| 11. |
- Lahesmaa, M., et al.
(författare)
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Hyperthyroidism increases brown fat metabolism in humans
- 2014
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 99:1
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Tidskriftsartikel (refereegranskat)abstract
- Context: Thyroid hormones are important regulators of brown adipose tissue (BAT) development and function. In rodents, BAT metabolism is up-regulated by thyroid hormones. Objective: The purpose of this article was to investigate the impact of hyperthyroidism on BAT metabolism in humans. Design: This was a follow-up study using positron emission tomography imaging. Main Outcome Measures: Glucose uptake (GU) and perfusion of BAT, white adipose tissue, skeletal muscle, and thyroid gland were measured using [18F]2-fluoro-2-deoxy-D- glucose and [15O]H2Oand positron emission tomography in 10 patients with overt hyperthyroidism and in 8 healthy participants. Five of the hyperthyroid patients were restudied after restoration of euthyroidism. Supraclavicular BAT was quantified with magnetic resonance imaging or computed tomography and energy expenditure (EE) with indirect calorimetry. Results: Compared with healthy participants, hyperthyroid participants had 3-fold higher BAT GU (2.7 ± 2.3 vs 0.9 ± 0.1 ±mol/100 g/min, P = .0013), 90% higher skeletal muscle GU (P < .005), 45% higher EE (P<.005), and a 70% higher lipid oxidation rate (P = .001). These changes were reversible after restoration of euthyroidism. During hyperthyroidism, serum free T4 and free T3 were strongly associated with EE and lipid oxidation rates (P < .001). TSH correlated inversely with BAT and skeletal muscle glucose metabolism (P < .001). Hyperthyroidism had no effect on BAT perfusion, whereas it stimulated skeletal muscle perfusion (P = .04). Thyroid gland GU did not differ between hyperthyroid and euthyroid study subjects. Conclusions: Hyperthyroidism increases GU in BAT independently of BAT perfusion. Hyperthyroid patients are characterized by increased skeletal muscle metabolism and lipid oxidation rates. (J Clin Endocrinol Metab 99: E28-E35, 2014). © Copyright 2014 by The Endocrine Society.
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| 12. |
- Orava, J., et al.
(författare)
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Blunted Metabolic Responses to Cold and Insulin Stimulation in Brown Adipose Tissue of Obese Humans
- 2013
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Ingår i: Obesity. - : Wiley. - 1930-7381. ; 21:11, s. 2279-2287
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Inactive brown adipose tissue (BAT) may predispose to weight gain. This study was designed to measure metabolism in the BAT of obese humans, and to compare it to that in lean subjects. The impact of weight loss on BAT and the association of detectable BAT with various metabolic characteristics were also assessed. Design and Methods: Using positron emission tomography (PET), cold-and insulin-stimulated glucose uptake and blood flow in the BAT of obese and lean humans were quantified. Further, cold-induced glucose uptake was measured in obese subjects before and after a 5-month conventional weight loss. Results: Mean responses in BAT glucose uptake rate to both cold and insulin stimulation were twice as large in lean as in obese subjects. Blood flow in BAT was also lower in obese subjects under cold conditions. The increase in cold-induced BAT glucose uptake rate after weight loss was not statistically significant. Subjects with cold-activated detectable BAT were leaner and had higher whole-body insulin sensitivity than BAT-negative subjects, irrespective of age and gender. Conclusions: The effects of cold and insulin on BAT activity are severely blunted in obesity, and the presence of detectable BAT may contribute to a metabolically healthy status.
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| 13. |
- Wu, J., et al.
(författare)
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Beige Adipocytes Are a Distinct Type of Thermogenic Fat Cell in Mouse and Human
- 2012
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 150:2, s. 366-376
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Tidskriftsartikel (refereegranskat)abstract
- Brown fat generates heat via the mitochondrial uncoupling protein UCP1, defending against hypothermia and obesity. Recent data suggest that there are two distinct types of brown fat: classical brown fat derived from a myf-5 cellular lineage and UCP1-positive cells that emerge in white fat from a non-myf-5 lineage. Here, we report the isolation of "beige" cells from murine white fat depots. Beige cells resemble white fat cells in having extremely low basal expression of UCP1, but, like classical brown fat, they respond to cyclic AMP stimulation with high UCP1 expression and respiration rates. Beige cells have a gene expression pattern distinct from either white or brown fat and are preferentially sensitive to the polypeptide hormone irisin. Finally, we provide evidence that previously identified brown fat deposits in adult humans are composed of beige adipocytes. These data provide a foundation for studying this mammalian cell type with therapeutic potential.
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| 14. |
- Borga, Magnus, et al.
(författare)
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Brown adipose tissue in humans: detection and functional analysis using PET (positron emission tomography), MRI (magnetic resonance imaging), and DECT (dual energy computed tomography).
- 2014
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Ingår i: Methods in enzymology. - : Elsevier. - 1557-7988. ; 537, s. 141-59, s. 141-159
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Tidskriftsartikel (refereegranskat)abstract
- If the beneficial effects of brown adipose tissue (BAT) on whole body metabolism, as observed in nonhuman experimental models, are to be translated to humans, tools that accurately measure how BAT influences human metabolism will be required. This chapter discusses such techniques, how they can be used, what they can measure and also some of their limitations. The focus is on detection and functional analysis of human BAT and how this can be facilitated by applying advanced imaging technology such as positron emission tomography, magnetic resonance imaging, and dual energy computed tomography.
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| 15. |
- Cevher, Murat A., et al.
(författare)
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Nuclear deadenylation/polyadenylation factors regulate 3 ' processing in response to DNA damage
- 2010
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Ingår i: EMBO Journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 29:10, s. 1674-1687
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Tidskriftsartikel (refereegranskat)abstract
- We previously showed that mRNA 3' end cleavage reaction in cell extracts is strongly but transiently inhibited under DNA-damaging conditions. The cleavage stimulation factor-50 (CstF-50) has a role in this response, providing a link between transcription-coupled RNA processing and DNA repair. In this study, we show that CstF-50 interacts with nuclear poly(A)-specific ribonuclease (PARN) using in vitro and in extracts of UV-exposed cells. The CstF-50/PARN complex formation has a role in the inhibition of 3' cleavage and activation of deadenylation upon DNA damage. Extending these results, we found that the tumour suppressor BARD1, which is involved in the UV-induced inhibition of 3' cleavage, strongly activates deadenylation by PARN in the presence of CstF-50, and that CstF-50/BARD1 can revert the cap-binding protein-80 (CBP80)mediated inhibition of PARN activity. We also provide evidence that PARN along with the CstF/BARD1 complex participates in the regulation of endogenous transcripts under DNA-damaging conditions. We speculate that the interplay between polyadenylation, deadenylation and tumour-suppressor factors might prevent the expression of prematurely terminated messengers, contributing to control of gene expression under different cellular conditions.
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| 16. |
- Dalgaard, Marlene D., et al.
(författare)
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A genome-wide association study of men with symptoms of testicular dysgenesis syndrome and its network biology interpretation
- 2012
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 49:1, s. 58-65
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Tidskriftsartikel (refereegranskat)abstract
- Background Testicular dysgenesis syndrome (TDS) is a common disease that links testicular germ cell cancer, cryptorchidism and some cases of hypospadias and male infertility with impaired development of the testis. The incidence of these disorders has increased over the last few decades, and testicular cancer now affects 1% of the Danish and Norwegian male population. Methods To identify genetic variants that span the four TDS phenotypes, the authors performed a genome-wide association study (GWAS) using Affymetrix Human SNP Array 6.0 to screen 488 patients with symptoms of TDS and 439 selected controls with excellent reproductive health. Furthermore, they developed a novel integrative method that combines GWAS data with other TDS-relevant data types and identified additional TDS markers. The most significant findings were replicated in an independent cohort of 671 Nordic men. Results Markers located in the region of TGFBR3 and BMP7 showed association with all TDS phenotypes in both the discovery and replication cohorts. An immunohistochemistry investigation confirmed the presence of transforming growth factor beta receptor type III (TGFBR3) in peritubular and Leydig cells, in both fetal and adult testis. Single-nucleotide polymorphisms in the KITLG gene showed significant associations, but only with testicular cancer. Conclusions The association of single-nucleotide polymorphisms in the TGFBR3 and BMP7 genes, which belong to the transforming growth factor b signalling pathway, suggests a role for this pathway in the pathogenesis of TDS. Integrating data from multiple layers can highlight findings in GWAS that are biologically relevant despite having border significance at currently accepted statistical levels.
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| 17. |
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| 18. |
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| 19. |
- Fransson, Eleonor, 1971-, et al.
(författare)
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Job strain as a risk factor for leisure-time physical inactivity : an individual-participant meta-analysis of up to 170,000 men and women
- 2012
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Ingår i: American Journal of Epidemiology. - Cary : Oxford University Press. - 0002-9262 .- 1476-6256. ; 176:12, s. 1078-1089
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Forskningsöversikt (refereegranskat)abstract
- Unfavorable work characteristics, such as low job control and too high or too low job demands, have been suggested to increase the likelihood of physical inactivity during leisure time, but this has not been verified in large-scale studies. The authors combined individual-level data from 14 European cohort studies (baseline years from 19851988 to 20062008) to examine the association between unfavorable work characteristics and leisure-time physical inactivity in a total of 170,162 employees (50 women; mean age, 43.5 years). Of these employees, 56,735 were reexamined after 29 years. In cross-sectional analyses, the odds for physical inactivity were 26 higher (odds ratio 1.26, 95 confidence interval: 1.15, 1.38) for employees with high-strain jobs (low control/high demands) and 21 higher (odds ratio 1.21, 95 confidence interval: 1.11, 1.31) for those with passive jobs (low control/low demands) compared with employees in low-strain jobs (high control/low demands). In prospective analyses restricted to physically active participants, the odds of becoming physically inactive during follow-up were 21 and 20 higher for those with high-strain (odds ratio 1.21, 95 confidence interval: 1.11, 1.32) and passive (odds ratio 1.20, 95 confidence interval: 1.11, 1.30) jobs at baseline. These data suggest that unfavorable work characteristics may have a spillover effect on leisure-time physical activity.
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| 20. |
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