetal CPR. The soluble Fms-like tyrosine kinase-1/Placental Growth Factor ratio was also markedly elevated in this cohort. We also demonstrated significant inverse correlations between the fetal CPR and Carbonic Anydrase 9, soluble Fms-like tyrosine kinase and Hepatocyte Growth Factor.

CONCLUSIONS

A low fetal CPR is associated with changes in some hypoxia-responsive and angiogenesis factors in the maternal circulation in pregnancies with normally grown fetuses.

Inhibitors of class I histone deacetylases attenuate thioacetamide-induced liver fibrosis in mice by suppressing hepatic type 2 inflammation

BACKGROUND AND PURPOSE

Chronic liver diseases feature excessive collagen and matrix protein deposition or crosslinking that characterises fibrosis, leads to scar tissue, and disrupts liver functions. There is no effective treatment. This study investigated whether treatment with selective histone deacetylase (HDAC) inhibitors might specifically reduce type 2 inflammation in the injured liver, thereby attenuating fibrogenesis in mice.

EXPERIMENTAL APPROACH

Thioacetamide (TAA) was used to induce hepatic inflammation, fibrosis, and liver damage in female C57BL/6 mice, similar to the clinical features of chronic human liver disease. We used eight inhibitors of different human HDAC enzymes to probe histological (IHC and TUNEL), biochemical and immunological changes (flow cytometry, qPCR, Legendplex, and ELISA) in pathology, fibrosis, hepatic immune cell flux, and inflammatory cytokine expression.

KEY RESULTS

Inhibitors of class I, but not class II, HDAC enzymes potently suppressed chronic hepatic inflammation and fibrosis in mice, attenuating accumulation and activation of IL-33-dependent, but not IL-25-dependent, group 2 innate lymphoid cells (ILC2) and inhibiting type 2 inflammation that drives hepatic stellate cells to secrete excessive collagen and matrix proteins.

CONCLUSIONS AND IMPLICATIONS

The results show that potent and selective inhibitors of class I only HDAC enzymes profoundly inhibit hepatocyte death and type 2 inflammation to prevent TAA-induced liver fibrosis in mice. The specific HDAC enzymes identified here may be key promoters of inflammation in chronic liver fibrosis.

Identifying areas of need relative to liver disease: geographic clustering within a health service district

Background Many people with chronic liver disease (CLD) are not detected until they present to hospital with advanced disease, when opportunities for intervention are reduced and morbidity is high. In order to build capacity and liver expertise in the community, it is important to focus liver healthcare resources in high-prevalence disease areas and specific populations with an identified need. The aim of the present study was to examine the geographic location of people seen in a tertiary hospital hepatology clinic, as well as ethnic and sociodemographic characteristics of these geographic areas. Methods The geographic locations of hepatology out-patients were identified via the out-patient scheduling database and grouped into statistical area (SA) regions for demographic analysis using data compiled by the Australian Bureau of Statistics. Results During the 3-month study period, 943 individuals from 71 SA Level 3 regions attended clinic. Nine SA Level 3 regions accounted for 55% of the entire patient cohort. Geographic clustering was seen especially for people living with chronic hepatitis B virus. There was a wide spectrum of socioeconomic advantage and disadvantage in areas with high liver disease prevalence. Conclusions The geographic area from which people living with CLD travel to access liver health care is extensive. However, the greatest demand for tertiary liver disease speciality care is clustered within specific geographic areas. Outreach programs targeted to these areas may enhance liver disease-specific health service resourcing. What is known about the topic? The demand for tertiary hospital clinical services in CLD is rising. However, there is limited knowledge about the geographic areas from which people living with CLD travel to access liver services, or the ethnic, socioeconomic and education characteristics of these areas. What does this paper add? The present study demonstrates that a substantial proportion of people living with CLD and accessing tertiary hospital liver services are clustered within specific geographic areas. The most striking geographic clustering was seen for people living with chronic hepatitis B, in regions with a relatively high proportion of people born in Vietnam and China. In addition to ethnicity, the data show an apparent ecological association between liver disease and both socioeconomic and educational and/or occupational disadvantage. What are the implications for practitioners? Identifying where demand for clinical services arises is an important step for service planning and preparing for potential outreach programs to optimise community-based care. It is likely that outreach programs to engage and enhance primary care services in geographic areas from which the greatest demand for tertiary liver disease speciality care arises would yield greater relative return on investment than non-targeted outreach programs.

Phenotypic impacts of CSF1R deficiencies in humans and model organisms

Mϕ proliferation, differentiation, and survival are controlled by signals from the Mϕ CSF receptor (CSF1R). Mono-allelic gain-of-function mutations in CSF1R in humans are associated with an autosomal-dominant leukodystrophy and bi-allelic loss-of-function mutations with recessive skeletal dysplasia, brain disorders, and developmental anomalies. Most of the phenotypes observed in these human disease states are also observed in mice and rats with loss-of-function mutations in Csf1r or in Csf1 encoding one of its two ligands. Studies in rodent models also highlight the importance of genetic background and likely epistatic interactions between Csf1r and other loci. The impacts of Csf1r mutations on the brain are usually attributed solely to direct impacts on microglial number and function. However, analysis of hypomorphic Csf1r mutants in mice and several other lines of evidence suggest that primary hydrocephalus and loss of the physiological functions of Mϕs in the periphery contribute to the development of brain pathology. In this review, we outline the evidence that CSF1R is expressed exclusively in mononuclear phagocytes and explore the mechanisms linking CSF1R mutations to pleiotropic impacts on postnatal growth and development.

Overexpression of miRNA-25-3p inhibits Notch1 signaling and TGF-β-induced collagen expression in hepatic stellate cells

During chronic liver injury hepatic stellate cells (HSCs), the principal source of extracellular matrix in the fibrotic liver, transdifferentiate into pro-fibrotic myofibroblast-like cells - a process potentially regulated by microRNAs (miRNAs). Recently, we found serum miRNA-25-3p (miR-25) levels were upregulated in children with Cystic Fibrosis (CF) without liver disease, compared to children with CF-associated liver disease and healthy individuals. Here we examine the role of miR-25 in HSC biology. MiR-25 was detected in the human HSC cell line LX-2 and in primary murine HSCs, and increased with culture-induced activation. Transient overexpression of miR-25 inhibited TGF-β and its type 1 receptor (TGFBR1) mRNA expression, TGF-β-induced Smad2 phosphorylation and subsequent collagen1α1 induction in LX-2 cells. Pull-down experiments with biotinylated miR-25 revealed Notch signaling (co-)activators ADAM-17 and FKBP14 as miR-25 targets in HSCs. NanoString analysis confirmed miR-25 regulation of Notch- and Wnt-signaling pathways. Expression of Notch signaling pathway components and endogenous Notch1 signaling was downregulated in miR-25 overexpressing LX-2 cells, as were components of Wnt signaling such as Wnt5a. We propose that miR-25 acts as a negative feedback anti-fibrotic control during HSC activation by reducing the reactivity of HSCs to TGF-β-induced collagen expression and modulating the cross-talk between Notch, Wnt and TGF-β signaling.

Medication-Related Problems in Outpatients With Decompensated Cirrhosis: Opportunities for Harm Prevention

People with decompensated cirrhosis are often prescribed a complex regimen of therapeutic and prophylactic medications. In other chronic diseases, polypharmacy increases the risk of medication misadventure and medication-related problems (MRPs), with associated increased morbidity, mortality, and health care costs. This study examined MRPs in a cohort of ambulatory patients with a history of decompensated cirrhosis who were enrolled in a randomized controlled trial of a pharmacist-led, patient-oriented medication education intervention and assessed the association between MRPs and patient outcomes. A total of 375 MRPs were identified among 57 intervention patients (median, 6.0; interquartile range, 3.5-8.0 per patient; maximum 17). Nonadherence (31.5%) and indication issues (29.1%) were the most prevalent MRP types. The risk of potential harm associated with MRPs was low in 18.9% of instances, medium in 33.1%, and high in 48.0%, as categorized by a clinician panel using a risk matrix tool. Patients had a greater incidence rate of high-risk MRPs if they had a higher Child-Pugh score (incidence rate ratio [IRR], 1.31; 95% confidence interval [CI], 1.09-1.56); greater comorbidity burden (IRR, 1.15; 95% CI, 1.02-1.29); and were taking more medications (IRR, 1.12; 95% CI, 1.04-1.22). A total of 221 MRPs (58.9%) were resolved following pharmacist intervention. A greater proportion of high-risk MRPs were resolved compared to those of low and medium risk (68.9% versus 49.7%; P < 0.001). During the 12-month follow-up period, intervention patients had a lower incidence rate of unplanned admissions compared to usual care (IRR, 0.52; 95% CI, 0.30-0.92). Conclusion: High-risk MRPs are prevalent among adults with decompensated cirrhosis. Pharmacist intervention facilitated identification and resolution of high-risk MRPs and was associated with reduced incidence rate of unplanned hospital admissions in this group.