Reducing scope 3 carbon emissions in gastrointestinal endoscopy: results of the prospective study of the 'Green Endoscopy Project Würzburg'.

OBJECTIVE: Carbon emissions generated by gastrointestinal endoscopy have been recognised as a critical issue. Scope 3 emissions are mainly caused by the manufacturing, packaging and transportation of purchased goods. However, to our knowledge, there are no prospective data on the efficacy of measurements aimed to reduce scope 3 emissions. DESIGN: The study was performed in a medium-sized academic endoscopy unit. Manufacturers of endoscopic consumables were requested to answer a questionnaire on fabrication, origin, packaging and transport. Based on these data, alternative products were purchased whenever possible. In addition, staff was instructed on how to avoid waste. Thereafter, the carbon footprint of each item purchased was calculated from February to May 2023 (intervention period), and scope 3 emissions were compared with the same period of the previous year (control period). RESULTS: 26 of 40 companies answered the questionnaire. 229 of 322 products were classified as unfavourable. A switch to alternative items was possible for 47/229 items (20.5%). 1666 endoscopies were performed during the intervention period compared with 1751 examinations during the control period (-4.1%). The number of instruments used decreased by 10.0% (3111 vs 3457). Using fewer and alternative products resulted in 11.5% less carbon emissions (7.09 vs 8.01 tons of carbon equivalent=tCO2 e). Separation of waste led to a reduction of 20.1% (26.55 vs 33.24 tCO2e). In total, carbon emissions could be reduced by 18.4%. CONCLUSION: Use of fewer instruments per procedure, recycling packaging material and switching to alternative products can reduce carbon emissions without impairing the endoscopic workflow.

Progression from Nonalcoholic Fatty Liver to Nonalcoholic Steatohepatitis Is Marked by a Higher Frequency of Th17 Cells in the Liver and an Increased Th17/Resting Regulatory T Cell Ratio in Peripheral Blood and in the Liver.

Nonalcoholic fatty liver disease is increasing in prevalence. It can be subdivided into nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). Five to twenty percent of cases progress from NAFL to NASH. Increased hepatic Th17 cells and IL-17 expression were observed in NASH mice and patients, respectively. We analyzed CD4(+) effector T cells and regulatory T cells (Tregs) from peripheral blood and livers of NAFL and NASH patients. A total of 51 NAFL patients, 30 NASH patients, 31 nonalcoholic fatty liver disease patients (without histology), and 43 healthy controls were included. FACS analysis was performed on PBMCs and intrahepatic lymphocytes. Compared with healthy controls, a lower frequency of resting Tregs (rTregs; CD4(+)CD45RA(+)CD25(++)) and higher frequencies of IFN-γ(+) and/or IL-4(+) cells were detected among CD4(+) T cells of peripheral blood in NASH, and to a lesser degree in NAFL. In hepatic tissue, NAFL to NASH progression was marked by an increase in IL-17(+) cells among intrahepatic CD4(+) T cells. To define immunological parameters in peripheral blood to distinguish NAFL from NASH, we calculated different ratios. Th17/rTreg and Th2/rTreg ratios were significantly increased in NASH versus NAFL. The relevance of our findings for NASH pathogenesis was highlighted by the normalization of all of the changes 1 y after bariatric surgery. In conclusion, our data indicate that NAFL patients show changes in their immune cell profile compared with healthy controls. NAFL to NASH progression is marked by an increased frequency of IL-17(+) cells among intrahepatic CD4(+) T cells and higher Th17/rTreg and Th2/rTreg ratios in peripheral blood.

Feasibility of liver stiffness measurement in morbidly obese patients undergoing bariatric surgery using XL probe.

OBJECTIVE: Prevalence of non-alcoholic fatty liver disease is rising in the Western world and reaches up to 90% in patients undergoing bariatric surgery. Fibroscan(®) as a non-invasive tool for liver stiffness measurement (LSM) has several limitations in morbidly obese patients. Only few data exist about the technical feasibility and accuracy of LSM in these patients. We aimed to analyse the feasibility of LSM by Fibroscan(®) in bariatric patients. MATERIALS AND METHODS: In morbidly obese patients, LSM was performed using XL probe. Measurements were termed reliable if 10 successful measurements with a success rate ≥60% and an interquartile range/median (IQR/M) <0.3 were obtained, unreliable if 10 successful measurements were obtained but the IQR/M was >0.3, and they were termed failed if they were neither reliable nor unreliable. RESULTS: A total of 149 patients were included (87 with liver biopsies); mean BMI was 51.6 ± 8.5 kg/m(2). In 41% LSM using XL-probe was reliable, in 22% unreliable and in 37% failed. Failed LSM was significantly more frequent in patients with higher BMI compared to reliable and unreliable measurements (p < 0.05). In patients with failed measurement, sonographic paramedian and intercostal distances were significantly higher compared to reliable measurements. All three patients with F4 fibrosis could successfully be differentiated by LSM from patients without fibrosis. CONCLUSIONS: LSM with XL probe is feasible in almost two-thirds of morbidly obese patients with a BMI ≥50 kg/m(2). Reliable prediction of advanced fibrosis appears to be possible even if formal criteria of successful measurements are not met.

LOH and copy neutral LOH (cnLOH) act as alternative mechanism in sporadic colorectal cancers with chromosomal and microsatellite instability.

BACKGROUND AND AIMS: Tumor suppressor genes are often located in frequently deleted chromosomal regions of colorectal cancers (CRCs). In contrast to microsatellite stable (MSS) tumors, only few loss of heterozygosity (LOH) studies were performed in microsatellite instable (MSI) tumors, because MSI carcinomas are generally considered to be chromosomally stable and classical LOH studies are not feasible due to MSI. The single nucleotide polymorphism (SNP) array technique enables LOH studies also in MSI CRC. The aim of our study was to analyse tissue from MSI and MSS CRC for the existence of (frequently) deleted chromosomal regions and tumor suppressor genes located therein. METHODS AND RESULTS: We analyzed tissues from 32 sporadic CRCs and their corresponding normal mucosa (16 MSS and 16 MSI tumors) by means of 50K SNP array analysis. MSS tumors displayed chromosomal instability that resulted in multiple deleted (LOH) and amplified regions and led to the identification of MTUS1 (8p22) as a candidate tumor suppressor gene in this region. Although the MSI tumors were chromosomally stable, we found several copy neutral LOHs (cnLOH) in the MSI tumors; these appear to be instrumental in the inactivation of the tumor suppressor gene hMLH1 and a gene located in chromosomal region 6pter-p22. DISCUSSION: Our results suggest that in addition to classical LOH, cnLOH is an important mutational event in relation to the carcinogenesis of MSS and MSI tumors, causing the inactivation of a tumor suppressor gene without copy number alteration of the respective region; this is crucial for the development of MSI tumors and for some chromosomal regions in MSS tumors.

Wnt/ß-Catenin Signaling Regulates CXCR4 Expression and [68Ga] Pentixafor Internalization in Neuroendocrine Tumor Cells.

Loss of Somatostatin Receptor 2 (SSTR2) expression and rising CXC Chemokine Receptor Type 4 (CXCR4) expression are associated with dedifferentiation in neuroendocrine tumors (NET). In NET, CXCR4 expression is associated with enhanced metastatic and invasive potential and worse prognosis but might be a theragnostic target. Likewise, activation of Wnt/ß-catenin signaling may promote a more aggressive phenotype in NET. We hypothesized an interaction of the Wnt/ß-catenin pathway with CXCR4 expression and function in NET. The NET cell lines BON-1, QGP-1, and MS-18 were exposed to Wnt inhibitors (5-aza-CdR, quercetin, and niclosamide) or the Wnt activator LiCl. The expressions of Wnt pathway genes and of CXCR4 were studied by qRT-PCR, Western blot, and immunohistochemistry. The effects of Wnt modulators on uptake of the CXCR4 ligand [68Ga] Pentixafor were measured. The Wnt activator LiCl induced upregulation of CXCR4 and Wnt target gene expression. Treatment with the Wnt inhibitors had opposite effects. LiCl significantly increased [68Ga] Pentixafor uptake, while treatment with Wnt inhibitors decreased radiopeptide uptake. Wnt pathway modulation influences CXCR4 expression and function in NET cell lines. Wnt modulation might be a tool to enhance the efficacy of CXCR4-directed therapies in NET or to inhibit CXCR4-dependent proliferative signaling. The underlying mechanisms for the interaction of the Wnt pathway with CXCR4 expression and function have yet to be clarified.

Novel findings on the metabolic effects of the low glycaemic carbohydrate isomaltulose (Palatinose).

The slow digestible disaccharide isomaltulose (iso; Palatinose) is available as novel functional carbohydrate ingredient for manufacturing of low glycaemic foods and beverages. Although basically characterised, various information on physiological effects of iso are still lacking. Thus, the objective of the present study was to expand scientific knowledge of physiological characteristics of iso by a set of three human intervention trials. Using an ileostomy model, iso was found to be essentially absorbed, irrespective of the nature of food (beverage and solid food). Apparent digestibility of 50 g iso from two different meals was 95.5 and 98.8 %; apparent absorption was 93.6 and 96.1 %, respectively. In healthy volunteers, a single dose intake of iso resulted in lower postprandial blood glucose and insulin responses than did sucrose (suc), while showing prolonged blood glucose delivery over 3 h test. In a 4-week trial with hyperlipidaemic individuals, regular consumption of 50 g/d iso within a Western-type diet was well tolerated and did not affect blood lipids. Fasting blood glucose and insulin resistance were lower after the 4-week iso intervention compared with baseline. This would be consistent with possible beneficial metabolic effects as a consequence of the lower and prolonged glycaemic response and lower insulinaemic burden. However, there was no significant difference at 4 weeks after iso compared with suc. In conclusion, the study shows that iso is completely available from the small intestine, irrespective of food matrix, leading to a prolonged delivery of blood glucose. Regular iso consumption is well tolerated also in subjects with increased risk for vascular diseases.

Imaging of Chemokine Receptor 4 Expression in Neuroendocrine Tumors - a Triple Tracer Comparative Approach.

C-X-C motif chemokine receptor 4 (CXCR4) and somatostatin receptors (SSTR) are overexpressed in gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). In this study, we aimed to elucidate the feasibility of non-invasive CXCR4 positron emission tomography/computed tomography (PET/CT) imaging in GEP-NET patients using [68Ga]Pentixafor in comparison to 68Ga-DOTA-D-Phe-Tyr3-octreotide ([68Ga]DOTATOC) and 18F-fluorodeoxyglucose ([18F]FDG). Twelve patients with histologically proven GEP-NET (3xG1, 4xG2, 5xG3) underwent [68Ga]DOTATOC, [18F]FDG, and [68Ga]Pentixafor PET/CT for staging and planning of the therapeutic management. Scans were analyzed on a patient as well as on a lesion basis and compared to immunohistochemical staining patterns of CXCR4 and somatostatin receptors SSTR2a and SSTR5. [68Ga]Pentixafor visualized tumor lesions in 6/12 subjects, whereas [18F]FDG revealed sites of disease in 10/12 and [68Ga]DOTATOC in 11/12 patients, respectively. Regarding sensitivity, SSTR-directed PET was the superior imaging modality in all G1 and G2 NET. CXCR4-directed PET was negative in all G1 NET. In contrast, 50% of G2 and 80% of G3 patients exhibited [68Ga]Pentixafor-positive tumor lesions. Whereas CXCR4 seems to play only a limited role in detecting well-differentiated NET, increasing receptor expression could be non-invasively observed with increasing tumor grade. Thus, [68Ga]Pentixafor PET/CT might serve as non-invasive read-out for evaluating the possibility of CXCR4-directed endoradiotherapy in advanced dedifferentiated SSTR-negative tumors.

Human rectal mucosal gene expression after consumption of digestible and non-digestible carbohydrates.

The effect of regular consumption of the low-digestible and prebiotic isomalt versus the digestible sucrose on gene expression in rectal mucosa was examined in a randomized double-blind crossover trial. Nineteen healthy volunteers received 30 g isomalt per day or 30 g sucrose as part of a controlled diet over two 4-week test periods with a 4-week washout period in between. At the end of each test phase rectal biopsies were obtained. After RNA extraction mucosal gene expression was assayed using GeneChip microarrays. In addition, expression of cathelicidin hCap18/LL37, cellular detoxification enzymes GSTpi, UGT1A1 and CYP3A4, cyclooxygenase 2 and barrier factors MUC2 and ZO-1 were determined by real-time RT-PCR. Microbiological analyses of fecal samples revealed a shift of the gut flora towards an increase of bifidobacteria following consumption of the diet containing isomalt. Isomalt consumption did not affect rectal mucosal gene expression in microarray analyses as compared to sucrose. In addition, the expression of cathelicidin LL37, GSTpi, UGT1A1, CYP3A4, COX-2, MUC2 and ZO-1 was not changed in rectal biopsies. We conclude that gene expression of the human rectal mucosa can reliably be measured in biopsy material taken at endoscopy. Dietary intervention with the low digestible isomalt compared with the digestible sucrose did not affect gene expression in the lining rectal mucosa.

SKY and genetic fingerprinting reveal a cross-contamination of the putative normal colon epithelial cell line NCOL-1.

In vitro studies addressing the primary prevention of colon carcinoma are preferably conducted using normal colonic cells, because these cells are more likely to represent the potential target for prevention in vivo. Established cell lines of normal colonic origin are mostly lacking; however, this is probably due to the difficulties associated with establishment of such cell lines. Cross-contamination with malignant cells is a frequent event, and so any successfully established cell line of normal origin should be scrutinized prior to further investigation. We performed a cytogenetic (spectral karyotyping) and genetic fingerprint (Promega PowerPlex ES multiplex system and Applied Biosystems AmpFlSTR SGM Plus multiplex system) analysis of the putative normal colon epithelial cell line NCOL-1, derived from two different sources (NCOL-1a and 1b). We show that NCOL-1a and 1b are probably derived from the colon carcinoma cell line LoVo, with a matching probability of 99.9995, most probably through cross-contamination. Karyotypes of LoVo and NCOL-1a were identical; NCOL-1b displayed additional marker chromosomes. Our findings highlight the importance of molecular and cytogenetic characterization of established cell lines to avoid drawing misleading conclusions from the original findings.

Histone-deacetylase inhibitors induce the cathelicidin LL-37 in gastrointestinal cells.

UNLABELLED: Histone-deacetylase (HDAC) -inhibitors enhance acetylation of core proteins and this is linked to formation of transcriptionally active chromatin in various cells. In this study, the effect of HDAC inhibitors (butyrate, trichostatin A (TSA)) on the expression of the cathelicidin LL-37 in colon, gastric and hepatocellular cells was investigated. METHODS: LL-37 expression was assessed in colon, gastric and hepatocellular cancer cells after treatment with HDAC-inhibitors. In parallel, histone H4 and HMGN2, a non-histone protein, acetylation was evaluated. In addition, the intracellular signalling pathway MEK-ERK was explored. RESULTS: In contrast to normal colon epithelial cells, gastrointestinal cancer cells lacked LL-37 expression. LL-37 was induced following treatment with HDAC-inhibitors in all investigated cell lines. This induction was time-dependent in butyrate-treated cells while TSA exerted a transient effect. Induction of LL-37 by butyrate was paralleled by acetylation of the histone H4 and the non-histone HMGN2. Again, TSA resulted in transient acetylation. Furthermore, inhibition of MEK-ERK blocked HDAC inhibitor-induced LL-37 expression in colonic and gastric cells. CONCLUSIONS: We have previously shown that butyrate induces LL-37 in colon epithelial cells. In the present study, we demonstrate that cathelicidin expression is modulated by HDAC-inhibitors in various gastrointestinal cells including gastric and hepatocellular cells. This is paralleled by changes in the acetylation of distinct core proteins suggesting a common regulatory mechanism of cathelicidin LL-37 regulation in these cells.

Butyrate inhibits leukocyte adhesion to endothelial cells via modulation of VCAM-1.

BACKGROUND: Leukocyte recruitment to areas of inflammation depends on Integrin-VCAM/ICAM interaction. Blocking the vascular cell adhesion molecule (VCAM-1) and the intracellular adhesion molecule (ICAM-1) may have therapeutic benefit for the inflammatory component of bowel disease. Notably, the induction of ICAM and VCAM is mediated by a nuclear factor kappaB (NF-kappaB)-dependent mechanism. We investigated whether the anti-inflammatory properties of butyrate are mediated via the modulation of VCAM and ICAM on human endothelial cells. METHODS: VCAM-1 and ICAM-1 expression on human endothelial cells upon tumor necrosis factor-alpha (TNF-alpha) stimulation was assessd by FACS analysis. A monocyte adhesion assay was performed to evaluate the relevance of a modulated CAM-expression. Electrophoretic mobility shift assays were applied to investigate NF-kappaB activation. RESULTS: The observed butyrate-associated inhibition of monocyte adhesion to endothelial cells is associated with an inhibition of NF-kappaB activation in human endothelial cells. In this context, the observed suppression of the TNF-alpha induced VCAM-1 expression is likely to play an essential role. CONCLUSIONS: Butyrate inhibits VCAM-1 mediated leukocyte adhesion to human endothelial cells. This inhibition may contribute to the anti-inflammatory effects of butyrate in patients with distal ulcerative colitis.

Butyrate-enhanced TNFalpha-induced apoptosis is associated with inhibition of NF-kappaB.

BACKGROUND: Tumor necrosis factor (TNFalpha)-induced apoptosis is limited by concomitant activation of nuclear factor kappa B (NF-kappaB)-dependent anti-apoptotic genes. Butyrate inhibits NF-kappaB activation so that co-treatment with butyrate effectively enhances TNFalpha-induced apoptosis. In this context, the inhibition of NF-kappaB activation and subsequent modulation of (NF-kappaB)-dependent genes was assessed MATERIALS AND METHODS: Human colon adenocarcinoma cells (SW620) were incubated with TNFalpha and butyrate. Apoptosis was determined by annexin V/propidium iodide staining and flow cytometry. NF-kappaB activation was detected by electrophoretic mobility shift assay. The expression of NF-kappaB-dependent genes was assessed by RNase protection assay (RPA) RESULTS: The TNFalpha/butyrate combination yielded an additive increase in the number of apoptotic cells. NF-kappaB nuclear translocation was successfully inhibited by co-incubation with butyrate. However, the expression pattern of NF-kappaB-dependent genes remained essentially unchanged CONCLUSION: Butyrate enhances TNFalpha-induced apoptosis in the human adenocarcinoma cell line SW620. This additive effect may, at least in part, be mediated by the inhibition of NF-kappaB activation, presumably by impairing the anti-apoptotic properties of NF-kappaB.

Pretherapeutic estimation of kidney function in patients treated with peptide receptor radionuclide therapy: can renal scintigraphy be safely omitted?

OBJECTIVE: A pretherapeutic assessment of kidney function before peptide receptor radionuclide therapy (PRRT) is considered essential because of the potential renal toxicity associated with PRRT. The aim of this study was to investigate the diagnostic performance of laboratory testing and Tc-mercaptoacetyltriglycine (MAG3) renal scintigraphy with a focus on patients treated with PRRT. MATERIALS AND METHODS: From January to December 2013 the kidney function of 152 patients was assessed using laboratory tests [creatinine, blood urea nitrogen (BUN), and glomerular filtration rate (GFR)] and Tc-MAG3 clearance. In 27 patients, kidney function was assessed before PRRT. Results of blood tests and Tc-MAG3 renal scintigraphy, considered the reference standard, were compared in the entire patient cohort (n=152) and in both subgroups (PRRT and non-PRRT) using Student's t-test. The cutoff values for the laboratory tests for the prediction of abnormal Tc-MAG3 clearance were determined by means of receiver operating characteristic analysis. In a further mathematical approach using discriminant analysis, a formula was derived for the prediction of kidney function that included all of the serum parameters. RESULTS: In the PRRT subgroup, laboratory test-derived kidney function correlated significantly with Tc-MAG3 clearance (creatinine: r=-0.429, P=0.037; BUN: r=-0.45, P=0.027; GFR: r=0.44, P=0.022). The correlation was confirmed in the non-PRRT subgroup. The receiver operating characteristic analysis for prediction of abnormal Tc-MAG3 clearance resulted in area under the curves of 0.779 for creatinine alone (sensitivity 74.3%, specificity 71.1%; cutoff ≥0.995 mg/dl) and for the combination of creatinine, BUN, and GFR (sensitivity was 74.3% and specificity was 69.3%). CONCLUSION: Laboratory tests of kidney function correlate significantly with Tc-MAG3 clearance. Because of the moderate accuracy for laboratory tests, Tc-MAG3 clearance is recommended as a standard test to assess kidney function before PRRT.