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Background/Aims: To develop a clinically relevant immunocompetent murine model to study pancreatic cancer using two different syngeneic pancreatic cancer cell lines and to assess MRI for its applicability in this model. Methods: Two cell lines, 6606PDA and Panc02, were employed for the experiments. Cell proliferation and migration were monitored in vitro. Matrigel™ was tested for its role in tumor induction. Tumor cell growth was assessed after orthotopic injection of tumor cells into the pancreatic head of C57/BL6 mice by MRI and histology. Results: Proliferation and migration of Panc02 were significantly faster than those of 6606PDA. Matrigel did not affect tumor growth/migration but prevented tumor cell spread after injection thus avoiding undesired peritoneal tumor growth. MRI could reliably monitor longitudinal tumor growth in both cell lines: Panc02 had a more irregular finger-like growth, and 6606PDA grew more spherically. Both tumors showed local invasiveness. Histologically, Panc02 showed a sarcoma-like undifferentiated growth pattern, whereas 6606PDA displayed a moderately differentiated glandular tumor growth. Panc02 mice had a significantly shorter (28 days) survival than 6606PDA mice (50 days). Conclusion: This model closely mimics human pancreatic cancer. MRI was invaluable for longitudinal monitoring of tumor growth thus reducing the number of mice required. Employing two different cell lines, this model can be used for various treatment and imaging studies.
Objective: In acute pancreatitis (AP), bacterial translocation and subsequent infection of pancreatic necrosis are the main risk factors for severe disease and late death. Understanding how immunological host defence mechanisms fail to protect the intestinal barrier is of great importance in reducing the mortality risk of the disease. Here, we studied the role of the Treg/Th17 balance for maintaining the intestinal barrier function in a mouse model of severe AP.
Design: AP was induced by partial duct ligation in C57Bl/6 or DEREG mice, in which regulatory T-cells (Treg) were depleted by intraperitoneal injection of diphtheria toxin. By flow cytometry, functional suppression assays and transcriptional profiling we analysed Treg activation and characterised T-cells of the lamina propria as well as intraepithelial lymphocytes (IELs) regarding their activation and differentiation. Microbiota composition was examined in intestinal samples as well as in murine and human pancreatic necrosis by 16S rRNA gene sequencing.
Results: The prophylactic Treg-depletion enhanced the proinflammatory response in an experimental mouse model of AP but stabilised the intestinal immunological barrier function of Th17 cells and CD8+/γδTCR+ IELs. Treg depleted animals developed less bacterial translocation to the pancreas. Duodenal overgrowth of the facultative pathogenic taxa Escherichia/Shigella which associates with severe disease and infected necrosis was diminished in Treg depleted animals.
Conclusion: Tregs play a crucial role in the counterbalance against systemic inflammatory response syndrome. In AP, Treg-activation disturbs the duodenal barrier function and permits translocation of commensal bacteria into pancreatic necrosis. Targeting Tregs in AP may help to ameliorate the disease course.
Background: Abdominal obesity is a major driver for adverse medical conditions. While an interaction between adipose tissue and thyroid function is thought to exist, to our knowledge, no study has examined the effect of thyroid-stimulating hormone (TSH) on visceral adipose tissue (VAT) in a population-based context. Objective: We determined an association between serum TSH levels and VAT. Methods: A sample of 1,021 female and 956 male adults aged 20-79 years was drawn from registry offices in the cross-sectional, population-based Study of Health in Pomerania Trend (SHIP Trend) in Northeast Germany from 2008 to 2012. Our main exposure was serum TSH levels. Our main outcome was VAT measured using magnetic resonance imaging. The possibly mediating role of leptin on the TSH-VAT association was also assessed. Results: A total of 1,719 participants (87.9%) had serum TSH levels within the reference range. The mean volume of VAT was 5.33 liters for men and 2.83 liters for women. No association between TSH and VAT (β = 0.06, 95% CI: -0.02, 0.14) was observed, and there were no differences detected between sexes. VAT was strongly associated with leptin with a greater effect in women than in men. Leptin was strongly associated with TSH. Conclusions: No association between TSH and VAT was observed. Other biomarkers such as leptin may play a role in the relationship between thyroid function and metabolic risk.
Abstract
Study Objective
Long‐term intake of proton pump inhibitors (PPIs) might increase the risk of cardiovascular events. One suggested mechanism is that PPIs inhibit the enzyme dimethylarginine dimethylaminohydrolase (DDAH) and thereby block the degradation of endothelial asymmetrical dimethylarginine (ADMA). Excess ADMA in turn leads to impaired endothelial nitric oxide (NO) generation. So far, this mechanism has only been established in human cell cultures. Previous studies that examined this pathway in human populations measured circulating ADMA and found no association with PPI use and excess plasma ADMA. But in a recent study, plasma ADMA was not correlated with intracellular ADMA. We therefore focused on changes in plasma citrulline as an indicator for potential DDAH inhibition.
Design
We analyzed the association between regular daily PPI intake and flow‐mediated dilation (FMD) of the brachial artery as well as plasma concentrations of citrulline, arginine, ADMA, and symmetric dimethylarginine using inverse probability weighting to adjust for confounding and censoring.
Data Source
Data of 1298 participants from two independent cohorts of the population‐based Study of Health in Pomerania were used.
Participants
Participants of the population‐based Study of Health in Pomerania are a stratified random sample of the study region.
Exposure
Regular daily intake of PPIs.
Measurements
FMD of the brachial artery and plasma concentrations of citrulline, arginine, ADMA, and symmetric dimethylarginine.
Main Results
Eighty‐seven participants (57.5% female) were regular daily users of PPIs. In the fully adjusted models, associations were identified for FMD and plasma citrulline concentrations. PPI users revealed a 0.99% (95% CI: −1.96 to −0.02) lower FMD and 3.03 µmol/L (95% CI: −4.96 to −1.10) lower plasma citrulline levels as compared to non‐users.
Conclusion
Our data provide evidence that long‐term intake of PPIs might inhibit human DDAH activity, resulting in impaired endothelial NO production and reduced vascular function. In the long run, this might explain an increased risk for cardiovascular diseases associated with long‐term PPI use.
Introduction
Patients with bariatric surgery often show poor long-term compliance to recommendations for prevention of nutrient deficiency but it is unclear which factors contribute. We investigated the associations of age, sex, and socioeconomic status (SES) with adherence to guideline recommendations on protein intake and micronutrient supplementation.
Methods
In a monocentric cross-sectional study we prospectively recruited patients with sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) and a minimum postoperative period of 6 months. Clinical and demographic data were obtained from the patients’ medical files and by questionnaire. Patients reported on supplement usage, recorded their dietary intake for seven days and underwent physical examinations including blood testing.
Results
We included 35 patients (SG: n = 25, RYGB: n = 10) with a mean (+SD) postoperative period of 20.2 (±10.4) months. Distributions of age, sex and SES were comparable between the SG and RYGB groups. Non-adherence to recommended protein intake was associated with age ≥ 50 years (p = 0.041) but not sex or SES. Protein intake inversely correlated with markers of obesity. There were no significant associations of age or sex with micronutrient supplementation. Only for vitamins A (p = 0.049) and B1 (p = 0.047) higher SES was associated with greater compliance. The only manifest deficiency associated with non-adherence to micronutrient supplementation was that for folic acid (p = 0.044).
Conclusion
In patients after bariatric surgery, those of older age and of lower SES might have a greater risk of unfavorable outcome and may require greater attention to micronutrient and protein supplementation.
Abstract
Introduction
Transabdominal ultrasound (US) and magnetic resonance imaging (MRI) are commonly used for the examination of the pancreas in clinical routine. We therefore were interested in the concordance of these two imaging methods for the size measurement of the pancreas and how age, gender, and body mass index (BMI) affect the organ size.
Methods
A total of 342 participants from the Study of Health in Pomerania underwent whole‐body MRI and transabdominal US on the same day, and the diameter of the pancreatic head, body, and tail were measured. The agreement between US and MRI measurements was assessed by Bland and Altman plots. Intraclass correlation coefficients were used to compare observers. A multivariable regression model was applied using the independent variables age, gender, and body mass index.
Results
Compared to MRI, abdominal US returned smaller values for each segment of the pancreas, with a high level of inconsistency between these two methods. The mean difference was 0.39, 0.18, and 0.54 cm for the head, body, and tail, respectively. A high interobserver variability was detected for US. Multivariable analysis showed that pancreatic size in all three segments increased with BMI in both genders whereas pancreatic head and tail size decreased with age, an effect more marked in women.
Conclusions
Agreement of pancreatic size measurements is poor between US and MRI. These limitations should be considered when evaluating morphologic features for pathologic conditions or setting limits of normal size. Adjustments for BMI, gender, and age may also be warranted.
Determination of the Pathological Features of NPC1 Variants in a Cellular Complementation Test
(2019)
Niemann-Pick Type C (NP-C) is a rare disorder of lipid metabolism caused by mutations
within the NPC1 and NPC2 genes. NP-C is a neurovisceral disease leading to a heterogeneous,
multisystemic spectrum of symptoms in those affected. Until now, there is no investigative tool to
demonstrate the significance of single variants within the NPC genes. Hence, the aim of the study
was to establish a test that allows for an objective assessment of the pathological potential of NPC1
gene variants. Chinese hamster ovary cells defective in the NPC1 gene accumulate cholesterol in
lysosomal storage organelles. The cells were transfected with NPC1-GFP plasmid vectors carrying
distinct sequence variants. Filipin staining was used to test for complementation of the phenotype.
The known variant p.Ile1061Thr showed a significantly impaired cholesterol clearance after 12 and
24 h compared to the wild type. Among the investigated variants, p.Ser954Leu and p.Glu1273Lys
showed decelerated cholesterol clearance as well. The remaining variants p.Gln60His, p.Val494Met,
and p.Ile787Val showed a cholesterol clearance indistinguishable from wild type. Further, p.Ile1061Thr
acquired an enhanced clearance ability upon 25-hydroxycholesterol treatment. We conclude that the
variants that caused an abnormal clearance phenotype are highly likely to be of clinical relevance.
Moreover, we present a system that can be utilized to screen for new drugs.
Background: Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer death worldwide and compared to other malignancies its share in cancer mortality is expected to rise further. This is due to a lack of sensitive diagnostic tools that would permit earlier detection in a potentially curable stage and the very slow progress in finding effective drug treatments for pancreatic cancer. Key Messages: Aside from genetic predispositions and environmental agents, chronic pancreatitis is by far the greatest risk factor for PDAC. It also shares several etiological factors with pancreatic cancer and represents its most challenging differential diagnosis. Biomarkers that can distinguish between chronic pancreatitis and PDAC may therefore be suitable for the latter's early detection. Moreover, targeting the natural history of chronic pancreatitis would be one approach to prevent PDAC. Targeting tumor-cell signaling directly by interfering with receptor tyrosine kinases has shown some efficacy, although the results in clinical trials were less encouraging than for other cancers. Other compounds developed have targeted the formation of extracellular matrix around the tumor, the proteolytic activity in the tumor environment, histone deacetylases, hedgehog signaling and heat shock proteins, but none has yet found its way into routine patient care. Attempts to individualize treatment according to the tumor's somatic mutation profile are novel but so far impractical. Conclusions: Progress in the treatment of pancreatic cancer has been exceedingly slow and mostly dependent on improved pharmaceutical preparations or combinations of established chemotherapeutic agents. The promise of major breakthroughs implied in targeting tumor signal transduction events has so far not materialized.
Abstract
Background and aims: Intestinal adaptation in short bowel syndrome (SBS) includes morphologic processes and functional mechanisms. This study investigated whether digestive enzyme expression in the duodenum and colon is upregulated in SBS patients. Method: Sucrase‐isomaltase (SI), lactase‐phlorizin hydrolase (LPH), and neutral Aminopeptidase N (ApN) were analyzed in duodenal and colonic biopsies from nine SBS patients in a late stage of adaptation as well as healthy and disease controls by immunoelectron microscopy (IEM), Western blots, and enzyme activities. Furthermore, proliferation rates and intestinal microbiota were analyzed in the mucosal specimen. Results: We found significantly increased amounts of SI, LPH, and ApN in colonocytes in most SBS patients with large variation and strongest effect for SI and ApN. Digestive enzyme expression was only partially elevated in duodenal enterocytes due to a low proliferation level measured by Ki‐67 staining. Microbiome analysis revealed high amounts of Lactobacillus resp. low amounts of Proteobacteria in SBS patients with preservation of colon and ileocecal valve. Colonic expression was associated with a better clinical course in single cases. Conclusion: In SBS patients disaccharidases and peptidases can be upregulated in the colon. Stimulation of this colonic intestinalization process by drugs, nutrients, and pre‐ or probiotics might offer better therapeutic approaches.