| 11. |
- Tivesten, Åsa, 1969, et al.
(författare)
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Growth hormone-induced blood pressure decrease is associated with increased mRNA levels of the vascular smooth muscle KATP channel.
- 2004
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Ingår i: The Journal of endocrinology. - : Bioscientifica. - 0022-0795 .- 1479-6805. ; 183:1, s. 195-202
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Tidskriftsartikel (refereegranskat)abstract
- Growth hormone (GH) deficiency is associated with abnormal vascular reactivity and development of atherosclerosis. GH treatment in GH deficient states restores systemic vascular resistance, arterial compliance, endothelium-dependent and endothelium-independent vasodilation, and may reverse markers of early atherosclerosis. However, very little is known about the molecular mechanisms underlying these effects. In the present study, male Sprague Dawley rats were hypophysectomized and treated for two weeks with GH (recombinant human GH, 2 mg/kg/day) or saline as s.c. injections twice daily. GH decreased aortic systolic blood pressure compared with saline-treated animals, while the diastolic blood pressure was not significantly changed. GH treatment increased cardiac output as determined by Doppler-echocardiography and the calculated systemic vascular resistance was markedly reduced. In order to identify GH-regulated genes of importance for vascular function, aortic mRNA levels were analyzed by the microarray technique and correlated to the systolic blood pressure levels. Using this approach, we identified 18 GH-regulated genes with possible impact on vascular tone and atherogenesis. In particular, mRNA levels of the inwardly rectifying potassium channel Kir6.1 and the sulfonylurea receptor 2B, which together form the vascular smooth muscle ATP-sensitive potassium channel, were both up-regulated by GH treatment and highly correlated to systolic blood pressure. Our findings establish a major role for GH in the regulation of vascular physiology and gene expression. Increased expression of the ATP-sensitive potassium channel, recently shown to be crucial in the regulation of vascular tone, constitutes a possible mechanism by which GH governs vascular tone.
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| 12. |
- Tivesten, Åsa, 1969, et al.
(författare)
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Liver-derived insulin-like growth factor-I is involved in the regulation of blood pressure in mice.
- 2002
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Ingår i: Endocrinology. - 0013-7227. ; 143:11, s. 4235-42
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Tidskriftsartikel (refereegranskat)abstract
- IGF-I has been suggested to be of importance for cardiovascular structure and function, but the relative role of locally produced and liver-derived endocrine IGF-I remains unclear. Using the Cre-LoxP recombination system, we have previously created transgenic mice with a liver-specific, inducible IGF-I knockout (LI-IGF-I-/-). To examine the role of liver-derived IGF-I in cardiovascular physiology, liver-derived IGF-I was inactivated at 4 wk of age, resulting in a 79% reduction of serum IGF-I levels. At 4 months of age, systolic blood pressure (BP) was increased in LI-IGF-I-/- mice. Echocardiography showed increased posterior wall thickness in combination with decreased stroke volume and cardiac output, whereas other systolic variables were unchanged, suggesting that these cardiac effects were secondary to increased peripheral resistance. Acute nitric oxide-synthase inhibition increased systolic BP more in LI-IGF-I-/- mice than in control mice. LI-IGF-I-/- mice showed impaired acetylcholine-induced vasorelaxation in mesenteric resistance vessels and increased levels of endothelin-1 mRNA in aorta. Thus, the increased peripheral resistance in LI-IGF-I-/- mice might be attributable to endothelial dysfunction associated with increased expression of endothelin-1 and impaired vasorelaxation of resistance vessels. In conclusion, our findings suggest that liver-derived IGF-I is involved in the regulation of BP in mice.
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| 13. |
- Wickelgren, Ruth, 1965, et al.
(författare)
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Expression of exon 3-retaining and exon 3-excluding isoforms of the human growth hormone-receptor is regulated in an interindividual, rather than a tissue-specific, manner.
- 1995
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Ingår i: The Journal of clinical endocrinology and metabolism. - 0021-972X. ; 80:7, s. 2154-7
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Tidskriftsartikel (refereegranskat)abstract
- GH has multiple effects on growth and metabolism, and these functions are mediated through binding to specific cell surface receptors. The human GH receptor (GHR) exists in two known isoforms; in one form exon 3 is present (GHR3+), and in the other, exon 3 is absent (GHR3-). Recent reports have suggested that the expression of the two isoforms is tissue specific and/or developmentally regulated. We used a reverse transcription-polymerase chain reaction assay to study the expression pattern of the two isoforms in a variety of tissues from normal subjects and patients with acromegaly. In skeletal muscle from both normal subjects and patients with acromegaly, the GHR3+ transcript was expressed, either alone or together with the shorter (GHR3-) transcript. When multiple tissues from six subjects were tested, the expression of the two isoforms varied among subjects, whereas different tissues from the same subject showed the same expression pattern. These results indicate that the expression of the GHR isoforms is not tissue specific. Instead, the expression of the GHR isoforms appears to be specific for each individual, suggesting that it is under the control of factors that affect all tissues in the body.
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| 14. |
- Adlanmerini, M., et al.
(författare)
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Mutation of Arginine 264 on ER alpha (Estrogen Receptor Alpha) Selectively Abrogates the Rapid Signaling of Estradiol in the Endothelium Without Altering Fertility
- 2020
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Ingår i: Arteriosclerosis, Thrombosis, and Vascular Biology. - : Ovid Technologies (Wolters Kluwer Health). - 1079-5642 .- 1524-4636. ; 40:9, s. 2143-2158
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Tidskriftsartikel (refereegranskat)abstract
- Objective: ER alpha (estrogen receptor alpha) exerts nuclear genomic actions and also rapid membrane-initiated steroid signaling. The mutation of the cysteine 451 into alanine in vivo has recently revealed the key role of this ER alpha palmitoylation site on some vasculoprotective actions of 17 beta-estradiol (E2) and fertility. Here, we studied the in vivo role of the arginine 260 of ER alpha which has also been described to be involved in its E2-induced rapid signaling with PI-3K (phosphoinositide 3-kinase) as well as G protein in cultured cell lines. Approach and Results: We generated a mouse model harboring a point mutation of the murine counterpart of this arginine into alanine (R264A-ER alpha). In contrast to theC451A-ER alpha, theR264A-ER alpha females are fertile with standard hormonal serum levels and normal control of hypothalamus-pituitary ovarian axis. Although R264A-ER alpha protein abundance was normal, the well-described membrane ER alpha-dependent actions of estradiol, such as the rapid dilation of mesenteric arteries and the acceleration of endothelial repair of carotid, were abrogated inR264A-ER alpha mice. In striking contrast, E2-regulated gene expression was highly preserved in the uterus and the aorta, revealing intact nuclear/genomic actions in response to E2. Consistently, 2 recognized nuclear ER alpha-dependent actions of E2, namely atheroma prevention and flow-mediated arterial remodeling were totally preserved. Conclusions: These data underline the exquisite role of arginine 264 of ER alpha for endothelial membrane-initiated steroid signaling effects of E2 but not for nuclear/genomic actions. This provides the first model of fertile mouse with no overt endocrine abnormalities with specific loss-of-function of rapid ER alpha signaling in vascular functions.
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| 15. |
- Aguilar-Pimentel, Juan Antonio, et al.
(författare)
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Increased estrogen to androgen ratio enhances immunoglobulin levels and impairs B cell function in male mice.
- 2020
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Sex steroids, such as estrogens and androgens, are important regulators of the humoral immune response. Studies in female mice have demonstrated that alteration of circulating estrogen concentration regulates antibody-mediated immunity. As males have normally little endogenous estrogen, we hypothesized that in males high estrogens and low androgens affect the immune system and enhance the allergic inflammatory response. Here, we studied transgenic male mice expressing human aromatase (AROM+). These animals have a high circulating estrogen to androgen ratio (E/A), causing female traits such as gynecomastia. We found that AROM+ male mice had significantly higher plasma immunoglobulin levels, particularly IgE. Flow cytometry analyses of splenocytes revealed changes in mature/immature B cell ratio together with a transcriptional upregulation of the Igh locus. Furthermore, higher proliferation rate and increased IgE synthesis after IgE class-switching was found. Subsequently, we utilized an ovalbumin airway challenge model to test the allergic response in AROM+ male mice. In line with above observations, an increase in IgE levels was measured, albeit no impact on immune cell infiltration into the lungs was detected. Together, our findings suggest that high circulating E/A in males significantly alters B cell function without any significant enhancement in allergic inflammation.
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| 16. |
- Ahluwalia, T. S., et al.
(författare)
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Genome-wide association study of circulating interleukin 6 levels identifies novel loci
- 2021
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Ingår i: Human molecular genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 30:5, s. 393-409
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin 6 (IL-6) is a multifunctional cytokine with both pro- and anti-inflammatory properties with a heritability estimate of up to 61%. The circulating levels of IL-6 in blood have been associated with an increased risk of complex disease pathogenesis. We conducted a two-staged, discovery and replication meta genome-wide association study (GWAS) of circulating serum IL-6 levels comprising up to 67428 (n(discovery)=52654 and n(replication)=14774) individuals of European ancestry. The inverse variance fixed effects based discovery meta-analysis, followed by replication led to the identification of two independent loci, IL1F10/IL1RN rs6734238 on chromosome (Chr) 2q14, (P-combined=1.8x10(-11)), HLA-DRB1/DRB5 rs660895 on Chr6p21 (P-combined=1.5x10(-10)) in the combined meta-analyses of all samples. We also replicated the IL6R rs4537545 locus on Chr1q21 (P-combined=1.2x10(-122)). Our study identifies novel loci for circulating IL-6 levels uncovering new immunological and inflammatory pathways that may influence IL-6 pathobiology.
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| 17. |
- Ahmad, T, et al.
(författare)
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Skeletal changes in type-2 diabetic Goto-Kakizaki rats.
- 2003
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Ingår i: The Journal of endocrinology. - : Bioscientifica. - 0022-0795 .- 1479-6805. ; 178:1, s. 111-6
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Tidskriftsartikel (refereegranskat)abstract
- We characterized appendicular and axial bones in rats with type-2 diabetes in five female Goto-Kakizaki (GK) rats, a strain developed from the Wistar rat showing spontaneous type-2 diabetes, and five age- and sex-matched non-diabetic Wistar rats. The humerus, tibia, metatarsals and vertebral bodies were analysed by peripheral quantitative computerized tomography (pQCT). In diabetic rats, the height of the vertebral bodies and length of the humerus were decreased while the length of the metatarsals was increased. A decreased cross-sectional area was found in the vertebral end-plate region and the tibial metaphysis. Notably, the diaphysis in all long bones showed expansion of periosteal and endosteal circumference. In tibia this resulted in increased cortical thickness, whereas in humerus and metatarsal it was unchanged. Areal moment of inertia was increased in all diaphyses suggesting greater bending strength. The most conspicuous finding in diabetic rats pertained to trabecular osteopenia. Thus, trabecular bone mineral density was significantly reduced in all bones examined, by 33-53%. Our pQCT study of axial and appendicular bones suggests that the typical feature of diabetic osteopathy in the GK rat is loss of trabecular bone and expansion of the diaphysis. The loss of metaphyseal trabecular bone if also present in diabetic patients may prove to underlie the susceptibility to periarticular fracture and Charcot arthropathy. The findings suggest that the risk of fracture in diabetes varies according to the specific sub-regions of a bone. The approach described may prove to be useful in the early detection of osteopathy in diabetic patients who may be amenable to preventive treatment.
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| 18. |
- Almehed, Katarina, 1966, et al.
(författare)
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Prevalence and risk factors of osteoporosis in female SLE patients-extended report
- 2007
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Ingår i: Rheumatology (Oxford). - : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 46:7, s. 1185-90
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To determine the frequency of osteoporosis and possible risk factors of low bone mineral density (BMD) in women with systemic lupus erythematous (SLE) in western Sweden. In addition, to evaluate if adequate anti-osteoporotic treatment was provided. METHODS: BMD was measured at radius, lumbar spine and hip by dual X-ray absorptiometry (DXA). An 'expected' control BMD was calculated for each patient. Simple and multiple linear regression analyses were performed to determine associations between BMD and demographic and disease-related variables. RESULTS: One hundred and sixty-three women were included. Median age was 47 (20-82) yrs, 89 (55%) were post-menopausal and 85 (52%) were taking glucocorticosteroids. BMD was significantly reduced in all measured sites compared with expected BMD. Thirty-seven (23%), 18 (11%) and 6 (4%) of the patients were osteoporotic in at least one, two and three or more measured locations. Bisphosphonates were used by 23 (27%) of patients taking glucocorticosteroids and 13 (35%) with osteoporosis. High age and low weight or BMI were associated with low BMD in all measured sites. In total hip, high SLICC/American Collage of Rheumatology (ACR), ESR and 'combinations of DMARD' were additional markers of low BMD. High S-creatinine was associated with low BMD in lumbal spine whereas high S-creatinine and CRP were markers in radius. CONCLUSION: Women with SLE are at greater risk of osteoporosis compared with controls and few are treated adequately. Factors associated with low BMD in SLE are high age and low weight but also markers of inflammation, impaired kidney function and disease damage, however glucocorticosteroids were not associated.
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| 19. |
- Almehed, Katarina, 1966, et al.
(författare)
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Prevalence and risk factors of vertebral compression fractures in female SLE patients.
- 2010
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Ingår i: Arthritis research & therapy. - : Springer Science and Business Media LLC. - 1478-6362 .- 1478-6354. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: INTRODUCTION: Our objective was to determine the frequency of and factors associated with prevalent vertebral compression fractures in female SLE patients attending rheumatologists in Western Sweden. METHODS: In this cross sectional study 150 women were included. They were examined with x-ray of thoracic and lumbar spine (Th4-L4). A reduction of at least 20% of any vertebral height, assessed by Genant's semiquantitative method, was defined as a fracture. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry (DXA). RESULTS: Median patient age was 47 years (20-82) and disease duration 11 years (1-41). Only 6 (4%) women had a history of clinical compressions whereas 43 (29%) had at least one radiological fracture each. The patients with at least one fracture at any site were characterized by higher age (p<0.001), being postmenopausal (p<0.01), higher Systemic Lupus International Collaborative Clinics Damage Index (p<0.05), lower BMD total hip and femoral neck (p<0.05), more peripheral fractures (p< 0.01), medication with bisphosphonates (p<0.05) and calcium and vitamin D3 (p<0.05). There were no significant differences regarding current or cumulative glucocorticosteroid dose between the groups. In logistic regression analyses high age remained as risk factor of at least one vertebral fracture at any site whereas low BMD in total hip was associated with vertebral fracture in lumbar spine. CONCLUSION: Radiological compression fractures are common but seldom diagnosed in SLE patients. High age and low BMD in total hip, but not in spine, was associated with vertebral fractures.
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| 20. |
- Amzaleg, Y., et al.
(författare)
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Estrogens and selective estrogen receptor modulators differentially antagonize Runx2 in ST2 mesenchymal progenitor cells
- 2018
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Ingår i: Journal of Steroid Biochemistry and Molecular Biology. - : Elsevier BV. - 0960-0760 .- 1879-1220. ; 183, s. 10-17
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Tidskriftsartikel (refereegranskat)abstract
- Estrogens attenuate bone turnover by inhibiting both osteoclasts and osteoblasts, in part through antagonizing Runx2. Apparently conflicting, stimulatory effects in osteoblast lineage cells, however, sway the balance between bone resorption and bone formation in favor of the latter. Consistent with this dualism, 17 beta-estradiol (E2) both stimulates and inhibits Runx2 in a locus-specific manner, and here we provide evidence for such locus specific regulation of Runx2 by E2 in vivo. We also demonstrate dual, negative and positive, regulation of Runx2-driven alkaline phosphatase (ALP) activity by increasing E2 concentrations in ST2 osteoblast progenitor cells. We further compared the effects of E2 to those of the Selective Estrogen Receptor Modulators (SERMs) raloxifene (ral) and lasofoxifene (las) and the phytoestrogen puerarin. We found that E2 at the physiological concentrations of 0.1-1 nM, as well as ral and las, but not puerarin, antagonize Runx2-driven ALP activity. At >= 10 nM, E2 and puerarin, but not ral or las, stimulate ALP relative to the activity measured at 0.1-1 nM. Contrasting the difference between E2 and SERMs in ST2 cells, they all shared a similar dose-response profile when inhibiting preosteoclast proliferation. That ral and las poorly mimic the locus-and concentration-dependent effects of E2 in mesenchymal progenitor cells may help explain their limited clinical efficacy.
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