| 1. |
- Ahmad, F., et al.
(författare)
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Cyclic Nucleotide Phosphodiesterase 3 Signaling Complexes
- 2012
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 1439-4286 .- 0018-5043. ; 44:10, s. 776-785
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Forskningsöversikt (refereegranskat)abstract
- The superfamily of cyclic nucleotide phosphodiesterases is comprised of 11 gene families. By hydrolyzing cAMP and cGMP, PDEs are major determinants in the regulation of intracellular concentrations of cyclic nucleotides and cyclic nucleotide-dependent signaling pathways. Two PDE3 subfamilies, PDE3A and PDE3B, have been described. PDE3A and PDE3B hydrolyze cAMP and cGMP with high affinity in a mutually competitive manner and are regulators of a number of important cAMP- and cGMP-mediated processes. PDE3B is relatively more highly expressed in cells of importance for the regulation of energy homeostasis, including adipocytes, hepatocytes, and pancreatic beta-cells, whereas PDE3A is more highly expressed in heart, platelets, vascular smooth muscle cells, and oocytes. Major advances have been made in understanding the different physiological impacts and biochemical basis for recruitment and subcellular localizations of different PDEs and PDE-containing macromolecular signaling complexes or signalosomes. In these discrete compartments, PDEs control cyclic nucleotide levels and regulate specific physiological processes as components of individual signalosomes which are tethered at specific locations and which contain PDEs together with cyclic nucleotide-dependent protein kinases (PKA and PKG), adenylyl cyclases, Epacs (guanine nucleotide exchange proteins activated by cAMP), phosphoprotein phosphatases, A-Kinase anchoring proteins (AKAPs), and pathway-specific regulators and effectors. This article highlights the identification of different PDE3A- and PDE3B-containing signalosomes in specialized subcellular compartments, which can increase the specificity and efficiency of intracellular signaling and be involved in the regulation of different cAMP-mediated metabolic processes.
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| 2. |
- Ahrén, Bo
(författare)
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GLP-1 and extra-islet effects.
- 2004
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 1439-4286 .- 0018-5043. ; 36:11-12, s. 842-845
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Forskningsöversikt (refereegranskat)
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| 3. |
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| 4. |
- Ahrén, Bo, et al.
(författare)
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Improved meal-related insulin processing contributes to the enhancement of B-Cell function by the DPP-4 inhibitor vildagliptin in patients with type 2 diabetes
- 2007
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 1439-4286 .- 0018-5043. ; 39:11, s. 826-829
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the contribution of insulin processing to the improved meal-related B-cell function previously shown with the DPP-4 inhibitor vildagliptin. Fifty-five patients with type 2 diabetes (56.5 +/- 1.5 years; BMI=29.6 +/- 0.5kg/m(2); FPG = 9.9 +/- 0.2 mmol/l; HbA1c=7.7 +/- 0.1 %) were studied: 29 pateients were treated with vildagliptin and 26 patients with placebo, both added to an ongoing metformin regimen (1.5-3.0g/day). A standardized breakfast was given at baseline and after 52 weeks of treatment, and proinsulin related to insulin secretion was measured with C-peptide in the fasting and postprandial (over 4h post-meal) states to evaluate B-cell function. The between-treatment difference (vildaglip-tin-placebo) in mean change from baseline in fasting proinsulin to C-peptide ratio (fastP/C) was -0.007 +/- 0.009 (p=0.052). Following the standard breakfast, 52 weeks of treatment with vildagliptin significantly decreased the dynamic proinsulin to C-peptide ratio (dynP/C) relative to placebo by 0.010 +/- 0.008 (p = 0.037). Importantly, when the P/C was expressed in relation to the glucose stimulus (i.e., the fasting glucose and glucose AUC(0-240min), respectively), the P/C relative to glucose was significantly reduced with vildagliptin vs. placebo, both in the fasting state (p = 0.023) and postprandially (p = 0.004). In conclusion, a more efficient B-cell insulin processing provides further evidence that vildagliptin treatment ameliorates abnormal B-cell function in patients with type 2 diabetes.
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| 5. |
- Ahrén, Bo, et al.
(författare)
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Incretin hormones and insulin secretion.
- 2004
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 1439-4286 .- 0018-5043. ; 36:11-12, s. 733-734
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Tidskriftsartikel (refereegranskat)
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| 6. |
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| 7. |
- Arnqvist, Hans
(författare)
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The role of IGF-system in vascular insulin resistance
- 2008
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 40:9, s. 588-592
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Forskningsöversikt (refereegranskat)abstract
- Insulin and IGF-I are closely related peptides, which interact by several mechanisms. In high supraphysiological concentrations (=10-8M), they cross-react with each other's receptors with 100- to 1000-fold lower affinity than with their cognate receptors. This can cause confusion, since in many in vitro studies, insulin has been used in high unphysiological concentrations, which activate IGF-I receptors. Due to the differences in affinity, insulin and IGF-I probably do not activate each other's receptors in vivo. IGF-I receptors are several-fold more abundant than insulin receptors in human micro- and macrovascular endothelial cells and in human vascular smooth muscle cells. Both insulin and IGF-I receptor protein can be demonstrated and they are activated by their cognate ligand at physiological concentrations of 10-9-10-10M. In vascular smooth muscle cells, IGF-I but not insulin stimulates metabolism and growth. IGF-I stimulates DNA-synthesis and growth in microvascular endothelial cells, but neither insulin nor IGF-I have any effect on macrovascular endothelial cells. Both insulin and IGF-I have been shown to stimulate nitric oxide production in endothelial cells, but only the effect of IGF-I was obtained at a physiological concentration. In both endothelial and vascular smooth muscle cells, insulin and IGF-I receptors occur as insulin/ICF-I hybrid receptors with high affinity to IGF-I and low for insulin. Due to the low number of insulin receptors and the presence of hybrid receptors the insulin receptor signal is probably too attenuated to elicit biological effects, explaining the insulin resistance of vascular cells in vitro. In vivo both insulin and IGF-I have been reported to increase muscle blood flow in physiological concentrations. Whether this is due to direct effects on endothelial cells or indirectly induced is not clear. The effect of insulin is attenuated by insulin resistance. In conclusion, the in vitro data suggest that endothelial cells and vascular smooth muscle cells are sensitive to IGF-I, but insensitive to insulin, and this is due to a preponderance of IGF-I receptors and the presence of insulin/IGF-l hybrid receptors. © Georg Thieme Verlag KG Stuttgart · New York.
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| 8. |
- Boersma, Greta J., et al.
(författare)
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Altered Glucose Uptake in Muscle, Visceral Adipose Tissue, and Brain Predict Whole-Body Insulin Resistance and may Contribute to the Development of Type 2 Diabetes: A Combined PET/MR Study
- 2018
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 50:8
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Tidskriftsartikel (refereegranskat)abstract
- We assessed glucose uptake in different tissues in type 2 diabetes (T2D), prediabetes, and control subjects to elucidate its impact in the development of whole-body insulin resistance and T2D. Thirteen T2D, 12 prediabetes, and 10 control subjects, matched for age and BMI, underwent OGTT and abdominal subcutaneous adipose tissue (SAT) biopsies. Integrated whole-body 18F-FDG PET and MRI were performed during a hyperinsulinemic euglycemic clamp to asses glucose uptake rate (MRglu) in several tissues. MRglu in skeletal muscle, SAT, visceral adipose tissue (VAT), and liver was significantly reduced in T2D subjects and correlated positively with M-values (r = 0.884, r = 0.574, r = 0.707 and r = 0.403, respectively). Brain MRglu was significantly higher in T2D and prediabetes subjects and had a significant inverse correlation with M-values (r = -0.616). Myocardial MRglu did not differ between groups and did not correlate with the M-values. A multivariate model including skeletal muscle, brain and VAT MRglu best predicted the M-values (adjusted r2 = 0.85). In addition, SAT MRglu correlated with SAT glucose uptake ex vivo (r = 0.491). In different stages of the development of T2D, glucose uptake during hyperinsulinemia is elevated in the brain in parallel with an impairment in peripheral organs. Impaired glucose uptake in skeletal muscle and VAT together with elevated glucose uptake in brain were independently associated with whole-body insulin resistance, and these tissue-specific alterations may contribute to T2D development.
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| 9. |
- Cerri, Perparim, et al.
(författare)
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Serum CYR61 Levels are Associated with Graves' Ophthalmopathy and Smoking in Patients with Graves' Disease
- 2021
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 54:3, s. 168-174
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Tidskriftsartikel (refereegranskat)abstract
- Smoking is a well-known risk factor for Graves' ophthalmopathy (GO) in patients suffering from Graves' disease (GD). Cysteine-rich angiogenic inducer 61 (CYR61), which has multiple physiological functions, has been shown to be associated with GD and GO. In this study, we aimed to investigate the association between smoking and CYR61 concentrations in GD patients with and without GO. Serum CYR61 was measured by ELISA. The association between CYR61 concentration and GO was assessed with binary logistic regression in all patients and in subgroups of smokers and nonsmokers. The Spearman correlation coefficient was used to determine the correlations between CYR61 concentration and clinical parameters. CYR61 levels were significantly higher in GD patients with GO than in patients without GO, in smokers than in nonsmokers and in individuals older than 50 years than in those younger than 50 years. The subgroup of GO smokers had the highest CYR61 levels [median (IQR), 119 pg/ml (129.8)], compared with GO nonsmokers [84.2 pg/ml (90.8), p=0.04], no GO smokers [88.9 pg/ml (109.8), p=0.01] and no GO nonsmokers [79.4 pg/ml (129.89), p=0.003]. For each unit increase in CYR61 concentration, the odds of having GO in smokers significantly and independently increased by 1% (OR=1.010; 95% CI: 1.002-1.018, p=0.012). In conclusion, our results indicate that smoking and age increase serum CYR61 levels in patients with GD and GO. The role of CYR61 as a predictor of GO in patients with GD should be evaluated in prospective studies.
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| 10. |
- Daskalakis, Kosmas, et al.
(författare)
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Magnetic Resonance Imaging or Endoscopic Ultrasonography for Detection and Surveillance of Pancreatic Neuroendocrine Neoplasms in Patients with Multiple Endocrine Neoplasia Type 1?
- 2019
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Ingår i: Hormone and Metabolic Research. - : GEORG THIEME VERLAG KG. - 0018-5043 .- 1439-4286. ; 51:9, s. 580-585
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Tidskriftsartikel (refereegranskat)abstract
- Our aim was to compare the clinical utility of Magnetic Resonance Imaging (MRI) and Endoscopic Ultrasonography (EUS) in identifying Pancreatic Neurondocrine Neoplasms (PanNENs) and monitoring size alterations in Multiple Endocrine Neoplasia type 1 (MEN1) patients. Thirty-one MEN1 patients with PanNENs and concurrent screening by EUS and abdominal MRI were included and 129 pancreatic lesions were detected in total. MRI detected fewer lesions than EUS (n=73 vs. 110, p=0.006). MRI sensitivity and specificity compared to EUS at 20 and 10 mm cut-offs of maximal lesion diameter were 96 and 88% (20 mm cut-off) and 90 and 82%(10 mm cut-off), respectively (concordance rates of 97 and 87% and Cohen's kappa=0.912 and 0.718, respectively). Lesions<1 cm were more often detected with EUS (p=0.025). Data from sequential concurrent imaging on lesion growth rate [n=7 (mean +/- SD: 2 mm/year +/- 3.4 mm vs. 1.9 mm/year +/- 3.6 mm)] over a period of at least two years as well as pathology data in connection to preoperative concurrent imaging were available in a small number of patients (n=7, p=0.933 for mean differences in maximal lesion diameter). MRI of the pancreas was more readily available and less expensive than EUS in an outpatient setting. In conclusion, MRI performs well compared to EUS for the detection and subsequent surveillance of MEN1-related panNENs larger than 10 mm and seems to be cost-effective. Both modalities could be used at initial assessment and MRI alone could be utilized thereafter in patient surveillance. EUS retains its value in surgical planning and the detection of small mostly functional PanNENs.
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