Theodor Kudlich

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.

Butyrate Inhibits Leukocyte Adhesion to Endothelial Cells via Modulation of VCAM-1

BackgroundLeukocyte 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-&kgr;B)-dependent mechanism. We investigated whether the anti-inflammatory properties of butyrate are mediated via the modulation of VCAM and ICAM on human endothelial cells. MethodsVCAM-1 and ICAM-1 expression on human endothelial cells upon tumor necrosis factor-&agr; (TNF-&agr;) 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-&kgr;B activation. ResultsThe observed butyrate-associated inhibition of monocyte adhesion to endothelial cells is associated with an inhibition of NF-&kgr;B activation in human endothelial cells. In this context, the observed suppression of the TNF-&agr; induced VCAM-1 expression is likely to play an essential role. ConclusionsButyrate 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.

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.

Effects of isomalt consumption on gastrointestinal and metabolic parameters in healthy volunteers

The polyol isomalt (Palatinit) is a well established sugar replacer. The impact of regular isomalt consumption on metabolism and parameters of gut function in nineteen healthy volunteers was examined in a randomised, double-blind, cross-over trial with two 4-week test periods. Volunteers received 30 g isomalt or 30 g sucrose daily as part of a controlled diet. In addition to clinical standard diagnostics, biomarkers and parameters currently discussed as risk factors for CHD, diabetes or obesity were analysed. Urine and stool Ca and phosphate excretions were measured. In addition, mean transit time, defecation frequency, stool consistency and weight were determined. Consumption of test products was affirmed by the urinary excretion of mannitol. Blood lipids were comparable in both phases, especially in volunteers with hyperlipidaemia, apart from lower apo A-1 (P=0.03) for all subjects. Remnant-like particles, oxidised LDL, NEFA, fructosamine and leptin were comparable and not influenced by isomalt. Ca and phosphate homeostasis was not affected. Stool frequency was moderately increased in the isomalt phase (P=0.006) without changes in stool consistency and stool water. This suggests that isomalt is well tolerated and that consumption of isomalt does not impair metabolic function or induce hypercalciuria. In addition, the study data indicate that isomalt could be useful in improving bowel function.

SNP-Array genotyping and spectral karyotyping reveal uniparental disomy as early mutational event in MSS- and MSI-colorectal cancer cell lines

In this study nine colorectal cancer cell lines were analysed by 10K SNP-arrays and spectral karyotyping (SKY). Complex chromosomal alterations and breakpoints of deleted or translocated fragments found by SKY could further be characterized by SNP-array analysis. Interestingly many monoallelic regions identified by SNP-array analysis display no copy number alterations, representing uniparental disomy (UPD). It was demonstrated that UPD seems to be involved in activation of early-acting tumor suppressor genes in MSS- (APC, CDKN2A) and MSI- (MLH1, MSH2, APC, CDKN2A) colorectal cancer cell lines. Genes involved later on in the adenoma-carcinoma sequence (i.e. TP53/SMAD4) were not found to be inactivated by UPD. Furthermore, identified amplified monoallelic regions may include oncogenes activated by allele-specific-amplification (i.e. Cyclin D1). However, at present, the majority of the monoallelic regions located in the present study have not yet been associated with known tumor suppressor genes and oncogenes. Further studies are warranted to identify relevant genes in the respective regions and to further verify the results presented here.

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.

SPECT- and PET-based patient-tailored treatment in neuroendocrine tumors: a comprehensive multidisciplinary team approach.

Abstract The overexpression of somatostatin receptors on the tumor cell surface of neuroendocrine tumors (NETs) detected by multimodal functional imaging modalities such as SPECT and PET tracers constitutes a therapeutic option using targeting radiolabeled compounds. We will introduce the theranostic concept in general, explain in more detail its development in NETs, and discuss available SPECT and PET tracers regarding their potential for diagnostic imaging, visualization of target expression, and treatment tailoring. Moreover, we will discuss the currently available peptide receptor radionuclide therapy principles and compare them to previously published studies. Finally, we will discuss which new concepts will most likely influence the theranostic treatment approach in NETs in the future.

Abstract 5179: Inhibition of U937-cell adhesion to human endothelial cells by glycosylated lysozyme mutants

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL The evascularization of cells is an important step in defense reactions and the spreading of metastases. During inflammation, the endothelium of the affected tissue becomes activated and interacts with cells bearing cognate structures such as sialyl Lewis X (sLex) substances. In this study, we present the sLex-antagonist hLysII/IV-FUCTVI by which a significant inhibition of adhesion is achieved at 1ng/ml (0.07 nM), making it the most potent known inhibitors of adhesion described to date. In our study we overexpressed the glycosylated human lysozyme mutant hLysII/IV in CHO cells stably expressing fucosyltransferases FUCIII, IV, V, VI, or VII. Digestional analysis with endo- and exoglycosidases showed that hLysII/IV-FUCTVI contains predominantly biantennary complex N-glycans with a variable number of lactosamine repeats; these were terminally sialylated and fucosylated, suggesting the presence of the sLex antigen. In contrast, hLysII/IV-FUCTIII and IV were not terminally sialylated and hLysII/IV-FUCV and VII were not terminally fucosylated. In a static adhesion assay, binding of U937 to activated HUVEC cells was exclusively blocked in the presence of medium supernatant containing hLysII/IV-FUCTVI and by affinity-purified hLysII/IV-FUCTVI. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5179. doi:1538-7445.AM2012-5179

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

ObjectiveA 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 99mTc-mercaptoacetyltriglycine (MAG3) renal scintigraphy with a focus on patients treated with PRRT. Materials and methodsFrom 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 99mTc-MAG3 clearance. In 27 patients, kidney function was assessed before PRRT. Results of blood tests and 99mTc-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 99mTc-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. ResultsIn the PRRT subgroup, laboratory test-derived kidney function correlated significantly with 99mTc-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 99mTc-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%). ConclusionLaboratory tests of kidney function correlate significantly with 99mTc-MAG3 clearance. Because of the moderate accuracy for laboratory tests, 99mTc-MAG3 clearance is recommended as a standard test to assess kidney function before PRRT.

Spectral karyotyping and SNP microarray analysis define uniparental disomy (UPD) as a novel mutational mechanism in MSI- and CSI-colorectal cancers ∗

Spectral karyotyping greatly improves recognition and definition of chromosomal aberrations [1]. In previous studies, we applied spectral karyotyping to a number of colorectal cancer cell lines derived from metastatic and primary tumors [2]. As expected, we observed complex marker chromosomes and pronounced chromosomal instability (CSI) in tumors devoid of microsatellite instability. In contrast, microsatellite instable (MSI) tumors uniformly displayed stable karyotypes [3]. Likewise, a newly characterized adenoma cell line lacked karyotypic alterations [4]. Recently, we complemented our spectral karyotyping studies by SNP-array analyses of multiple MSIand CSI-cell lines [5]. Results were verified by the analysis of 15 primary MSIand 15 CSI-tumors (unpublished data). SNP analysis greatly facilitated the interpretation of complex chromosomal alterations of CSI-cell lines. Monoallelic regions could be correlated with sites of inactivated tumor suppressor genes and activated oncogenes. Some of the genes relevant for colon carcinogenesis are inactivated by allelic loss (e.g. p53, SMAD4). Monoallelic regions with increased copy number may represent oncogene loci activated by allele-specific amplification (e.g. Cyclin D1 in CSI-cell lines). Monoallelic regions without copy number alterations fulfill the criteria of uniparental disomy (UPD). In the tested colorectal cell lines and primary tumors, UPD appears to instrumental in the inactivation of early-acting tumor suppressor genes, including APC in CSIand hMLH1/hMSH2 in MSI-cellular phenotypes. Our results suggest that following initial mutational inactivation of one of the APC or hMLH1/hMSH2 alleles the remaining wildtype allele is deleted, concomitant with re-duplication of the mutated allele. Alternatively, UPD may have arisen through some type of gene conversion. In addition to the APC and hMLH1/hMSH2 chromosomal