| 1. |
- Fagerberg, Björn, 1943, et al.
(författare)
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Differences in lesion severity and cellular composition between in vivo assessed upstream and downstream sides of human symptomatic carotid atherosclerotic plaques
- 2010
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Ingår i: Journal of Vascular Surgery. - 1423-0135. ; 47:3, s. 221-230
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Tidskriftsartikel (refereegranskat)abstract
- Background: The heterogeneous structure of carotid atherosclerotic plaques may be better understood if it is related to blood flow variations, influencing gene expression and cellular functions. Upstream of the maximum stenosis there is laminar blood flow and high shear stress, downstream there is turbulence and low shear stress. We studied if these variations were associated with differences in plaque morphology and composition between sites located up- and downstream of the maximum stenosis in symptomatic carotid plaques. Methods: Patients with symptomatic carotid stenosis were examined with magnetic resonance angiography to localize the maximum stenosis in-vivo, prior to endarterectomy. In 41 endarterectomized specimens, transverse tissue sections prepared up- and downstream of the maximum stenosis were compared using histopathology and immunohistochemistry. Results: The location of maximum stenosis relative the carotid bifurcation varied considerably between plaques. Compared with the downstream side, the upstream side of the stenosis had higher incidence of severe lesions with cap rupture and intraplaque hemorrhage, more macrophages, less smooth muscle cells and more collagen. Conclusions: The up- and downstream sides of symptomatic carotid plaques differed in plaque morphology and composition. This implies that the intraplaque location of sampling sites may be a confounding factor in studies of atherosclerotic plaques.
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| 2. |
- Fogelstrand, Per, 1971, et al.
(författare)
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Increased Vascular Injury Reduces the Degree of Intimal Hyperplasia following Angioplasty in Rabbits.
- 2011
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Ingår i: Journal of vascular research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 48:4, s. 307-15
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: Formation of intimal hyperplasia following angioplastic procedures can lead to complications, including restenosis and accelerated atherosclerosis. The vessel wall media is a main source of neointimal cells. However, evidence suggests that there are additional cell sources, such as the adventitia. Here we investigate whether an extensive loss of vascular smooth muscle cells (VSMCs) in the media results in less intimal hyperplasia or if there is compensatory cell recruitment from the adventitia. Methods:A balloon catheter was pulled through the rabbit carotid artery 4 times (major injury) or 2 times (minor injury). Adventitial cells were labeled with 5-bromo-2-deoxyuridine or PKH26. Results:The major injury, but not the minor injury, resulted in a complete loss of VSMCs in large parts of the media and significant leukocyte infiltration. The major injury resulted in less neointima compared with the minor injury. The thinnest neointima was seen at the most injured parts of the media in the major injury group. Cell-tracking experiments showed that the media, but not the adventitia, served as a source of neointimal cells. Conclusion: An augmented angioplastic injury with extensive VSMC loss in rabbits reduced the degree of intimal hyperplasia. No compensatory recruitment of neointimal cells from the adventitia occurred.
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| 3. |
- Haarhaus, Mathias, et al.
(författare)
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Calcifying Human Aortic Smooth Muscle Cells Express Different Bone Alkaline Phosphatase Isoforms, Including the Novel B1x Isoform
- 2013
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Ingår i: Journal of Vascular Research. - : S. Karger. - 1018-1172 .- 1423-0135. ; 50:2, s. 167-174
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Tidskriftsartikel (refereegranskat)abstract
- Background: Vascular calcification, causing cardiovascular morbidity and mortality, is associated with hyperphosphatemia in chronic kidney disease (CKD). In vitro, phosphate induces transdifferentiation of vascular smooth muscle cells to osteoblast-like cells that express alkaline phosphatase (ALP). In vivo, raised serum ALP activities are associated with increased mortality. A new bone ALP isoform (B1x) has been identified in serum from CKD patients. The present study investigated the different ALP isoforms in calcifying human aortic smooth muscle cells (HAoSMCs). Methods: HAoSMCs were cultured for 30 days in medium containing 5 or 10 mmol/l beta-glycerophosphate in the presence or absence of the ALP-specific inhibitor tetramisole. Results: All known bone-specific ALP (BALP) isoforms (B/I, B1x, B1 and B2) were identified in HAoSMCs. beta-Glycerophosphate stimulated calcification of HAoSMCs, which was associated with increased BALP isoforms B/I, B1x and B2. Tetramisole inhibited the beta-glycerophosphate-induced HAoSMC calcification, which was paralleled by the inhibition of the B1x and B/I, but not the other isoforms. Conclusions: HAoSMCs express the four known BALP isoforms. B/I, B1x and B2 could be essential for soft tissue calcification. B/I and B1x were more affected by tetramisole than the other isoforms, which suggests different biological functions during calcification of HAoSMCs.
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| 4. |
- Holm, Anders, et al.
(författare)
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The G Protein-Coupled Estrogen Receptor 1 (GPER1/GPR30) Agonist G-1 Regulates Vascular Smooth Muscle Cell Ca Handling.
- 2013
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Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 50:5, s. 421-429
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Tidskriftsartikel (refereegranskat)abstract
- The G protein-coupled estrogen receptor GPER1/GPR30 is implicated in blood pressure regulation but the mechanisms are not identified. Here, we hypothesize that GPER1 controls blood pressure by regulating vascular smooth muscle cell Ca(2+) handling. Treatment with the GPER1 agonist G-1 (in the µM concentration range) acutely reduced spontaneous and synchronous Ca(2+) spike activity in A7r5 vascular smooth muscle cells expressing mRNA for GPER1. Furthermore, G-1 (1 µM) attenuated the thromboxane A2 analogue U46619-stimulated Ca(2+) spike activity but had no effect on the U46619-induced increase in the basal level of Ca(2+). The voltage-sensitive L-type Ca(2+) channel blocker nifedipine (100 nM) reduced Ca(2+) spike activity similar to G-1. Pharmacological, but not physiological, concentrations of the estrogen 17β-estradiol reduced Ca(2+) spike activity. The GPER1 antagonist G-15 blocked G-1-induced downregulation of Ca(2+) spike activity, supporting a GPER1-dependent mechanism. G-1 (1 µM) and nifedipine (100 nM) attenuated the 30-mM KCl-evoked rise in intracellular Ca(2+) concentration, suggesting that G-1 blocks inflow of Ca(2+) via voltage-sensitive Ca(2+) channels. In conclusion, we demonstrate that the GPER1 agonist G-1 regulates vascular smooth muscle cell Ca(2+) handling by lowering Ca(2+) spike activity, suggesting a role for this mechanism in GPER1-mediated control of blood pressure. © 2013 S. Karger AG, Basel.
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| 5. |
- Holm, Anders, et al.
(författare)
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The GPER1 Agonist G-1 Attenuates Endothelial Cell Proliferation by Inhibiting DNA Synthesis and Accumulating Cells in the S and G2 Phases of the Cell Cycle.
- 2011
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Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 48:4, s. 327-335
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Tidskriftsartikel (refereegranskat)abstract
- G protein-coupled receptor 30 (GPR30) or G protein-coupled estrogen receptor 1 (GPER1) is expressed in the vasculature, but the importance of vascular GPER1 remains to be clarified. Here we investigate effects of the GPER1 agonist G-1 on endothelial cell proliferation using mouse microvascular endothelial bEnd.3 cells. The bEnd.3 cells express mRNA for GPER1. The bEnd.3 cells expressed both ERα and ERβ immunoreactivities. Treatment with G-1 reduced DNA synthesis and cell number with IC(50) values of about 2 μM. GPER1 siRNA prevented G-1-induced attenuation of DNA synthesis. G-1 accumulated cells in S and G2 phases of the cell cycle, suggesting that G-1 blocks transition between G2 and M. G-1 had no effect on DNA synthesis in COS-7 cells only weakly expressing GPER1 mRNA. 17β-Estradiol had no effect on DNA synthesis in physiological concentrations (nM). The ER blocker ICI182780 reduced DNA synthesis with similar potency as G-1. Treatment with the ERK/MAP kinase inhibitor PD98059 had no effect on G-1-induced attenuation of DNA synthesis. G-1- induced antiproliferation was observed not only in bEnd.3 cells but also in human umbilical vein endothelial cells and HMEC-1 endothelial cells. We conclude that the GPER1 agonist G-1 attenuates endothelial cell proliferation via inhibition of DNA synthesis and by accumulation of cells in S and G2.
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| 6. |
- Mellor, Russell H, et al.
(författare)
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Mutations in FOXC2 in humans (lymphoedema distichiasis syndrome) cause lymphatic dysfunction on dependency.
- 2011
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Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1018-1172 .- 1423-0135. ; 48:5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Human lymphoedema distichiasis syndrome (LDS) results from germline mutations in transcription factor FOXC2. In a mouse model, lack of lymphatic and venous valves is observed plus abnormal smooth muscle cell recruitment to initial lymphatics. We investigated the mechanism of lymphoedema in humans with FOXC2 mutations, specifically the effect of gravitational forces on dermal lymphatic function.METHODS: We performed (1) quantitative fluorescence microlymphangiography (FML) on the skin of the forearm (non-swollen region) at heart level, and the foot (swollen region) below heart level (dependent) and then at heart level, and (2) immunohistochemical staining of microlymphatics in forearm and foot skin biopsies, using antibodies to podoplanin, LYVE-1 and smooth muscle actin.RESULTS: FML revealed a marked reduction in fluid uptake by initial lymphatics in the LDS foot during dependency, yet normal uptake (similar to controls) in the same foot at heart level and in LDS forearms. In control subjects, dependency did not impair initial lymphatic filling. Immunohistochemical microlymphatic density in forearm and foot did not differ between LDS and controls.CONCLUSIONS: FOXC2 mutations cause a functional failure of dermal initial lymphatics during gravitational stress (dependency), but not hypoplasia. The results reveal a pathophysiological mechanism contributing to swelling in LDS.
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| 7. |
- Ocaya, Pauline Ajok, 1977-, et al.
(författare)
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CYP26B1 plays a major role in the regulation of all-trans-retinoic acid metabolism and signaling in human aortic smooth muscle cells
- 2011
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Ingår i: Journal of Vascular Research. - : S. Karger. - 1018-1172 .- 1423-0135. ; 48:1, s. 23-30
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The cytochrome P450 enzymes of the CYP26 family are involved in the catabolism of the biologically active retinoid all-trans-retinoic acid (atRA). Since it is possible that an increased local CYP26 activity would reduce the effects of retinoids in vascular injury, we investigated the role of CYP26 in the regulation of atRA levels in human aortic smooth muscle cells (AOSMCs).Methods: The expression of CYP26 was investigated in cultured AOSMCs using real-time PCR. The metabolism of atRA was analyzed by high-performance liquid chromatography, and the inhibitor R115866 or small interfering RNA (siRNA) was used to suppress CYP26 activity/expression.Results: AOSMCs expressed CYP26B1 constitutively and atRA exposure augmented CYP26B1 mRNA levels. Silencing of the CYP26B1 gene expression or reduction of CYP26B1 enzymatic activity by using siRNA or the inhibitor R115866, respectively, increased atRA-mediated signaling and resulted in decreased cell proliferation. The CYP26 inhibitor also induced expression of atRA-responsive genes. Therefore, atRA-induced CYP26 expression accelerated atRA inactivation in AOSMCs, giving rise to an atRA-CYP26 feedback loop. Inhibition of this loop with a CYP26 inhibitor increased retinoid signaling.Conclusion: The results suggest that CYP26 inhibitors may be a therapeutic alternative to exogenous retinoid administration. Copyright (C) 2010 S. Karger AG, Basel
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| 8. |
- Persson, BP, et al.
(författare)
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Endotoxin induces differentiated contractile responses in porcine pulmonary arteries and veins
- 2011
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Ingår i: Journal of vascular research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 48:3, s. 206-218
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Tidskriftsartikel (refereegranskat)abstract
- <i>Background/Aims:</i> Sepsis-induced lung injury is characterized by pulmonary hypertension, edema and deteriorated gas exchange. As in vivo studies have indicated that bacterial endotoxin predominantly induces a pulmonary venous constriction, we aimed to investigate effects of endotoxin on isolated porcine pulmonary vessels. <i>Methods:</i> Pulmonary arteries and veins were examined using in vitro isometric force recordings. Endothelin-receptor protein expression and distribution were analyzed by Western blot and immunohistochemistry. Freshly isolated preparations and vessels incubated (24 h) with/without endotoxin (10 µg·ml<sup>–1</sup>) were compared. The contractile responses to phenylephrine, UK14.304, U46619, PGF<sub>2</sub><sub>α</sub>, endothelin-1 (ET-1) and sarafotoxin were recorded, as well as the relaxation in response to acetylcholine, isoproterenol and nitroprusside. <i>Results:</i> In freshly isolated vessels, phenylephrine-induced contractions had a 5-times larger amplitude in arteries than in veins. The amplitude of the contractions in response to sarafotoxin was nearly 2 times larger in veins than in arteries, but there was no difference in responses to ET-1. Endotoxin markedly reduced phenylephrine-induced contractions in both arteries and veins, whereas the responses to ET-1 and sarafotoxin were augmented in veins only. No apparent changes in ET receptor expression or distribution were detected with Western blot or immunohistochemistry. <i>Conclusion:</i> Endotoxin differentially and selectively alters the contractile responses of porcine pulmonary vessels in vitro, towards a situation where the α-1 adrenergic responses of arteries are attenuated and the ET responses of veins are augmented. In situations with high adrenergic activity and high circulating ET levels, such as sepsis, these results may provide a mechanism contributing to pulmonary hypertension and edema formation.
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| 9. |
- Rasmussen, Marianne N. P., et al.
(författare)
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Permanent Distal Occlusion of Middle Cerebral Artery in Rat Causes Local Increased ETB, 5-HT1B and AT(1) Receptor-Mediated Contractility Downstream of Occlusion
- 2013
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Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 50:5, s. 396-409
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: In response to experimental stroke, a characteristic functional and expressional upregulation of contractile G-protein-coupled receptors has been uncovered in the affected cerebral vasculature; however, the mechanism initiating this phenomenon remains unknown. Methods: Using a model of permanent distal occlusion of rat middle cerebral arteries, we investigated whether there was a regional difference in receptor-mediated contractility of segments located upstream and downstream of the occlusion site. The contractile response to endothelin, angiotensin and 5-hydroxytryptamine receptor stimulation was studied by sensitive wire myograph. Results: Only downstream segments exhibited an augmented contractile response to stimulation with each of the three ligands, with the response towards sarafotoxin 6c being especially augmented compared to sham, upstream and contralateral controls. This functional increase did not seem to relate to ischemic tissue damage, inflammatory cell infiltration or the element of reperfusion. Interestingly, immunohistochemistry did not show any difference in the level of immunoreactivity towards endothelin B (ETB) receptors between groups. Conclusion: Single artery occlusion without significant visible infarct resulted in locally increased ETB, angiotensin type 1 and 5-hydroxytryptamine 1B receptor-mediated contractile responses only in segments located downstream of the occlusion site. This suggests lack of wall stress as an initiating trigger leading to regulation of contractile response after cerebral stroke. (C) 2013 S. Karger AG, Basel
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| 10. |
- Rousseau, Andreas, et al.
(författare)
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Prostaglandins and Radical Oxygen Species Are Involved in Microvascular Effects of Hyperoxia
- 2010
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Ingår i: JOURNAL OF VASCULAR RESEARCH. - : S. Karger AG. - 1018-1172 .- 1423-0135. ; 47:5, s. 441-450
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Tidskriftsartikel (refereegranskat)abstract
- Hyperoxia causes vasoconstriction in most tissues, by mechanisms that are not fully understood. We investigated microvascular effects of breathing 100% oxygen in healthy volunteers, using iontophoresis to deliver acetylcholine (ACh) and sodium nitroprusside (SNP). Aspirin and vitamin C were used to test for involvement of prostaglandins and radical oxygen species. Forearm skin perfusion was measured using laser Doppler perfusion imaging. Results were analysed using dose-response modelling. The response to ACh was reduced by 30% during oxygen breathing compared to air breathing [0.98 (0.81-1.15) PU vs. 1.45 (1.30-1.60) PU, p andlt; 0.001]. ED50 values were unchanged [2.25 (1.84-2.75) vs. 2.21 (1.79-2.74), not significant]. Aspirin pre-treatment abolished the difference in response between oxygen breathing and air breathing [maximum: 1.03 (0.90-1.16) vs. 0.89 (0.77-1.01), not significant; ED50: 1.83 (1.46-2.30) vs. 1.95 (1.65-2.30), not significant]. ACh-mediated vasodilatation during 100% oxygen breathing was partially restored after pre-treatment with vitamin C. Breathing 100% oxygen did not change the microvascular response to SNP [1.45 (1.28-1.62) vs. 1.40 (1.26-1.53), not significant]. These results favour the hypothesis that hyperoxic vasoconstriction is mediated by inhibition of prostaglandin synthesis. Radical oxygen species may be involved as vitamin C, independently of aspirin, partially restored ACh-mediated vasodilatation during hyperoxia.
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