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- Ahnstedt, Hilda, et al.
(författare)
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Cytokines and growth factors modify the upregulation of contractile endothelin ET(A) and ET(B) receptors in rat cerebral arteries after organ culture.
- 2012
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Ingår i: Acta Physiologica. - : Wiley. - 1748-1708. ; 205:2, s. 266-278
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Experimental cerebral ischemia and organ culture of cerebral arteries induce an increased endothelin ET(B) receptor-mediated contraction. The aim of the present study was to examine if cytokines and growth factors, known to be activated in ischemia, can influence the expression and function of endothelin receptors after organ culture. Methods: Rat middle cerebral arteries were cultured for 24 h at 37°C in humidified 5% CO(2) and air in culture medium alone, or with tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), platelet-derived growth factor (PDGF), epidermal growth factor (EGF) or basic fibroblast growth factor (bFGF). Concentration-response curves were obtained for sarafotoxin 6c (ET(B) receptor agonist) and endothelin-1 (here ET(A) receptor agonist, because of ET(B) receptor desensitization). The receptor mRNA expression was examined by real-time PCR and the protein expression by immunohistochemistry and Western blot. Results: TNF-α (100 ng/ml) and EGF (20 ng/ml) potentiated the ET(B) receptor-mediated contraction (increase in pEC(50) without change in E(max) ). bFGF (10 ng/ml) and IL-1β (10 ng/ml) induced an enhanced ET(A) receptor-mediated contraction. bFGF (10 ng/ml) significantly increased the ET(B) mRNA level, and EGF (20 ng/ml) increased the ET(A) receptor protein. Increased ET(B) receptor mRNA and protein level also were observed after treatment with IL-1β (10 ng/ml). Conclusion: The present study show that TNF-α, IL-1β, EGF and bFGF can modify the expression and function of endothelin receptors during organ culture. Since there is similar receptor upregulation in experimental stroke, the effect of cytokines and growth factors on endothelin receptor upregulation is an interesting aspect to study in vivo.
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| 2. |
- Ahnstedt, Hilda, et al.
(författare)
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Human cerebrovascular contractile receptors are upregulated via a B-Raf/MEK/ERK-sensitive signaling pathway.
- 2011
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Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: Cerebral ischemia results in a rapid increase in contractile cerebrovascular receptors, such as the 5-hydroxytryptamine type 1B (5-HT1B), angiotensin II type 1 (AT1), and endothelin type B (ETB) receptors, in the vessel walls within the ischemic region, which further impairs local blood flow and aggravates tissue damage. This receptor upregulation occurs via activation of the mitogen-activated protein kinase pathway. We therefore hypothesized an important role for B-Raf, the first signaling molecule in the pathway. To test our hypothesis, human cerebral arteries were incubated at 37°C for 48 h in the absence or presence of a B-Raf inhibitor: SB-386023 or SB-590885. Contractile properties were evaluated in a myograph and protein expression of the individual receptors and activated phosphorylated B-Raf (p-B-Raf) was evaluated immunohistochemically. RESULTS: 5-HT1B, AT1, and ETB receptor-mediated contractions were significantly reduced by application of SB-590885, and to a smaller extent by SB-386023. A marked reduction in AT1 receptor immunoreactivity was observed after treatment with SB-590885. Treatment with SB-590885 and SB-386023 diminished the culture-induced increase of p-B-Raf immunoreactivity. CONCLUSIONS: B-Raf signaling has a key function in the altered expression of vascular contractile receptors observed after organ culture. Therefore, specific targeting of B-Raf might be a novel approach to reduce tissue damage after cerebral ischemia by preventing the previously observed upregulation of contractile receptors in smooth muscle cells.
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| 4. |
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| 5. |
- Ahnstedt, Hilda, et al.
(författare)
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Male-female differences in upregulation of vasoconstrictor responses in human cerebral arteries.
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- Male-female differences may significantly impact stroke prevention and treatment in men and women, however underlying mechanisms for sexual dimorphism in stroke are not understood. We previously found in males that cerebral ischemia upregulates contractile receptors in cerebral arteries, which is associated with lower blood flow. The present study investigates if cerebral arteries from men and women differ in cerebrovascular receptor upregulation.
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| 6. |
- Ahnstedt, Hilda
(författare)
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Stroke, Sex and Vascular Receptor Changes in the Brain
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Stroke is a severe cerebrovascular disease in which the neuronal tissue and vasculature of the brain undergo ischemia-evoked alterations. We have demonstrated an increased expression of cerebrovascular contractile receptors in the brain. This is hypothesized to mitigate cerebral blood flow and exacerbate tissue damage after stroke. An increased contractile property of these receptors has been demonstrated to occur by MEK/ERK1/2 signaling. The majority of pre-clinical studies on stroke are performed in young healthy male animals, despite the fact there is a difference in male and female stroke incidence. The present thesis therefore aimed to investigate the status of vascular receptor changes after experimental stroke and organ culture, with two focus areas that previously have been missing – studies on human material and female subjects. In human cerebral arteries, we found that increased vasoconstriction of 5-HT1B, AT1 and ETB receptors during organ culture, a model of ischemic-like receptor changes, is mediated by B-Raf/MEK/ERK1/2 signaling. Although, increased mRNA and protein of these receptors were found in arteries from both sexes, the contraction to Ang II and ET-1 was markedly lower in female arteries. Focal cerebral ischemia in female rats induced an enhanced contractile property of cerebrovascular ETB receptors, similar to previous observations in males. Ovariectomy, and thereby loss of progesterone and estrogen, resulted in less ischemia-induced ETB receptor upregulation. Hormone therapy with progesterone, but not estrogen, reversed these changes. The increased ETB receptor expression and vasoconstriction after cerebral ischemia in female rat was demonstrated to be mediated by MEK/ERK1/2 signaling. MEK1/2 inhibition attenuated the ETB receptor upregulation and improved the neurological outcome. The present thesis demonstrates for the first time sex differences in vascular function of human cerebral arteries. The underlying mechanism in decreased responsiveness of female arteries remains to be elucidated. This may involve differences in receptor coupling or signal transduction influenced by female sex steroid hormones, or biological sex. Our experimental studies on stroke suggest the loss of progesterone after ovariectomy suppresses ischemia-induced ETB receptor upregulation. Further, the signal transduction pathway involved in vascular receptor changes after cerebral ischemia is suggested to be similar in both sexes. MEK1/2 inhibition is therefore a promising therapeutic target for stroke therapy in both males and females.
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| 7. |
- Ahnstedt, Hilda, et al.
(författare)
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U0126 attenuates cerebral vasoconstriction and improves long-term neurologic outcome after stroke in female rats.
- 2015
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 1559-7016 .- 0271-678X. ; 35:3, s. 454-460
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Tidskriftsartikel (refereegranskat)abstract
- Sex differences are well known in cerebral ischemia and may impact the effect of stroke treatments. In male rats, the MEK1/2 inhibitor U0126 reduces ischemia-induced endothelin type B (ETB) receptor upregulation, infarct size and improves acute neurologic function after experimental stroke. However, responses to this treatment in females and long-term effects on outcome are not known. Initial experiments used in vitro organ culture of cerebral arteries, confirming ERK1/2 activation and increased ETB receptor-mediated vasoconstriction in female cerebral arteries. Transient middle cerebral artery occlusion (tMCAO, 120 minutes) was induced in female Wistar rats, with U0126 (30 mg/kg intraperitoneally) or vehicle administered at 0 and 24 hours of reperfusion, or with no treatment. Infarct volumes were determined and neurologic function was assessed by 6-point and 28-point neuroscores. ETB receptor-mediated contraction was studied with myograph and protein expression with immunohistochemistry. In vitro organ culture and tMCAO resulted in vascular ETB receptor upregulation and activation of ERK1/2 that was prevented by U0126. Although no effect on infarct size, U0126 improved the long-term neurologic function after experimental stroke in female rats. In conclusion, early prevention of the ERK1/2 activation and ETB receptor-mediated vasoconstriction in the cerebral vasculature after ischemic stroke in female rats improves the long-term neurologic outcome.Journal of Cerebral Blood Flow & Metabolism advance online publication, 10 December 2014; doi:10.1038/jcbfm.2014.217.
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| 9. |
- Edvinsson, Lars, et al.
(författare)
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Differential localization and characterization of functional calcitonin gene-related peptide receptors in human subcutaneous arteries.
- 2014
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Ingår i: Acta Physiologica. - : Wiley. - 1748-1716 .- 1748-1708. ; 210:4, s. 811-822
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Tidskriftsartikel (refereegranskat)abstract
- Calcitonin gene-related peptide (CGRP) and its receptor are widely distributed within the circulation and the mechanism behind its vasodilation not only differs from one animal species to another but is also dependent on the type and size of vessel. The present study examines the nature of CGRP-induced vasodilation, characteristics of the CGRP receptor antagonist telcagepant and localization of the key components calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1 (RAMP1) of the CGRP receptor in human subcutaneous arteries.
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| 10. |
- Edvinsson, Marie-Louise, et al.
(författare)
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Characterization of Relaxant Responses to Natriuretic Peptides in the Human Microcirculation In Vitro and In Vivo
- 2016
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Ingår i: Microcirculation. - : Wiley. - 1073-9688. ; 23:6, s. 438-446
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Tidskriftsartikel (refereegranskat)abstract
- Objective: We characterized the vasodilatory effects of ANP, BNP, and CNP in human subcutaneous arterioles in vitro and the cutaneous microcirculation in vivo. Methods: The in vitro experiments were performed using wire myography and the responses were characterized by the use of inhibitors for nitric oxide (L-NAME), prostaglandin synthesis (indomethacin), or the endothelium-derived hyperpolarization factor. In vivo, the vasorelaxant effect of iontophoretically administrated BNP or CNP was measured with a noninvasive laser Doppler technique. Involvement of nitric oxide or prostaglandins was assessed by L-NAME or indomethacin given by iontophoresis. Results: In vitro all three peptides showed significant vasodilatation with the efficacy order: CNP > BNP = ANP. The BNP-induced vasodilatation, but not that of ANP or CNP, was significantly reduced by pretreatment with indomethacin or L-NAME. In vivo administration of BNP induced a marked vasodilatory response that was attenuated by local pretreatment of L-NAME. Indomethacin by itself resulted in increased cutaneous perfusion. Conclusions: NPs are potent vasodilators in the human subcutaneous circulation. The response to BNP differs from that of the other peptides as it seems dependent on cyclooxygenase products and nitric oxide.
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