| 1. |
- Eriksson, Anna-Lena, 1971, et al.
(författare)
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Association between the low activity genotype of catechol-O-methyltransferase and myocardial infarction in a hypertensive population
- 2004
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Ingår i: Eur Heart J. ; 25:5, s. 386-91
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Tidskriftsartikel (refereegranskat)abstract
- AIM: Estrogens regulate several biological processes involved in the pathogenesis of myocardial infarction. Catechol-O-methyltransferase (COMT) is a key enzyme in the degradation of estrogens. There is a functional polymorphism in the COMT gene (Val158Met), affecting the activity of the enzyme. We investigated if the low activity genotype of COMT is associated with an altered risk of myocardial infarction. METHODS AND RESULTS: In a prospectively followed hypertensive cohort we identified 174 patients who suffered a myocardial infarction during the study and compared them to 348 controls from the same cohort. The COMT polymorphism and serum levels of sex hormones were analysed. Patients homozygous for the low activity COMT genotype had a decreased risk of myocardial infarction compared to those with the high activity genotype, odds ratio 0.65 (95% CI 0.44-0.97, p=0.033 ). The protective effect of the low activity genotype was most evident among older patients (> 58 years of age), odds ratio 0.43 (95% CI 0.23-0.79, p=0.006 ). Serum levels of estradiol were increased ( p=0.006 ) in males with the low activity genotype. CONCLUSIONS: Our findings suggest that the low activity COMT genotype is protective against myocardial infarction. One may speculate that the altered estrogen status could be involved in this effect.
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| 2. |
- Lindberg, Marie K, 1975, et al.
(författare)
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Estrogen receptor (ER)-beta reduces ERalpha-regulated gene transcription, supporting a "ying yang" relationship between ERalpha and ERbeta in mice.
- 2003
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Ingår i: Molecular endocrinology (Baltimore, Md.). - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 17:2, s. 203-8
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen is of importance for the regulation of adult bone metabolism. The aim of the present study was to determine the role of estrogen receptor-beta (ERbeta) in vivo on global estrogen-regulated transcriptional activity in bone. The effect of estrogen in bone of ovariectomized mice was determined using microarray analysis including 9400 genes. Most of the genes (95% = 240 genes) that were increased by estrogen in wild-type (WT) mice were also increased by estrogen in ERbeta-inactivated mice. Interestingly, the average stimulatory effect of estrogen on the mRNA levels of these genes was 85% higher in ERbeta-inactivated than in WT mice, demonstrating that ERbeta reduces estrogen receptor-alpha (ERalpha)-regulated gene transcription in bone. The average stimulatory effect of estrogen on estrogen-regulated bone genes in ERalpha-inactivated mice was intermediate between that seen in WT and ERalphabeta double-inactivated mice. Thus, ERbeta inhibits ERalpha-mediated gene transcription in the presence of ERalpha, whereas, in the absence of ERalpha, it can partially replace ERalpha. In conclusion, our in vivo data indicate that an important physiological role of ERbeta is to modulate ERalpha-mediated gene transcription supporting a "Ying Yang" relationship between ERalpha and ERbeta in mice.
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| 3. |
- Lindberg, Marie K, 1975, et al.
(författare)
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Identification of estrogen-regulated genes of potential importance for the regulation of trabecular bone mineral density.
- 2002
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Ingår i: Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. - : Wiley. - 0884-0431. ; 17:12, s. 2183-95
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen is of importance for the regulation of trabecular bone mineral density (BMD). The aim of this study was to search for possible mechanisms of action of estrogen on bone. Ovariectomized (OVX) mice were treated with 17beta-estradiol. Possible effects of estrogen on the expression of 125 different bone-related genes in humerus were analyzed using the microarray technique. Estrogen regulated 12 of these genes, namely, two growth factor-related genes, 8 cytokines, and 2 bone matrix-related genes. Five of the 12 genes are known to be estrogen-regulated, and the remaining 7 genes are novel estrogen-regulated genes. Seven genes, including interleukin-1 receptor antagonist (IL-1ra), IL-1receptor type II (IL-1RII), insulin-like growth factor-binding protein 4 (IGFBP-4), transforming growth factor beta (TGF-beta), granulocyte colony-stimulating factor receptor (G-CSFR), leukemia inhibitory factor receptor (LIFR), and soluble IL-4 receptor (sIL-4R) were selected as probable candidate genes for the trabecular bone-sparing effect of estrogen, as the mRNA levels of these genes were highly correlated (r2 > 0.65) to the trabecular BMD. The regulation of most of these seven genes was predominantly estrogen receptor alpha (ER-alpha)-mediated (5/7) while some genes (2/7) were regulated both via ER-alpha and ER-beta. In conclusion, by using the microarray technique, we have identified four previously known and three novel estrogen-regulated genes of potential importance for the trabecular bone-sparing effect of estrogen.
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| 4. |
- Lindberg, Marie K, 1975, et al.
(författare)
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Two different pathways for the maintenance of trabecular bone in adult male mice.
- 2002
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Ingår i: Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. - : Wiley. - 0884-0431. ; 17:4, s. 555-62
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Tidskriftsartikel (refereegranskat)abstract
- Androgens may regulate the male skeleton either directly via activation of the androgen receptor (AR) or indirectly via aromatization of androgens into estrogen and, thereafter, via activation of estrogen receptors (ERs). There are two known estrogen receptors, ER-alpha and ER-beta. The aim of this study was to investigate the relative roles of ER-alpha, ER-beta, and AR in the maintenance of trabecular bone in male mice. Seven-month-old male mice, lacking ER-alpha (ERKO), ER-beta (BERKO), or both receptors (DERKO), were orchidectomized (orx) and treated for 3 weeks with 0.7 microg/mouse per day of 17beta-estradiol or vehicle. No reduction in trabecular bone mineral density (BMD) was seen in ERKO, BERKO, or DERKO mice before orx, showing that neither ER-a nor ER-beta is required for the maintenance of a normal trabecular BMD in male mice. After orx, there was a pronounced decrease in trabecular BMD, similar for all groups, resulting in equal levels of trabecular BMD in all genotypes. This reduction was reversed completely in wild-type (WT) and BERKO mice treated with estrogen, and no significant effect of estrogen was found in ERKO or DERKO mice. In summary, the trabecular bone is preserved both by a testicular factor, presumably testosterone acting via AR and by an estrogen-induced activation of ER-alpha. These results indicate that AR and ER-alpha are redundant in the maintenance of the trabecular bone in male mice. In contrast, ER-beta is of no importance for the regulation of trabecular bone in male mice.
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| 5. |
- Movérare, Sofia, et al.
(författare)
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Differential effects on bone of estrogen receptor alpha and androgen receptor activation in orchidectomized adult male mice.
- 2003
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 100:23, s. 13573-8
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Tidskriftsartikel (refereegranskat)abstract
- Androgens may regulate the male skeleton either directly by stimulation of the androgen receptor (AR) or indirectly by aromatization of androgens into estrogens and, thereafter, by stimulation of the estrogen receptors (ERs). To directly compare the effect of ER activation on bone in vivo with the effect of AR activation, 9-month-old orchidectomized wild-type and ER-inactivated mice were treated with the nonaromatizable androgen 5alpha-dihydrotestosterone, 17beta-estradiol, or vehicle. Both ERalpha and AR but not ERbeta activation preserved the amount of trabecular bone. ERalpha activation resulted both in a preserved thickness and number of trabeculae. In contrast, AR activation exclusively preserved the number of trabeculae, whereas the thickness of the trabeculae was unaffected. Furthermore, the effects of 17beta-estradiol could not be mediated by the AR, and the effects of 5alpha-dihydrotestosterone were increased rather than decreased in ER-inactivated mice. ERalpha, but not AR or ERbeta, activation resulted in preserved thickness, volumetric density, and mechanical strength of the cortical bone. ERalpha activation increased serum levels of insulin-like growth factor I, which were positively correlated with all the cortical and trabecular bone parameters that were specifically preserved by ERalpha activation but not by AR activation, suggesting that insulin-like growth factor I might mediate these effects of ERalpha activation. Thus, the in vivo bone-sparing effect of ERalpha activation is distinct from the bone-sparing effect of AR activation in adult male mice. Because these two pathways are clearly distinct from each other, one may speculate that a combined treatment of selective ER modulators and selective AR modulators might be beneficial in the treatment of osteoporosis.
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| 6. |
- Movérare, Sofia, et al.
(författare)
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Estrogen increases coagulation factor V mRNA levels via both estrogen receptor-alpha and -beta in murine bone marrow/bone.
- 2004
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Ingår i: European journal of endocrinology / European Federation of Endocrine Societies. - : Oxford University Press (OUP). - 0804-4643 .- 1479-683X. ; 151:2, s. 259-63
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Both oral estrogen-based hormone-replacement therapy and contraceptives increase the risk of venous thromboembolism. Several circulating factors involved in coagulation/fibrinolysis are expressed mainly in the liver whilst some are expressed in extrahepatic tissues, including bone marrow. The aim of this study was to identify estrogen-responsive target genes involved in the pathogenesis of estrogen-induced venous thromboembolism. METHODS: Ovariectomized mice were treated with 17beta-estradiol and possible effects on the expression of genes related to coagulation/fibrinolysis were investigated using DNA microarray analyses. RESULTS: None of the selected genes was regulated by 17beta-estradiol in the liver. Interestingly, 17beta-estradiol increased mRNA levels of coagulation factor V in the bone marrow/bone. Furthermore, this stimulatory effect of 17beta-estradiol on coagulation factor V expression can be mediated via both estrogen receptor-alpha and -beta. CONCLUSIONS: The expression of bone marrow-derived, but not liver-derived, coagulation factor V is increased by estrogen treatment in mice. The pathophysiological importance of this finding for estrogen-induced venous thromboembolism remains to be determined.
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| 7. |
- Sjögren, Klara, 1970, et al.
(författare)
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Liver-derived insulin-like growth factor I (IGF-I) is the principal source of IGF-I in blood but is not required for postnatal body growth in mice.
- 1999
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424. ; 96:12, s. 7088-92
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Tidskriftsartikel (refereegranskat)abstract
- The body growth of animals is regulated by growth hormone and IGF-I. The classical theory of this regulation is that most IGF-I in the blood originates in the liver and that body growth is controlled by the concentration of IGF-I in the blood. We have abolished IGF-I production in the livers of mice by using the Cre/loxP recombination system. These mice demonstrated complete inactivation of the IGF-I gene in the hepatocytes. Although the liver accounts for less than 5% of body mass, the concentration of IGF-I in the serum was reduced by 75%. This finding confirms that the liver is the principal source of IGF-I in the blood. However, the reduction in serum IGF-I concentration had no discernible effect on postnatal body growth. We conclude that postnatal body growth is preserved despite complete absence of IGF-I production by the hepatocytes.
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| 8. |
- Skrtic, Stanko, 1970, et al.
(författare)
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Cortisol decreases hepatocyte growth factor levels in human osteoblast-like cells.
- 2000
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Ingår i: Calcified tissue international. - 0171-967X. ; 66:2, s. 108-12
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Tidskriftsartikel (refereegranskat)abstract
- Osteoporosis is a well-known side effect of long-term treatment with glucocorticoids. The hepatocyte growth factor (HGF) receptor is expressed by human osteoclasts and osteoblasts, and mouse osteoblasts also express HGF, indicating that HGF may regulate bone metabolism. Because HGF could be a candidate factor in the local paracrine signaling between osteoblasts and osteoclasts in bone, we decided to study whether human osteoblasts secrete HGF and whether glucocorticoids regulate the expression of HGF. HGF was easily detectable in the culture medium from human osteoblast-like cells (hOB). The HGF protein released into the culture medium was increased with increasing confluency. Hydrocortisone decreased the amount of HGF released into the culture medium from hOB in a dose-dependent manner with a maximal effect at 10(-6) M. Time-course studies revealed that hydrocortisone decreased the amount of HGF released into the culture medium significantly after 16 hours of stimulation (65 +/- 2% of control culture). This effect of hydrocortisone was maximal after 24 hours of stimulation (52 +/- 8% of control culture). In conclusion, HGF is produced by primary cultured hOB cells. Furthermore, the amount of HGF released into the culture medium is decreased by glucocorticoids. The biological significance of this finding remains to be demonstrated.
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| 9. |
- Skrtic, Stanko, 1970, et al.
(författare)
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Possible roles of insulin-like growth factor in regulation of physiological and pathophysiological liver growth.
- 2001
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Ingår i: Hormone research. - 0301-0163. ; 55 Suppl 1, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND/AIMS: Almost all circulating insulin-like growth factor-1 (IGF-1) is produced and secreted from the liver. However, the possible role of IGF-1 in local regulation of liver functions including liver growth is unclear. In the present study, we investigated the role of IGF-1 on liver growth in vivo and in hepatic stellate cell function in vitro. RESULTS: Liver-specific knock-out of the IGF-1 gene by use of the cre-loxP system caused enhanced liver growth, possibly reflecting increased growth hormone (GH) secretion due to decreased negative feedback by IGF-1. Studies on cultured rat hepatic stellate cells (HSC) showed that IGF-1 and hepatocyte-conditioned medium (PCcM) time- and dose-dependently increased hepatocyte growth factor (HGF) mRNA and HGF immunoreactivity. IGF-1 and PCcM also enhanced DNA synthesis in the HSC cultures. The PCcM did not contain bioactive IGF-1 and was also able to stimulate proliferation when prepared under serum- and hormone-free conditions. CONCLUSION: In vivo results show that IGF-1 is not essential for normal growth of the intact liver. The in vitro results indicate that both IGF-1 and IGF- 1-independent factor(s) from hepatocytes can stimulate HGF production by HSC. It remains to be investigated whether these effects are of importance for liver regeneration or pathological conditions.
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| 10. |
- Wallerstedt, Susanna Maria, 1970, et al.
(författare)
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Association analysis of the polymorphism T1128C in the signal peptide of neuropeptide Y in a Swedish hypertensive population.
- 2004
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Ingår i: Journal of hypertension. - : Ovid Technologies (Wolters Kluwer Health). - 0263-6352. ; 22:7, s. 1277-81
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The neuropeptide Y (NPY) signal peptide polymorphism T1128C has been linked to several risk factors for cardiovascular disease. The aim of the present study was to evaluate the significance of this polymorphism for cardiovascular and cerebrovascular disease outcome. DESIGN: In a prospective study cohort, 1032 hypertensive patients (174 myocardial infarction and 170 stroke patients and 688 matched controls) were analysed for the T1128C polymorphism in the NPY gene. METHODS: The dynamic allele specific hybridization (DASH) method was used for genotyping. Serum from the same participants was analysed for total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and triglycerides. RESULTS: The frequency of the NPY T1128C polymorphism was 8.4% among patients with a myocardial infarction or stroke, as compared to 5.1% in the control group (P = 0.040). The difference remained significant after adjustment for the cardiovascular risk factors age, sex, smoking status, body mass index, systolic and diastolic blood pressure, presence of diabetes, total cholesterol, HDL, LDL and triglycerides. CONCLUSIONS: The present study indicates that the NPY T1128C polymorphism is an independent predictor for myocardial infarction and stroke in a Swedish hypertensive population.
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