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The enteric nervous system (ENS) forms a versatile sensory system along the gastrointestinal tract that interacts with most cell types in the bowel. Herein, we portray host-environment interactions at the intestinal mucosal surface through the lens of the enteric nervous system. We describe local cellular interactions as well as long-range circuits between the enteric, central, and peripheral nervous systems. Additionally, we discuss recently discovered mechanisms by which enteric neurons and glia respond to biotic and abiotic environmental changes and how they regulate intestinal immunity and inflammation. The enteric nervous system emerges as an integrative sensory system with manifold immunoregulatory functions under both homeostatic and pathophysiological conditions.

BackgroundIrritable bowel syndrome (IBS) is one of the most common functional digestive disorders. Our understanding about its comorbidities, biomarkers, or long-term risks is still incomplete. ObjectiveTo characterize comorbidities and biomarkers for IBS and establish the effect of IBS on overall- and cause specific mortality. MethodsWe analyzed data from the population-based cohort of the UK Biobank (UKB) with 493,974 participants, including self-reported physician-diagnosed (n = 20,603) and ICD-10 diagnosed (n = 7656) IBS patients, with a mean follow-up of 11 years. We performed a phenome-wide association study (PheWAS) and competing risk analysis to characterize common clinical features in IBS patients. ResultsIn PheWAS analyses, 260 PheCodes were significantly overrepresented in self-reported physician-diagnosed IBS patients, 633 in patients with ICD-10 diagnosed IBS (ICD-10-IBS), with 221 (40%) overlapping. In addition to gastrointestinal diseases, psychiatric, musculoskeletal, and endocrine/metabolic disorders represented the most strongly associated PheCodes in IBS patients. Self-reported physician-diagnosed IBS was not associated with increased overall mortality and the risk of death from cancer was decreased (hazard ratio [HR] = 0.78 [95% CI = 0.7-0.9]). Lastly, we evaluated changes in serum metabolites in IBS patients and identified glycoprotein acetyls (GlycA) as a potential biomarker in IBS. One standard deviation increase in GlycA raised the risk of self-reported IBS/ICD-10 coded by 9%-20% (odds ratio [OR] = 1.09 [95% CI = 1.1-1.1]/OR = 1.20 [95% CI = 1.1-1.3]) and the risk of overall mortality in ICD-10-IBS patients by 28% (HR = 1.28 [95% CI = 1.1-1.5]). ConclusionOur large-scale association study determined IBS patients having an increased risk of several different comorbidities and that GlycA was increased in IBS patients.

Colorectal cancer (CRC) is among the most frequent forms of cancer, and new strategies for its prevention and therapy are urgently needed

Aging is characterized by an increased vulnerability to infection and the development of inflammatory diseases, such as atherosclerosis, frailty, cancer and neurodegeneration. Here, we find that aging is associated with the loss of diurnally rhythmic innate immune responses, including monocyte trafficking from bone marrow to blood, response to lipopolysaccharide and phagocytosis. This decline in homeostatic immune responses was associated with a striking disappearance of circadian gene transcription in aged compared to young tissue macrophages. Chromatin accessibility was significantly greater in young macrophages than in aged macrophages; however, this difference did not explain the loss of rhythmic gene transcription in aged macrophages. Rather, diurnal expression of Kruppel-like factor 4 (Klf4), a transcription factor (TF) well established in regulating cell differentiation and reprogramming, was selectively diminished in aged macrophages. Ablation ofKlf4expression abolished diurnal rhythms in phagocytic activity, recapitulating the effect of aging on macrophage phagocytosis. Examination of individuals harboring genetic variants ofKLF4revealed an association with age-dependent susceptibility to death caused by bacterial infection. Our results indicate that loss of rhythmicKlf4expression in aged macrophages is associated with disruption of circadian innate immune homeostasis, a mechanism that may underlie age-associated loss of protective immune responses.

The microbiome modulates brain function, but the precise routes of gut-brain communication remain unclear. In a recent issue of Science, Gabanyi et al. discover that hypothalamic GABAergic neurons directly recognize microbial muropeptides via NOD2, leading to reduced neuronal activity, loss of appetite, and aberrant thermoregulation.

ZusammenfassungDie nichtalkoholische Fettlebererkrankung (NAFLD) ist mit weiter steigender Inzidenz die weltweit häufigste Lebererkrankung. Während Adipositas der wichtigste Risikofaktor für die Entstehung einer NAFLD ist, demonstrieren aktuelle Forschungsarbeiten, dass neben genetischen Faktoren und westlicher Diät die Darm-Leber-Achse und besonders die intestinale Mikrobiota eine Schlüsselrolle während der Krankheitsprogression spielen. Eine ungünstige Komposition der Mikrobiota beeinflusst nicht nur den Leberstoffwechsel, sondern moduliert durch mikrobielle Moleküle und Metaboliten das inflammatorische Milieu in der Leber. Hier zeigen sich vielversprechende Regelkreise für die zukünftige Diagnostik und Therapie.

ObjectiveAlpha-1 antitrypsin deficiency (AATD) is a common, potentially lethal inborn disorder caused by mutations in alpha-1 antitrypsin (AAT). Homozygosity for the ‘Pi*Z’ variant of AAT (Pi*ZZ genotype) causes lung and liver disease, whereas heterozygous ‘Pi*Z’ carriage (Pi*MZ genotype) predisposes to gallstones and liver fibrosis. The clinical significance of the more common ‘Pi*S’ variant remains largely undefined and no robust data exist on the prevalence of liver tumours in AATD.DesignBaseline phenotypes of AATD individuals and non-carriers were analysed in 482 380 participants in the UK Biobank. 1104 participants of a multinational cohort (586 Pi*ZZ, 239 Pi*SZ, 279 non-carriers) underwent a comprehensive clinical assessment. Associations were adjusted for age, sex, body mass index, diabetes and alcohol consumption.ResultsAmong UK Biobank participants, Pi*ZZ individuals displayed the highest liver enzyme values, the highest occurrence of liver fibrosis/cirrhosis (adjusted OR (aOR)=21.7 (8.8–53.7)) and primary liver cancer (aOR=44.5 (10.8–183.6)). Subjects with Pi*MZ genotype had slightly elevated liver enzymes and moderately increased odds for liver fibrosis/cirrhosis (aOR=1.7 (1.2–2.2)) and cholelithiasis (aOR=1.3 (1.2–1.4)). Individuals with homozygous Pi*S mutation (Pi*SS genotype) harboured minimally elevated alanine aminotransferase values, but no other hepatobiliary abnormalities. Pi*SZ participants displayed higher liver enzymes, more frequent liver fibrosis/cirrhosis (aOR=3.1 (1.1–8.2)) and primary liver cancer (aOR=6.6 (1.6–26.9)). The higher fibrosis burden was confirmed in a multinational cohort. Male sex, age ≥50 years, obesity and the presence of diabetes were associated with significant liver fibrosis.ConclusionOur study defines the hepatobiliary phenotype of individuals with the most relevant AATD genotypes including their predisposition to liver tumours, thereby allowing evidence-based advice and individualised hepatological surveillance.

IMPORTANCE: Telomeres protect DNA from damage. Because they shorten with each mitotic cycle, leukocyte telomere length (LTL) serves as a mitotic clock. Reduced LTL has been associated with multiple human disorders. OBJECTIVE: To determine the association between LTL and overall as well as disease-specific mortality and morbidity. DESIGN, SETTING, AND PARTICIPANTS: This multicenter, community-based cohort study conducted from March 2006 to December 2010 included longitudinal follow-up (mean [SD], 12 [2] years) for 472 432 English participants from the United Kingdom Biobank (UK Biobank) and analyzed morbidity and mortality. The data were analyzed in 2021. MAIN OUTCOMES AND MEASURES: Hazard ratios (HRs) and odds ratios for mortality and morbidity associated with a standard deviation change in LTL, adjusted for age, sex, body mass index (calculated as weight in kilograms divided by height in meters squared), and ethnicity. RESULTS: This study included a total of 472 432 English participants, of whom 54% were women (mean age, 57 years). Reduced LTL was associated with increased overall (HR, 1.08; 95% CI, 1.07-1.09), cardiovascular (HR, 1.09; 95% CI, 1.06-1.12), respiratory (HR, 1.40; 95% CI, 1.34-1.45), digestive (HR, 1.26; 95% CI, 1.19-1.33), musculoskeletal (HR, 1.51; 95% CI, 1.35-1.92), and COVID-19 (HR, 1.15; 95% CI, 1.07-1.23) mortality, but not cancer-related mortality. A total of 214 disorders were significantly overrepresented and 37 underrepresented in participants with shorter LTL. Respiratory (11%), digestive/liver-related (14%), circulatory (18%), and musculoskeletal conditions (6%), together with infections (5%), accounted for most positive associations, whereas (benign) neoplasms and endocrinologic/metabolic disorders were the most underrepresented entities. Malignant tumors, esophageal cancer, and lymphoid and myeloid leukemia were significantly more common in participants with shorter LTL, whereas brain cancer and melanoma were less prevalent. While smoking and alcohol consumption were associated with shorter LTL, additional adjustment for both factors, as well as cognitive function/major comorbid conditions, did not significantly alter the results. CONCLUSIONS AND RELEVANCE: This cohort study found that shorter LTL was associated with a small risk increase of overall mortality, but a higher risk of mortality was associated with specific organs and diseases.

INTRODUCTION: Vitamin E supplementation is recommended for the treatment of non-alcoholic fatty liver disease (NAFLD) for nondiabetic patients, but its preventative effects are unclear. METHODS: We assessed dietary Vitamin E intake with disease phenotypes and evaluated Vitamin E levels with the development of NAFLD. RESULTS: Data from >210,000 participants demonstrate that increased dietary Vitamin E associates with reduced rates of several gastrointestinal diseases and reduced overall mortality. Diabetic and overweight subjects with increased Vitamin E intake have fewer NAFLD diagnoses. CONCLUSION: Our findings reveal the relevance of Vitamin E consumption for several gastrointestinal diseases and warrant further mechanistic and therapeutic investigations.

Liver international 42(3), 640-650 (2022). doi:10.1111/liv.15161, Published by Wiley-Blackwell, Oxford

International audience; Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown aetiology for which there are no approved therapeutic options. Patients with PSC display changes in gut microbiota and in bile acid (BA) composition; however, the contribution of these alterations to disease pathogenesis remains controversial. Here we identify a role for microbiota-dependent changes in BA synthesis that modulates PSC pathophysiology. In a genetic mouse model of PSC, we show that loss of microbiota-mediated negative feedback control of BA synthesis results in increased hepatic BA concentrations, disruption of bile duct barrier function and, consequently, fatal liver injury. We further show that these changes are dependent on decreased BA signalling to the farnesoid X receptor, which modulates the activity of the rate-limiting enzyme in BA synthesis, CYP7A1. Moreover, patients with advanced stages of PSC show suppressed BA synthesis as measured by serum C4 levels, which is associated with poor disease prognosis. Our preclinical data highlight the microbiota-dependent dynamics of BA metabolism in cholestatic liver disease, which could be important for future therapies targeting BA and gut microbiome interactions, and identify C4 as a potential biomarker to functionally stratify patients with PSC and predict disease outcomes.

Gut microbes 13(1), 1-21 (2021). doi:10.1080/19490976.2020.1854008, Published by Landes Bioscience, Austin, Tex.

Background & Aims In chronic liver diseases, inflammation induces oxidative stress and thus may contribute to the progression of liver injury, fibrosis, and carcinogenesis. The KEAP1/NRF2 axis is a major regulator of cellular redox balance. In the present study, we investigated whether the KEAP1/NRF2 system is involved in liver disease progression in humans and mice. Methods The clinical relevance of oxidative stress was investigated by liver RNA sequencing in a well-characterized cohort of patients with non-alcoholic fatty liver disease (n = 63) and correlated with histological and clinical parameters. For functional analysis, hepatocyte-specific Nemo knockout (NEMOΔhepa) mice were crossed with hepatocyte-specific Keap1 knockout (KEAP1Δhepa) mice. Results Immunohistochemical analysis of human liver sections showed increased oxidative stress and high NRF2 expression in patients with chronic liver disease. RNA sequencing of liver samples in a human pediatric NAFLD cohort revealed a significant increase of NRF2 activation correlating with the grade of inflammation, but not with the grade of steatosis, which could be confirmed in a second adult NASH cohort. In mice, microarray analysis revealed that Keap1 deletion induces NRF2 target genes involved in glutathione metabolism and xenobiotic stress (e.g., Nqo1). Furthermore, deficiency of one of the most important antioxidants, glutathione (GSH), in NEMOΔhepa livers was rescued after deleting Keap1. As a consequence, NEMOΔhepa/KEAP1Δhepa livers showed reduced apoptosis compared to NEMOΔhepa livers as well as a dramatic downregulation of genes involved in cell cycle regulation and DNA replication. Consequently, NEMOΔhepa/KEAP1Δhepa compared to NEMOΔhepa livers displayed decreased fibrogenesis, lower tumor incidence, reduced tumor number, and decreased tumor size. Conclusions NRF2 activation in patients with non-alcoholic steatohepatitis correlates with the grade of inflammation, but not steatosis. Functional analysis in mice demonstrated that NRF2 activation in chronic liver disease is protective by ameliorating fibrogenesis, initiation and progression of hepatocellular carcinogenesis. Lay summary The KEAP1 (Kelch-like ECH-associated protein-1)/NRF2 (erythroid 2-related factor 2) axis has a major role in regulating cellular redox balance. Herein, we show that NRF2 activity correlates with the grade of inflammation in patients with non-alcoholic steatohepatitis. Functional studies in mice actually show that NRF2 activation, resulting from KEAP1 deletion, protects against fibrosis and cancer.

British journal of pharmacology (2021). doi:10.1111/bph.15622, Published by Wiley, Malden, MA

Background & Aims Acute liver failure (ALF) represents an unmet medical need in Western countries. Although the link between intestinal dysbiosis and chronic liver disease is well-established, there is little evidence for a functional role of gut-liver interaction during ALF. Here we hypothesized that intestinal dysbiosis may affect ALF. Methods To test this hypothesis, we assessed the association of proton pump inhibitor (PPI) or long-term antibiotics (ABx) intake, which have both been linked to intestinal dysbiosis, and occurrence of ALF in the 500,000 participants of the UK BioBank population-based cohort. For functional studies, male Nlrp6-/- mice were used as a dysbiotic mouse model and injected with a sublethal dose of acetaminophen (APAP) or lipopolysaccharide (LPS) to induce ALF. Results Multivariate Cox regression analyses revealed a significantly increased risk (odds ratio, 2.3–3) for developing ALF in UK BioBank participants with PPI or ABx. Similarly, dysbiotic Nlrp6-/- mice displayed exacerbated APAP- and LPS-induced liver injury, which was linked to significantly reduced gut and liver tissue microbiota diversity and correlated with increased intestinal permeability at baseline. Fecal microbiota transfer (FMT) from Nlrp6-/- mice into wild-type (WT) mice augmented liver injury on APAP treatment in recipient WT mice, resembling the inflammatory phenotype of Nlrp6-/- mice. Specifically, FMT skewed monocyte polarization in WT mice toward a Ly6Chi inflammatory phenotype, suggesting a critical function of these cells as sensors of gut-derived signals orchestrating the inflammatory response. Conclusions Our data show an important yet unknown function of intestinal microbiota during ALF. Intestinal dysbiosis was transferrable to healthy WT mice via FMT and aggravated liver injury. Our study highlights intestinal microbiota as a targetable risk factor for ALF., Graphical abstract

Background & Aims Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine and an important regulator of innate immune responses. We hypothesised that serum concentrations of MIF are associated with disease severity and outcome in patients with decompensated cirrhosis and acute-on-chronic liver failure (ACLF). Methods Circulating concentrations of MIF and its soluble receptor CD74 (sCD74) were determined in sera from 292 patients with acute decompensation of cirrhosis defined as new onset or worsening of ascites requiring hospitalisation. Of those, 78 (27%) had ACLF. Short-term mortality was assessed 90 days after inclusion. Results Although serum concentrations of MIF and sCD74 did not correlate with liver function parameters or ACLF, higher MIF (optimum cut-off >2.3 ng/ml) and lower concentrations of sCD74 (optimum cut-off, Graphical abstract, Highlights • MIF serum concentrations do not correlate with hepatic function but with systemic inflammation in decompensated cirrhosis patients. • MIF serum concentrations are independent of genetic MIF promoter polymorphisms in patients with decompensated cirrhosis. • MIF and sCD74 serum concentrations predict transplant-free 90-day survival in patients with decompensated cirrhosis. • Patients with decompensated cirrhosis and both high MIF and low sCD74 serum concentrations have impaired survival. • Patients with decompensated cirrhosis show a transhepatic gradient with higher MIF concentrations in right atrial blood.

Hepatology 73(5), 1836-1854 (2020). doi:10.1002/hep.31494, Published by Wiley Interscience, New York [u.a.]

Clostridium difficile infection (CDI) represents one of the most common healthcare-associated infections. Due to increasing numbers of recurrences and therapy failures, CDI has become a major disease burden. Studies have shown that fecal microbiota transplantation (FMT) can both be a safe and highly efficacious therapy for patients with therapy-refractory CDI. However, patients undergoing solid organ transplantation are at high risk for CDI due to long-term immunosuppression, previous antibiotic therapy, and proton pump inhibitor use. Additionally, these patients may be especially prone to adverse events related to FMT. Here, we report a successful FMT in a patient with severe therapy-refractory CDI after liver transplantation.

Background & Aims Previous studies have identified physical activity as an important lifestyle factor in the pathogenesis of chronic liver diseases (CLD). However, most studies were short in follow-up, and based on self-reported activity. Moreover, it is unknown whether physical activity affects the risk of liver disease development in the general population. Herein, we aimed to clarify the association between physical activity and CLD by examining the risk of liver disease and progression in relation to accelerometer-based physical activity in a large subset of prospectively recruited participants in the UK Biobank. Methods We analysed data from 96,688 participants that recorded their physical activity through the use of a wrist accelerometer. Relative risks for development of liver diseases were calculated using multivariable-adjusted Cox regression models. In a subgroup of participants without any previously diagnosed liver disease (n = 95,974), a total of 374 liver disease cases were diagnosed during follow-up (mean = 5.5 years). Results Participants in the top compared with the bottom quartile of physical activity had a reduced risk of both overall CLD (hazard ratio [HR]: 0.41 [0.29–0.59]) and NAFLD (HR: 0.39 [0.21–0.70]). An activity increase of an additional 2,500 steps per day, was associated with a 38% reduction in CLD and a 47% reduction in NAFLD development, independent of adiposity. In the subgroup of participants with previously diagnosed liver disease (n = 714), participants in the top compared with the bottom quartile of physical activity had a striking 89% risk reduction in liver-related death (HR: 0.11 [0.02–0.86]), and 85% risk reduction in all-cause mortality (adjusted HR: 0.15 [0.05–0.44]). Walking an additional 2,500 steps per day was associated with 44% reduction in liver disease progression. Conclusions Greater physical activity is associated with a dose-dependent reduction in liver disease, which appears to be independent of adiposity. Lay summary In this study, we aimed to clarify the association between accelerometer-measured physical activity and chronic liver disease by examining risk of overall and specific liver diseases and their progression in relation to accelerometer-based physical activity in 96,688 participants in the UK Biobank. Our results show a clear, dose-dependent protective association between accelerometer-measured physical activity and liver disease development and progression. The linkage of device-measured activity could therefore create a framework for using wearables for personalised prevention of liver diseases., Graphical abstract, Highlights • Physical activity is associated with a dose-dependent reduction in liver disease that appears to be independent of adiposity. • An increase of 2,500 steps per day was associated with a 38% reduction in liver disease and a 47% reduction in NAFLD. • In patients with liver disease, activity was associated with a reduction in liver disease progression and cirrhosis development. • In patients with liver disease, increased physical activity significantly reduced the risk of liver-related death.

Two polymorphisms in the promoter region of macrophage migration inhibitory factor (MIF) - rs755622 and rs5844572 - exhibit prognostic relevance in inflammatory diseases. The aim of this study was to investigate a correlation between these MIF promoter polymorphisms and the severity of hepatitis C virus (HCV)-induced liver fibrosis. Our analysis included two independent patient cohorts with HCV-induced liver fibrosis (504 and 443 patients, respectively). The genotype of the single nucleotide polymorphism (SNP) -173 G/C and the repeat number of the microsatellite polymorphism -794 CATT5&ndash, 8 were determined in DNA samples and correlated with fibrosis severity. In the first cohort, homozygous carriers of the C allele in the rs755622 had lower fibrosis stages compared to heterozygous carriers or wild types (1.25 vs. 2.0 vs. 2.0, p = 0.03). Additionally, &ge, 7 microsatellite repeats were associated with lower fibrosis stages (&lt, F2) (p = 0.04). Comparable tendencies were observed in the second independent cohort, where fibrosis was assessed using transient elastography. However, once cirrhosis had been established, the C/C genotype and higher microsatellite repeats correlated with impaired liver function and a higher prevalence of hepatocellular carcinoma. Our study demonstrates that specific MIF polymorphisms are associated with disease severity and complications of HCV-induced fibrosis in a stage- and context-dependent manner.