BACKGROUND:Colorectal cancer (CRC) exhibits increased levels of arachidonic acid-derived pro-inflammatory derivatives indicating an uptake of dietary polyunsaturated fatty acids (PUFAs). OBJECTIVE:We aimed to investigate uptake of extrinsic fatty acids (FAs) in tumours and their relevance for CRC lipid metabolism and progression. DESIGN:Total FAs were quantified using gas chromatography-mass spectrometry in non-diseased mucosa and tumour tissue from patients with CRC of a discovery cohort (n=152), validated in an independent cohort (n=28) and associated with clinical, genomic and microbiome data. The genetic mouse tumour model Apc1638N was used to track the flux of stable isotope-labelled FAs in tumours from the intestinal lumen. The relationship between FA uptake and tumour progression was investigated in 2D and 3D cell models. RESULTS:Extrinsic long chain PUFAs, including arachidonic acid, accumulate in CRC, particularly in right-sided tumours, and in tumours of Apc1638N mice. The CRC-specific FA profiles were independent of sex, molecular subtypes, early-disease or late-disease onset. The absorption of FAs from the intestinal lumen in tumours was confirmed in specific pathogen-free Apc1638N mice. In the absence of the microbiome, in germ-free Apc1638N mice, fewer tumours were developed, and survival was increased. Inhibition of FA import or β-oxidation reduces cancer cell proliferation. CONCLUSION:Extrinsic FAs accumulate in CRC, verifying a central role of arachidonic acid-derived inflammatory mediators, but also suggesting a relevance of dietary FAs for cancer cell proliferation. It will be intriguing to explore to what extent targeting this flux pathway together with the interrelated microbiome opens new therapeutic avenues for CRC in humans.

Despite the widespread use of locomotion and activity analyses in neurobehavioral research and severity assessment, comparative evidence on the sensitivity and informative value of available monitoring techniques remains limited. Our study addresses these gaps by systematically evaluating activity data from multiple techniques across different interventions and disease models. The meta-analysis of datasets from the DFG FOR2591 consortium assessed how horizontal activity and locomotion change following surgical procedures, during stress paradigms, and in non-genetic and genetic disease models. Invasive interventions consistently resulted in post-surgical declines in activity, while neurological and psychiatric models were associated either with hypo- or hyperlocomotion, highlighting the bidirectional nature of activity alterations. A comparative evaluation of the techniques revealed that continuous home-cage telemetry and video-based tracking during the dark phase were more sensitive than clinical scoring systems, Neuroscores, or Open field tests. Voluntary wheel running emerged as the most informative of the alternatives. The analysis supports the integration of automated, continuous monitoring technologies to overcome the limitations of traditional daytime and observer-dependent methods. Since horizontal activity and locomotion have proven to be valuable readout parameters for most interventions and disease models, it is recommended that a sensitive analysis be integrated into multidimensional approaches to severity assessment.

Single outcome measures often fall short of the sensitivity and objectivity expected under European Directive 2010/63, particularly in fast progressing disease models. To address this gap, the German Research Foundation consortium FOR2591 collated data from 55 routinely used models in six species and narrowed more than 50 candidate readouts down to a 15-parameter core panel spanning behaviour, physiology, biochemistry and imaging. Quantitative tools such as the Composite Measure Schemes, the endpointR and the Relative Severity Assessment algorithm fuse these multidimensional streams into more objective severity scores that outperform singular readouts such as body weight change and clinical scoring in detecting early distress and refine humane endpoint decisions. More than 10 external laboratories have already integrated the open-source toolbox, illustrating practical scalability. A consortium survey showed that no single metric is both widely applied and consistently valued, underscoring the need for multi-parameter monitoring. Ongoing Phase III analyses extract model specific digital fingerprints that trigger real-time risk alerts in home-cage systems. By providing a shared yet adaptable framework, FOR2591 charts a feasible path toward Directive 2010/63 compliance, improved model validity and individualized animal care, establishing a path of a more evidence-based severity assessment.

The Porsolt Forced Swim Test (FST), primarily utilized for phenotyping and screening novel antidepressants in rodents, is one of the most widely used tests in depression research. Despite its popularity, this test has received increasing criticism mainly due to welfare concerns and interpretation discrepancies, a conflict that potentially reduces the predictive validity of this test through false positive results. To ensure both animal welfare and the reliable interpretation of reproducible test results, experiments must be designed and analyzed with utmost rigor to ensure the test is used appropriately. To assist with this, we provide a comprehensive, accessible database of all experimental setups and tested drugs in rats, to help avoid duplication of experiments and support future study design with adequate protocols that maximize animal welfare without compromising the research focus. While many reviews have covered the FST, none is as comprehensive as our systematic mapping review, which covers the 3907 manuscripts published on the FST in rats from 1977 until Dec 31, 2021. As the field remains divided over whether the FST portrays despair or rather adaptive coping and learning, we aim to inspire a consensus on the interpretation of the FST, thereby strengthening its translational validity and relevance as a potential component of a wider test battery for depression. We intend to raise awareness for these critical aspects of the FST, to balance the current reliance on it and minimize animal distress until valid (non-animal) alternatives are developed, which also cover the behavioral dimension of depression.

The gut microbiota influences host metabolism, but the mechanisms of lipid uptake from food remain mysterious. Here we used stable isotope-labelled tracers in gnotobiotic mouse models, which revealed that host uptake of dietary lipids depends on microbial colonization. Systemic lipid metabolism modelling predicted that the gut microbiota restricts intestinal lipid absorption, and labelled lipid administration verified that the gut contents of microbiota-colonized mice contained up to 12-fold more lipids than those of germ-free animals. A combination of lipidomics and proteomics showed that gut microbes trigger Myd88 signalling, leading to a downregulation of hepatic Cyp7b1 activity and increased taurocholate production. Taurocholate stimulates phospholipase A1 activity in bile, causing the degradation of phosphatidylcholine that is essential for luminal micelle formation and lipid uptake. A diverse microbiome was associated with lower phosphatidylcholine content. This previously unrecognized host-gut microbiota interplay via enzymes in bile could provide future targets to modulate dietary lipid absorption.

IntroductionThe intestinal immune system is organized into regionally specialized lymphatic drainage networks that coordinate adaptive responses according to the anatomical site of microbial encounter. During Citrobacter rodentium (C. rodentium) infection in mice, initial colonization occurs in the cecum and proximal colon, where antigen‑presenting cells drain to the corresponding mesenteric lymph nodes (mLN), before the pathogen progresses to dominant attachment in the distal colon at peak infection. These segment‑specific patterns of colonization are matched by segment‑specific lymphatic drainage, such that distinct lymph node compartments support immune priming in different intestinal regions. Understanding how these proximal draining mLN contribute to the development of colonic immunity, despite the later dominance of distal‑colonic infection, remains an important open question.MethodsTo examine the contribution of the colon‑draining mLN, we surgically removed either the entire mLN chain or only the nodes draining the cecum and colon, followed by C. rodentium infection. Immune responses were analyzed at day 10 and day 18, corresponding to phases in which distal‑colonic colonization dominates.ResultsWe found that Th17 effector responses in the colon were maintained independently of the removed mLN, consistent with the fact that local colonic activation is the primary driver of the observed T cell phenotype at these time points. In contrast, B cell differentiation was markedly impaired in mLN‑resected animals: both plasma cell frequencies in the colon and pathogen‑specific serum IgG1 and IgG2a responses were significantly reduced.DiscussionThese findings indicate that, although distal‑colonic T cell activation proceeds locally, effective B cell activation and class switching depend on the presence of the appropriate draining lymph nodes. Overall, this study highlights the segment‑specific organization of intestinal immunity and demonstrates that B cell responses during C. rodentium infection are critically dependent on the lymph nodes draining the cecum and colon, whereas local T cell activation in the distal colon can occur independently of these structures.

Salmonella enterica serovar Typhimurium is a food-borne pathogen and a major cause of gastroenteritis in humans. The intestinal microbiota provides colonization resistance to enteric pathogens such as S. Typhimurium. Akkermansia muciniphila is an anaerobic bacterium commonly found in the intestinal tract of humans and other mammals and specializes in the degradation of mucin. To study the role of A. muciniphila in affecting the outcome of S. Typhimurium colonization and pathology, we used gnotobiotic mice colonized with a defined simplified human (SIHUMI) or mouse (OMM11) intestinal microbiota and infected them with the attenuated S. Typhimurium ΔaroA strain. By comparing SIHUMI and OMM11 mice to mice additionally colonized with A. muciniphila, we demonstrate that the presence of A. muciniphila leads to a decrease in intestinal Salmonella colonization. In addition, Salmonella-induced colitis is significantly reduced in the presence of A. muciniphila including improved histopathological changes as well as decreased levels of inflammatory cytokines. Furthermore, we demonstrate that viable A. muciniphila inhibit adhesion of Salmonella to the intestinal epithelium in vivo as well as to differentiated, polarized HT29-MTX-E12 epithelial cells. These data indicate that A. muciniphila plays an important role in mediating protection from S. Typhimurium colitis by inhibiting adhesion of Salmonella to the intestinal epithelium.

Epigenetic modifications are critical for the regulation of CD4+ T cell differentiation and function. Previously, we identified Acyl-CoA Synthetase Bubble Gum 1 (Acsbg1), a gene involved in fatty acid metabolism, as part of an epigenetic signature that was selectively demethylated in ex vivo isolated T helper 17 (TH17) cells. However, its functional relevance for CD4+ T cells remains incompletely understood. Here, we used in vitro differentiation assays and the adoptive transfer colitis model to investigate the role of Acsbg1 in the differentiation and function of TH1, TH17, and regulatory T (Treg) cells. In vitro, Acsbg1 was expressed in both TH17 and in vitro-induced Treg (iTreg) cells, whereas TH1 cells lacked Acsbg1 expression. Accordingly, Acsbg1 deficiency resulted in impaired TH17 and iTreg differentiation, whereas TH1 differentiation was unaffected. In vivo, upon adoptive transfer of Acsbg1⁻/⁻ Tnaïve cells, immunodeficient recipient mice exhibited an exacerbated colitis, characterized by an altered balance of TH17 and Treg cells, indicating that Acsbg1 expression is essential for optimal TH17 and Treg cell differentiation and function. Our findings highlight the importance of fatty acid (FA) metabolism in maintaining immune homeostasis by regulating T cell differentiation and provide novel insights into the metabolic targeting of inflammatory diseases.

Aging manifests a decline of immune function, induces microbiome dysbiosis, drives organ inflammation, and impedes the resolution of inflammation. However, the mechanisms underlying age-related intestinal inflammation remain poorly described. Here, we find that the resolution of T cell-initiated intestinal inflammation is impaired with aging. This impairment is mediated by disrupting the immune-microbiota interplay, controlled by intestinal eicosanoid metabolism. Pharmacologically inhibiting eicosanoid biosynthesis, blocking the prostaglandin E receptor subtype 4 (EP4), or genetically ablating EP4 diminishes age-related impairment of intestinal inflammation resolution. Mechanistically, mononuclear phagocyte-intrinsic eicosanoid-EP4 signaling impedes the resolution of intestinal inflammation through fostering gut microbial dysbiosis and, more importantly, interrupting segmented filamentous bacterial adhesion to the intestinal epithelium. Colonization with EP4-ablated mouse microbiota or segmented filamentous bacteria improves the resolution of intestinal inflammation. These findings reveal that eicosanoid-dependent immune-microbiota interactions impair inflammation resolution in the aged intestine, highlighting potential intervention strategies for improving age-related gut health.

Catatonia is a psychiatric disorder, which subsumes a plethora of affective, motor and behavioral symptoms. In the last two decades, the number of behavioral and neuroimaging studies on catatonia has steadily increased. The majority of behavioral and neuroimaging studies in psychiatric patients suggested aberrant higher-order frontoparietal networks which, on the biochemical level, are insufficiently modulated by gamma-aminobutyric acid (GABA)-ergic and glutamatergic transmission. However, the pathomechanisms of catatonic symptoms have rarely been studied using rodent models. Here, we performed a scoping review of literature available on PubMed for studies on rodent models of catatonia. We sought to identify what we could learn from pre-clinical animal models of catatonia-like symptoms, their underlying neuronal correlates, and the complex molecular (i.e. genes and neurotransmitter) mechanisms by which its modulation exerts its effects. What becomes evident is that although many transgenic models present catatonia-like symptoms, they have not been used to better understand the pathophysiological mechanisms underlying catatonia so far. However, the identified neuronal correlates of catatonia-like symptoms correlate to a great extent with findings from neuroscience research in psychiatric patients. This points us towards fundamental cortical-striatal-thalamocortical and associated networks modulated by white matter inflammation as well as aberrant dopaminergic, GABAergic, and glutamatergic neurotransmission that is involved in catatonia. Therefore, this scoping review opens up the possibility of finally using transgenic models to help with identifying novel target mechanisms for the development of new drugs for the treatment of catatonia.

To address unmet treatment needs in cystic fibrosis (CF), preclinical and clinical studies are warranted. Because it directly reflects the function of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR), the nasal potential difference test (nPD) can not only be used as a reliable diagnostic test for CF but also to assess efficacy of experimental treatments. We performed a full comprehensive systematic review of the effect of CF treatments on the nPD compared to control conditions tested in separate groups of animal and human subjects. Our review followed a preregistered protocol. We included 34 references: 20 describing mouse studies, 12 describing human studies, and 2 describing both. We provide a comprehensive list of these studies, which assessed the effects of antibiotics, bone marrow transplant, CFTR protein, CFTR RNA, directly and indirectly CFTR-targeting drugs, non-viral and viral gene transfer, and other treatments. Our results support the nPD representing a reliable method for testing treatment effects in both animal models and human patients, as well as for diagnosing CF. However, we also observed the need for improved reporting to ensure reproducibility of the experiments and quantitative comparability of the results within and between species (e.g., with meta-analyses). Currently, data gaps warrant further primary studies.

Inflammatory bowel diseases (IBDs) are chronic conditions characterized by periods of spontaneous intestinal inflammation and are increasing in industrialized populations. Combined with host genetics, diet and gut bacteria are thought to contribute prominently to IBDs, but mechanisms are still emerging. In mice lacking the IBD-associated cytokine, interleukin-10, we show that a fiber-deprived gut microbiota promotes the deterioration of colonic mucus, leading to lethal colitis. Inflammation starts with the expansion of natural killer cells and altered immunoglobulin-A coating of some bacteria. Lethal colitis is then driven by Th1 immune responses to increased activities of mucin-degrading bacteria that cause inflammation first in regions with thinner mucus. A fiber-free exclusive enteral nutrition diet also induces mucus erosion but inhibits inflammation by simultaneously increasing an anti-inflammatory bacterial metabolite, isobutyrate. Our findings underscore the importance of focusing on microbial functions-not taxa-contributing to IBDs and that some diet-mediated functions can oppose those that promote disease.

While undisputedly important, and part of any systematic review (SR) by definition, evaluation of the risk of bias within the included studies is one of the most time-consuming parts of performing an SR. In this paper, we describe a case study comprising an extensive analysis of risk of bias (RoB) and reporting quality (RQ) assessment from a previously published review (CRD42021236047). It included both animal and human studies, and the included studies compared baseline diseased subjects with controls, assessed the effects of investigational treatments, or both. We compared RoB and RQ between the different types of included primary studies. We also assessed the “informative value” of each of the separate elements for meta-researchers, based on the notion that variation in reporting may be more interesting for the meta-researcher than consistently high/low or reported/non-reported scores. In general, reporting of experimental details was low. This resulted in frequent unclear risk-of-bias scores. We observed this both for animal and for human studies and both for disease-control comparisons and investigations of experimental treatments. Plots and explorative chi-square tests showed that reporting was slightly better for human studies of investigational treatments than for the other study types. With the evidence reported as is, risk-of-bias assessments for systematic reviews have low informative value other than repeatedly showing that reporting of experimental details needs to improve in all kinds of in vivo research. Particularly for reviews that do not directly inform treatment decisions, it could be efficient to perform a thorough but partial assessment of the quality of the included studies, either of a random subset of the included publications or of a subset of relatively informative elements, comprising, e.g. ethics evaluation, conflicts of interest statements, study limitations, baseline characteristics, and the unit of analysis. This publication suggests several potential procedures.

Ultrasound is widely used in the diagnosis and therapy of cancer. Tumors can be treated by thermal or mechanical tissue ablation. Furthermore, tumors can be manipulated by hyperthermia, sonodynamic therapy and sonoporation, e.g., by increasing tumor perfusion or the permeability of biological barriers to enhance drug delivery. These treatments induce various immune responses in tumors. However, conflicting data and high heterogeneity between experimental settings make it difficult to generalize the effects of ultrasound on tumor immunity. Therefore, we performed a systematic review to answer the question: "Does ultrasound alter the immune reaction of peripheral solid tumors in humans and animals compared to control conditions without ultrasound?" A systematic literature search was performed in PubMed, EMBASE, and Web of Science and 24,401 potentially relevant publications were identified. Of these, 96 publications were eligible for inclusion in the systematic review. Experiments were performed in humans, rats, and mice and focused on different tumor types, primarily breast and melanoma. We collected data on thermal and non-thermal ultrasound settings, the use of sono-sensitizers or sono-enhancers, and anti-tumor therapies. Six meta-analyses were performed to quantify the effect of ultrasound on tumor infiltration by T cells (cytotoxic, helper, and regulatory T cells) and on blood cytokines (interleukin-6, interferon-γ, tumor necrosis factor-α). We provide robust scientific evidence that ultrasound alters T cell infiltration into tumors and increases blood cytokine concentrations. Furthermore, we identified significant differences in immune cell infiltration based on tumor type, ultrasound settings, and mouse age. Stronger effects were observed using hyperthermia in combination with sono-sensitizers and in young mice. The latter may impair the translational impact of study results as most cancer patients are older. Thus, our results may help refining ultrasound parameters to enhance anti-tumor immune responses for therapeutic use and to minimize immune effects in diagnostic applications.

Accurate and standardized methods for assessing the vital status of patients are crucial for patient care and scientific research. This study introduces the Patient Vital Status (PVS), which quantifies and contextualizes a patient's physical status based on continuous variables such as vital signs and deviations from age-dependent normative values. The vital signs, heart rate, oxygen saturation, respiratory rate, mean arterial blood pressure, and temperature were selected as input to the PVS pipeline. The method was applied to 70 pediatric patients in the intensive care unit (ICU), and its efficacy was evaluated by matching high values with septic events at different time points in patient care. Septic events included systemic inflammatory response syndrome (SIRS) and suspected or proven sepsis. The comparison of maximum PVS values between the presence and absence of a septic event showed significant differences (SIRS/No SIRS: p < 0.0001, η2 = 0.54; Suspected Sepsis/No Suspected Sepsis: p = 0.00047, η2 = 0.43; Proven Sepsis/No Proven Sepsis: p = 0.0055, η2 = 0.34). A further comparison between the most severe PVS in septic patients with the PVS at ICU discharge showed even higher effect sizes (SIRS: p < 0.0001, η2 = 0.8; Suspected Sepsis: p < 0.0001, η2 = 0.8; Proven Sepsis: p = 0.002, η2 = 0.84). The PVS is emerging as a data-driven tool with the potential to assess a patient's vital status in the ICU objectively. Despite real-world data challenges and potential annotation biases, it shows promise for monitoring disease progression and treatment responses. Its adaptability to different disease markers and reliance on age-dependent reference values further broaden its application possibilities. Real-time implementation of PVS in personalized patient monitoring may be a promising way to improve critical care. However, PVS requires further research and external validation to realize its true potential.

Systematic reviews (SRs) are an important tool in implementing the 3Rs in preclinical research. With the ever-increasing amount of scientific literature, SRs require increasing time-investments. Thus, using the most efficient review tools is essential. Most available tools aid the screening process, tools for data-extraction and / or multiple review phases are relatively scarce. Using a single platform for all review phases allows for auto-transfer of references from one phase to the next, which enables work on multiple phases at the same time. We performed succinct formal tests of four multiphase review tools that are free or relatively affordable: Covidence, Eppi, SRDR+ and SYRF. Our tests comprised full-text screening, sham data extraction and discrepancy resolution in the context of parts of a systematic review. Screening was performed as per protocol. Sham data extraction comprised free text, numerical and categorial data. Both reviewers kept a log of their experiences with the platforms throughout. These logs were qualitatively summarized and supplemented with further user experiences. We show value of all tested tools in the SR process. Which tool is optimal depends on multiple factors, comprising previous experience with the tool, but also review type, review questions and review team member enthusiasm.

Cholestatic liver diseases, such as primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), lead to inflammation and severe hepatic damage with limited therapeutic options. This study assessed the efficacy of the inverse RORγt agonist, GSK805, both in vitro using the hepatic stellate cell-line LX-2 and in vivo using male bile duct-ligated BALB/c mice. In vitro, 0.3 μM GSK805 reduced alpha-smooth muscle actin expression in LX-2 cells. In vivo, GSK805 significantly decreased IL-23R, TNF-α, and IFN-γ expression in cholestatic liver. Despite high concentrations of GSK805 in the liver, no significant reduction in fibrosis was noticed. GSK805 significantly increased aspartate aminotransferase and alanine aminotransferase activity in the blood, while levels of glutamate dehydrogenase, alkaline phosphatase, and bilirubin were not substantially increased. Importantly, GSK805 did neither increase an animal distress score nor substantially reduce body weight, burrowing activity, or nesting behavior. These results suggest that a high liver concentration of GSK805 is achieved by daily oral administration and that this drug modulates inflammation in cholestatic mice without impairing animal well-being.