[The treatment of diabetes mellitus: myths and evidence]

For more than 3500 years, metabolic disorders were recognized by symptoms similar to those indicating diabetes mellitus today. Over centuries, explanations remained elusive and shed sparse light on the origin of the disease and any treatments. The poor prognosis triggered myths and misconceptions, some even lasting until today. Two hundred years ago, major advances were made in the understanding of the pathophysiology, which has led to more successful treatments. Presently, useful preventive, diagnostic, and therapeutic procedures exist. However, old myths and misconceptions still influence the treatments. This article reviews ongoing myths dealing with the genesis and treatment of diabetes and the growing evidence for improved therapies.Increasingly more studies focus on cardiovascular endpoints while considering more realistic therapeutic goals. This paves the way to polyvalent treatment concepts reaching beyond the classic glucocentric treatment concept of type 2 diabetes. The introduction of molecular medicine, the current opportunities and future prospects of new drugs, personalized medicine, and technical innovations prompt hopes and expectations for a change of paradigms in therapeutic concepts. It is quite possible that traditional and newly generated myths will accompany this development. This has to be kept in mind when developing new concepts for treatment.

HEV-positive blood donations represent a relevant infection risk for immunosuppressed recipients

BACKGROUND & AIMS

Routine HEV testing of blood products has recently been implemented in Great Britain and the Netherlands. The relevance of transfusion-transmitted HEV infections is still controversially discussed in Europe.

METHODS

All blood donations at the University Medical Center Hamburg-Eppendorf were prospectively tested for HEV RNA by pooled PCR from October 2016 to May 2017. Reactive samples were individually retested. Additionally, stored samples from previous donations of positive donors were tested to determine the duration of HEV viraemia. HEV RNA-positive donors and a control cohort were asked to answer a questionnaire.

RESULTS

Twenty-three out of 18,737 HEV RNA-positive donors were identified (0.12%). Only two of the positive donors (8.7%) presented with elevated aminotransferases at time of donation (alanine aminotransferase: 192 and 101 U/L). The retrospective analysis of all positive donors revealed that four asymptomatic donors had been HEV viraemic for up to three months with the longest duration of HEV viraemia exceeding four months. Despite the HEV-testing efforts, 14 HEV RNA-positive blood products were transfused into 12 immunocompromised and two immunocompetent patients. One recipient of these products developed fatal acute-on-chronic liver failure complicated by Pseudomonas septicemia. The questionnaire revealed that HEV RNA-positive donors significantly more often consumed raw pork meat (12 out of 18; 67%) than controls (89 out of 256; 35%; p = 0.01). In two donors, undercooked pork liver dishes were identified as the source of infection. HEV genotyping was possible in 7 out of 23 of HEV viraemic donors and six out of seven isolates belonged to HEV Genotype 3, Group 2.

CONCLUSIONS

Prolonged HEV viraemia can be detected at a relatively high rate in Northern German blood donors, leading to transfusion-transmitted HEV infections in several patients with the risk of severe and fatal complications. Eating raw pork tartare represented a relevant risk for the acquisition of HEV infection.

LAY SUMMARY

The relevance of transfusion-transmitted hepatitis E virus infections has been discussed controversially. Herein, we present the first report on routine hepatitis E virus screening of blood donations at a tertiary care centre in Germany. Hepatitis E viraemia was found at a relatively high rate of 0.12% among blood donors, which represents a relevant transfusion-related risk for vulnerable patient populations.

γ-Catenin acts as a tumor suppressor through context-dependent mechanisms in colorectal cancer

PURPOSE

γ-Catenin is a protein closely related to β-catenin. While the overexpression of β-catenin has been linked with impaired prognosis and survival in various malignancies, both oncogenic and tumor suppressor functions have been described for γ-catenin. Thus, its role in cancer remains controversial. In this study, we examined the impact of γ-catenin expression on the malignant potential of colorectal cancer cells.

METHODS

γ-Catenin was knocked down by short interfering RNA in the γ-catenin-proficient DLD-1 cell line and stably overexpressed in the γ-catenin-deficient cell line RKO. The effects of these molecular manipulations on the malignant potential of the cell lines were tested in vitro and in vivo in a xenograft tumor model.

RESULTS

γ-Catenin contributed to Wnt signaling independent of the cellular context. Unlike its sister molecule β-catenin, γ-catenin inhibited cellular invasion and anoikis in cells endogenously expressing γ-catenin. In line with this tumor suppressor function, its de novo expression in RKO cells inhibited proliferation via cell cycle arrest. In a xenograft tumor model, overexpression of γ-catenin starkly reduced tumor growth in vivo.

CONCLUSIONS

This is the first report demonstrating a tumor-suppressive effect of γ-catenin in colorectal cancer both in vitro and in vivo. Detailed in vitro analysis revealed that effects of γ-catenin differ in γ-catenin proficient and deficient cells, indicating that its function in colorectal cancer is dependent on the cellular context. This finding adds to our understanding of γ-catenin and may have implications for future studies of catenin/Wnt targeted cancer therapies.

A synthetic lethal screen identifies ATR-inhibition as a novel therapeutic approach for POLD1-deficient cancers

The phosphoinositide 3-kinase-related kinase ATR represents a central checkpoint regulator and mediator of DNA-repair. Its inhibition selectively eliminates certain subsets of cancer cells in various tumor types, but the underlying genetic determinants remain enigmatic. Here, we applied a synthetic lethal screen directed against 288 DNA-repair genes using the well-defined ATR knock-in model of DLD1 colorectal cancer cells to identify potential DNA-repair defects mediating these effects. We identified a set of DNA-repair proteins, whose knockdown selectively killed ATR-deficient cancer cells. From this set, we further investigated the profound synthetic lethal interaction between ATR and POLD1. ATR-dependent POLD1 knockdown-induced cell killing was reproducible pharmacologically in POLD1-depleted DLD1 cells and a panel of other colorectal cancer cell lines by using chemical inhibitors of ATR or its major effector kinase CHK1. Mechanistically, POLD1 depletion in ATR-deficient cells caused caspase-dependent apoptosis without preceding cell cycle arrest and increased DNA-damage along with impaired DNA-repair. Our data could have clinical implications regarding tumor genotype-based cancer therapy, as inactivating POLD1 mutations have recently been identified in small subsets of colorectal and endometrial cancers. POLD1 deficiency might thus represent a predictive marker for treatment response towards ATR- or CHK1-inhibitors that are currently tested in clinical trials.

Screening for Colorectal Cancer Is Associated With Lower Disease Stage: A Population-Based Study

BACKGROUND & AIMS

Screening for colorectal cancer (CRC) using fecal occult blood tests (FOBT) is associated with reduced CRC incidence and mortality. Population-based FOBT screening has led to identification of CRCs at earlier stages and longer patient survival times. We investigated the stage distribution of CRCs detected by colonoscopy in a large outpatient cohort.

METHODS

We performed a retrospective analysis of colonoscopies performed on 524,954 outpatients (age, ≥55 y) in Germany from January 2006 through December 2009. Patients with chronic inflammatory bowel diseases, and those with a personal history of adenoma or CRC, were excluded. Colonoscopy findings were categorized on the basis of the most advanced lesion found; histologic samples were obtained from all patients with suspected cancer and analyzed. Cancers were staged based on Union Internationale Contre le Cancer criteria. We analyzed absolute and relative frequencies of CRCs identified and tumor stages for patients who underwent colonoscopy for screening, evaluation of a positive FOBT, and evaluation of symptoms.

RESULTS

Of the 6065 CRCs identified, 1750 were found in the screening group, 1075 in subjects with positive FOBT, and 3240 in patients with symptoms. Stage I CRC was detected more frequently in subjects who received screening colonoscopies (41.15%) or in those with positive FOBT (39.10%), than in individuals with symptoms (24.42%; P < .001). In contrast, the detection rates of stage IV CRC were 10.67%, 10.76%, and 18.64%, respectively (P < .001). We observed a shift toward lower T stages in the screening and FOBT work-up groups compared with the group with symptoms. Compared with subjects with symptoms, the odds of diagnosing CRC at an advanced stage were significantly lower in the screening group (odds ratio, 0.533; 95% confidence interval, 0.451-0.631) and the FOBT work-up group (odds ratio, 0.570; 95% confidence interval, 0.469-0.694).

CONCLUSIONS

In this large population-based study, CRC detected by colonoscopies performed for screening and evaluation of positive FOBTs had a lower stage than those diagnosed by colonoscopies in symptomatic patients. These findings support the value of screening colonoscopy to reduce the burden of CRC.

Cabozantinib and Tivantinib, but Not INC280, Induce Antiproliferative and Antimigratory Effects in Human Neuroendocrine Tumor Cells in vitro: Evidence for 'Off-Target' Effects Not Mediated by c-Met Inhibition

BACKGROUND/AIMS

The hepatocyte growth factor/transmembrane tyrosine kinase receptor c-Met has been defined as a potential target in antitumoral treatment of various carcinomas. We aimed to investigate the direct effect of c-Met inhibition on neuroendocrine tumor cells in vitro.

METHODS

The effects of the multi-tyrosine kinase inhibitors cabozantinib and tivantinib and of the highly specific c-Met inhibitor INC280 were investigated in human pancreatic neuroendocrine BON1, bronchopulmonary NCI-H727 and midgut GOT1 cells in vitro.

RESULTS

INC280, cabozantinib and tivantinib inhibited c-Met phosphorylation, respectively. However, while equimolar concentrations (10 μM) of cabozantinib and tivantinib inhibited cell viability and cell migration, INC280 had no inhibitory effect. Knockdown experiments with c-Met siRNA also did not demonstrate effects on cell viability. Cabozantinib and tivantinib caused a G2 arrest in neuroendocrine tumor cells.

CONCLUSIONS

Our in vitro data suggest that c-Met inhibition alone is not sufficient to exert direct antitumoral or antimigratory effects in neuroendocrine tumor cells. The multi-tyrosine kinase inhibitors cabozantinib and tivantinib show promising antitumoral and antimigratory effects in neuroendocrine tumor cells, which are most probably 'off-target' effects, not mediated by c-Met.

Additive Anti-Tumor Effects of Lovastatin and Everolimus In Vitro through Simultaneous Inhibition of Signaling Pathways

Background

The mTORC1-inhibitor everolimus shows limited efficacy in treating patients with gastro-entero-pancreatic or pulmonary neuroendocrine tumors (NETs), and poor outcome in patients with malignant pheochromocytoma or hepatic carcinoma. We speculated that any effect may be enhanced by antogonising other signaling pathways.

Methods

Therefore, we tested the effect of lovastatin—known to inhibit both ERK and AKT signaling—and everolimus, separately and in combination, on cell viability and signaling pathways in human midgut (GOT), pancreatic (BON1), and pulmonary (H727) NET, hepatocellular carcinoma (HepG2, Huh7), and mouse pheochromocytoma (MPC, MTT) cell lines.

Results

Lovastatin and everolimus separately significantly reduced cell viability in H727, HepG2, Huh7, MPC and MTT cells at clinically relevant doses (P ≤ 0.05). However, high doses of lovastatin were necessary to affect GOT or BON1 cell viability. Clinically relevant doses of both drugs showed additive anti-tumor effects in H727, HepG2, Huh7, MPC and MTT cells (P ≤ 0.05), but not in BON1 or GOT cells. In all cell lines investigated, lovastatin inhibited EGFR and AKT signaling. Subsequently, combination treatment more strongly inhibited EGFR and AKT signaling than everolimus alone, or at least attenuated everolimus-induced EGFR or AKT activation. Vice versa, everolimus constantly decreased pp70S6K and combination treatment more strongly decreased pp70S6K than lovastatin alone, or attenuated lovastatin-induced p70S6K activation: in BON1 cells lovastatin-induced EGFR inhibition was least pronounced, possibly explaining the low efficacy and consequent absent additive effect.

Conclusion

In summary, clinically relevant doses of lovastatin and everolimus were effective separately and showed additive effects in 5 out of 7 cell lines. Our findings emphasize the importance of targeting several interacting signaling pathways simultaneously when attempting to attenuate tumor growth. However, the variable reactions of the different cell lines highlight the necessity to understand the unique molecular aberrations in any tumor. Nevertheless, this combination seems worthy of being tested in vivo.

Thyroid hormones and tetrac: new regulators of tumour stroma formation via integrin αvβ3

To improve our understanding of non-genomic, integrin αvβ3-mediated thyroid hormone action in tumour stroma formation, we examined the effects of triiodo-l-thyronine (T3), l-thyroxine (T4) and integrin-specific inhibitor tetrac on differentiation, migration and invasion of mesenchymal stem cells (MSCs) that are an integral part of the tumour's fibrovascular network. Primary human bone marrow-derived MSCs were treated with T3 or T4 in the presence of hepatocellular carcinoma (HCC) cell-conditioned medium (CM), which resulted in stimulation of the expression of genes associated with cancer-associated fibroblast-like differentiation as determined by qPCR and ELISA. In addition, T3 and T4 increased migration of MSCs towards HCC cell-CM and invasion into the centre of three-dimensional HCC cell spheroids. All these effects were tetrac-dependent and therefore integrin αvβ3-mediated. In a subcutaneous HCC xenograft model, MSCs showed significantly increased recruitment and invasion into tumours of hyperthyroid mice compared to euthyroid and, in particular, hypothyroid mice, while treatment with tetrac almost completely eliminated MSC recruitment. These studies significantly improve our understanding of the anti-tumour activity of tetrac, as well as the mechanisms that regulate MSC differentiation and recruitment in the context of tumour stroma formation, as an important prerequisite for the utilisation of MSCs as gene delivery vehicles.

Addition of local hepatic therapy to sorafenib in patients with advanced hepatocellular carcinoma (stage BCLC C)

BACKGROUND/AIMS

For most patients with hepatocellular carcinoma (HCC), diagnosis is invariably done only in the advanced stages of the disease. For advanced, non-metastatic stage, standard therapy is transarterial chemoembolization (TACE). For metastatic disease, the recommended therapy is systemic treatment with sorafenib. In this study, we evaluated the benefit of an additional local hepatic treatment for patients with advanced metastatic disease.

METHODS

In a retrospective study, we assessed the overall survival (OS), time to progression (TTP), and disease control rate (DCR) in 37 patients with metastasized HCC treated with sorafenib. Sixteen patients received additional local therapy, while 21 patients received only sorafenib.

RESULTS

Median OS of patients with combined therapy was significantly higher with 25 months (95% CI: 13.7-36.3 months) as compared to 11 months (95% CI: 6.2-15.8 months) in patients treated with sorafenib alone. TTP was 7 months (95% CI: 5.3-8.7 months) compared to 5 months (95% CI: 3-7 months) and DCR was 87 versus 72% after 3 months and 31 versus 22% after 9 months.

CONCLUSION

These data suggest that control of the liver tumor burden by local therapy in combination with sorafenib might prove beneficial for metastasized HCC. Randomised studies are needed to confirm this exploratory finding.

Tivantinib (ARQ 197) affects the apoptotic and proliferative machinery downstream of c-MET: role of Mcl-1, Bcl-xl and Cyclin B1

Tivantinib, a c-MET inhibitor, is investigated as a second-line treatment of HCC. It was shown that c-MET overexpression predicts its efficacy. Therefore, a phase-3 trial of tivantinib has been initiated to recruit "c-MET-high" patients only. However, recent evidence indicates that the anticancer activity of tivantinib is not due to c-MET inhibition, suggesting that c-MET is a predictor of response to this compound rather than its actual target. By assessing the mechanisms underlying the anticancer properties of tivantinib we showed that this agent causes apoptosis and cell cycle arrest by inhibiting the anti-apoptotic molecules Mcl-1 and Bcl-xl, and by increasing Cyclin B1 expression regardless of c-MET status. However, we found that tivantinib might antagonize the antiapoptotic effects of c-MET activation since HGF enhanced the expression of Mcl-1 and Bcl-xl. In summary, we show that the activity of tivantinib is independent of c-MET and describe Mcl-1, Bcl-xl and Cyclin B1 as effectors of its antineoplastic effects in HCC cells. We suggest that the predictive effect of c-MET expression in part reflects the c-MET-driven overexpression of Mcl-1 and Bcl-xl in c-MET-high patients and that these molecules are considered as possible response predictors.

Establishment of an Effective Radioiodide Thyroid Ablation Protocol in Mice

Due to the high variance in available protocols on iodide-131 ((131)I) ablation in rodents, we set out to establish an effective method to generate a thyroid-ablated mouse model that allows the application of the sodium iodide symporter (NIS) as a reporter gene without interference with thyroidal NIS. We tested a range of (131)I doses with and without prestimulation of thyroidal radioiodide uptake by a low-iodine diet and thyroid-stimulating hormone (TSH) application. Efficacy of induction of hypothyroidism was tested by measurement of serum T4 concentrations, pituitary TSHβ and liver deiodinase type 1 (DIO1) mRNA expression, body weight analysis, and (99m)Tc-pertechnetate scintigraphy. While 200 µCi (7.4 MBq) (131)I alone was not sufficient to abolish thyroidal T4 production, 500 µCi (18.5 MBq) (131)I combined with 1 week of a low-iodine diet decreased serum concentrations below the detection limit. However, the high (131)I dose resulted in severe side effects. A combination of 1 week of a low-iodine diet followed by injection of bovine TSH before the application of 150 µCi (5.5 MBq) (131)I decreased serum T4 concentrations below the detection limit and significantly increased pituitary TSHβ concentrations. The systemic effects of induced hypothyroidism were shown by growth arrest and a decrease in liver DIO1 expression below the detection limit. (99m)Tc-pertechnetate scintigraphy revealed absence of thyroidal (99m)Tc-pertechnetate uptake in ablated mice. In summary, we report a revised protocol for radioiodide ablation of the thyroid gland in the mouse to generate an in vivo model that allows the study of thyroid hormone action using NIS as a reporter gene.

[Fecal microbiota transfer (FMT) in a patient with refractory irritable bowel syndrome]

Irritable bowel syndrome is a disorder of the gastrointestinal tract with unknown etiology. Recent clinical data support a link between changes in fecal microbiota with decreased biodiversity and the development of irritable bowel syndrome. Whether these changes of the microbiota are caused by the disease or whether they develop during the course of the disease remains unclear. Several studies demonstrated that fecal microbiota transfer (FMT) successfully attenuates Clostridium difficile infection by restoring the disturbed bacterial flora of the gut and case reports suggest that FMT may relief symptoms in patients with irritable bowel syndrome (IBS). Here we report a 47-year-old male patient with longstanding refractory diarrhea predominant IBS, who was successfully treated with a single FMT. The beneficial effect on the patient's symptoms was associated with changes of the stool microbiome. Post-FMT the recipient's microbiome resembled the donor's microbiome.

Mesenchymal stem cell-mediated, tumor stroma-targeted radioiodine therapy of metastatic colon cancer using the sodium iodide symporter as theranostic gene

The tumor-homing property of mesenchymal stem cells (MSCs) allows targeted delivery of therapeutic genes into the tumor microenvironment. The application of sodium iodide symporter (NIS) as a theranostic gene allows noninvasive imaging of MSC biodistribution and transgene expression before therapeutic radioiodine application. We have previously shown that linking therapeutic transgene expression to induction of the chemokine CCL5/RANTES allows a more focused expression within primary tumors, as the adoptively transferred MSC develop carcinoma-associated fibroblast-like characteristics. Although RANTES/CCL5-NIS targeting has shown efficacy in the treatment of primary tumors, it was not clear if it would also be effective in controlling the growth of metastatic disease.

METHODS

To expand the potential range of tumor targets, we investigated the biodistribution and tumor recruitment of MSCs transfected with NIS under control of the RANTES/CCL5 promoter (RANTES-NIS-MSC) in a colon cancer liver metastasis mouse model established by intrasplenic injection of the human colon cancer cell line LS174t. RANTES-NIS-MSCs were injected intravenously, followed by (123)I scintigraphy, (124)I PET imaging, and (131)I therapy.

RESULTS

Results show robust MSC recruitment with RANTES/CCL5-promoter activation within the stroma of liver metastases as evidenced by tumor-selective iodide accumulation, immunohistochemistry, and real-time polymerase chain reaction. Therapeutic application of (131)I in RANTES-NIS-MSC-treated mice resulted in a significant delay in tumor growth and improved overall survival.

CONCLUSION

This novel gene therapy approach opens the prospect of NIS-mediated radionuclide therapy of metastatic cancer after MSC-mediated gene delivery.

Effects of the glucagon-like peptide-1 receptor agonist liraglutide in juvenile transgenic pigs modeling a pre-diabetic condition

Background

The glucagon-like peptide-1 receptor (GLP1R) agonist liraglutide improves glycemic control and reduces body weight of adult type 2 diabetic patients. However, efficacy and safety of liraglutide in adolescents has not been systematically investigated. Furthermore, possible pro-proliferative effects of GLP1R agonists on the endocrine and exocrine pancreas need to be further evaluated. We studied effects of liraglutide in adolescent pigs expressing a dominant-negative glucose-dependent insulinotropic polypeptide receptor (GIPR^dn) in the beta-cells, leading to a pre-diabetic condition including disturbed glucose tolerance, reduced insulin secretion and progressive reduction of functional beta-cell mass.

Methods

Two-month-old GIPR^dn transgenic pigs were treated daily with liraglutide (0.6-1.2 mg per day) or placebo for 90 days. Glucose homeostasis was evaluated prior to and at the end of the treatment period by performing mixed meal and intravenous glucose tolerance tests (MMGTT and IVGTT). Finally animals were subjected to necropsy and quantitative-stereological analyses were performed for evaluation of alpha- and beta-cell mass, beta-cell proliferation as well as acinus-cell proliferation.

Results

MMGTT at the end of the study revealed 23% smaller area under the curve (AUC) for glucose, a 36% smaller AUC insulin, and improved insulin sensitivity, while IVGTT showed a 15% smaller AUC glucose but unchanged AUC insulin in liraglutide- vs. placebo-treated animals. Liraglutide led to marked reductions in body weight gain (-31%) and food intake (-30%) compared to placebo treatment, associated with reduced phosphorylation of insulin receptor beta (INSRB)/insulin-like growth factor-1 receptor beta (IGF1RB) and protein kinase B (AKT) in skeletal muscle. Absolute alpha- and beta-cell mass was reduced in liraglutide-treated animals, but alpha- and beta-cell mass-to-body weight ratios were unchanged. Liraglutide neither stimulated beta-cell proliferation in the endocrine pancreas nor acinus-cell proliferation in the exocrine pancreas, excluding both beneficial and detrimental effects on the pig pancreas.

Conclusions

Although plasma liraglutide levels of adolescent transgenic pigs treated in our study were higher compared to human trials, pro-proliferative effects on the endocrine or exocrine pancreas or other liraglutide-related side-effects were not observed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0431-2) contains supplementary material, which is available to authorized users.

Overexpression of heat shock protein 27 (HSP27) increases gemcitabine sensitivity in pancreatic cancer cells through S-phase arrest and apoptosis

We previously established a role for HSP27 as a predictive marker for therapeutic response towards gemcitabine in pancreatic cancer. Here, we investigate the underlying mechanisms of HSP27-mediated gemcitabine sensitivity. Utilizing a pancreatic cancer cell model with stable HSP27 overexpression, cell cycle arrest and apoptosis induction were analysed by flow cytometry, nuclear staining, immunoblotting and mitochondrial staining. Drug sensitivity studies were performed by proliferation assays. Hyperthermia was simulated using mild heat shock at 41.8°C. Upon gemcitabine treatment, HSP27-overexpressing cells displayed an early S-phase arrest subsequently followed by a strongly increased sub-G1 fraction. Apoptosis was characterized by PARP-, CASPASE 3-, CASPASE 8-, CASPASE 9- and BIM- activation along with a mitochondrial membrane potential loss. It was reversible through chemical caspase inhibition. Importantly, gemcitabine sensitivity and PARP cleavage were also elicited by heat shock-induced HSP27 overexpression, although to a smaller extent, in a panel of pancreatic cancer cell lines. Finally, HSP27-overexpressing pancreatic cancer cells displayed an increased sensitivity also towards death receptor-targeting agents, suggesting another pro-apoptotic role of HSP27 along the extrinsic apoptosis pathway. Taken together, in contrast to the well-established anti-apoptotic properties of HSP27 in cancer, our study reveals novel pro-apoptotic functions of HSP27—mediated through both the intrinsic and the extrinsic apoptotic pathways—at least in pancreatic cancer cells. HSP27 could represent a predictive marker of therapeutic response towards specific drug classes in pancreatic cancer and provides a novel molecular rationale for current clinical trials applying the combination of gemcitabine with regional hyperthermia in pancreatic cancer patients.

Anticancer effects of metformin on neuroendocrine tumor cells in vitro

Metformin is a widely used oral antidiabetic drug with good tolerability. Recent studies suggest that it also possesses adjuvant potent anticancer properties in a variety of tumors. Neuroendocrine tumors (NETs) of the gastro-entero-pancreatic system (GEP) comprise a heterogeneous group of tumors with increasing incidence and limited effective therapeutic options. Here we report the antiproliferative effects of metformin in neuroendocrine tumor cells in vitro. Treatment of human pancreatic BON1, bronchopulmonary NCI-H727, and midgut GOT1 neuroendocrine tumor cells with increasing concentrations of metformin (0.1-10 mM) dose-dependently suppressed cell viability and cell counts. Metformin induced AMPK phosphorylation in pancreatic BON1 and midgut GOT1 but suppressed AMPK activity in bronchopulmonary NCI-H727. Thus, AMPK-dependent and AMPK-independent properties may be operative in NETs of different origin. Metformin suppressed mTORC1 signaling in all three tumor cell types, evidenced by suppression of 4EBP1, pP70S6K, and S6 phosphorylation, and was associated with compensatory AKT activity. We observed induction of ERK phosphorylation in BON1 and NCI-H727 and inhibition of ERK in midgut GOT1 cells, while all three tumor cell types responded with induction of GSK3 phosphorylation. This suggests a central role for GSK3 in metformin-mediated signal transduction. Inhibition of cell proliferation by metformin was associated with apoptosis induction only in midgut GOT1, evidenced by increased subG0/1 fraction and PARP cleavage. These results suggest a potential role of metformin as a (adjuvant) therapeutic for patients with NETs.

DRO1 inactivation drives colorectal carcinogenesis in ApcMin/+ mice

Colorectal cancer develops from adenomatous precursor lesions by a multistep process that involves several independent mutational events in oncogenes and tumor suppressor genes. Inactivation of the adenomatous polyposis coli (APC) tumor suppressor gene is an early event and a prerequisite for the development of human colorectal adenoma. Previous in vitro studies identified DRO1 (CCDC80) to be a putative tumor suppressor gene that is negatively regulated in colorectal cancers and downregulated upon neoplastic transformation of epithelial cells. To investigate the in vivo role of DRO1 in colorectal carcinogenesis, a constitutive DRO1 knockout mouse model was generated. Disruption of DRO1 did not result in spontaneous intestinal tumor formation, consistent with the notion that DRO1 might have a role in suppressing the development of colon tumors in Apc(Min) (/+) mice, a widely used model for studying the role of APC in intestinal tumorigenesis that is hampered by the fact that mice predominantly develop adenomas in the small intestine and not in the colon. Here, deletion of DRO1 in Apc(Min) (/+) mice results in earlier death, a dramatically increased colonic tumor burden, and frequent development of colorectal carcinoma. Furthermore, enhanced phosphorylation of ERK1/2 is observed in colon epithelium and tumors from DRO1 knockout mice. Thus, this study reveals that inactivation of DRO1 is required for colorectal carcinogenesis in the Apc(Min) (/+) mouse and establishes a new mouse model for the study of colorectal cancer.

IMPLICATIONS

This report characterizes a new mouse model for the study of colorectal cancer and establishes DRO1 (CCDC80) as a tumor suppressor via a mechanism involving ERK phosphorylation.

Combination of 13-Cis retinoic acid and lovastatin: marked antitumor potential in vivo in a pheochromocytoma allograft model in female athymic nude mice

Currently, there are no reliably effective therapeutic options for metastatic pheochromocytoma (PCC) and paraganglioma. Moreover, there are no therapies that may prevent the onset or progression of tumors in patients with succinate dehydrogenase type B mutations, which are associated with very aggressive tumors. Therefore, we tested the approved and well-tolerated drugs lovastatin and 13-cis-retinoic acid (13cRA) in vitro in an aggressive PCC mouse cell line, mouse tumor tissue-derived (MTT) cells, and in vivo in a PCC allograft nude mouse model, in therapeutically relevant doses. Treatment was started 24 hours before sc tumor cell injection and continued for 30 more days. Tumor sizes were measured from outside by caliper and sizes of viable tumor mass by bioluminescence imaging. Lovastatin showed antiproliferative effects in vitro and led to significantly smaller tumor sizes in vivo compared with vehicle treatment. 13cRA promoted tumor cell growth in vitro and led to significantly larger viable tumor mass and significantly faster increase of viable tumor mass in vivo over time compared with vehicle, lovastatin, and combination treatment. However, when combined with lovastatin, 13cRA enhanced the antiproliferative effect of lovastatin in vivo. The combination-treated mice showed slowest tumor growth of all groups with significantly slower tumor growth compared with the vehicle-treated mice and significantly smaller tumor sizes. Moreover, the combination-treated group displayed the smallest size of viable tumor mass and the slowest increase in viable tumor mass over time of all groups, with a significant difference compared with the vehicle- and 13cRA-treated group. The combination-treated tumors showed highest extent of necrosis, lowest median microvessel density and highest expression of α-smooth muscle actin. The combination of high microvessel density and low α-smooth muscle actin is a predictor of poor prognosis in other tumor entities. Therefore, this drug combination may be a well-tolerated novel therapeutic or preventive option for malignant PCC.

Rate and predictors of mucosal healing in patients with inflammatory bowel disease treated with anti-TNF-alpha antibodies

OBJECTIVE

Mucosal healing (MH) is an important treatment goal in patients with inflammatory bowel disease (IBD), but factors predicting MH under medical therapy are largely unknown. In this study, we aimed to characterize predictive factors for MH in anti-TNF-alpha antibody-treated IBD patients.

METHODS

We retrospectively analyzed 248 IBD patients (61.3% CD, 38.7% UC) treated with anti-TNF-alpha antibodies (infliximab and/or adalimumab) for MH, defined as macroscopic absence of inflammatory lesions (Mayo endoscopy score 0 or SES-CD score 0) in colonoscopies which were analyzed before and after initiation of an anti-TNF-alpha antibody treatment.

RESULTS

In patients treated with only one anti-TNF-alpha antibody ("TNF1 group", n = 202), 56 patients (27.7%) achieved complete MH at follow-up colonoscopy (median overall follow-up time: 63 months). In a second cohort (n = 46), which comprised patients who were consecutively treated with two anti-TNF-alpha antibodies ("TNF2 group"), 13 patients (28.3%) achieved complete MH (median overall follow-up time: 64.5 months). Compared to patients without MH, CRP values at follow-up colonoscopy were significantly lower in patients with MH (TNF1 group: p = 8.35×10-5; TNF2 group: p = 0.002). Multivariate analyses confirmed CRP at follow-up colonoscopy as predictor for MH in the TNF1 group (p = 0.012). Overall need for surgery was lower in patients with MH (TNF1 group: p = 0.01; TNF2 group: p = 0.03).

CONCLUSIONS

We identified low serum CRP level at follow-up colonoscopy as predictor for MH, while MH was an excellent negative predictor for the need for surgery.

Risk of malignancies in patients with inflammatory bowel disease treated with thiopurines or anti-TNF alpha antibodies

PURPOSE

We aimed to analyse malignancy rates and predictors for the development of malignancies in a large German inflammatory bowel disease (IBD) cohort treated with thiopurines and/or anti-tumour necrosis factor (TNF) antibodies.

METHODS

De novo malignancies in 666 thiopurine-treated and/or anti-TNF-treated IBD patients were analysed. Patients (n = 262) were treated with thiopurines alone and never exposed to anti-TNF antibodies (TP group). In addition, patients (n = 404) were exposed to anti-TNF antibodies (TNF+ group) with no (7.4%), discontinued (80.4%) or continued (12.1%) thiopurine therapy.

RESULTS

In the TP group, 20 malignancies were observed in 18 patients compared with 8 malignancies in 7 patients in the TNF+ group (hazard ratio 4.15; 95% CI 1.82-9.44; p = 0.0007; univariate Cox regression). Moreover, 18.2% of all patients in the TP group ≥50 years of age developed a malignancy, compared with 3.8% of all patients <50 years of age (p = 0.0008). In the TNF+ group, 6.5% of all patients ≥50 years of age developed malignancies compared with 0.3% of all patients <50 years of age (p = 0.0007). In both groups combined, thiopurine treatment duration ≥4 years was associated with the risk for skin cancer (p = 0.0024) and lymphoma (p = 0.0005).

CONCLUSIONS

Our data demonstrate an increased risk for the development of malignancies in IBD patients treated with thiopurines in comparison with patients treated with anti-TNF antibodies with or without thiopurines.

Oncostatin M mediates STAT3-dependent intestinal epithelial restitution via increased cell proliferation, decreased apoptosis and upregulation of SERPIN family members

Objective

Oncostatin M (OSM) is produced by activated T cells, monocytes, and dendritic cells and signals through two distinct receptor complexes consisting of gp130 and LIFR (I) or OSMR-β and gp130 (II), respectively. Aim of this study was to analyze the role of OSM in intestinal epithelial cells (IEC) and intestinal inflammation.

Methods

OSM expression and OSM receptor distribution was analyzed by PCR and immunohistochemistry experiments, signal transduction by immunoblotting. Gene expression studies were performed by microarray analysis and RT-PCR. Apoptosis was measured by caspases-3/7 activity. IEC migration and proliferation was studied in wounding and water soluble tetrazolium assays.

Results

The IEC lines Caco-2, DLD-1, SW480, HCT116 and HT-29 express mRNA for the OSM receptor subunits gp130 and OSMR-β, while only HCT116, HT-29 and DLD-1 cells express LIFR mRNA. OSM binding to its receptor complex activates STAT1, STAT3, ERK-1/2, SAPK/JNK-1/2, and Akt. Microarray analysis revealed 79 genes that were significantly up-regulated (adj.-p≤0.05) by OSM in IEC. Most up-regulated genes belong to the functional categories “immunity and defense” (p = 2.1×10⁻⁷), “apoptosis” (p = 3.7×10⁻⁴) and “JAK/STAT cascade” (p = 3.4×10⁻⁶). Members of the SERPIN gene family were among the most strongly up-regulated genes. OSM significantly increased STAT3- and MEK1-dependent IEC cell proliferation (p<0.05) and wound healing (p = 3.9×10⁻⁵). OSM protein expression was increased in colonic biopsies of patients with active inflammatory bowel disease (IBD).

Conclusions

OSM promotes STAT3-dependent intestinal epithelial cell proliferation and wound healing in vitro. Considering the increased OSM expression in colonic biopsy specimens of patients with active IBD, OSM upregulation may modulate a barrier-protective host response in intestinal inflammation. Further in vivo studies are warranted to elucidate the exact role of OSM in intestinal inflammation and the potential of OSM as a drug target in IBD.

Pathogenese und Epidemiologie der Sigmadivertikulose

From an epidemiological point of view, left-sided diverticulosis represents a civilizational disease of Western countries. It occurs rarely during childhood and frequently in later years. A diet high in fat and meat, low in vegetables, and with insufficient fiber content apparently encourages its genesis. Physical activity seems to counteract diverticulosis while alcohol consumption, smoking, and caffeine ingestion have no effect. The extent of diverticulosis is not commensurate with the extent of complaints. Only a few patients with diverticula develop diverticulitis. Pathogenetically, several factors play a role in the development of diverticulosis. Elevated intraluminal pressure as well as acquired structural changes of the intestinal wall seem to be decisive factors, which intensify with increasing age. These changes are caused by ultrastructural alterations of the muscle and connective tissue related to collagen and elastin metabolism, which presumably can be genetically determined. Intestinal disturbances of innervation and motility also contribute to the formation of diverticula. The term "hypersegmentation" is an attempt to combine these factors into a single pathogenetic model.

A direct comparison of the prevalence of advanced adenoma and cancer between surveillance and screening colonoscopies

BACKGROUND/AIMS

Surveillance colonoscopy is recommended after polypectomy of adenoma and surgery for colorectal cancer. The purpose of this study was to assess the frequency of advanced adenoma and cancer in colonoscopies performed for surveillance compared to screening colonoscopies.

METHODS

Analysis of relative frequencies of findings in colonoscopies performed for post-adenoma surveillance (post-ad), post-cancer surveillance (post-crc), screening, and follow-up of a positive fecal occult blood test (FOBT). Logistic regression was used to identify the risk for advanced adenoma (adenoma ≥10 mm, containing high-grade dysplasia, or villous histology) and cancer.

RESULTS

324,912 colonoscopies were included in the analysis: 81,877 post-ad, 26,896 post-crc, 178,305 screening, 37,834 positive FOBT. Advanced adenoma (cancer) was diagnosed in 8.0% (0.4%) of post-ad, 5.0% (1.0%) of post-crc, 7.4% (1.1%) of screening, and 11.7% (3.6%) of positive FOBT colonoscopies. Compared to screening, the odds ratios for finding advanced adenoma were 0.93 (95% CI 0.88-0.98) for post-ad, 0.96 (0.86-1.08) for post-crc, and 1.18 (1.09-1.28) for positive FOBT colonoscopies. The odds ratios for the diagnosis of cancer were 0.29 (0.24-0.36) for post-ad, 0.81 (0.61-1.07) for post-crc, and 2.77 (2.43-3.17) for positive FOBT.

CONCLUSION

Colonoscopy for post-ad surveillance but not colonoscopy for post-crc surveillance is associated with a lower risk of diagnosis of advanced adenoma and cancer.

Defining the role of GLP-1 in the enteroinsulinar axis in type 2 diabetes using DPP-4 inhibition and GLP-1 receptor blockade

Understanding the incretin pathway has led to significant advancements in the treatment of type 2 diabetes (T2D). Still, the exact mechanisms are not fully understood. In a randomized, placebo-controlled, four-period, crossover study in 24 patients with T2D, dipeptidyl peptidase-4 (DPP-4) inhibition and its glucose-lowering actions were tested after an oral glucose tolerance test (OGTT). The contribution of GLP-1 was examined by infusion of the GLP-1 receptor (GLP-1r) antagonist exendin-9. DPP-4 inhibition reduced glycemia and enhanced insulin levels and the incretin effect (IE). Glucagon was suppressed, and gastric emptying (GE) was decelerated. Exendin-9 increased glucose levels and glucagon secretion, attenuated insulinemia and the IE, and accelerated GE. With the GLP-1r antagonist, the glucose-lowering effects of DPP-4 inhibition were reduced by ∼ 50%. However, a significant effect on insulin secretion remained during GLP-1r blockade, whereas the inhibitory effects of DPP-4 inhibition on glucagon and GE were abolished. Thus, in this cohort of T2D patients with a substantial IE, GLP-1 contributed ∼ 50% to the insulin excursion after an OGTT with and without DPP-4 inhibition. Thus, a significant DPP-4-sensitive glucose-lowering mechanism contributes to glycemic control in T2D patients that may be not mediated by circulating GLP-1.

Role of cysteinyl-leukotrienes for portal pressure regulation and liver damage in cholestatic rat livers

Kupffer cells (KCs) have a major role in liver injury, and cysteinyl-leukotrienes (Cys-LTs) are known to be involved as well. The KC-mediated pathways for the production and secretion of Cys-LT in cholestatic liver injury have not yet been elucidated. Here, we hypothesized that KC activation by Toll-like receptor ligands results in Cys-LT-mediated microcirculatory alterations and liver injury in acute cholestasis. We hypothesized further that this situation is associated with changes in the secretion and production of Cys-LT. One week after bile duct ligation (BDL), livers showed typical histological signs of cholestatic liver injury. Associated microcirculatory disturbances caused increased basal and maximal portal pressure following KC activation. These differences were determined in BDL livers compared with sham-operated livers in vivo (KC activation by LPS 4 mg/kg b.w.) and in isolated perfused organs (KC activation by Zymosan A, 150 μg/ml). Treatment with the 5-lipoxygenase inhibitor MK-886 alone did not alter portal perfusion pressure, lactate dehydrogenase (LDH) efflux, or bile duct proliferation in BDL animals. Following KC activation, portal perfusion pressure increased. The degree of cell injury was attenuated by MK-886 (3 μM) treatment as estimated by LDH efflux. In normal rats, a large amount of Cys-LT efflux was found in the bile. Only a minor amount was found in the effluent perfusate. In BDL livers, the KC-mediated Cys-LT efflux into the sinusoidal system increased, although the absolute Cys-LT level was still grossly lower than the biliary excretion in sham-operated livers. In conclusion, our results indicate that treatment with Cys-LT inhibitors might be a relevant target for attenuating cholestatic liver damage.

Intestinal DMBT1 expression is modulated by Crohn's disease-associated IL23R variants and by a DMBT1 variant which influences binding of the transcription factors CREB1 and ATF-2

OBJECTIVES

DMBT is an antibacterial pattern recognition and scavenger receptor. In this study, we analyzed the role of DMBT1 single nucleotide polymorphisms (SNPs) regarding inflammatory bowel disease (IBD) susceptibility and examined their functional impact on transcription factor binding and downstream gene expression.

METHODS

Seven SNPs in the DMBT1 gene region were analyzed in 2073 individuals including 818 Crohn's disease (CD) patients and 972 healthy controls in two independent case-control panels. Comprehensive epistasis analyses for the known CD susceptibility genes NOD2, IL23R and IL27 were performed. The influence of IL23R variants on DMBT1 expression was analyzed. Functional analysis included siRNA transfection, quantitative PCR, western blot, electrophoretic mobility shift and luciferase assays.

RESULTS

IL-22 induces DMBT1 protein expression in intestinal epithelial cells dependent on STAT3, ATF-2 and CREB1. IL-22 expression-modulating, CD risk-associated IL23R variants influence DMBT1 expression in CD patients and DMBT1 levels are increased in the inflamed intestinal mucosa of CD patients. Several DMBT1 SNPs were associated with CD susceptibility. SNP rs2981804 was most strongly associated with CD in the combined panel (p = 3.0 × 10(-7), OR 1.42; 95% CI 1.24-1.63). All haplotype groups tested showed highly significant associations with CD (including omnibus P-values as low as 6.1 × 10(-18)). The most strongly CD risk-associated, non-coding DMBT1 SNP rs2981804 modifies the DNA binding sites for the transcription factors CREB1 and ATF-2 and the respective genomic region comprising rs2981804 is able to act as a transcriptional regulator in vitro. Intestinal DMBT1 expression is decreased in CD patients carrying the rs2981804 CD risk allele.

CONCLUSION

We identified novel associations of DMBT1 variants with CD susceptibility and discovered a novel functional role of rs2981804 in regulating DMBT1 expression. Our data suggest an important role of DMBT1 in CD pathogenesis.

Potent antitumor activity of the novel HSP90 inhibitors AUY922 and HSP990 in neuroendocrine carcinoid cells

The heat shock protein (HSP) 90 chaperone machine involved in numerous oncogenic signaling pathways is over-expressed in cancer cells and is currently being evaluated for anticancer therapy. Neuroendocrine tumors (NETs) of the gastroenteropancreatic (GEP) system comprise a heterogeneous group of tumors with increasing incidence and poor prognosis. Here, we report the antiproliferative effects of the HSP90 inhibitors AUY922 and HSP990 in neuroendocrine tumor cells. Treatment of human pancreatic BON1, bronchopulmonary NCI-H727 and midgut carcinoid GOT1 neuroendocrine tumor cells with increasing concentrations of AUY922 and HSP990 dose-dependently suppressed cell viability. Significant effects on neuroendocrine cell viability were observed with inhibitor concentrations as low as 5 nM. Inhibition of cell viability was associated with the induction of apoptosis as demonstrated by an increase in sub-G1 events and PARP cleavage. HSP90 inhibition was associated with decreased neuroendocrine ErbB and IGF-I receptor expression, decreased Erk and Akt phosphorylation and the induction of HSP70 expression. These findings provide evidence that targeted inhibition of upregulated HSP90 activity could be useful for the treatment of aggressive neuroendocrine tumors resistant to conventional therapy.

Portal pressure regulation following Kupffer cell activation: control of prostaglandin production by heme oxygenases

BACKGROUND

Portal pressure (PP) results from the interplay of vasoconstrictors and vasodilators. Recently, we have shown that Kupffer cell (KC) activation increases PP.

AIMS

The role of the vasodilating compounds nitric oxide (NO) and carbon monoxide (CO) was studied. The hypothesis of the present study was that these vasodilators counteract the PP increase following KC activation.

METHODS

Livers of rats weighing 180-200 g were isolated and perfused. KCs were activated by zymosan A (cell wall particles from yeast; 150 µg/ml). The effects of NO and guanylate cyclase (GC) were evaluated by the NO synthase inhibitor N(G)-nitro-L-arginine methylester (L-NAME; 0.3 mM, and the GC inhibitor 4H-8-bromo-1,2,4-oxadiazolo(3,4-d)benz(b)(1,4)oxazin-1-one (NS-2028, 1.0 µM); the effects of the heme oxygenase (HO) derived compound CO were evaluated by direct administration of CO or inhibition of HO by zinc protoporphyrin IX (ZnPP IX, 1.0 µM).

RESULTS

In isolated perfused rat livers, administration of L-NAME or NS-2028 further raised PP increase following KC activation. This effect could be reduced by the cGMP analogue 8-Br-cGMP. Inhibition of HO caused marked amplification of PP increase in zymosan-treated organs. CO prevented this PP increase cGMP independently. Interestingly, KC activation and simultaneous inhibition of HO augmented the production of prostaglandins D2 and F2α and of thromboxane A2. Accordingly, indomethacin blunted the increase of PP in zymosan/ZnPP-treated livers.

CONCLUSIONS

NO restricts the initial PP increase after KC activation by GC-mediated cGMP. CO from heme degradation limits the increase of PP after KC activation eicosanoid dependently, but cGMP independently.

[Diseases in gastroenterology]

Autoimmune diseases of gastrointestinal organs require a timely diagnosis to facilitate appropriate treatment. It is an important challenge to differentiate autoimmune pancreatitis (AIP) from pancreatic carcinoma. This is hampered by the occurrence of focal changes in the pancreatic parenchyma in AIP. Additionally, lymphadenopathy and duct obstruction are present. Autoimmune hepatitis (AIH) results in liver cirrhosis and organ failure if not discovered in time. In 40 % of patients with AIH the initial diagnosis is not achieved at an early stage. Intestinal tuberculosis must be differentiated from Crohn's disease, especially if modern biotherapies employing antibodies are planned.

Stromal targeting of sodium iodide symporter using mesenchymal stem cells allows enhanced imaging and therapy of hepatocellular carcinoma

The tumor-homing property of mesenchymal stem cells (MSC) has lead to their use as delivery vehicles for therapeutic genes. The application of the sodium iodide symporter (NIS) as therapy gene allows noninvasive imaging of functional transgene expression by (123)I-scintigraphy or PET-imaging, as well as therapeutic application of (131)I or (188)Re. Based on the critical role of the chemokine RANTES (regulated on activation, normal T-cell expressed and presumably secreted)/CCL5 secreted by MSCs in the course of tumor stroma recruitment, use of the RANTES/CCL5 promoter should allow tumor stroma-targeted expression of NIS after MSC-mediated delivery. Using a human hepatocellular cancer (HCC) xenograft mouse model (Huh7), we investigated distribution and tumor recruitment of RANTES-NIS-engineered MSCs after systemic injection by gamma camera imaging. (123)I-scintigraphy revealed active MSC recruitment and CCL5 promoter activation in the tumor stroma of Huh7 xenografts (6.5% ID/g (123)I, biological half-life: 3.7 hr, tumor-absorbed dose: 44.3 mGy/MBq). In comparison, 7% ID/g (188)Re was accumulated in tumors with a biological half-life of 4.1 hr (tumor-absorbed dose: 128.7 mGy/MBq). Administration of a therapeutic dose of (131)I or (188)Re (55.5 MBq) in RANTES-NIS-MSC-treated mice resulted in a significant delay in tumor growth and improved survival without significant differences between (131)I and (188)Re. These data demonstrate successful stromal targeting of NIS in HCC tumors by selective recruitment of NIS-expressing MSCs and by use of the RANTES/CCL5 promoter. The resulting tumor-selective radionuclide accumulation was high enough for a therapeutic effect of (131)I and (188)Re opening the exciting prospect of NIS-mediated radionuclide therapy of metastatic cancer using genetically engineered MSCs as gene delivery vehicles.

Functional relevance of the cannabinoid receptor 2 - heme oxygenase pathway: a novel target for the attenuation of portal hypertension

AIMS

In liver cirrhosis, inflammation triggers portal hypertension. Kupffer cells (KC) produce vasoconstrictors upon activation by bacterial constituents. Here, we hypothesize that the anti-inflammatory action of the cannabinoid receptor 2 (CB2) agonists JWH-133 and GP 1a attenuate portal hypertension.

MAIN METHODS

In vivo measurements of portal pressures and non-recirculating liver perfusions were performed in rats 4weeks after bile duct ligation (BDL). Zymosan (150μg/ml, isolated liver perfusion) or LPS (4mg/kgb.w., in vivo) was infused to activate the KC in the absence or presence of JWH-133 (10mg/kgb.w.), GP 1a (2.5mg/kgb.w.) or ZnPP IX (1μM). Isolated KC were treated with Zymosan (0.5mg/ml) in addition to JWH-133 (5μM). The thromboxane (TX) B2 levels in the perfusate and KC media were determined by ELISA. Heme oxygenase-1 (HO-1) and CB2 were analyzed by Western blot or confocal microscopy.

KEY FINDINGS

JWH-133 or GP 1a pre-treatment attenuated portal pressures following KC activation in all experimental settings. In parallel, HO-1 expression increased with JWH-133 pre-treatment. However, the inhibition of HO-1 enhanced portal hypertension, indicating the functional role of this novel pathway. In isolated KC, the expression of CB2 and HO-1 increased with Zymosan, LPS and JWH-133 treatment while TXB2 production following KC activation was attenuated by JWH-133 pre-treatment.

SIGNIFICANCE

JWH-133 or GP 1a treatment attenuates portal hypertension. HO-1 induction by JWH-133 plays a functional role. Therefore, the administration of JWH-133 or GP 1a represents a promising new treatment option for portal hypertension triggered by microbiological products.

Systemic image-guided liver cancer radiovirotherapy using dendrimer-coated adenovirus encoding the sodium iodide symporter as theranostic gene

Currently, major limitations for the clinical application of adenovirus-mediated gene therapy are high prevalence of neutralizing antibodies, widespread expression of the coxsackie-adenovirus receptor (CAR), and adenovirus sequestration by the liver. In the current study, we used the sodium iodide symporter (NIS) as a theranostic gene to investigate whether coating of adenovirus with synthetic dendrimers could be useful to overcome these hurdles in order to develop adenoviral vectors for combination of systemic oncolytic virotherapy and NIS-mediated radiotherapy.

METHODS

We coated replication-deficient (Ad5-CMV/NIS) (CMV is cytomegalovirus) and replication-selective (Ad5-E1/AFP-E3/NIS) adenovirus serotype 5 carrying the hNIS gene with poly(amidoamine) dendrimers generation 5 (PAMAM-G5) in order to investigate transduction efficacy and altered tropism of these coated virus particles by (123)I scintigraphy and to evaluate their therapeutic potential for systemic radiovirotherapy in a liver cancer xenograft mouse model.

RESULTS

After dendrimer coating, Ad5-CMV/NIS demonstrated partial protection from neutralizing antibodies and enhanced transduction efficacy in CAR-negative cells in vitro. In vivo (123)I scintigraphy of nude mice revealed significantly reduced levels of hepatic transgene expression after intravenous injection of dendrimer-coated Ad5-CMV/NIS (dcAd5-CMV/NIS). Evasion from liver accumulation resulted in significantly reduced liver toxicity and increased transduction efficiency of dcAd5-CMV/NIS in hepatoma xenografts. After PAMAM-G5 coating of the replication-selective Ad5-E1/AFP-E3/NIS, a significantly enhanced oncolytic effect was observed after intravenous application (virotherapy) that was further increased by additional treatment with a therapeutic dose of (131)I (radiovirotherapy) and was associated with markedly improved survival.

CONCLUSION

These results demonstrate efficient liver detargeting and tumor retargeting of adenoviral vectors after coating with synthetic dendrimers, thereby representing a promising innovative strategy for systemic NIS gene therapy. Moreover, our study-based on the function of NIS as a theranostic gene allowing the noninvasive imaging of NIS expression by (123)I scintigraphy-provides detailed characterization of in vivo vector biodistribution and localization, level, and duration of transgene expression, essential prerequisites for exact planning and monitoring of clinical gene therapy trials that aim to individualize the NIS gene therapy concept.

Risk factors for advanced neoplasia within subcentimetric polyps: implications for diagnostic imaging

OBJECTIVE

Diagnostic imaging by CT colonography and capsule endoscopy is used to detect colonic lesions. Controversy exists regarding the work-up of subcentimetric lesions. The aim of this study was to identify risk indicators for advanced neoplasia (AN) in subcentimetric polyps.

DESIGN

Colonoscopies were classified on the basis of the largest lesion found. AN was defined as high-grade dysplasia, villous histology, or cancer. Logistic regression models were developed to identify risk factors for AN, and validated on separate datasets. A risk index based on the logistic regression was generated, and the number needed to screen (NNS) to detect AN was determined.

RESULTS

1,077,956 colonoscopies identified 106,270 intermediate (5-9 mm) and 198,954 diminutive (≤ 4 mm) lesions; 13% of intermediate and 3.7% of diminutive lesions contained AN. The risk of AN was higher in intermediate than in diminutive lesions (OR 3.1; 95% CI 3.0 to 3.3). Age ≥ 85 versus <45 years was associated with ORs of 2.4 (95% CI 1.8 to 3.1) for intermediate polyps and 3.2 (95% CI 2.3 to 4.5) for diminutive polyps. Pedunculated versus sessile morphology was associated with a higher risk of AN in intermediate (OR 2.0; 95% CI 1.9 to 2.2) and diminutive (OR 3.5; 95% CI 2.9 to 4.1) lesions. In the combined analysis for subcentimetric lesions, ORs were 2.7 (95% CI 2.2 to 3.3) for age ≥ 85 versus <45 years, 1.1 (95% CI 1.1 to 1.2) for male sex, 1.6 (95% CI 1.4 to 1.7) for occult blood, 1.3 (95% CI 1.2 to 1.5) for overt blood in stool, 1.3 (95% CI 1.2 to 1.4) for more than four lesions, and 2.2 (95% CI 2.1 to 2.3) for pedunculated versus sessile lesions. At median risk index values, the NNS was 9.3 (95% CI 9.1 to 9.5) in individuals with intermediate lesions and 29.4 (95% CI 28.5 to 30.2) in those with diminutive lesions. Compared with the NNS of 15 of the whole cohort, the majority of intermediate, but a minority of diminutive, lesions were deemed at high risk of AN.

CONCLUSION

This study successfully identified risk factors and established a risk index for subcentimetric lesions. This has implications for the work-up of patients with subcentimetric lesions identified on diagnostic imaging.

Effect of sleeve gastrectomy on postprandial lipoprotein metabolism in morbidly obese patients

BACKGROUND

Obesity is associated with abnormal fasting and postprandial lipids, which may link obesity with atherosclerosis. We explored fasting and postprandial lipids in morbidly obese patients treated with sleeve gastrectomy and in control subjects.

METHODS

After fasting for 12 h 15 morbidly obese patients (BMI 51.4±6.5 kg/m2, 43.7±12.6 years) received a standardized oral fat load before and 3 months after bariatric surgery (sleeve gastrectomy). Controls (n=9, BMI 23.1±1.4 kg/m²) were studied once. Plasma was obtained fasting and then postprandially every 2 h for 8 h. Triglycerides (TG), chylomicron-TG (CM-TG), VLDL/chylomicron-remnant (VLDL/CR)-TG, cholesterol, LDL-cholesterol, VLDL/CR-cholesterol and HDL-cholesterol were isolated by ultracentrifugation at each time point. Postprandial values were expressed as area under the curve (AUC) and incremental area under the curve (iAUC). In addition, fasting glucose and insulin values and HOMA-IR-Index was measured (n=14).

RESULTS

Compared to controls morbidly obese patients had elevated TG and slightly altered postprandial lipids. Following surgery (weight loss 23.4 kg±6.2 kg; p<0.001) fasting TG (-19.1%; p=0.04), VLDL/CR-TG (-20.0%; p=0.05) decreased significantly, while fasting cholesterol, VLDL-, HDL- and LDL-cholesterol did not change. AUC and iAUC decreased significantly for VLDL/CR-TG (-20.4%, p=0.04 and -38.5%, p=0.04, respectively). Neither fasting nor postprandial changes correlated with the change in weight. In patients with preoperatively elevated TG (>150 mg/dl) a similar pattern was observed. Fasting insulin and HOMA were reduced significantly (-51.9%; p=0.004 and -47.9%; p=0.011).

CONCLUSIONS

Three months after sleeve gastrectomy fasting and postprandial lipoprotein metabolism and glucose metabolism is improved in morbidly obese patients. The potential mechanisms may relate to decreased caloric intake but also to hormonal changes.

A role for O-1602 and G protein-coupled receptor GPR55 in the control of colonic motility in mice

Objective

The G protein-coupled receptor 55 (GPR55) is a novel cannabinoid (CB) receptor, whose role in the gastrointestinal (GI) tract remains unknown. Here we studied the significance of GPR55 in the regulation of GI motility.

Design

GPR55 mRNA and protein expression were measured by RT-PCR and immunohistochemistry. The effects of the GPR55 agonist O-1602 and a selective antagonist cannabidiol (CBD) were studied in vitro and in vivo and compared to a non-selective cannabinoid receptor agonist WIN55,212-2. CB_1/2^−/− and GPR55^−/− mice were employed to identify the receptors involved.

Results

GPR55 was localized on myenteric neurons in mouse and human colon. O-1602 concentration-dependently reduced evoked contractions in muscle strips from the colon (∼60%) and weakly (∼25%) from the ileum. These effects were reversed by CBD, but not by CB₁ or CB₂ receptor antagonists. I.p. and i.c.v. injections of O-1602 slowed whole gut transit and colonic bead expulsion; these effects were absent in GPR55^−/− mice. WIN55,212-2 slowed whole gut transit effects, which were counteracted in the presence of a CB1 antagonist AM251. WIN55,212-2, but not O-1602 delayed gastric emptying and small intestinal transit. Locomotion, as a marker for central sedation, was reduced following WIN55,212-2, but not O-1602 treatment.

Conclusion

GPR55 is strongly expressed on myenteric neurons of the colon and it is selectively involved in the regulation of colonic motility. Since activation of GPR55 receptors is not associated with central sedation, the GPR55 receptor may serve as a future target for the treatment of colonic motility disorders.

•

G protein-coupled receptor 55 (GPR55) is a binding site for cannabinoids.

•

No conclusive information was available on function of GPR55 in the GI tract.

•

We found that targeting GPR55 at peripheral or central sites slows GI motility.

•

Slowing effect of GPR55 activation on GI motility is primarily observed in colon.

•

Targeting GPR55 may be a future tool for treatment of colonic motility disorders.

Saxagliptin vs. glipizide as add-on therapy in patients with type 2 diabetes mellitus inadequately controlled on metformin alone: long-term (52-week) extension of a 52-week randomised controlled trial

AIM

To compare the long-term safety, tolerability and efficacy of saxagliptin vs. glipizide as add-on therapy to metformin.

METHODS

Adults with glycated haemoglobin (HbA1c) > 6.5-10% (on stable metformin ≥ 1500 mg/day) were randomised to saxagliptin 5 mg/day (n = 428) or glipizide titrated from 5 to 20 mg/day (mean dose 15 mg/day; n = 430) for 52 weeks with a 52-week extension (NCT00575588). Assessment of the long-term safety, tolerability and efficacy of add-on saxagliptin vs. glipizide after 104 weeks was a tertiary objective of the initial 52-week study.

RESULTS

Saxagliptin was well tolerated during the 104-week period; 67.1% of patients receiving saxagliptin vs. 72.6% receiving glipizide had ≥ 1 adverse event (AE), and few patients (4.9% vs. 5.6%) discontinued owing to AEs. Fewer patients treated with saxagliptin experienced hypoglycaemia (3.5% vs. 38.4% with glipizide; difference, -34.9%, 95% CI, -39.8 to -30.0) or confirmed hypoglycaemia (0 vs. 9.1% with glipizide). Weight loss was observed with saxagliptin (-1.5 kg) vs. weight gain with glipizide (+1.3 kg; between-group difference, -2.8 kg, 95% CI, -3.32 kg to -2.20 kg). Change from baseline in HbA1c was -0.41 ± 0.04% with saxagliptin and -0.35 ± 0.04% with glipizide (between-group difference, -0.05%, 95% CI, -0.17 to 0.06%). A post hoc analysis showed that the proportion of patients with baseline HbA1c ≥ 7% who achieved HbA1c < 7% (observed data) at week 104 was 23.1% for saxagliptin + metformin and 22.7% for glipizide + metformin.

DISCUSSION AND CONCLUSION

A lower risk of hypoglycaemia and reduced body weight were observed with saxagliptin vs. glipizide. No other clinically significant differences were observed between groups in safety profile. No significant between-group differences were observed for reductions in glycaemic parameters. After week 24, a smaller weekly rise in HbA1c was observed with saxagliptin vs. glipizide as add-on therapy to metformin.

Magnetic resonance colonography for the detection of colorectal neoplasia in asymptomatic adults

BACKGROUND & AIMS

Colonoscopy is the preferred screening test for colorectal neoplasia; the fecal occult blood test (FOBT) detects neoplasias with low levels of sensitivity. Computed tomographic colonography detects neoplasias with high levels of sensitivity but involves exposure to radiation. We investigated whether magnetic resonance colonography (MRC) can be used to screen for colorectal adenomas and cancers.

METHODS

We analyzed data from 286 asymptomatic adults (40-82 years old) who underwent 3 Tesla MRC and colonoscopic examinations on the same day. FOBT was performed before bowel preparation. Colonoscopists were initially blinded to the findings on MRC and unblinded after withdrawal from the respective segments. Sensitivities for adenoma and per-patient sensitivities and specificities were calculated based on the unblinded results of colonoscopy.

RESULTS

We detected 133 adenomas and 2 cancers in 86 patients; 37 adenomas were ≥6 mm, and 20 adenomas were advanced. Sensitivities of MRC and colonoscopy for adenomas ≥6 mm were 78.4% (95% confidence interval [CI], 61.8-90.2) and 97.3% (95% CI, 85.8-99.9); for advanced adenomas these values were 75% (95% CI, 50.9-91.3) and 100% (95% CI, 83.2-100.0), respectively. MRC identified 87.1% (95% CI, 70.2-96.4), colonoscopy 96.8% (95% CI, 83.3-99.9), and FOBT 10.0% (95% CI, 2.1-26.5) of individuals with adenomas ≥6 mm and 83.8% (95% CI, 58.6-96.4), 100% (95% CI, 81.5-100.0), and 17.6% (95% CI, 3.8-43.4) of individuals with advanced neoplasia. Specificities of MRC, colonoscopy, and FOBT for individuals with adenomas ≥6 mm were 95.3% (95% CI, 91.9-97.5), 96.9% (95% CI, 93.9-98.6), and 91.8% (95% CI, 87.6-94.9), respectively.

CONCLUSIONS

3 Tesla MRC detects colorectal adenomas ≥6 mm and advanced neoplasia with high levels of sensitivity and specificity. Although MRC detects colorectal neoplasia with lower levels of sensitivity than colonoscopy, it strongly outperforms one-time FOBT.