TRPV6 modulates proliferation of human pancreatic neuroendocrine BON-1 tumour cells

Highly Ca2+ permeable receptor potential channel vanilloid type 6 (TRPV6) modulates a variety of biological functions including calcium-dependent cell growth and apoptosis. So far, the role of TRPV6 in controlling growth of pancreatic neuroendocrine tumour (NET) cells is unknown. In the present study, we characterize the expression of TRPV6 in pancreatic BON-1 and QGP-1 NET cells. Furthermore, we evaluate the impact of TRPV6 on intracellular calcium, the activity of nuclear factor of activated T-cells (NFAT) and proliferation of BON-1 cells. TRPV6 expression was assessed by real-time PCR and Western blot. TRPV6 mRNA expression and protein production were down-regulated by siRNA. Changes in intracellular calcium levels were detected by fluorescence calcium imaging (fura-2/AM). NFAT activity was studied by NFAT reporter assay; cell proliferation by bromodeoxyuridine (BrdU), MTT and propidium iodine staining. TRPV6 mRNA and protein are present in BON-1 and QGP-1 NET-cells. Down-regulation of TRPV6 attenuates BON-1 cell proliferation. TRPV6 down- regulation is associated with decreased Ca2+ response pattern and reduced NFAT activity. In conclusion, TRPV6 is expressed in pancreatic NETs and modulates cell proliferation via Ca2+-dependent mechanism, which is accompanied by NFAT activation

PuraStat in gastrointestinal bleeding: results of a prospective multicentre observational pilot study

Background: A recently developed haemostatic peptide gel for endoscopic application has been introduced to improve the management of gastrointestinal bleeding. The aim of this pilot study was to evaluate the feasibility, safety, efficacy and indication profiles of PuraStat in a clinical setting. Methods: In this prospective observational multicentre pilot study, patients with acute non-variceal gastrointestinal bleeding (upper and lower) were included. Primary and secondary application of PuraStat was evaluated. Haemoglobin, prothrombin time, platelets and transfusion behaviour were documented before and after haemostasis. The efficacy of PuraStat was assessed during the procedure, at 3 days and 1 week after application. Results: 111 patients with acute gastrointestinal bleeding were recruited into the study. 70 percent (78/111) of the patients had upper gastrointestinal bleeding and 30% (33/111) had lower gastrointestinal bleeding. After primary application of PuraStat, initial haemostatic success was achieved in 94% of patients (74/79, 95% CI 88-99%), and in 75% of the patients when used as a secondary haemostatic product, following failure of established techniques (24/32, 95% CI 59-91%). The therapeutic success rates (absence of rebleeding) after 3 and 7 days were 91% and 87% after primary use, and 87% and 81% in all study patients. Overall rebleeding rate at 30 day follow-up was 16% (18/111). In the 5 patients who finally required surgery (4.5%), PuraStat allowed temporary haemostasis and stabilisation. Conclusions: PuraStat expanded the therapeutic toolbox available for an effective treatment of gastrointestinal bleeding sources. It could be safely applied and administered without complications as a primary or secondary therapy. PuraStat may additionally serve as a bridge to surgery in order to achieve temporary haemostasis in case of refractory severe bleeding, possibly playing a role in preventing immediate emergency surgery

Evaluation of islet hormone receptors of the pancreas for the experimental therapy of type 2 diabetes mellitus and obesity

Titelblatt und Inhaltsverzeichnis 1 Einführung 5 1.1 Morphologie und Physiologie des endokrinen Pankreas 5 1.2 Bedeutung pankreatischer A-, B-, und D-Zellen für die Regulation der Glukosehomöostase 6 1.3 Rolle des endokrinen Pankreas für die Pathophysiologie des Diabetes mellitus Typ 2 8 1.4 Aktuelle Therapieoptionen des Diabetes mellitus Typ 2 9 1.5 Basis für die Entwicklung nichtpeptiderger Modulatoren der Insulin-, Glukagon- und Somatostatinrezeptoren 10 2 Zielsetzung 12 3 Ergebnisse 13 3.1 Wirkungen von Insulinrezeptor-Aktivatoren bei der Adipositas und beim Diabetes mellitus Typ 2 14 3.2 Charakterisierung der in vivo Effekte von Glukagonrezeptor-Antagonisten in Mausmodellen des Diabetes mellitus Typ 2 20 3.3 Effekte Somatostatinrezeptor-Subtyp-selektiver Agonisten bei der Adipositas und beim Diabetes mellitus Typ 2 23 4 Relevante Originalarbeiten 31 5 Zusammenfassung und Diskussion 32 6 Abkürzungsverzeichnis 38 7 Literaturverzeichnis 39Eine gestörte Sekretion und Wirkung pankreatischer Inselhormone trägt beträchtlich zur Hyperglykämie des Diabetes mellitus Typ 2 bei. Zu den wesentlichen Merkmalen dieser Erkrankung gehören periphere Insulinresistenz, Hyperinsulinämie, Hyperglukagonämie und Adipositas. Die Inzidenz des Diabetes mellitus Typ 2 nimmt zu, der Krankheitsprogress lässt sich trotz Basismaßnahmen, medikamentöser und Insulintherapie häufig nicht aufhalten. Kürzlich wurden nichtpeptiderge, oral bioverfügbare Agonisten und Antagonisten für die pankreatischen Inselhormonrezeptoren entwickelt. Ziel vorliegender Untersuchungen ist es zu prüfen, ob die Anwendung dieser neuartigen Modulatoren der Inselhormonrezeptoren, eine sinnvolle Therapie des Diabetes mellitus Typ 2 und der Adipositas bieten kann. Niedermolekulare Agonisten für Somatostatinrezeptoren, Insulinrezeptor-Aktivatoren sowie Glukagonrezeptor- Antagonisten wurden in Tiermodellen des Diabetes mellitus Typ 2 und der Adipositas eingesetzt und ihre Effekte auf die metabolischen Determinanten beider Erkrankungen untersucht. Die Studien zeigen, dass Agonisten für Somatostatinrezeptoren, Insulinrezeptor-Aktivatoren sowie Glukagonrezeptor- Antagonisten die Hyperglykämie, Hyperglukagonämie, Insulinresistenz sowie das Körpergewicht in Tiermodellen des Diabetes mellitus Typ 2 und der Adipositas günstig beeinflussen können. Zusammenfassend stellt die Aktivierungen von Somatostatin-, Insulinrezeptoren und die Antagonisierung Glukagonrezeptor- abhängiger Wirkungen durch oral-bioverfügbare Pharmaka eine neuartige, alternative und weiter zu evaluierende Therapieoption für Patienten mit Diabetes mellitus Typ 2 und/oder der Insulin-resistenten Adipositas dar.Impaired secretion and action of pancreatic islet hormones significantly contributes to hyperglycemia in Type 2 diabetes. Hallmarks of Type 2 diabetes are hyperglycemia, peripheral insulin resistance, hyperinsulinemia, hyperglucagonemia and obesity. The incidence of Type 2 diabetes is constantly increasing and despite life-style modification, antidiabetic medication or administration of exogenous insulin the disease progresses. Recently, orally bioavailable non-peptidal agonists and antagonists for the pancreatic islet hormones have been developed. Aim of the current study is to evaluate whether modulators of pancreatic hormone receptors provide a therapeutic option for the insulin-resistant, obese Type 2 diabetics and for obesity. Small molecule somatostatin agonists, insulin receptor activators and glucagon receptor antagonists were used in animals with experimentally-induced Type 2 diabetes as well as in animal models of diet-induced obesity and their effects on crucial metabolic determinants were characterized. The study demonstrates that somatostatin agonists, insulin receptor activators and glucagon receptor antagonists can alleviate hyperglycemia, insulin resistance and hyperglucagonemia and reduce body weight in animal models of Type 2 diabetes and obesity. In summary, results of these studies implicate that activation of receptors for somatostatin and insulin as well as antagonism of glucagon receptors by orally-bioavailable agents may provide a potential therapeutical option for Type 2 diabetes and obesity

Adropin as A Fat-Burning Hormone with Multiple Functions—Review of a Decade of Research

Adropin is a unique hormone encoded by the energy homeostasis-associated (Enho) gene. Adropin is produced in the liver and brain, and also in peripheral tissues such as in the heart and gastrointestinal tract. Furthermore, adropin is present in the circulatory system. A decade after its discovery, there is evidence that adropin may contribute to body weight regulation, glucose and lipid homeostasis, and cardiovascular system functions. In this review, we summarize and discuss the physiological, metabolic, and pathophysiological factors regulating Enho as well as adropin. Furthermore, we review the literature addressing the role of adropin in adiposity and type 2 diabetes. Finally, we elaborate on the role of adropin in the context of the cardiovascular system, liver diseases, and cancer

The Role of Neuropeptide B and Its Receptors in Controlling Appetite, Metabolism, and Energy Homeostasis

Neuropeptide B (NPB) is a peptide hormone that was initially described in 2002. In humans, the biological effects of NPB depend on the activation of two G protein-coupled receptors, NPBWR1 (GPR7) and NPBWR2 (GPR8), and, in rodents, NPBWR1. NPB and its receptors are expressed in the central nervous system (CNS) and in peripheral tissues. NPB is also present in the circulation. In the CNS, NPB modulates appetite, reproduction, pain, anxiety, and emotions. In the peripheral tissues, NPB controls secretion of adrenal hormones, pancreatic beta cells, and various functions of adipose tissue. Experimental downregulation of either NPB or NPBWR1 leads to adiposity. Here, we review the literature with regard to NPB-dependent control of metabolism and energy homeostasis

Adropin Slightly Modulates Lipolysis, Lipogenesis and Expression of Adipokines but Not Glucose Uptake in Rodent Adipocytes

Adropin is a peptide hormone which modulates energy homeostasis and metabolism. In animals with diet-induced obesity, adropin attenuates adiposity and improves lipid and glucose homeostasis. Adropin promotes the proliferation of rodent white preadipocytes and suppresses their differentiation into adipocytes. By contrast, the effects of adropin on mature white adipocytes are unknown. Therefore, we aimed to evaluate the effects of adropin on lipolysis, lipogenesis and glucose uptake in white rodent adipocytes. We assessed the effects of adropin on the mRNA expression of adiponectin, resistin and visfatin. White preadipocytes were isolated from male Wistar rats. Differentiated 3T3-L1 cells were used as a surrogate model of white adipocytes. Lipolysis was measured by the evaluation of glycerol and free fatty acid secretion using colorimetric kits. The effects of adropin on lipogenesis and glucose uptake were measured using radioactive-labelled glucose. The expression of adipokine mRNA was studied using real-time PCR. Our results show that adropin slightly promotes lipolysis in rat adipocytes and 3T3-L1 cells. Adropin suppresses lipogenesis in rat adipocytes without influencing glucose uptake. In addition, adropin stimulates adiponectin mRNA expression and suppresses the expression of resistin and visfatin. These results indicate that adropin may be involved in controlling lipid metabolism and adipokine expression in white rodent adipocytes

GIP_HUMAN [22–51] Peptide Encoded by the Glucose-Dependent Insulinotropic Polypeptide (GIP) Gene Suppresses Insulin Expression and Secretion in INS-1E Cells and Rat Pancreatic Islets

GIP_HUMAN [22–51] is a recently discovered peptide that shares the same precursor molecule with glucose-dependent insulinotropic polypeptide (GIP). In vivo, chronic infusion of GIP_HUMAN [22–51] in ApoE−/− mice enhanced the development of aortic atherosclerotic lesions and upregulated inflammatory and proatherogenic proteins. In the present study, we evaluate the effects of GIP_HUMAN [22–51] on insulin mRNA expression and secretion in insulin-producing INS-1E cells and isolated rat pancreatic islets. Furthermore, we characterize the influence of GIP_HUMAN [22–51] on cell proliferation and death and on Nf-kB nuclear translocation. Rat insulin-producing INS-1E cells and pancreatic islets, isolated from male Wistar rats, were used in this study. Gene expression was evaluated using real-time PCR. Cell proliferation was studied using a BrdU incorporation assay. Cell death was quantified by evaluating histone-complexed DNA fragments. Insulin secretion was determined using an ELISA test. Nf-kB nuclear translocation was detected using immunofluorescence. GIP_HUMAN [22–51] suppressed insulin (Ins1 and Ins2) in INS-1E cells and pancreatic islets. Moreover, GIP_HUMAN [22–51] promoted the translocation of NF-κB from cytoplasm to the nucleus. In the presence of a pharmacological inhibitor of NF-κB, GIP_HUMAN [22–51] was unable to suppress Ins2 mRNA expression. Moreover, GIP_HUMAN [22–51] downregulated insulin secretion at low (2.8 mmol/L) but not high (16.7 mmol/L) glucose concentration. By contrast, GIP_HUMAN [22–51] failed to affect cell proliferation and apoptosis. We conclude that GIP_HUMAN [22–51] suppresses insulin expression and secretion in pancreatic β cells without affecting β cell proliferation or apoptosis. Notably, the effects of GIP_HUMAN [22–51] on insulin secretion are glucose-dependent

Daily Treatment of Mice with Type 2 Diabetes with Adropin for Four Weeks Improves Glucolipid Profile, Reduces Hepatic Lipid Content and Restores Elevated Hepatic Enzymes in Serum

Adropin is a peptide hormone encoded by Energy Homeostasis Associated gene. Adropin modulates energy homeostasis and metabolism of lipids and carbohydrates. There is growing evidence demonstrating that adropin enhances insulin sensitivity and lowers hyperlipidemia in obese mice. The aim of this study was to investigate the effects of daily administration of adropin for four weeks in mice with experimentally induced type 2 diabetes (T2D). Adropin improved glucose control without modulating insulin sensitivity. Adropin reduced body weight, size of adipocytes, blood levels of triacylglycerol and cholesterol in T2D mice. T2D mice treated with adropin had lower liver mass, reduced hepatic content of triacylglycerol and cholesterol. Furthermore, adropin attenuated elevated blood levels of hepatic enzymes (ALT, AST, GGT and ALP) in T2D mice. In T2D mice, adropin increased the circulating adiponectin level. Adropin had no effects on circulating insulin and glucagon levels and did not alter pancreatic islets morphology. These results suggest that adropin improves glucose control, lipid metabolism and liver functions in T2D. In conjunction with reduced lipid content in hepatocytes, these results render adropin as an interesting candidate in therapy of T2D