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- Fagman, Johan Bourghardt, 1980, et al.
(författare)
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Androgen receptor-dependent and independent atheroprotection by testosterone in male mice.
- 2010
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Ingår i: Endocrinology. - : The Endocrine Society. - 1945-7170 .- 0013-7227. ; 151:11, s. 5428-37
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Tidskriftsartikel (refereegranskat)abstract
- The atheroprotective effect of testosterone is thought to require aromatization of testosterone to estradiol, but no study has adequately addressed the role of the androgen receptor (AR), the major pathway for the physiological effects of testosterone. We used AR knockout (ARKO) mice on apolipoprotein E-deficient background to study the role of the AR in testosterone atheroprotection in male mice. Because ARKO mice are testosterone deficient, we sham operated or orchiectomized (Orx) the mice before puberty, and Orx mice were supplemented with placebo or a physiological testosterone dose. From 8 to 16 wk of age, the mice consumed a high-fat diet. In the aortic root, ARKO mice showed increased atherosclerotic lesion area (+80%, P < 0.05). Compared with placebo, testosterone reduced lesion area both in Orx wild-type (WT) mice (by 50%, P < 0.001) and ARKO mice (by 24%, P < 0.05). However, lesion area was larger in testosterone-supplemented ARKO compared with testosterone-supplemented WT mice (+57%, P < 0.05). In WT mice, testosterone reduced the presence of a necrotic core in the plaque (80% among placebo-treated vs. 12% among testosterone-treated mice; P < 0.05), whereas there was no significant effect in ARKO mice (P = 0.20). In conclusion, ARKO mice on apolipoprotein E-deficient background display accelerated atherosclerosis. Testosterone treatment reduced atherosclerosis in both WT and ARKO mice. However, the effect on lesion area and complexity was more pronounced in WT than in ARKO mice, and lesion area was larger in ARKO mice even after testosterone supplementation. These results are consistent with an AR-dependent as well as an AR-independent component of testosterone atheroprotection in male mice.
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- Stubelius, Alexandra, 1983, et al.
(författare)
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Role of 2-methoxyestradiol as inhibitor of arthritis and osteoporosis in a model of postmenopausal rheumatoid arthritis
- 2011
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Ingår i: Clinical Immunology. - : Elsevier BV. - 1521-6616. ; 140:1, s. 37-46
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Tidskriftsartikel (refereegranskat)abstract
- In postmenopausal rheumatoid arthritis, both the inflammatory disease and estrogen deficiency contribute to the development of osteoporosis. As hormone replacement therapy is no longer an option, we hypothesized that 2-methoxyestradiol (2me2) could be beneficial, and asked if such therapy was associated with effects on reproductive organs. Mice were ovariectomized and arthritis was induced, whereafter mice were administered 2me2, estradiol, or placebo. Clinical and histological scores of arthritis, together with bone mineral density were evaluated. Uteri weight, reactive oxygen species (ROS) from spleen cells, and characterization of cells from joints and lymph nodes were analyzed. In addition, in vivo activation of estrogen response elements (ERE) by 2me2 was evaluated. Treatment with 2me2 and estradiol decreased the frequency and severity of arthritis and preserved bone. Joint destruction was reduced, neutrophils diminished and ROS production decreased. The uterine weight increased upon long-term 2me2 exposure, however short-term exposure did not activate ERE in vivo.
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- Stubelius, Alexandra, 1983, et al.
(författare)
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Sexual dimorphisms in the immune system of catechol-O-methyltransferase knockout mice
- 2012
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Ingår i: Immunobiology. - : Elsevier BV. - 0171-2985. ; 217:8, s. 751-760
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Tidskriftsartikel (refereegranskat)abstract
- The enzyme catechol-O-methyltransferase (COMT) is part of the metabolic pathway of 17 beta-estradiol, converting 2-hydroxyestradiol to 2-methoxyestradiol. We recently showed that administration of the COMT product 2-methoxyestradiol has anti-inflammatory and anti-osteoporotic effects. We have now investigated whether COMT affects the immune system, by immunologically phenotyping COMT deficient (COMT-/-) mice. Immunoglobulin production, T lymphocyte proliferation, NK cell cytotoxicity and oxygen radical production were assessed. In male COMT-/--mice, the total number of T-, and B-lymphocytes from spleen increased but the T-cell proliferative response decreased. The NK cell population shifted toward less mature cells, leaving cytotoxic capacity unaffected. In COMT-/--females, a higher frequency of neutrophils was found but the oxygen radical production was unaltered. In conclusion, only minor changes of the immune system were seen in COMT deficient mice, and the changes were usually seen in males. This study provides clues into how COMT activity, and hence gender differences, affects the immune system. (c) 2012 Elsevier GmbH. All rights reserved.
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- Wilhelmson, Anna S K, et al.
(författare)
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Catechol-O-methyltransferase is dispensable for vascular protection by estradiol in mouse models of atherosclerosis and neointima formation.
- 2011
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Ingår i: Endocrinology. - : The Endocrine Society. - 1945-7170 .- 0013-7227. ; 152:12, s. 4683-90
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Tidskriftsartikel (refereegranskat)abstract
- Estradiol is converted to the biologically active metabolite 2-methoxyestradiol via the activity of the enzyme catechol-O-methyltransferase (COMT). Exogenous administration of both estradiol and 2-methoxyestradiol reduces experimental atherosclerosis and neointima formation, and COMT-dependent formation of 2-methoxyestradiol likely mediates the antimitogenic effect of estradiol on smooth muscle cells in vitro. This study evaluated whether 2-methoxyestradiol mediates the vasculoprotective actions of estradiol in vivo. Wild-type (WT) and COMT knockout (COMTKO) mice on an apolipoprotein E-deficient background were gonadectomized and treated with estradiol or placebo. Exogenous estradiol reduced atherosclerotic lesion formation in both females (WT, -78%; COMTKO, -82%) and males (WT, -48%; COMTKO, -53%) and was equally effective in both genotypes. We further evaluated how exogenous estradiol affected neointima formation after ligation of the carotid artery in ovariectomized female mice; estradiol reduced intimal hyperplasia to a similar extent in both WT (-80%) and COMTKO (-77%) mice. In ovarian-intact female COMTKO mice, atherosclerosis was decreased (-25%) compared with WT controls. In conclusion, the COMT enzyme is dispensable for vascular protection by exogenous estradiol in experimental atherosclerosis and neointima formation in vivo. Instead, COMT deficiency in virgin female mice with intact endogenous production of estradiol results in relative protection against atherosclerosis.
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