Effects of Bile Duct Ligation and Ghrelin Treatment on the Colonic Barrier and Microbiome of Mice.

INTRODUCTION: Cholestatic liver disease (CLD) is associated with intestinal barrier dysfunction. The peptide hormone ghrelin may exert both hepatoprotective and barrier-strengthening effects. Here, we have evaluated these effects under the conditions of experimental cholestasis. METHODS: C57BL/6J mice with bile duct ligation (BDL) or sham surgery were treated with ghrelin or solvent for 9 days. Liver injury was assessed by histological and laboratory analyses. Paracellular macromolecule permeability and transmural electrical resistance (TMER) of colonic tissues were measured using a Ussing chamber. Expression of tight junction (TJ) genes was quantified by real-time PCR. Amplicon metagenomic sequencing was employed to analyze bacterial 16S rRNA from colonic stool samples. RESULTS: Mice with BDL exhibited weight loss and signs of severe liver injury. These changes were unaffected by ghrelin treatment. FITC-4-kDa-dextran flux was increased and TMER decreased after BDL. Treatment with ghrelin tended to reduce these effects. Furthermore, application of ghrelin was associated with higher mRNA levels of claudin-4, occludin, and ZO-1 in colonic tissues of mice with BDL. Reduced alpha-diversity of the microbiome was observed in solvent-treated mice with BDL but not in ghrelin-treated animals. CONCLUSION: Ghrelin treatment did not improve weight loss and liver damage but increased gene expression of colonic TJ proteins and restored the alpha-diversity of the microbiome. Since protective effects of ghrelin might be masked by the severity of the model, we suggest follow-up studies in models of milder CLD.

YAP activates pancreatic stellate cells and enhances pancreatic fibrosis.

BACKGROUND: Pancreatic stellate cells (PSCs) foster the progression of pancreatic adenocarcinoma and chronic pancreatitis (CP) by producing a dense fibrotic stroma. However, the incomplete knowledge of PSCs biology hampers the exploration of antifibrotic therapies. Here, we explored the role of the Hippo pathway in the context of PSCs activation and experimental CP. METHODS: CP model was created in rats with the tail vein injection of dibutyltin dichloride (DBTC). The expression of Yes-associated protein (YAP) in CP tissue was assessed. Primary and immortalized rats PSCs were treated with the YAP-inhibitor verteporfin. Furthermore, YAP siRNA was employed. Subsequently, DNA synthesis, cell survival, levels of α-smooth muscle actin (α-SMA) protein, presence of lipid droplets and PSCs gene expression were evaluated. Upstream regulators of YAP signaling were studied by reporter gene assays. RESULTS: In DBTC-induced CP, pronounced expression of YAP in areas of tubular structures and periductal fibrosis was observed. Verteporfin diminished DNA replication in PSCs in a dose-dependent fashion. Knockdown of YAP reduced cell proliferation. Primary cultures of PSCs were characterized by a decrease of lipid droplets and increased synthesis of α-SMA protein. Both processes were not affected by verteporfin. At the non-cytotoxic concentration of 100 nmol/L, verteporfin significantly reduced mRNA levels of transforming growth factor-ß1 (Tgf-ß1) and Ccn family member 1 (Ccn1). YAP signaling was activated by TGF-ß1, but repressed by interferon-γ. CONCLUSIONS: Activated YAP enhanced PSCs proliferation. The antifibrotic potential of Hippo pathway inhibitors warrants further investigation.

Nutritional management of chronic pancreatitis: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND AND AIM: Malnutrition is a frequent complication of chronic pancreatitis. Adequate nutritional support is imperative, but there is still uncertainty about the optimal nutritional treatment. This work systematically compiles evidence from randomized controlled trials investigating dietary interventions in chronic pancreatitis and, in a further step, contrasts those findings with existing dietary recommendations. METHODS: The literature search (PubMed and Cochrane Central Register of Controlled Trials) included English and German full-text articles, which had been published in peer-reviewed journals. Two independent reviewers identified and selected studies. For meta-analysis, forest plots with 95% confidence intervals were generated using a random-effects model. RESULTS: Eleven randomized controlled trials fulfilled all selection criteria. In these trials, the following dietary interventions were tested: antioxidant treatment (n = 6), vitamin D supplementation (n = 3), supplementation with oral nutritional supplements (n = 1), and symbiotics supplementation (n = 1). Studies were of good methodological quality (mean Jadad score of 3.6) but heterogeneous in terms of interventions and study populations. Only for vitamin D, there was convincing evidence for efficacy of supplementation. We found no effect for antioxidant treatment on pain relief (standardized mean difference = -0.12; 95% confidence interval -0.73 to 0.48) and limited generalizability for interventions with oral nutritional supplements and symbiotics. CONCLUSIONS: Nutritional management in chronic pancreatitis remains challenging. As well-designed randomized controlled trials are scarce, in large part, recommendations can only be based on low-level evidence studies or expert opinion. For now, consumption of a balanced diet remains the cornerstone recommendation for prevention, whereas more goal-directed interventions are indicated for specific nutrient deficiencies.

Preclinical insights into the gut-skeletal muscle axis in chronic gastrointestinal diseases.

Muscle wasting represents a constant pathological feature of common chronic gastrointestinal diseases, including liver cirrhosis (LC), inflammatory bowel diseases (IBD), chronic pancreatitis (CP) and pancreatic cancer (PC), and is associated with increased morbidity and mortality. Recent clinical and experimental studies point to the existence of a gut-skeletal muscle axis that is constituted by specific gut-derived mediators which activate pro- and anti-sarcopenic signalling pathways in skeletal muscle cells. A pathophysiological link between both organs is also provided by low-grade systemic inflammation. Animal models of LC, IBD, CP and PC represent an important resource for mechanistic and preclinical studies on disease-associated muscle wasting. They are also required to test and validate specific anti-sarcopenic therapies prior to clinical application. In this article, we review frequently used rodent models of muscle wasting in the context of chronic gastrointestinal diseases, survey their specific advantages and limitations and discuss possibilities for further research activities in the field. We conclude that animal models of LC-, IBD- and PC-associated sarcopenia are an essential supplement to clinical studies because they may provide additional mechanistic insights and help to identify molecular targets for therapeutic interventions in humans.

SNX27 regulates DRA activity and mediates its direct recycling by PDZ-interaction in early endosomes at the apical pole of Caco2 cells.

DRA (downregulated in adenoma, SLC26A3) and NHE3 (Na+/H+ exchanger 3, SLC9A3) together mediate intestinal electroneutral NaCl absorption. Both transporters contain PDZ (postsynaptic density 95, disc large, zonula occludens 1) binding motifs and interact with PDZ adaptor proteins regulating their activity and recycling. SNX27 (sorting nexin 27) contains a PDZ domain and is involved in the recycling of cargo proteins including NHE3. The interaction of SNX27 with DRA and its potential role for the activity and recycling of DRA have been evaluated in this study. SNX27 specifically interacts with DRA via its PDZ domain. The knockdown (KD) of SNX27 reduced DRA activity by 50% but was not accompanied by a decrease of DRA surface expression. This indicates that DRA is trafficked to specific functional domains in the plasma membrane in which DRA is particularly active. Consistently, the disruption of lipid raft integrity by methyl-ß-cyclodextrin has an inhibitory effect on DRA activity that was strongly reduced after SNX27 KD. In differentiated intestinal Caco2 cells, superresolution microscopy and a novel quantitative axial approach revealed that DRA and SNX27 colocalize in rab5-positive early endosomes at the apical pole. SNX27 regulates the activity of DRA in the apical plasma membrane through binding with its PDZ domain. This interaction occurs in rab5-positive early endosomes at the apical pole of differentiated intestinal Caco2 cells. SNX27 is involved in the direct recycling of DRA to the plasma membrane where it is inserted into lipid rafts facilitating increased activity.NEW & NOTEWORTHY SNX27 has a PDZ domain and is involved in the regulation and recycling of transmembrane proteins. The role of SNX27 on the activity and recycling of the intestinal Cl-/HCO3- exchanger DRA has not yet been studied. This study shows that SNX27 directly interacts with DRA in early endosomes at the apical pole of intestinal Caco2 cells and mediates its direct recycling to facilitate high activity in lipid rafts in the apical plasma membrane.

Teduglutide Promotes Epithelial Tight Junction Pore Function in Murine Short Bowel Syndrome to Alleviate Intestinal Insufficiency.

BACKGROUND: In short bowel syndrome, epithelial surface loss results in impaired nutrient absorption and may lead to intestinal insufficiency or intestinal failure. Nucleotide oligomerization domain 2 (Nod2) dysfunction predisposes to the development of intestinal failure after intestinal resection and is associated with intestinal barrier defects. Epithelial barrier function is crucial for intestinal absorption and for intestinal adaptation in the short bowel situation. AIMS: The aim of the study was to characterize the effects of the GLP-2 analogue Teduglutide in the small intestine in the presence and absence of Nod2 in a mouse model of short bowel syndrome. METHODS: Mice underwent 40% ICR and were thereafter treated with Teduglutide versus vehicle injections. Survival, body weight, stool water, and sodium content and plasma aldosterone concentrations were determined. Intestinal and kidney tissue was examined with light and fluorescence microscopy, Ussing chamber studies and quantitative PCR in wild type and transgenic mice. RESULTS: Teduglutide reduced intestinal failure incidence in Nod2 k.o. mice. In wt mice, Teduglutide attenuated intestinal insufficiency as indicated by reduced body weight loss and lower plasma aldosterone concentrations, lower stool water content, and lower stool sodium losses. Teduglutide treatment was associated with enhanced epithelial paracellular pore function and enhanced claudin-10 expression in tight junctions in the villus tips, where it colocalized with sodium-glucose cotransporter 1 (SGLT-1), which mediates Na-coupled glucose transport. CONCLUSIONS: In the SBS situation, Teduglutide not only maximizes small intestinal mucosal hypertrophy but also partially restores small intestinal epithelial function through an altered distribution of claudin-10, facilitating sodium recirculation for Na-coupled glucose transport and water absorption.

Molecular Mechanism Contributing to Malnutrition and Sarcopenia in Patients with Liver Cirrhosis.

Liver cirrhosis is frequently accompanied by disease-related malnutrition (DRM) and sarcopenia, defined as loss of skeletal muscle mass and function. DRM and sarcopenia often coexist in cirrhotic patients and are associated with increased morbidity and mortality. The clinical manifestation of both comorbidities are triggered by multifactorial mechanisms including reduced nutrient and energy intake caused by dietary restrictions, anorexia, neuroendocrine deregulation, olfactory and gustatory deficits. Maldigestion and malabsorption due to small intestinal bacterial overgrowth, pancreatic insufficiency or cholestasis may also contribute to DRM and sarcopenia. Decreased protein synthesis and increased protein degradation is the cornerstone mechanism to muscle loss, among others mediated by disease- and inflammation-mediated metabolic changes, hyperammonemia, increased myostatin and reduced human growth hormone. The concise pathophysiological mechanisms and interactions of DRM and sarcopenia in liver cirrhosis are not completely understood. Furthermore, most knowledge in this field are based on experimental models, but only few data in humans exist. This review summarizes known and proposed molecular mechanisms contributing to malnutrition and sarcopenia in liver cirrhosis and highlights remaining knowledge gaps. Since, in the prevention and treatment of DRM and sarcopenia in cirrhotic patients, more research is needed to identify potential biomarkers for diagnosis and development of targeted therapeutic strategies.

Nod2 deficiency functionally impairs adaptation to short bowel syndrome via alterations of the epithelial barrier function.

Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) gene mutations are a risk factor for Crohn's disease and also associated with worse outcome in short bowel syndrome (SBS) patients independent of the underlying disease. The aim of this study was to analyze the effect of Nod2 deficiency on barrier function and stool microbiome after extensive ileocecal resection in mice. Male C57BL6/J wild-type (WT) and Nod2-knockout (KO) mice underwent 40% ileocecal resection. Sham control mice received simple transection of the ileum. Clinical outcome was monitored daily. Barrier function was measured with Ussing chambers using FITC-4-kDa-Dextran flux, transmucosal electrical resistance, and dilution potentials. Immunofluorescence of claudin-2 was studied. Composition of the stool microbiome was assessed by 16S rRNA gene sequencing. Resected Nod2-KO mice had impaired clinical outcome compared with resected WT mice. This was accompanied by increased stool water contents and increased plasma aldosterone. Histomorphological adaptation was independent of Nod2. Barrier function studies revealed impaired sodium to chloride permeability and altered claudin-2 localization in the absence of Nod2. Resection induced decreases of bacterial diversity and a shift of bacteriodetes-to-firmicutes ratios. Ileum and cecum resection-induced increase in proteobacteria was absent in Nod2-deficient mice. Verrucomicrobia were temporarily increased in Nod2-KO mice. Nod2 deficiency functionally impairs adaptation to short bowel syndrome via a lesser increase of epithelial sodium pore permeability, altered epithelial barrier function, and the microbiome.NEW & NOTEWORTHYNOD2 gene mutations are associated with the development of severe short bowel syndrome and intestinal failure. The influence of Nod2 mutations on intestinal adaptation in experimental short bowel syndrome has not been studied yet. Here, we provide data that Nod2 deficiency worsens clinical outcome and functional adaptation under SBS conditions in mice, indicating that NOD2 is required for successful adaptation after ileocecal resection.

Villus Growth, Increased Intestinal Epithelial Sodium Selectivity, and Hyperaldosteronism Are Mechanisms of Adaptation in a Murine Model of Short Bowel Syndrome.

BACKGROUND: Short bowel syndrome results from extensive small bowel resection and induces adaptation of the remaining intestine. Ileocecal resection (ICR) is the most frequent situation in humans. Villus hypertrophy is one hallmark of mucosal adaptation, but the functional mechanisms of mucosal adaptation are incompletely understood. AIMS: The aim of the study was to characterize a clinically relevant model of short bowel syndrome but not intestinal failure in mice and to identify outcome predictors and mechanisms of adaptation. METHODS: Male C57BL6/J mice underwent 40% ICR and were followed for 7 or 14 days. Small bowel transection served as control. All mice underwent autopsy. Survival, body weight, wellness score, stool water content, plasma aldosterone concentrations, and paracellular permeability were recorded. RESULTS: Unlike controls, resected mice developed significant diarrhea with increased stool water. This was accompanied by sustained weight loss throughout follow-up. Villus length increased but did not correlate positively with adaptation. Plasma aldosterone concentrations correlated inversely with body weight at day 14. After ICR, intestinal epithelial (i.e., tight junctional) sodium permeability was increased. CONCLUSIONS: 40% ICR results in moderate to severe short bowel syndrome. Successful adaptation to the short bowel situation involves villus elongation but does not correlate with the degree of villus elongation alone. In addition, increased intestinal epithelial sodium permeability facilitates sodium-coupled solute transport. Hyperaldosteronism correlates with the severity of weight loss, indicates volume depletion, and counterregulates water loss.

Alterations in the mucosa-associated bacterial composition in Crohn's disease: a pilot study.

INTRODUCTION: Changes in the intestinal bacterial composition seem to play a major role in the pathogenesis and in the clinical course of inflammatory bowel diseases (IBD), which consist of Crohn's disease (CD), and ulcerative colitis (UC). Mutations in the NOD2 gene are the most important genetic risk factors for the development of CD. In this study, the association between mucosal biopsies and the mucosa-associated bacterial composition from CD and UC patients regarding their genetic risk factors (mutations in the NOD2 gene), their endoscopic activity, and their medical therapy (TNF-α blocking therapy) was examined. MATERIAL AND METHODS: Seventy biopsies from routine colonoscopies from 33 IBD patients (26 CD and 7 UC) were obtained. Disease activity and clinical characteristics were assessed. Seven different bacterial strains (Bacteroides fragilis, Escherichia coli, Prevotella melaninogenica, Clostridium coccoides, Clostridium difficile, Bifidobacterium bifidum, and Faecalibacterium prausnitzii) were quantified using real-time PCR. NOD2 genotyping from patients with CD was performed. RESULTS: Five of the 24 patients were positive for at least one mutation in the NOD2 gene. The bacterial composition was different in CD compared to UC, in macroscopic healthy compared to macroscopic inflamed biopsies, in NOD2 mutated compared to NOD2 wildtype patients, and in patients receiving TNF-α blocking therapy compared to patients without this treatment. CONCLUSION: This study further characterizes the mucosa-associated bacteria in IBD patients. Different clinical situations lead to an altered mucosa-associated bacterial composition. The analyzed bacteria could be promising targets for cost-effective surveillance or therapies in IBD patients.

Anti-apoptotic therapeutic approaches in liver diseases: do they really make sense?

A variety of data suggesting apoptotic cell death as a key feature of liver injury stimulated researchers to investigate the therapeutic potential of anti-apoptotic strategies in experimental models. However, the overestimated role of apoptotic cell death in liver injury has tempered the clinical translation of the protection afforded by anti-apoptotic regimes in experimental models. Thus, the hope for apoptosis modulation as potential treatment strategy for injured liver in humans could not be confirmed. Herein, we evaluated the degree of apoptosis in different hepatic stress models which are relevant for the human pathophysiology. Using morphological criteria of apoptosis, caspase-3 activation as well as TUNEL assay in combination with a positive control of apoptosis in liver injury, we quantified apoptotic cell death discriminating between parenchymal and non-parenchymal cells and confirmed these results by cleaved caspase-3 and PARP-1 protein expression. Discussing our findings and relating them to the existing literature on the potential role of apoptotic cell death, we strongly recommend reconsidering anti-apoptotic strategies to ameliorate liver injury efficiently.

Ileocolonic Healing after Small Ileocecal Resection in Mice: NOD2 Deficiency Impairs Anastomotic Healing by Local Mechanisms.

Ileocecal resection (ICR) is frequently performed in Crohn's disease (CD). NOD2 mutations are risk factors for CD. Nod2 knockout (ko) mice show impaired anastomotic healing after extended ICR. We further investigated the role of NOD2 after limited ICR. C57B16/J (wt) and Nod2 ko littermates underwent limited ICR including 1-2 cm terminal ileum and were randomly assigned to vehicle or MDP treatment. Bursting pressure was measured on POD 5, and the anastomosis was analyzed for matrix turn-over and granulation tissue. Wound fibroblasts from subcutaneously implanted sponges were used for comparison. The M1/M2 macrophage plasma cytokines were analyzed. Mortality was not different between groups. Bursting pressure was significantly decreased in ko mice. This was associated with less granulation tissue but was not affected by MDP. However, anastomotic leak (AL) rate tended to be lower in MDP-treated ko mice (29% vs. 11%, p = 0.07). mRNA expression of collagen-1α (col1 α), collagen-3α (col3 α), matrix metalloproteinase (mmp)2 and mmp9 was increased in ko mice, indicating increased matrix turn-over, specifically in the anastomosis. Systemic TNF-α expression was significantly lower in ko mice. Ileocolonic healing is impaired in Nod2 ko mice after limited ICR by local mechanisms maybe including local dysbiosis.

Analysis of ESPEN and GLIM algorithms reveals specific drivers for the diagnosis of malnutrition in patients with chronic gastrointestinal diseases.

OBJECTIVES: Disease-related malnutrition (MN) is common in patients with liver cirrhosis (LC), short bowel syndrome (SBS), and chronic pancreatitis (CP). Different MN risk screening tools and diagnostic criteria of the European Society for Clinical Nutrition and Metabolism (ESPEN) and Global Leadership Initiative on Malnutrition (GLIM) algorithms were analyzed for their diagnostic accuracy and role as specific drivers to diagnose MN in patients with LC, SBS, and CP. METHODS: A total of 187 patients with LC, SBS, and CP, as well as control patients were prospectively recruited in a multicenter cross-sectional study. MN risk was screened using Nutritional Risk Screening 2002 (NRS-2002), the Malnutrition Universal Screening Tool (MUST), and the Royal Free Hospital Nutritional Prioritizing Tool (RFH-NPT), and diagnosed using the ESPEN, GLIM, and GLIMCRP+ (GLIM incorporating C-reactive protein [CRP] >5 mg/L) algorithms. For each of the individual diagnostic criteria, relative frequency, sensitivity, specificity, as well as positive and negative predictive values were calculated. RESULTS: NRS-2002 was only sensitive in conjunction with ESPEN, while MUST was sensitive additionally with the GLIM algorithm. RFH-NPT worked the best for LC. GLIM and GLIMCRP+ diagnosed MN more frequently than the ESPEN algorithm. Diagnostic criteria were detected at remarkably different relative frequencies starting with reduced food intake/malabsorption and chronic disease/inflammation, followed by weight loss, reduced fat-free mass index, low body mass index, and body mass index <18.5 kg/m². Relative frequencies differed between LC, SBS, and CP. Weight loss in LC and CP and reduced fat-free mass index and food intake in SBS had good diagnostic accuracy, suggesting that these criteria act as specific drivers for MN. CONCLUSIONS: RFH-NPT and MUST performed better in conjunction with the GLIM algorithm than NRS-2002. MN was diagnosed more frequently by GLIM than the ESPEN algorithm in LC, SBS, and CP. Individual criteria acted as specific drivers in MN in chronic gastrointestinal diseases.

Orally compensated short bowel patients are thin, potentially malnourished but rarely sarcopenic.

BACKGROUND AND AIM: In short bowel syndrome, insufficient absorptive capacity of the remnant bowel may lead to metabolic and nutritional consequences including electrolyte disturbances, severe diarrhea and malnutrition. While intestinal failure requires parenteral nutrition, short bowel patients with intestinal insufficiency (SB/II) have achieved oral autonomy. The aim of this exploratory study was to assess the nutritional, muscular and functional status of orally compensated SB/II patients. METHODS: 28 orally compensated SB/II patients with a mean of 46 months after termination of parenteral nutrition and 56 age- and sex-matched healthy controls (HC) were compared regarding anthropometric parameters, body composition using bioelectrical impedance analysis, handgrip strength and gait speed, blood parameters as well as nutritional intake and physical activity using validated questionnaires. Malnutrition and sarcopenia were diagnosed according to the criteria of the GLIM or EWGSOP2. RESULTS: SB/II patients had lower body mass index (BMI) and anthropometric parameters than HC but were within the normal weight range. The GLIM algorithm operationally diagnosed malnutrition in 39% (n = 11) of SB/II patients. Reduced skeletal muscle mass index and phase angle were rarely accompanied by a reduction of handgrip strength below cut-off values and the subsequent diagnosis of sarcopenia in SB/II patients (15%, n = 4). Compared to 11% of HC, 37% of SB/II patients had low physical activity level. Female SB/II patients had higher caloric and macronutrient intake. Caloric intake negatively correlated with body weight indicating compensatory hyperphagia in patients with lower body weight. Some of the SB/II patients showed signs of dehydration. CONCLUSIONS: Orally compensated SB/II patients are thinner than HC but have mostly normal BMI. Malnutrition is frequently diagnosed but may be overestimated due to the underlying malabsorption and its interplay with hyperphagia. Muscle mass is often reduced but is rarely accompanied by functional impairment leading to sarcopenia diagnosis. Thus, SB/II patients long term after termination of parenteral support may be malnourished but usually do not develop sarcopenia.

Body impedance analysis to estimate malnutrition in inflammatory bowel disease patients - A cross-sectional study.

OBJECTIVE: Malnutrition is a common clinical problem in patients with inflammatory bowel diseases (IBD). However, a gold standard for the detection of malnutrition in IBD patients is lacking. METHODS: A cross-sectional study to assess malnutrition in patients with IBD and healthy controls (HCs). Clinical characteristics (Montreal classification, disease activity, previous surgery) and mutations in the NOD2 gene in patients with Crohn's disease (CD) were obtained. We performed a nutritional assessment with screening for nutritional risk and diagnosis for malnutrition (Malnutrition Universal Screening Tool [MUST]) score, NRS-2002, European Society for Clinical Nutrition and Metabolism (ESPEN), and Global Leadership Initiative on Malnutrition (GLIM) criteria and performed body impedance analysis (BIA). RESULTS: 101 IBD patients (57 CD and 44 ulcerative colitis (UC) and 50 HC were included in a single northern German tertiary center. GLIM criteria detected malnutrition significantly more often compared to the ESPEN criteria. Active disease, a long-standing disease course, and previous surgery were associated with reduced muscle mass. IBD patients had a higher fat mass index compared to HC. Mutations in the NOD2 gene had no effect on nutritional status. CONCLUSIONS: The GLIM criteria detect malnutrition at a higher rate compared to ESPEN. Specific disease factors might put IBD patients at a higher risk for the development of malnutrition, so these patients might benefit from a frequently performed screening, which might result in a favorable disease course.

In silico investigation of molecular networks linking gastrointestinal diseases, malnutrition, and sarcopenia.

Malnutrition (MN) is a common primary or secondary complication in gastrointestinal diseases. The patient's nutritional status also influences muscle mass and function, which can be impaired up to the degree of sarcopenia. The molecular interactions in diseases leading to sarcopenia are complex and multifaceted, affecting muscle physiology, the intestine (nutrition), and the liver at different levels. Although extensive knowledge of individual molecular factors is available, their regulatory interplay is not yet fully understood. A comprehensive overall picture of pathological mechanisms and resulting phenotypes is lacking. In silico approaches that convert existing knowledge into computationally readable formats can help unravel mechanisms, underlying such complex molecular processes. From public literature, we manually compiled experimental evidence for molecular interactions involved in the development of sarcopenia into a knowledge base, referred to as the Sarcopenia Map. We integrated two diseases, namely liver cirrhosis (LC), and intestinal dysfunction, by considering their effects on nutrition and blood secretome. We demonstrate the performance of our model by successfully simulating the impact of changing dietary frequency, glycogen storage capacity, and disease severity on the carbohydrate and muscle systems. We present the Sarcopenia Map as a publicly available, open-source, and interactive online resource, that links gastrointestinal diseases, MN, and sarcopenia. The map provides tools that allow users to explore the information on the map and perform in silico simulations.

Malnutrition Is Highly Prevalent in Patients With Chronic Pancreatitis and Characterized by Loss of Skeletal Muscle Mass but Absence of Impaired Physical Function.

Background/Aims: Patients with chronic pancreatitis (CP) have an increased risk of malnutrition, a condition linked to reduced muscle mass and physical performance. We have investigated the risk factors, phenotypic presentation, and health implications associated with malnutrition in CP. Materials and Methods: In a multicenter cross-sectional study we recruited patients with confirmed CP and healthy volunteers as a control group. Malnutrition was diagnosed according to the criteria proposed by the Global Leadership Initiative on Malnutrition. We performed detailed examinations of body composition and physical function as well as testing of routine blood parameters and markers of inflammation. Results: We included 66 patients [mean (±SD) age: 56.0 (±14.5) years; 51 males] and an equal number of age- and sex-matched controls. Moderate malnutrition was diagnosed in 21% (n = 14) and severe malnutrition in 42% (n = 28) of patients. Besides weight loss malnourished patients showed lower fat and skeletal muscle mass compared to both non-malnourished subjects and healthy controls. Only in severe malnutrition, blood parameters reflected elevated inflammation and reduced muscle reserves. Handgrip strength in patients did not differ by nutritional status but there was a significant correlation (rho = 0.705, p < 0.001) with skeletal muscle mass. Although 20 patients (30%) had pathologically reduced skeletal muscle mass, only two individuals (3%) had sarcopenia with concomitantly reduced handgrip strength. Conclusion: Malnutrition is a frequent complication of CP characterized by loss of skeletal muscle mass. As this condition becomes evident only at an advanced stage, regular testing for altered body composition is recommended. Suitable biomarkers and the link between loss of muscle mass and physical function require further investigation. Clinical Trial Registration: [https://clinicaltrials.gov/ct2/show/NCT04474743], identifier [NCT04474743].

Ileocolonic Healing After Extended Small Bowel Resection in Mice: NOD2 Deficiency Impairs Anastomotic Healing and Postoperative Outcome.

BACKGROUND: Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) mutations are a genetic risk factor for Crohn disease. Ileocecal resection is the most often performed surgery in Crohn disease. We investigated the effect of Nod2 knockout (KO) status on anastomotic healing after extended ileocecal resection (ICR) in mice. METHODS: Male C57BL6/J wild-type and Nod2 KO mice underwent an 11 cm resection of the terminal ileum including the cecum. An end-to-end jejuno-colostomy was performed. Animals were killed after 5 days investigating bursting pressure, hydroxyproline content, and expression of matrix metabolism genes, key cytokines, and histology of the anastomosis. RESULTS: Mortality was higher in the Nod2 KO group but not because of local or septic complications. Bursting pressure was significantly reduced in the Nod2 KO mice (32.5 vs 78.0 mmHg, P < 0.0024), whereas hydroxyprolin content was equal. The amount of granulation tissue at the anastomosis was similar but more unstructured in the Nod2 KO mice. Gene expression measured by real-time polymerase chain reaction showed significantly increased expression for Collagen 1alpha and for collagen degradation as measured by matrix metalloproteinase-2, -9, and -13 in the Nod2 KO mice. Gelatinase activity from anastomotic tissue was enhanced by Nod2 status. Gene expression of arginase I, tumor necrosis factor-α, and transforming growth factor-ß but not inducible nitric oxide synthase were also increased at the anastomosis in the Nod2 KO mice compared with the control mice. CONCLUSIONS: We found that Nod2 deficiency results in significantly reduced bursting pressure after ileocecal resection. This effect is mediated via an increased matrix turnover. Patients with genetic NOD2 variations may be prone to anastomotic failure after bowel resection.

Mucosa-attached bacterial community in Crohn's disease coheres with the clinical disease activity index.

In inflammatory bowel diseases (IBD), microbial communities often become imbalanced suggesting abnormal microbial-gut interactions. In this study, we analysed the mucosa-attached gut microbiota from 26 Crohn's disease (CD) patients using 16S rRNA gene amplicon sequencing. The samples were stratified according to their disease activity (Crohn's disease activity index, CDAI). The different disease activity categories had a comparable bacterial richness. Bacterial communities of patients in remission and intermediate CDAI (0-220) were relatively similar and dominated by the genus Bacteroides (>40%). The bacterial composition of patients assigned to a high CDAI category was dominated by Pelomonas (25%) and Flavobacterium (13%) but had a low relative abundance of Bacteroidetes (4%). This indicates the presence of specific abundant bacterial taxa at different CDAI levels. In addition, bacterial communities were also significantly influenced when a tumour necrosis factor (TNF)-α inhibitor was applied or by the local mucosal inflammation level. As a consequence, a shift of the microbial composition may also indicate a change of the disease activity in CD patients.