| 1. |
- Ahlkvist, Linda, et al.
(författare)
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Evidence for neural contribution to islet effects of DPP-4 inhibition in mice
- 2016
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 780, s. 46-52
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Tidskriftsartikel (refereegranskat)abstract
- It has been suggested that neural mechanisms may contribute to effects of the incretin hormones, and, therefore, also to the effects of dipeptidyl peptidase (DPP-4) inhibition. We therefore examined whether muscarinic mechanisms are involved in the stimulation of insulin secretion by DPP-4 inhibition. Fasted, anesthetized mice were given intraperitoneal saline or the muscarinic antagonist atropine (5mg/kg) before duodenal glucose (75mg/mouse), with or without the DPP-4 inhibitor NVPDPP728 (0.095mg/mouse), or before intravenous glucose (0.35g/kg) with or without co-administration with GLP-1 or glucose-dependent insulinotropic polypeptide (GIP) (both 3nmol/kg). Furthermore, isolated islets were incubated (1h) in 2.8 and 11.1mM glucose, with or without GIP or GLP-1 (both 100nM), in the presence or absence of atropine (100µM). Duodenal glucose increased circulating insulin and this effect was potentiated by DPP-4 inhibition. The increase in insulin achieved by DPP-4 inhibition was reduced by atropine by approximately 35%. Duodenal glucose also elicited an increase in circulating intact GLP-1 and GIP and this was augmented by DPP-4 inhibition, but these effects were not affected by atropine. Atropine did also not affect the augmentation by GLP-1 and GIP on glucose-stimulated insulin secretion from isolated islets. Based on these findings, we suggest that muscarinic mechanisms contribute to the stimulation of insulin secretion by DPP-4 inhibition through neural effects induced by GLP-1 and GIP whereas neural effects do not affect the levels of GLP-1 or GIP or the islet effects of the two incretin hormones.
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| 2. |
- Andersen, Birgitte, et al.
(författare)
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Fibroblast growth factor 21 prevents glycemic deterioration in insulin deficient mouse models of diabetes.
- 2015
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 764, s. 189-194
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Tidskriftsartikel (refereegranskat)abstract
- In type 1 diabetes, there is a rapid loss of glycemic control immediately after onset of the disease. We aimed to determine if the deterioration of glycemic control that occurs early after the onset of insulin-deficient diabetes could be blunted by treatment with recombinant fibroblast growth factor 21 (FGF21). Normal C57BL/6J mice made diabetic by a single high dose injection of streptozotocin (STZ) were randomized to receive twice daily subcutaneous injection of vehicle or recombinant human FGF21 at doses of 0.3 and 1.0mg/kg for 10 days. Body weight was recorded daily and 5h fasted glucose, insulin, glucagon, free fatty acids and ketones were determined at 6 and 10 days post-randomization. The increase in fasting plasma glucose induced by STZ in untreated mice was prevented with FGF21 at 0.3mg/kg BID. In contrast, at 1.0mg/kg BID, FGF21 did not prevent the rise in plasma glucose after STZ. At the end of the study, plasma glucagon was significantly higher in the diabetic group treated with FGF21 1.0mg/kg BID than in the untreated group. This was not seen for the group treated with FGF21 0.3mg/kg BID. There were significant dose dependent reductions in plasma free fatty acids with FGF21 treatment but no significant change in plasma ketones (β-hydroxybutyrate). FGF21 treatment did not have significant effects on body weight in lean insulin deficient mice. In conclusion, FGF21 prevents increases in glycaemia and has lipid lowering properties in mouse models of insulin deficient diabetes, although by increasing the dose increased glucagon levels are seen and hyperglycemia persists.
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| 3. |
- Babateen, Omar, et al.
(författare)
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Etomidate, propofol and diazepam potentiate GABA-evoked GABAA currents in a cell line derived from Human glioblastoma
- 2015
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 748, s. 101-107
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Tidskriftsartikel (refereegranskat)abstract
- GABAA receptors are pentameric chloride ion channels that are opened by GABA. We have screened a cell line derived from human glioblastoma, U3047MG, for expression of GABAA receptor subunit isoforms and formation of functional ion channels. We identified GABAA receptors subunit α2, α3, α5, β1, β2, β3, δ, γ3, π, and θ mRNAs in the U3047MG cell line. Whole-cell GABA-activated currents were recorded and the half-maximal concentration (EC50) for the GABA-activated current was 36μM. The currents were activated by THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) and enhanced by the benzodiazepine diazepam (1μM) and the general anesthetics etomidate and propofol (50μM). In line with the expressed GABAA receptors containing at least the α3β3θ subunits, the receptors were highly sensitive to etomidate (EC50=55nM). Immunocytochemistry identified expression of the α3 and β3 subunit proteins. Our results show that the GABAA receptors in the glial cell line are functional and are modulated by classical GABAA receptor drugs. We propose that the U3047MG cell line may be used as a model system to study GABAA receptors function and pharmacology in glial cells.
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| 4. |
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| 5. |
- Cardilin, Tim, 1989, et al.
(författare)
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Evaluation and translation of combination therapies in oncology – A quantitative approach
- 2018
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 834, s. 327-336
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Tidskriftsartikel (refereegranskat)abstract
- Quantitative techniques improve our understanding of tumor volume data for combination treatments and its translation across in vivo models and species. The focus of this paper is therefore on understanding in vivo data, highlighting key structural elements of pharmacodynamic tumor models, and challenging these methods from a translational point of view. We introduce the concept of Tumor Static Exposure (TSE) both for single and multiple combined anticancer agents. The TSE curve separates all possible exposure combinations into regions of tumor growth and tumor shrinkage. Moreover, the degree of curvature of the TSE curve indicates the degree of synergy or antagonism. We demonstrate the TSE approach by two case studies. The first examines a combination of the drugs cetuximab and cisplatin. The TSE curve associated with this combination reveals a weak synergistic effect, suggesting only modest gains from combination therapy. The second case study examines combinations of ionizing radiation and a radiosensitizing agent. In this case, the TSE curve exhibits a pronounced curvature, indicating a strong synergistic effect; tumor regression can be achieved at significantly lower exposure levels and/or radiation doses. Finally, an allometric approach to human dose prediction demonstrates the translational power of the model and the TSE concept. We conclude that the TSE approach, which embodies model-based measures of both drug (potency) and target properties (tumor growth rate), has a strong potential for ranking of compounds, supporting compound selection, and translating preclinical findings to humans.
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| 6. |
- Changhui, Yu, et al.
(författare)
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Inhibition of Ras signalling reduces neutrophil infiltration and tissue damage in severe acute pancreatitis.
- 2015
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 746, s. 245-251
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophil recruitment is known to be a rate-limiting step in mediating tissue injury in severe acute pancreatitis (AP). However, the signalling mechanisms controlling inflammation and organ damage in AP remain elusive. Herein, we examined the role of Ras signalling in AP. Male C57BL/6 mice were treated with a Ras inhibitor (farnesylthiosalicylic acid, FTS) before infusion of taurocholate into the pancreatic duct. Pancreatic and lung tissues as well as blood were collected 24h after pancreatitis induction. Pretreatment with FTS decreased serum amylase levels by 82% and significantly attenuated acinar cell necrosis, tissue haemorrhage and oedema formation in taurocholate-induced pancreatitis. Inhibition of Ras signalling reduced myeloperoxidase (MPO) levels in the inflamed pancreas by 42%. In addition, administration of FTS decreased pancreatic levels of CXC chemokines as well as circulating levels of interleukin-6 and high-mobility group box 1 in animals exposed to taurocholate. Moreover, treatment with FTS reduced taurocholate-induced MPO levels in the lung. Inhibition of Ras signalling had no effect on neutrophil expression of Mac-1 in mice with pancreatitis. Moreover, FTS had no direct impact on trypsin activation in isolated pancreatic acinar cells. These results indicate that Ras signalling controls CXC chemokine formation, neutrophil recruitment and tissue injury in severe AP. Thus, our findings highlight a new signalling mechanism regulating neutrophil recruitment in the pancreas and suggest that inhibition of Ras signalling might be a useful strategy to attenuate local and systemic inflammation in severe AP.
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| 7. |
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| 8. |
- da Silva, Luiz A, et al.
(författare)
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Unravelling the intravenous and in situ vasopressin effects on the urinary bladder in anesthetized female rats: More than one vasopressin receptor subtype involved?
- 2018
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Ingår i: European journal of pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 834, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- Urinary bladder dysfunctions show high prevalence in women. We focused to investigate the intravenous and in situ (topic) vasopressin effects on the bladder and also to characterize the vasopressin receptor subtypes in the bladder. Adult female Wistar rats anesthetized with isoflurane underwent to the cannulation of the femoral artery and vein, and also urinary bladder for mean arterial pressure, heart rate and intravesical pressure (IP) recordings, respectively. Doppler flow probe was placed around the renal artery for blood flow measurement. After baseline recordings, intravenous injection of saline or vasopressin at different doses (0.25, 0.5, 1.0ng/ml/kg of b.w.); or 0.1ml of saline or 0.1ml of vasopressin at different doses (0.25, 0.5, 1.0ng/ml) was randomly dropped on the bladder. In another group of rats, the UB was harvest for gene expression by qPCR and also for protein expression by Western blotting of the vasopressin receptor subtypes. We observed that either intravenous or in situ vasopressin evoked a huge increase in the IP in a dose-dependent manner compared to saline, whilst no differences were observed in the cardiovascular parameters. The genes and the protein expression of V1a, V1b and V2 vasopressin receptors subtypes were found in the bladder. Intravenous injection of V1a or V2 receptor antagonist evoked a huge fall in IP and 30min later, i.v or in situ vasopressin evoked responses on IP were significantly attenuated. Therefore, intravenous or in situ vasopressin increases the IP due to binding in V1a or V2 receptors localized in the bladder.
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| 9. |
- Ermund, Anna, et al.
(författare)
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Hyper-osmolarity and calcium chelation: Effects on cystic fibrosis mucus
- 2015
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999. ; 764, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- A non-functional Cystic Fibrosis Transmembrane conductance Regulator (CFTR) leads to the disease cystic fibrosis (CF). Although the CFTR is expressed in multiple organs, pulmonary disease is the major cause of illness and death in patients with CF. Stagnant mucus, causing airway obstruction, bacterial overgrowth, persistent inflammation and tissue destruction characterizes the disease, but how the defect in CFTR function is coupled to the mucus phenotype is still controversial. We have recently shown that bicarbonate ions passing through CFTR are necessary for proper unfolding of the MUC2 mucin, thus highlighting the importance of bicarbonate ion transport via the CFTR and the ability of these ions to raise the pH and chelate calcium bound to the mucin as the important steps in forming normal mucus. In order to find potential CF treatments and expand our knowledge about the usefulness of bicarbonate as an active ingredient in formulations to alleviate mucus plugging, we used an Ussing-type chamber and explants from the F508del-CFTR mutant mouse ileum to test the effect of calcium chelators on mucus attachment, either in isolation or in combination with osmolytes such as mannitol or hypertonic saline. We found that increasing the concentration of bicarbonate, both alone or in combination with increased osmolarity of the solution, detached the otherwise attached CF mucus. (C) 2015 Elsevier B.V. All rights reserved.
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| 10. |
- Gabrielsson, Johan, et al.
(författare)
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Lost in translation: What's in an EC50? Innovative PK/PD reasoning in the drug development context
- 2018
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 835, s. 154-161
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Tidskriftsartikel (refereegranskat)abstract
- Translation across species and from in vitro to in vivo is a central tenet in drug discovery pharmacology. Successful implementation requires proper assessment of both in vivo potency and efficacy. This notwithstanding, in vivo data is typically defined mostly in terms of ligand-to-target binding affinity, similar to in vitro studies. As in vivo potency and efficacy involve a combination not only of drug, but also partitioning, target, and drug-target-complex events and processes, ignoring some of the central differences between in vivo and in vitro may result in serious miscalculations of in vivo efficacious exposure for translational predictions. We compare potency measures derived from two basic pharmacodynamic model situations: A 'closed' in vitro system defining target binding of a ligand when both concentrations remain essentially static, and an 'open' in vivo system where target turnover dynamics and elimination of the drug-target complex are also included. Corresponding equilibrium (steady-state) expressions in the central pharmacokinetic compartment are derived and presented. Three representative variants of 'open' in vivo systems are discussed, showing relationships for ligand-target complex and ligand for each of the systems and graphically illustrating corresponding shapes. The examples include i) two ligands competing for one target, ii) two targets competing for one ligand (/drug), and iii) target-ligand (/drug) interactions in a peripheral PK compartment. The expanded in vivo potency EC50 expression emphasises the contribution from target-related biology parameters that need accounting for, and particularly that 'closed' system (in vitro) properties should not be first choice when ranking compounds in vivo ('open' system).
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