Liver cirrhosis and antibiotic therapy but not TIPS application leads to a shift of the intestinal bacterial communities: A controlled, prospective study

OBJECTIVES

The gut-liver axis is discussed to play an important role in hepatic cirrhosis. Decompensated liver cirrhosis is associated with portal hypertension, which can lead to a variety of complications. Transjugular intrahepatic portosystemic shunt (TIPS) is an established treatment option for the complications of portal hypertension. In this study we focused on the effect of TIPS on intestinal microbial composition in cirrhotic patients.

METHODS

Thirty patients with liver cirrhosis were compared to 18 healthy adults. Seventeen patients with cirrhosis and portal hypertension received a TIPS. Clinical characteristics, including age, sex, and liver function measured with a Child-Pugh score and model for end-stage liver disease score, were obtained. Intestinal microbial composition was assessed via 16S rRNA gene amplicon sequencing from stool probes before and after TIPS.

RESULTS

TIPS led to a reduction of hepatic venous pressure gradient. However, TIPS did not cause a shift in the intestinal bacterial communities. Independent from the application of TIPS, antibiotic therapy was associated with a significant difference in the intestinal bacterial microbiota and also a reduced α-diversity. In addition, a significant difference was observed in the intestinal bacterial composition between patients with liver cirrhosis and healthy controls.

CONCLUSION

The presence of liver cirrhosis and the use of antibiotic therapy, but not the application of TIPS, were associated with a significant shift of the intestinal bacterial communities, showing a high impact on the microbiota of patients with liver cirrhosis.

Direct-Current Electrical Field Stimulation of Patient-Derived Colorectal Cancer Cells

Several cues for a directional migration of colorectal cancer cells were identified as being crucial in tumor progression. However, galvanotaxis, the directional migration in direct-current electrical fields, has not been investigated so far. Therefore, we asked whether direct-current electrical fields could be used to mobilize colorectal cancer cells along field vectors. For this purpose, five patient-derived low-passage cell lines were exposed to field strengths of 150-250 V/m in vitro, and migration along the field vectors was investigated. To further study the role of voltage-gated calcium channels on galvanotaxis and intracellular signaling pathways that are associated with migration of colorectal cancer cells, the cultures were exposed to selective inhibitors. In three out of five colorectal cancer cell lines, we found a preferred cathodal migration. The cellular integrity of the cells was not impaired by exposure of the cells to the selected field strengths. Galvanotaxis was sensitive to inhibition of voltage-gated calcium channels. Furthermore, signaling pathways such as AKT and MEK, but not STAT3, were also found to contribute to galvanotaxis in our in vitro model system. Overall, we identify electrical fields as an important contributor to the directional migration of colorectal cancer cells.

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.

Uncoupling protein 2 deficiency of non-cancerous tissues inhibits the progression of pancreatic cancer in mice

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a disease of the elderly mostly because its development from preneoplastic lesions depends on the accumulation of gene mutations and epigenetic alterations over time. How aging of non-cancerous tissues of the host affects tumor progression, however, remains largely unknown.

METHODS

We took advantage of a model of accelerated aging, uncoupling protein 2-deficient (Ucp2 knockout, Ucp2 KO) mice, to investigate the growth of orthotopically transplanted Ucp2 wild-type (WT) PDAC cells (cell lines Panc02 and 6606PDA) in vivo and to study strain-dependent differences of the PDAC microenvironment.

RESULTS

Measurements of tumor weights and quantification of proliferating cells indicated a significant growth advantage of Panc02 and 6606PDA cells in WT mice compared to Ucp2 KO mice. In tumors in the knockout strain, higher levels of interferon-γ mRNA despite similar numbers of tumor-infiltrating T cells were observed. 6606PDA cells triggered a stronger stromal reaction in Ucp2 KO mice than in WT animals. Accordingly, pancreatic stellate cells from Ucp2 KO mice proliferated at a higher rate than cells of the WT strain when they were incubated with conditioned media from PDAC cells.

CONCLUSIONS

Ucp2 modulates PDAC microenvironment in a way that favors tumor progression and implicates an altered stromal response as one of the underlying mechanisms.

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 GLIM^CRP+ (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 GLIM^CRP+ 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.

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-β1 (Tgf-β1) and Ccn family member 1 (Ccn1). YAP signaling was activated by TGF-β1, but repressed by interferon-γ.

CONCLUSIONS

Activated YAP enhanced PSCs proliferation. The antifibrotic potential of Hippo pathway inhibitors warrants further investigation.

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.

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

<b><i>Introduction:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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. <b><i>Conclusion:</i></b> 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.

Inhibition of KRAS, MEK and PI3K Demonstrate Synergistic Anti-Tumor Effects in Pancreatic Ductal Adenocarcinoma Cell Lines

Kirsten rat sarcoma virus (KRAS) mutations are widespread in pancreatic ductal adenocarcinoma (PDAC) and contribute significantly to tumor initiation, progression, tumor relapse/resistance, and prognosis of patients. Although inhibitors against KRAS mutations have been developed, this therapeutic approach is not routinely used in PDAC patients. We investigated the anti-tumor efficacy of two KRAS inhibitors BI-3406 (KRAS::SOS1 inhibitor) and sotorasib (KRAS G12C inhibitor) alone or in combination with MEK1/2 inhibitor trametinib and/or PI3K inhibitor buparlisib in seven PDAC cell lines. Whole transcriptomic analysis of combined inhibition and control groups were comparatively analyzed to explore the corresponding mechanisms of inhibitor combination. Both KRAS inhibitors and corresponding combinations exhibited cytotoxicity against specific PDAC cell lines. BI-3406 enhance the efficacy of trametinib and buparlisib in BXPC-3, ASPC-1 and MIA PACA-2, but not in CAPAN-1, while sotorasib enhances the efficacy of trametinib and buparlisib only in MIA PACA-2. The whole transcriptomic analysis demonstrates that the two triple-inhibitor combinations exert antitumor effects by affecting related cell functions, such as affecting the immune system, cell adhesion, cell migration, and cytokine binding. As well as directly involved in RAF/MEK/ERK pathway and PI3K/AKT pathway affect cell survival. Our current study confirmed inhibition of KRAS and its downstream pathways as a potential novel therapy for PDAC and provides fundamental data for in vivo evaluations.

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].

The dual GLP-1 and GLP-2 receptor agonist dapiglutide promotes barrier function in murine short bowel

Short bowel syndrome can occur after extensive intestinal resection, causing intestinal insufficiency or intestinal failure, which requires long-term parenteral nutrition. Glucagon-like peptide-2 (GLP-2) pharmacotherapy is now clinically used to reduce the disease burden of intestinal failure. However, many patients still cannot be weaned off from parenteral nutrition completely. The novel dual GLP-1 and GLP-2 receptor agonist dapiglutide has previously been shown to be highly effective in a preclinical murine short bowel model. Here, we studied the effects of dapiglutide on intestinal epithelial barrier function. In the jejunum, dapiglutide increased claudin-7 expression and tightened the paracellular tight junction leak pathway. At the same time, dapiglutide promoted paracellular tight junction cation size selectivity in the jejunum. This was paralleled by extension of the cation selective tight junction proteins claudin-2 and claudin-10b and preserved claudin-15 expression and localization along the crypt-villus axis in the jejunum. In the colon, no barrier effects from dapiglutide were observed. In the colon, dapiglutide attenuated the short bowel-associated, compensatorily increased epithelial sodium channel activity, likely secondary, by improved volume status. Future studies are needed to address the intestinal adaptation of the colon.

Dapiglutide, a novel dual GLP-1 and GLP-2 receptor agonist, attenuates intestinal insufficiency in a murine model of short bowel

BACKGROUND

Extensive intestinal resection may lead to short bowel (SB) syndrome, resulting in intestinal insufficiency or intestinal failure (IF). Intestinal insufficiency and IF involve deficiency of the proglucagon-derived hormones glucagon-like peptide-1 (GLP-1) and GLP-2. Two major problems of SB are epithelial surface loss and accelerated transit. Standard treatment now targets intestinal adaptation with a GLP-2 analogue to enlarge absorptive surface area. It is possible that additional benefit can be gained from a combination of GLP-1 and GLP-2 activity, with the aim to enlarge intestinal surface area and slow intestinal transit.

METHODS

The GLP-1- and GLP-2-specific effects of the novel dual GLP-1 receptor (GLP-1R) and GLP-2 receptor (GLP-2R) agonist dapiglutide (rINN) were characterized in rodents. Furthermore, in a murine SB model of intestinal insufficiency with 40% ileocecal resection, the influence of dapiglutide on intestinal growth, body weight, food intake, volume status, and stool water content was tested against vehicle and sham-operated male mice.

RESULTS

Dapiglutide significantly improves oral glucose tolerance, reduces intestinal transit time, and promotes intestinal growth. In the SB mouse model, dapiglutide promotes body weight recovery, despite unchanged intake of liquid diet. Dapiglutide promotes significant intestinal growth, as indicated by significantly increased villus height as well as intestinal length. Furthermore, dapiglutide reduces stool water losses, resulting in reduced plasma aldosterone.

CONCLUSION

Dapiglutide possesses specific and potent GLP-1R and GLP-2R agonist effects in rodents. In the murine SB model, combined unimolecular GLP-1R and GLP-2R stimulation with dapiglutide potently attenuates intestinal insufficiency and potentially also IF.

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.

Study protocol P-MAPS: microbiome as predictor of severity in acute pancreatitis-a prospective multicentre translational study

Background

Acute pancreatitis (AP) is an inflammatory disorder that causes a considerable economic health burden. While the overall mortality is low, around 20% of patients have a complicated course of disease resulting in increased morbidity and mortality. There is an emerging body of evidence that the microbiome exerts a crucial impact on the pathophysiology and course of AP. For several decades multiple clinical and laboratory parameters have been evaluated, and complex scoring systems were developed to predict the clinical course of AP upon admission. However, the majority of scoring systems are determined after several days and achieve a sensitivity around 70% for early prediction of severe AP. Thus, continued efforts are required to investigate reliable biomarkers for the early prediction of severity in order to guide early clinical management of AP patients.

Methods

We designed a multi-center, prospective clinical-translational study to test whether the orointestinal microbiome may serve as novel early predictor of the course, severity and outcome of patients with AP. We will recruit 400 AP patients and obtain buccal and rectal swabs within 72 h of admission to the hospital. Following DNA extraction, microbiome analysis will be performed using 3rd generation sequencing Oxford Nanopore Technologies (ONT) for 16S rRNA and metagenomic sequencing. Alpha- and beta-diversity will be determined and correlated to the revised Atlanta classification and additional clinical outcome parameters such as the length of hospital stay, number and type of complications, number of interventions and 30-day mortality.

Discussion

If AP patients show a distinct orointestinal microbiome dependent on the severity and course of the disease, microbiome sequencing could rapidly be implemented in the early clinical management of AP patients in the future.

Trial registration: ClinicalTrials.gov Identifier: NCT04777812

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.

Towards biomarkers for outcomes after pancreatic ductal adenocarcinoma and ischaemic stroke, with focus on (co)-morbidity and ageing/cellular senescence (SASKit): protocol for a prospective cohort study

INTRODUCTION

Ageing-related processes such as cellular senescence are believed to underlie the accumulation of diseases in time, causing (co)morbidity, including cancer, thromboembolism and stroke. Interfering with these processes may delay, stop or reverse morbidity. The aim of this study is to investigate the link between (co)morbidity and ageing by exploring biomarkers and molecular mechanisms of disease-triggered deterioration in patients with pancreatic ductal adenocarcinoma (PDAC) and (thromboembolic) ischaemic stroke (IS).

METHODS AND ANALYSIS

We will recruit 50 patients with PDAC, 50 patients with (thromboembolic) IS and 50 controls at Rostock University Medical Center, Germany. We will gather routine blood data, clinical performance measurements and patient-reported outcomes at up to seven points in time, alongside in-depth transcriptomics and proteomics at two of the early time points. Aiming for clinically relevant biomarkers, the primary outcome is a composite of probable sarcopenia, clinical performance (described by ECOG Performance Status for patients with PDAC and the Modified Rankin Scale for patients with stroke) and quality of life. Further outcomes cover other aspects of morbidity such as cognitive decline and of comorbidity such as vascular or cancerous events. The data analysis is comprehensive in that it includes biostatistics and machine learning, both following standard role models and additional explorative approaches. Prognostic and predictive biomarkers for interventions addressing senescence may become available if the biomarkers that we find are specifically related to ageing/cellular senescence. Similarly, diagnostic biomarkers will be explored. Our findings will require validation in independent studies, and our dataset shall be useful to validate the findings of other studies. In some of the explorative analyses, we shall include insights from systems biology modelling as well as insights from preclinical animal models. We anticipate that our detailed study protocol and data analysis plan may also guide other biomarker exploration trials.

ETHICS AND DISSEMINATION

The study was approved by the local ethics committee (Ethikkommission an der Medizinischen Fakultät der Universität Rostock, A2019-0174), registered at the German Clinical Trials Register (DRKS00021184), and results will be published following standard guidelines.

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.

Impact of diet and genes on murine autoimmune pancreatitis

The impact of environmental factors, such as diet, and the genetic basis of autoimmune pancreatitis (AIP) are largely unknown. Here, we used an experimental murine AIP model to identify the contribution of diet to AIP development, as well as to fine-map AIP-associated genes in outbred mice prone to develop the disease. For this purpose, we fed mice of an autoimmune-prone intercross line (AIL) three different diets (control, calorie-reduced and western diet) for 6 months, at which point the mice were genotyped and phenotyped for AIP. Overall, 269 out of 734 mice (36.6%) developed AIP with signs of parenchymal destruction, equally affecting mice of both sexes. AIP prevalence and severity were reduced by approximately 50% in mice held under caloric restriction compared to those fed control or western diet. We identified a quantitative trait locus (QTL) on chromosome 4 to be associated with AIP, which is located within a previously reported QTL. This association does not change when considering diet or sex as an additional variable for the mapping. Using whole-genome sequences of the AIL founder strains, we resolved this QTL to a single candidate gene, namely Map3k7. Expression of Map3k7 was largely restricted to islet cells as well as lymphocytes found in the exocrine pancreas of mice with AIP. Our studies suggest a major impact of diet on AIP. Furthermore, we identify Map3k7 as a novel susceptibility gene for experimental AIP. Both findings warrant clinical translation.

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.

Genetic association analysis of CLEC5A and CLEC7A gene single-nucleotide polymorphisms and Crohn’s disease

BACKGROUND

Crohn’s disease (CD) is characterized by a multifactorial etiology and a significant impact of genetic traits. While NOD2 mutations represent well established risk factors of CD, the role of other genes is incompletely understood.

AIM

To challenge the hypothesis that single nucleotide polymorphisms (SNPs) in the genes CLEC5A and CLEC7A, two members of the C-type lectin domain family of pattern recognition receptors, may be associated with CD.

METHODS

SNPs in CLEC5A, CLEC7A and the known CD risk gene NOD2 were studied using real time PCR-based SNP assays. Therefore, DNA samples from 175 patients and 157 healthy donors were employed. Genotyping data were correlated with clinical characteristics of the patients and the results of gene expression data analyses.

RESULTS

In accordance with previous studies, rs2066844 and rs2066847 in NOD2 were found to be significantly associated with CD (allelic P values = 0.0368 and 0.0474, respectively). Intriguingly, for genotype AA of rs1285933 in CLEC5A, a potential association with CD (recessive P = 0.0523; odds ratio = 1.90) was observed. There were no associations between CD and SNPs rs2078178 and rs16910631 in CLEC7A. Variants of rs1285933 had no impact on CLEC5A gene expression. In contrast, genotype-dependent differences of CXCL5 expression in peripheral blood mononuclear cells were observed. There is no statistical interaction between the tested SNPs of NOD2 and CLEC5A, suggesting of a novel pathway contributing to the disease.

CONCLUSION

Our data encourage enlarged follow-up studies to further address an association of SNP rs1285933 in CLEC5A with CD. The C-type lectin domain family member also deserves attention regarding a potential role in the pathophysiology of CD.

Different characteristics of chronic dibutyltin dichloride-induced pancreatitis and cholangitis in mouse and rat

BACKGROUND

Current animal models of chronic pancreatitis (CP) often provide only limited pathophysiological insights since they incompletely reflect the human disease. CP induced by injection of dibutyltin dichloride (DBTC-pancreatitis) shares with human CP the important feature of extended fibrosis and would be an even more attractive model if it could be transferred from rats to mice, as recently suggested in the context of combined ethanol and DBTC application. This study aimed to evaluate the effects of DBTC in pancreas and liver of C57BL/6 mice, a strain commonly used to engineer genetic mouse models.

METHODS

C57BL/6 mice and Lewis rats were exposed to variable doses of DBTC. After an investigation period of up to 4 weeks, laboratory findings and histopathological changes of pancreas and liver were evaluated.

RESULTS

Chronic DBTC-pancreatitis in rats was characterized by acinar cell damage, ductal changes, fibrosis, and inflammatory cell infiltrates. Mice treated with DBTC at 6-8 mg/kg body weight, the standard doses in rats, showed transient increases of lipase activities but no morphological signs of chronic DBTC-pancreatitis 4 weeks after injection of the drug. Increased doses of 10-12 mg/kg DBTC were intolerable due to their high toxicity. In contrast, mice and rats presented with a similar histopathology of the liver that can be characterized as a chronic-proliferative DBTC-cholangitis with predominating damage and proliferation of the small bile ducts as well as secondary portal inflammatory cell infiltrates and a beginning portal fibrosis.

CONCLUSIONS

The DBTC-model cannot be transferred from rats to C57BL/6 mice with respect to chronic DBTC-pancreatitis, but might be of interest to study DBTC-cholangitis in both species.

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.

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.

Blocking Autophagy in Cancer-Associated Fibroblasts Supports Chemotherapy of Pancreatic Cancer Cells

In this study we evaluated the interaction of pancreatic cancer cells, cancer-associated fibroblasts, and distinct drugs such as α-cyano-4-hydroxycinnamate, metformin, and gemcitabine. We observed that α-cyano-4-hydroxycinnamate as monotherapy or in combination with metformin could significantly induce collagen I deposition within the stromal reaction. Subsequently, we demonstrated that cancer-associated fibroblasts impaired the anti-proliferation efficacy of α-cyano-4-hydroxycinnamate, metformin and gemcitabine. Interestingly, inhibition of autophagy in these fibroblasts can augment the anti-proliferation effect of these chemotherapeutics in vitro and can reduce the tumor weight in a syngeneic pancreatic cancer model. These results suggest that inhibiting autophagy in cancer-associated fibroblasts may contribute to strategies targeting cancer.

Mutations in the NOD2 gene are associated with a specific phenotype and lower anti-tumor necrosis factor trough levels in Crohn's disease

OBJECTIVE

Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) gene mutations are known to be an important risk factor in the pathogenesis of Crohn's disease (CD). Specific disease phenotypes are associated with the presence of NOD2 gene mutation. One treatment option is to use an anti-tumor necrosis factor (TNF)-α agent. Therapeutic drug monitoring (TDM) is usually performed in cases of a loss of response. Our aim was to explore whether NOD2 gene mutations have an effect on the disease phenotype, vitamin D levels, and on TDM in CD patients.

METHODS

This was a retrospective genotype-phenotype association study on NOD2 gene mutations in 161 patients with CD.

RESULTS

Altogether 55 (34.2%) patients carried at least one mutant allele of NOD2. NOD2 gene mutations were associated with ileocecal disease, ileocecal resection, stricturing and perianal disease, and patients with NOD2 gene mutation had significantly less frequent colonic disease and received an ostomy less frequently. TDM in patients with NOD2 gene mutation showed more frequent anti-TNF trough levels in the subtherapeutic range and lower anti-TNF trough levels than in NOD2 wild-type (WT) patients.

CONCLUSIONS

CD patients with NOD2 gene mutation have a specific clinical phenotype and they may require higher doses of anti-TNF agents to achieve sufficient anti-TNF trough levels. They may therefore benefit from a proactive TDM than a reactive approach. This could be another step in the direction of personalized medicine.

Impact of hyperglycemia on autoimmune pancreatitis and regulatory T-cells

AIM

To evaluate the influence of hyperglycemia on the progression of autoimmune pancreatitis.

METHODS

We induced hyperglycemia by repetitive intraperitoneal (ip) injection of 50 mg/kg streptozotocin in MRL/MpJ mice, which develop autoimmune pancreatitis due to a genetic predisposition. We compared the extent of inflammation (histological score, CD3+ lymphocytes, CD8+ T-cells, CD4+ T-cells, Foxp3+ T-helper cells) in the pancreas of hyperglycemic and normoglycemic mice. We also analyzed the number of leukocytes, lymphocytes, granulocytes and monocytes in the blood. In addition, we determined the percentage of CD3+ lymphocytes, CD8+ T-cells, CD4+ T-cells, Foxp3+ T-helper cells, Foxp3+ CD25+ T-helper and Foxp3- T-helper cells in the spleen by flow cytometry.

RESULTS

Treatment with streptozotocin caused a strong induction of hyperglycemia and a reduction in body weight (P < 0.001). Severe hyperglycemia did not, however, lead to an aggravation, but rather to a slight attenuation of autoimmune pancreatitis. In the pancreas, both the histological score of the pancreas as well as the number of CD3+ lymphocytes (P < 0.053) were decreased by hyperglycemia. No major changes in the percentage of CD8+ T-cells, CD4+ T-cells, Foxp3+ T-helper cells were observed between hyperglycemic and normoglycemic mice. Hyperglycemia increased the numbers of leukocytes (P < 0.001), lymphocytes (P = 0.016), granulocytes and monocytes (P = 0.001) in the blood. Hyperglycemia also moderately reduced the percentage of CD3+ lymphocytes (P = 0.057), significantly increased the percentage of Foxp3+ T-helper cells (P = 0.018) and Foxp3+ CD25+ T-helper cells (P = 0.021) and reduced the percentage of Foxp3- T-helper cells (P = 0.034) in the spleen.

CONCLUSION

Hyperglycemia does not aggravate but moderately attenuates autoimmune pancreatitis, possibly by increasing the percentage of regulatory T-cells in the spleen.

Intramyocardial angiogenetic stem cells and epicardial erythropoietin save the acute ischemic heart

Ischemic heart failure is the leading cause of mortality worldwide. An early boost of intracardiac regenerative key mechanisms and angiogenetic niche signaling in cardiac mesenchymal stem cells (MSCs) could improve myocardial infarction (MI) healing. Epicardial erythropoietin (EPO; 300 U kg^-1) was compared with intraperitoneal and intramyocardial EPO treatments after acute MI in rats (n=156). Real-time PCR and confocal microscopy revealed that epicardial EPO treatment enhanced levels of intracardiac regenerative key indicators (SDF-1, CXCR4, CD34, Bcl-2, cyclin D1, Cdc2 and MMP2), induced transforming growth factor β (TGF-β)/WNT signaling in intramyocardial MSC niches through the direct activation of AKT and upregulation of upstream signals FOS and Fzd7, and augmented intracardiac mesenchymal proliferation 24 h after MI. Cardiac catheterization and tissue analysis showed superior cardiac functions, beneficial remodeling and increased capillary density 6 weeks after MI. Concomitant fluorescence-activated cell sorting, co-cultures with neonatal cardiomyocytes, angiogenesis assays, ELISA, western blotting and RAMAN spectroscopy demonstrated that EPO could promote cardiomyogenic differentiation that was specific of tissue origin and enhance paracrine angiogenetic activity in cardiac CD45^-CD44⁺DDR2⁺ MSCs. Epicardial EPO delivery might be the optimal route for efficient upregulation of regenerative key signals after acute MI. Early EPO-mediated stimulation of mesenchymal proliferation, synergistic angiogenesis with cardiac MSCs and direct induction of TGF-β/WNT signaling in intramyocardial cardiac MSCs could initiate an accelerated healing process that enhances cardiac recovery.

Vitamin D administration leads to a shift of the intestinal bacterial composition in Crohn's disease patients, but not in healthy controls

OBJECTIVE

Dysbiosis is a common feature in the pathogenesis of inflammatory bowel diseases (IBD). Environmental factors, such as vitamin D deficiency, seem to play a role in the intestinal inflammation of IBD. The aim of this study was to investigate whether vitamin D administration has an impact on the bacterial composition in Crohn's disease (CD) compared to healthy controls (HC).

METHODS

A prospective, longitudinal, controlled interventional analysis was conducted in seven patients with CD in clinical remission and 10 HC to investigate the effect of orally administrated vitamin D on the intestinal bacterial composition using 16S ribosomal RNA gene amplicon sequencing. Clinical parameters were assessed.

RESULTS

In contrast to HC, microbial communities of CD patients changed significantly during early vitamin D administration. However, a further increase in vitamin D level was associated with a reversal of this effect and additionally with a decrease in the bacterial richness in the CD microbiome. Specific species with a high abundancy were found during vitamin D administration in CD, but not in HC; the abundancy of Alistipes, Barnesiella, unclassified Porphyromonadaceae (both Actinobacteria), Roseburia, Anaerotruncus, Subdoligranulum and an unclassified Ruminococaceae (all Firmicutes) increased significantly after 1-week vitamin D administration in CD.

CONCLUSIONS

Vitamin D has a specific influence on the bacterial communities in CD, but not in HC. Administration of vitamin D may have a positive effect in CD by modulating the intestinal bacterial composition and also by increasing the abundance of potential beneficial bacterial strains.

NOD2- and disease-specific gene expression profiles of peripheral blood mononuclear cells from Crohn’s disease patients

AIM

To investigate disease-specific gene expression profiles of peripheral blood mononuclear cells (PBMCs) from Crohn’s disease (CD) patients in clinical remission.

METHODS

Patients with CD in clinical remission or with very low disease activity according to the Crohn’s disease activity index were genotyped regarding nucleotide-binding oligomerization domain 2 (NOD2), and PBMCs from wild-type (WT)-NOD2 patients, patients with homozygous or heterozygous NOD2 mutations and healthy donors were isolated for further analysis. The cells were cultured with vitamin D, peptidoglycan (PGN) and lipopolysaccharide (LPS) for defined periods of time before RNA was isolated and subjected to microarray analysis using Clariom S assays and quantitative real-time PCR. NOD2- and disease-specific gene expression profiles were evaluated with repeated measure ANOVA by a general linear model.

RESULTS

Employing microarray assays, a total of 267 genes were identified that were significantly up- or downregulated in PBMCs of WT-NOD2 patients, compared to healthy donors after challenge with vitamin D and/or a combination of LPS and PGN (P < 0.05; threshold: ≥ 2-fold change). For further analysis by real-time PCR, genes with known impact on inflammation and immunity were selected that fulfilled predefined expression criteria. In a larger cohort of patients and controls, a disease-associated expression pattern, with higher transcript levels in vitamin D-treated PBMCs from patients, was observed for three of these genes, CLEC5A (P < 0.030), lysozyme (LYZ; P < 0.047) and TREM1 (P < 0.023). Six genes were found to be expressed in a NOD2-dependent manner (CD101, P < 0.002; CLEC5A, P < 0.020; CXCL5, P < 0.009; IL-24, P < 0.044; ITGB2, P < 0.041; LYZ, P < 0.042). Interestingly, the highest transcript levels were observed in patients with heterozygous NOD2 mutations.

CONCLUSION

Our data identify CLEC5A and LYZ as CD- and NOD2-associated genes of PBMCs and encourage further studies on their pathomechanistic roles.

Polymorphisms of the murine mitochondrial ND4, CYTB and COX3 genes impact hematopoiesis during aging

During aging, mitochondrial DNA (mtDNA) can accumulate mutations leading to increasing levels of reactive oxygen species (ROS). Increased ROS were described to activate formerly quiescent hematopoietic stem cells (HSC). Mutations in mtDNA were shown to enhance the risk for myelodysplastic syndrome and leukemia. However, the complex relationship between mtDNA variations, ROS and aging of the hematopoietic system is not fully understood.

Herein, three mouse strains with mtDNA polymorphisms in genes of respiratory chain complexes I (ND4), III (CYTB) and IV (COX3) were compared to a reference strain during aging. Analysis focused on ROS and ATP levels, bone marrow composition and blood counts. Additionally, hematopoietic restoration capacity following cytotoxic stress was tested.

Mice with polymorphisms in ND4 and CYTB gene had significantly decreasing ROS levels in bone marrow cells during aging, without effecting ATP levels. In addition, the frequency of stem and progenitor cells increased during aging but the amount of lymphocytes in the peripheral blood decreased during aging.

In summary, the presence of mtDNA polymorphisms affecting the respiratory chain complexes I, III and IV was associated with altered ROS levels as well as changes in BM and peripheral blood composition during aging.

Adoptive transfer of CD3+ T cells and CD4+ CD44high memory T cells induces autoimmune pancreatitis in MRL/MpJ mice

The immunopathogenesis of autoimmune pancreatitis (AIP) is poorly understood. Here, we have used MRL/MpJ mice, a model of spontaneous AIP, to address the role of cellular autoimmune processes in the initiation and progression of the disease. Therefore, different T cell subpopulations were adoptively transferred from sick to still healthy (but susceptible) MRL/MpJ mice. Unpurified splenocytes and CD3⁺ T cells both efficiently induced AIP, while CD4⁺ and CD8⁺ T cells alone, as well as splenocytes from healthy mice, were insufficient to trigger the disease. Strikingly, CD4⁺CD44^high memory T cells, although transferred at lower numbers than other T cells, also induced AIP in recipient mice. Employing a modified experimental design, we also evaluated the effects of regulatory T cells (T_regs) on the progression of AIP in already diseased mice. Under the given experimental conditions, there was no significant suppressive effect of adoptively transferred T_regs on pancreatic histopathology. The results of our studies suggest a key role of T cell‐mediated processes in murine AIP. The effects of CD4⁺CD44^high memory T cells are in accordance with genetic studies of our group, which had previously implicated this cell type into the pathogenesis of AIP. In follow‐up studies, we will focus on the interplay of cellular and humoral autoimmunity in the context of AIP.

Antifibrogenic effects of vitamin D derivatives on mouse pancreatic stellate cells

AIM

To study the molecular effects of three different D-vitamins, vitamin D2, vitamin D3 and calcipotriol, in pancreatic stellate cells (PSCs).

METHODS

Quiescent PSCs were isolated from mouse pancreas and activated in vitro by seeding on plastic surfaces. The cells were exposed to D-vitamins as primary cultures (early-activated PSCs) and upon re-culturing (fully-activated cells). Exhibition of vitamin A-containing lipid droplets was visualized by oil-red staining. Expression of α-smooth muscle actin (α-SMA), a marker of PSC activation, was monitored by immunofluorescence and immunoblot analysis. The rate of DNA synthesis was quantified by 5-bromo-2’-deoxyuridine (BrdU) incorporation assays. Real-time PCR was employed to monitor gene expression, and protein levels of interleukin-6 (IL-6) were measured by ELISA. Uptake of proline was determined using ¹⁸F-proline.

RESULTS

Sustained culture of originally quiescent PSCs induced cell proliferation, loss of lipid droplets and exhibition of stress fibers, indicating cell activation. When added to PSCs in primary culture, all three D-vitamins diminished expression of α-SMA (to 32%-39% of the level of control cells; P < 0.05) and increased the storage of lipids (scores from 1.97-2.15 on a scale from 0-3; controls: 1.49; P < 0.05). No such effects were observed when Dvitamins were added to fully-activated cells, while incorporation of BrdU remained unaffected under both experimental conditions. Treatment of re-cultured PSCs with Dvitamins was associated with lower expression of IL-6 (-42% to -49%; P < 0.05; also confirmed at the protein level) and increased expression of the vitamin D receptor gene (209%-321% vs controls; P < 0.05). There was no effect of Dvitamins on the expression of transforming growth factor-β1 and collagen type 1 (chain α1). The lowest uptake of proline, a main component of collagen, was observed in calcipotriol-treated PSCs.

CONCLUSION

The three D-vitamins inhibit, with similar efficiencies, activation of PSCs in vitro, but cannot reverse the phenotype once the cells are fully activated.

The mitochondrial uncoupling protein 2 gene is causal for the spontaneous polycystic liver diseases in mice

Polycystic liver diseases (PCLDs) are autosomal dominant disorders. To date, 3 genes are known to be associated with the disease, SEC63 and PRKCSH and LRP5. Here, we report that mice deficient in the mitochondrial uncoupling protein 2 gene (Ucp2^-/-) spontaneously developed PCLDs when they were over 12months old. Macroscopical observation, blood chemistry as well as histopathological analysis demonstrated the PCLDs found in Ucp2^-/- mice were very similar to the findings in human PCLDs. This is the first report describing the gene encoding mitochondrial protein is causative for PCLDs. UCP2 may be a biomarker of the PCLDs in humans.

Application of in vivo imaging techniques to monitor therapeutic efficiency of PLX4720 in an experimental model of microsatellite instable colorectal cancer

OBJECTIVES

Patient-derived tumor cell lines are a powerful tool to analyze the sensitivity of individual tumors to specific therapies in mice. An essential prerequisite for such an approach are reliable quantitative techniques to monitor tumor progression in vivo.

METHODS

We have employed HROC24 cells, grown heterotopically in NMRI Foxn1^nu mice, as a model of microsatellite instable colorectal cancer to investigate the therapeutic efficiencies of 5'-fluorouracil (5'-FU) and the mutant BRAF inhibitor PLX4720, a vemurafenib analogue, by three independent methods: external measurement by caliper, magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) with 2-deoxy-2-(¹⁸F)fluoro-D-glucose (¹⁸F-FDG).

RESULTS

Repeated measure ANOVA by a general linear model revealed that time-dependent changes of anatomic tumor volumes measured by MRI differed significantly from those of anatomic volumes assessed by caliper and metabolic volumes determined by PET/CT. Over the investigation period of three weeks, neither 5'-FU, PLX4720 nor a combination of both drugs affected the tumor volumes. Also, there was no drug effect on the apparent diffusion constant (ADC) value as detected by MRI. Interestingly, however, PET/CT imaging showed that PLX4720-containing therapies transiently reduced the standardized uptake value (SUV), indicating a temporary response to treatment.

CONCLUSIONS

5'-FU and PLX4720 were largely ineffective with respect to HROC24 tumor growth. Tumoral uptake of ¹⁸F-FDG, as expressed by the SUV, proved as a sensitive indicator of small therapeutic effects. Metabolic imaging by ¹⁸F-FDG PET/CT is a suitable approach to detect effects of tumor-directed therapies early and even in the absence of morphological changes.

Uncoupling protein 2 deficiency reduces proliferative capacity of murine pancreatic stellate cells

BACKGROUND

Uncoupling protein 2 (UCP2) has been suggested to inhibit mitochondrial production of reactive oxygen species (ROS) by decreasing the mitochondrial membrane potential. Experimental acute pancreatitis is associated with increased UCP2 expression, whereas UCP2 deficiency retards regeneration of aged mice from acute pancreatitis. Here, we have addressed biological and molecular functions of UCP2 in pancreatic stellate cells (PSCs), which are involved in pancreatic wound repair and fibrogenesis.

METHODS

PSCs were isolated from 12 months old (aged) UCP2-/- mice and animals of the wild-type (WT) strain C57BL/6. Proliferation and cell death were assessed by employing trypan blue staining and a 5-bromo-2'-deoxyuridine incorporation assay. Intracellular fat droplets were visualized by oil red O staining. Levels of mRNA were determined by RT-PCR, while protein expression was analyzed by immunoblotting and immunofluorescence analysis. Intracellular ROS levels were measured with 2', 7'-dichlorofluorescin diacetate. Expression of senescence-associated beta-galactosidase (SA beta-Gal) was used as a surrogate marker of cellular senescence.

RESULTS

PSCs derived from UCP2-/- mice proliferated at a lower rate than cells from WT mice. In agreement with this observation, the UCP2 inhibitor genipin displayed dose-dependent inhibitory effects on WT PSC growth. Interestingly, ROS levels in PSCs did not differ between the two strains, and PSCs derived from UCP2-/- mice did not senesce faster than those from corresponding WT cells. PSCs from UCP2-/- mice and WT animals were also indistinguishable with respect to the activation-dependent loss of intracellular fat droplets, expression of the activation marker alpha-smooth muscle actin, type I collagen and the autocrine/paracrine mediators interleukin-6 and transforming growth factor-beta1.

CONCLUSIONS

A reduced proliferative capacity of PSC from aged UCP2-/- mice may contribute to the retarded regeneration after acute pancreatitis. Apart from their slower growth, PSC of UCP2-/- mice displayed no functional abnormalities. The antifibrotic potential of UCP2 inhibitors deserves further attention.

Intratumoral heterogeneity of the therapeutical response to gemcitabine and metformin

Cancer heterogeneity and microenvironmental aspects within a tumor are considered key factors influencing resistance of carcinoma cells to distinct chemotherapeutical agents. We evaluated a high concentration of metformin in combination with gemcitabine on a syngeneic orthotopic mouse model using 6606PDA cells. We observed reduced tumor size and reduced cancer cell proliferation after three weeks of chemotherapy with either compound and noticed an additive effect between gemcitabine and metformin on tumor weight. Interestingly, distinct areas of the carcinoma responded differently to either compound. Metformin inhibited the proliferation of cancer cells close to the desmoplastic reaction, whereas gemcitabine inhibited the proliferation of cancer cells mainly 360-570 μm distant to the desmoplastic reaction. Indeed, co-culture of pancreatic stellate cells with 6606PDA, 7265PDA or MIA PaCa-2 cells increased gemcitabine resistance. Metformin resistance, however, was increased by high glucose concentration in the medium. Other factors such as hypoxia or the pH of the medium had no influence on gemcitabine or metformin induced inhibition of cancer cell proliferation. These data demonstrate a spatial heterogeneity in drug resistance within pancreatic adenocarcinomas and that microenvironmental aspects such as supply of glucose and the presence of pancreatic stellate cells regulate cancer cell sensitivity towards metformin or gemcitabine.

In vitro studies implicate an imbalanced activation of dendritic cells in the pathogenesis of murine autoimmune pancreatitis

Objectives

MRL/MpJ mice spontaneously develop an autoimmune pancreatitis (AIP) and are widely used as a model to study the genetic, molecular and immunological basis of the disease. Here, we have addressed the question whether distinctive features of their dendritic cells (DCs) may predispose MRL/MpJ mice to the chronic inflammation.

Methods

Pancreatic lesions were analyzed employing histological methods. Cohorts of young (healthy) MRL/MpJ mice, adult (sick) individuals, and AIP-resistant CAST/EiJ mice were used to establish cultures of bone marrow (BM)-derived conventional DCs (cDCs). The cells were subsequently characterized regarding the expression profile of CD markers and selected genes, proliferative activity as well as cytokine secretion.

Results

In pancreatic lesions, large numbers of cells expressing the murine DC marker CD11c were detected in close spatial proximity to CD3⁺ cells. A high percentage of BM-derived cDCs from adult MRL/MpJ mice expressed typical markers of DC maturation (such as CD83) already prior to a treatment with lipopolysaccharide (LPS). After LPS-stimulation, cDC cultures of both MRL/MpJ mouse cohorts contained more mature cells, proliferated at a higher rate and secreted less interleukin-10 (but also less pro-inflammatory cytokines) than cultures of CAST/EiJ mice. Compared with corresponding cultures of the control strain, LPS-free cultured cDCs from MRL/MpJ mice expressed less mRNA of the inhibitory receptor triggering receptor expressed on myeloid cells 2 (trem2).

Conclusions

BM-derived cDCs from AIP-prone MRL/MpJ mice display functional features that are compatible with the hypothesis of an imbalanced DC activation in the context of murine AIP.

Autocrine TGF-β/ZEB/microRNA-200 signal transduction drives epithelial-mesenchymal transition: Kinetic models predict minimal drug dose to inhibit metastasis

The epithelial-mesenchymal transition (EMT) is the crucial step that cancer cells must pass before they can undergo metastasis. The transition requires the activity of complex functional networks that downregulate properties of the epithelial phenotype and upregulate characteristics of the mesenchymal phenotype. The networks frequently include reciprocal repressions between transcription factors (TFs) driving the EMT and microRNAs (miRs) inducing the reverse process, termed mesenchymal-epithelial transition (MET). In this work we develop four kinetic models that are based on experimental data and hypotheses describing how autocrine transforming growth factor-β (TGF-β) signal transduction induces and maintains an EMT by upregulating the TFs ZEB1 and ZEB2 which repress the expression of the miR-200b/c family members. After successful model calibration we validate our models by predicting requirements for the maintenance of the mesenchymal steady state which agree with experimental data. Finally, we apply our validated kinetic models for the design of experiments in cancer therapy. We demonstrate how steady state properties of the kinetic models, combined with data from tumor-derived cell lines of individual patients, can predict the minimal amount of an inhibitor to induce a MET.

Trametinib and dactolisib but not regorafenib exert antiproliferative effects on rat pancreatic stellate cells

BACKGROUND

Modulation of the stroma response is considered a promising approach for the treatment of chronic pancreatitis and pancreatic cancer. The aim of this study was to evaluate the effects of three clinically available small molecule kinase inhibitors, regorafenib, trametinib and dactolisib, on effector functions of activated pancreatic stellate cells (PSCs), which play a key role in pancreatic fibrosis.

METHODS

Cultured rat PSCs were exposed to small molecule kinase inhibitors. Proliferation and cell death were assessed by measuring the incorporation of 5-bromo-2'-deoxyuridine and cytotoxicity, respectively. Levels of mRNA were determined by real-time PCR, while protein expression and phosphorylation were analyzed by immunoblotting. Interleukin-6 levels in culture supernatants were quantified by ELISA. Zymography assays were performed to monitor collagenase activity in culture supernatants.

RESULTS

The MEK inhibitor trametinib and the dual phosphatidylinositol 3-kinase/mTOR inhibitor dactolisib, but not the multi-kinase inhibitor regorafenib, efficiently inhibited PSC proliferation. Trametinib as well as regorafenib suppressed the expression of two autocrine mediators of PSC activation, interleukin-6 and transforming growth factor-beta1. Dactolisib-treated cells expressed less alpha1 type I collagen and lower levels of alpha-smooth muscle actin, a marker of the myofibroblastic PSC phenotype. Simultaneous application of dactolisib and trametinib displayed additive inhibitory effects on cell growth without statistically significant cytotoxicity. Activity of matrix metalloproteinase-2 was not affected by any of the drugs.

CONCLUSION

We suggest the combination of two drugs, that specifically target two key signaling pathways in PSC, Ras-Raf-MEK-ERK (trametinib) and phosphatidylinositol 3-kinase-AKT-mTOR (dactolisib), as a concept to modulate the activation state of the cells in the context of fibrosis.

Quantitative Trait Locus Analysis Implicates CD4⁺/CD44high Memory T Cells in the Pathogenesis of Murine Autoimmune Pancreatitis

The mouse strain MRL/MpJ is prone to spontaneously develop autoimmune pancreatitis (AIP). To elucidate the genetic control towards the development of the phenotype and to characterize contributions of immunocompetent cell types, MRL/MpJ mice were interbred with three additional strains (BXD2/TYJ, NZM2410/J, CAST/EIJ) for four generations in an advanced intercross line. Cellular phenotypes were determined by flow cytometric quantification of splenic leukocytes and complemented by the histopathological evaluation of pancreatic lesions. An Illumina SNP array was used for genotyping. QTL analyses were performed with the R implementation of HAPPY. Out of 41 leukocyte subpopulations (B cells, T cells and dendritic cells), only three were significantly associated with AIP: While CD4⁺/CD44^high memory T cells and CD4⁺/CD69⁺ T helper (Th) cells correlated positively with the disease, the cytotoxic T cell phenotype CD8⁺/CD44^low showed a negative correlation. A QTL for AIP on chromosome 2 overlapped with QTLs for CD4⁺/CD44^high and CD8⁺/CD44^high memory T cells, FoxP3⁺/CD4⁺ and FoxP3⁺/CD8⁺ regulatory T cells (Tregs), and CD8⁺/CD69⁺ cytotoxic T cells. On chromosome 6, overlapping QTLs for AIP and CD4⁺/IL17⁺ Th17 cells and again FoxP3⁺/CD8⁺ Tregs were observed. In conclusion, CD4⁺/CD44^high memory T cells are the only leukocyte subtype that could be linked to AIP both by correlation studies and from observed overlapping QTL. The potential role of this cell type in the pathogenesis of AIP warrants further investigations.

Anti-inflammatory effects of reactive oxygen species - a multi-valued logical model validated by formal concept analysis

Background

Recent findings suggest that in pancreatic acinar cells stimulated with bile acid, a pro-apoptotic effect of reactive oxygen species (ROS) dominates their effect on necrosis and spreading of inflammation. The first effect presumably occurs via cytochrome C release from the inner mitochondrial membrane. A pro-necrotic effect – similar to the one of Ca²⁺ – can be strong opening of mitochondrial pores leading to breakdown of the membrane potential, ATP depletion, sustained Ca²⁺ increase and premature activation of digestive enzymes. To explain published data and to understand ROS effects during the onset of acute pancreatitis, a model using multi-valued logic is constructed. Formal concept analysis (FCA) is used to validate the model against data as well as to analyze and visualize rules that capture the dynamics.

Results

Simulations for two different levels of bile stimulation and for inhibition or addition of antioxidants reproduce the qualitative behaviour shown in the experiments. Based on reported differences of ROS production and of ROS induced pore opening, the model predicts a more uniform apoptosis/necrosis ratio for higher and lower bile stimulation in liver cells than in pancreatic acinar cells. FCA confirms that essential dynamical features of the data are captured by the model. For instance, high necrosis always occurs together with at least a medium level of apoptosis. At the same time, FCA helps to reveal subtle differences between data and simulations. The FCA visualization underlines the protective role of ROS against necrosis.

Conclusions

The analysis of the model demonstrates how ROS and decreased antioxidant levels contribute to apoptosis. Studying the induction of necrosis via a sustained Ca²⁺ increase, we implemented the commonly accepted hypothesis of ATP depletion after strong bile stimulation. Using an alternative model, we demonstrate that this process is not necessary to generate the dynamics of the measured variables. Opening of plasma membrane channels could also lead to a prolonged increase of Ca²⁺ and to necrosis. Finally, the analysis of the model suggests a direct experimental testing for the model-based hypothesis of a self-enhancing cycle of cytochrome C release and ROS production by interruption of the mitochondrial electron transport chain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12918-014-0101-7) contains supplementary material, which is available to authorized users.

Inbred mouse strains reveal biomarkers that are pro-longevity, antilongevity or role switching

Traditionally, biomarkers of aging are classified as either pro-longevity or antilongevity. Using longitudinal data sets from the large-scale inbred mouse strain study at the Jackson Laboratory Nathan Shock Center, we describe a protocol to identify two kinds of biomarkers: those with prognostic implication for lifespan and those with longitudinal evidence. Our protocol also identifies biomarkers for which, at first sight, there is conflicting evidence. Conflict resolution is possible by postulating a role switch. In these cases, high biomarker values are, for example, antilongevity in early life and pro-longevity in later life. Role-switching biomarkers correspond to features that must, for example, be minimized early, but maximized later, for optimal longevity. The clear-cut pro-longevity biomarkers we found reflect anti-inflammatory, anti-immunosenescent or anti-anaemic mechanisms, whereas clear-cut antilongevity biomarkers reflect inflammatory mechanisms. Many highly significant blood biomarkers relate to immune system features, indicating a shift from adaptive to innate processes, whereas most role-switching biomarkers relate to blood serum features and whole-body phenotypes. Our biomarker classification approach is applicable to any combination of longitudinal studies with life expectancy data, and it provides insights beyond a simplified scheme of biomarkers for long or short lifespan.