Agneta Månsson-Broberg

Karolinska Institutet, Stockholm, Stockholm, Sweden

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Publications (12)44.94 Total impact

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    ABSTRACT: To investigate whether, in the subacute phase of acute myocardial infarction, in the peri-infarcted area the expressions of the vascular endothelial growth factor (VEGF-A) and angiopoietin (Ang) ligand receptors are depressed, and whether overexpression of these angiogens counteracts a downregulation of myocardial function. Acute myocardial infarction was induced by left anterior descending artery ligation and overexpression through injection of human VEGF-A165 and Ang-1 plasmids. The capillary and arteriolar densities, Akt-1 phosphorylation and citrate synthase activity were measured concurrent with the expression of VEGF-A, VEGFR1 and R2, Ang-1, Ang-2 and Tie-2. One day after AMI, VEGR-2 was unchanged but all other measured factors in the two families were upregulated. After day 2, the Ang-2 expression increased but other measured factors decreased. After gene transfer, the vascular supply, Akt phosphorylation and citrate synthase activity were higher in the peri-infarcted area, where also the endogenous angiogenic growth factor expressions were increased. A rapid decrease in angiogenic stimulating factors occurs in the subacute phase of AMI and is related to a progressive decrease in myocardial contraction. A negative consequence of such a circuit is a successive reduction in the vascular supply and contractility in areas with reduced perfusion. These negative adaptations can be counteracted by angiogen overexpression.
    Coronary artery disease 12/2009; 21(2):65-71. · 1.56 Impact Factor
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    ABSTRACT: Eph/ephrin signaling is pivotal in prenatal angiogenesis while its potential role in postnatal angiogenesis largely remains to be explored. Therefore its putative angiogenic and therapeutic effects were explored in endothelium and in myocardial ischemia. In culture of human aortic endothelial cells the fusion protein ephrinB2-Fc induced cell proliferation (p<0.0005) and in the murine aortic ring model ephrinB2-Fc induced increased sprouting (p<0.05). Myocardial infarction was induced by ligation of the left anterior descending artery in mouse. During the following 2 weeks mRNA of the receptor/ligand pair EphB4/ephrinB2 was expressed dichotomously (p<0.05) and other Eph/ephrin pairs were expressed to a lesser degree. Twenty-four hours after intraperitoneal administration of ephrinB2-Fc it was detected in abundance throughout the myocardium along capillaries, showing signs of increased mitosis. After 4 weeks the capillary density was increased 28% in the periinfarcted area (p<0.05) to a level not different from healthy regions of the heart where no change was observed. These results implicate that EphB4/ephrinB2 is an important signaling pathway in ischemic heart disease and its modulation may induce therapeutic angiogenesis.
    Biochemical and Biophysical Research Communications 07/2008; 373(3):355-9. · 2.41 Impact Factor
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    ABSTRACT: In order to study the ability of costimulation blockade to induce tolerance to human embryonic stem cells (HESC), severe combined immunodeficient (SCID), and immunocompetent C57BL/6 mice treated with costimulation blockade received intratesticular and intramyocardial HESC transplants. All SCID mice with intratesticular HESC transplants developed teratoma. When SCID mice were transplanted intramyocardially, only two of five mice developed teratoma-like tumors. C57BL/6 mice transplanted intratesticularly and treated with costimulation blockade all developed teratoma and were surrounded by CD4(+)CD25(+)Foxp3(+) T-cells, while isotype control treated recipients rejected their grafts. Most C57BL/6 mice transplanted intramyocardially and treated with costimulation blockade demonstrated lymphocytic infiltrates 1 month after transplantation, whereas one maintained its graft. Isolation of regulatory T-cells from intramyocardial transplanted recipients treated with costimulation blockade demonstrated specificity toward undifferentiated HESC and down-regulated naive T-cell activation toward HESC. These results demonstrate that costimulation blockade is sufficiently robust to induce tolerance to HESC in the immune-privileged environment of the testis. HESC specific regulatory T-cells developed to HESC transplanted to the heart and the success of transplantation was similar to that seen in SCID mice.
    Stem Cells 06/2008; 26(7):1850-7. · 7.70 Impact Factor
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    ABSTRACT: This study investigates whether local sequential delivery of vascular endothelial growth factor-A(165) (VEGF-A(165)) followed by platelet-derived growth factor-BB (PDGF-BB) with alginate hydrogels could induce an angiogenic effect and functional improvement greater than single factors after myocardial infarction. Alginate hydrogels were prepared by combining high and low molecular weight alginate. Growth factor release rates were monitored over time in vitro with 125I-labelled VEGF-A(165) and PDGF-BB included in the gels. One week after myocardial infarction was induced in Fisher rats, gels with VEGF-A(165), PDGF-BB, or both were given intra-myocardially along the border of the myocardial infarction. Vessel density was analysed in hearts and cardiac function was determined by Tissue Doppler Echocardiography. In addition, the angiogenic effect of sequenced delivery was studied in vitro in aortic rings from C57B1/6 mice. Alginate gels were capable of delivering VEGF-A(165) and PDGF-BB in a sustainable manner, and PDGF-BB was released more slowly than VEGF-A(165). Sequential growth factor administration led to a higher density of alpha-actin positive vessels than single factors, whereas no further increment was found in capillary density. Sequential protein delivery increased the systolic velocity-time integral and displayed a superior effect than single factors. In the aortic ring model, sequential delivery led to a higher angiogenic effect than single factor administration. The alginate hydrogel is an effective and promising injectable delivery system in a myocardial infarction model. Sequential growth factor delivery of VEGF-A(165) and PDGF-BB induces mature vessels and improves cardiac function more than each factor singly. This may indicate clinical utility.
    Cardiovascular Research 08/2007; 75(1):178-85. · 5.94 Impact Factor
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    ABSTRACT: To compare gene transfer of plasmid (P) and adenovirus (Ad) encoding human vascular endothelial growth factor-A165 (hVEGF-A165) angiogenic efficacy and adverse effects as regards apoptosis and ectopic expression of the transgene in a rat myocardial infarction model. Myocardial infarction was provoked in Fisher rats. One week later, PhVEGF-A165, PLacZ, AdhVEGF-A165, or AdLacZ was transferred intramyocardially along the border of the myocardial infarction. hVEGF-A expression was detected with ELISA. Myocardial vessel density was analyzed 1 and 4 weeks after gene transfer. Apoptosis was detected by TUNEL staining. Cardiac function was assessed with Tissue Doppler Velocity Imaging. Although AdhVEGF-A165 had substantially higher myocardial hVEGF-A expression than PhVEGF-A165, AdhVEGF-A165 and PhVEGF-A165 induced angiogenic effects to a similar extent with maintained increased arteriolar density after 4 weeks of gene transfer (p < 0.05). The two treatments also improved left ventricular function similarly. Adenoviral gene transfer induced a higher number of TUNEL positive cells than plasmid (p < 0.02). Ectopic expression of the transgene was present with both vectors but substantially higher after adenoviral gene transfer. AdhVEGF-A165 has no obvious angiogenic advantage over PhVEGF-A165 but more side effects at least in a rat myocardial infarction model. This indicates that PhVEGF-A165 might be more applicable for therapeutic angiogenesis than AdhVEGF-A165.
    Cardiovascular Research 02/2007; 73(3):481-7. · 5.94 Impact Factor
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    ABSTRACT: Recent studies have suggested that human embryonic stem cells (HESC) are immune-privileged and may thereby circumvent rejection. The expression of immunologically active molecules was studied by DNA microarray analysis and by flow cytometry. HESC were transplanted into immunologically competent mice and traced by fluorescence in-situ hybridization (FISH) and immunohistochemistry. The ability of HESC to directly and indirectly induce immune responses in CD4+ T-cells from naive and transplanted mice was studied. Their ability to induce immune responses of human CD4+ T-cells, when cultured in the presence of dendritic cells (DC) syngeneic to responder T-cells, was also analysed. HESC demonstrated expression of HLA class I and HLA class II genes, but the cell surface expression of HLA class II molecules was low even after incubation with IFNgamma. In wild-type mice, HESC could be demonstrated by FISH until 3 days after transplantation and were surrounded by heavy infiltrates of T-cells and macrophages. HESC induced a similar immune response as human fibroblast cells (HFib) on naive and immunized T-cells, both directly and in the presence of syngeneic DC. A similar response was observed in the allogeneic setting. It is concluded that HESC are immunologically inert and do not inhibit immune responses during direct or indirect antigen presentation, and they were acutely rejected in a xenogeneic setting.
    Reproductive biomedicine online 12/2006; 13(5):712-24. · 2.68 Impact Factor
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    ABSTRACT: As the capability of human mesenchymal stem cells (hMSC) to engraft, differentiate and improve myocardial function cannot be studied in humans, exploration was performed in a xenomodel. The rats were divided into three groups depending on the type of rats used (Rowett nude (RNU) or Fischer rats +/- immunosuppression). Different groups were treated with intramyocardial injection of hMSC (1-2 million) either directly or three days after ligation of the left anterior descending artery (LAD). Myocardial function was investigated by echocardiography. The hMSC were identified with fluorescence in situ hybridization and myocardial differentiation was assessed by immunohistochemistry. When hMSC were injected directly after LAD ligation they could be identified in half (8/16) of the RNU rats (without immunosuppression) at 4 weeks. When injected 3 days after LAD ligation in immunosuppressed RNU rats they were identified in all (6/6) rats at 6 weeks. The surviving hMSC showed signs of differentiation into fibroblasts. No cardiomyocyte differentiation was observed. There was no difference in myocardial function in treated animals compared to controls. The hMSC survived in this xenomodel up to 6 weeks. However, hMSC required implantation into immunoincompetent animals as well as immunosuppression to survive, indicating that these cells are otherwise rejected. Furthermore, these cells did not differentiate into cardiomyocytes nor did they improve heart function in this xenomodel.
    Annals of Medicine 02/2006; 38(2):144-53. · 5.09 Impact Factor
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    ABSTRACT: The aim of this study was to test the hypothesis that angiotensin converting enzyme inhibition or angiotensin II antagonism can counteract cardiac human vascular endothelial growth factor-A165 (phVEGF-A165) induced angiogenesis. Mice were given a single intramyocardial injection of phVEGF-A165. Either enalapril or candesartan was given subcutaneously for 10 consecutive days. Hearts were harvested and capillary count was performed by immunohistochemistry. With similar design, groups of mice were sacrificed after 24 h for the determination of tissue expression of phVEGF-A protein, mRNA expression of mouse VEGF-A, and VEGF receptors 1 and 2, after pEGFP-Luc transfection for luciferase expression. Increased myocardial capillary density (P < .02) induced by phVEGF-A165 was counteracted by both enalapril (P < .07) and candesartan (P < .02) and then did not differ from control values. We found that phVEGF-A165 induced myocardial hVEGF-A expression (110 +/- 15 pg/heart, P < .0001). Both enalapril and candesartan decreased (P < .01) expression of hVEGF-A to a level not different from control values. Although phVEGF-A165 upregulated (P < .0001) mVEGFR-2, addition of candesartan downregulated endogenous mVEGF-A (P < .0001) and mVEGFR-2 (P < .0001) below the level in normal myocardium. Enalapril or candesartan did not effect luciferase expression. Enalapril and candesartan both specifically inhibit phVEGF-A165 induced myocardial angiogenesis in the normal heart. The mechanism of inhibition is a combination of inhibition of cardiac hVEGF-A expression and of decreased endogenous expression of the mVEGF ligand and receptor system.
    American Journal of Hypertension 10/2005; 18(10):1347-52. · 3.67 Impact Factor
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    ABSTRACT: Statins have cardioprotective roles. We explored the cardiac angiogenic effects of simvastatin in combination with transient overexpression of vascular endothelial growth factor (VEGF). Compared with normal mice, 1-year-old ApoE(-/-) mice fed on a high-fat diet (HFD) had about 30% less myocardial capillary (P < 0.001) and arteriolar (P < 0.03) densities, associated with decreased VEGF (55%), VEGFR-1 (56%) and VEGFR-2 (78%) mRNA expressions and myocardial endothelial nitric oxide synthase (eNOS) production (58%). By contrast, angiopoietin-1 and angiopoietin-2 mRNA expressions were increased (500% P < 0.02, and 400% P < 0.01, respectively) in the ApoE(-/-) hearts. No change was observed in Tie-2 gene expression. Phosphorylation of antiapoptotic Akt was lower and proapoptotic p38 mitogen-activated protein kinase (MAPK) was higher in the ApoE(-/-) mice compared with controls. Intramyocardial VEGF gene transfer increased capillary and arteriolar densities in the ApoE(-/-) mice, and simvastatin treatment further enhanced capillary density (P < 0.03) to a level similar to that of normal mice. Simvastatin did not change the lipid profile but blocked p38 MAPK phosphorylation in the ApoE(-/-) myocardium. Concurrent with these changes, there were increased levels of expression of mVEGF (P < 0.04) and VEGFR-2 (P < 0.03) mRNAs and increased production of eNOS (P < 0.05) in the ApoE(-/-) mice, while no changes were detected in the angiopoietin system. Thus, increased myocardial angiogenesis in the ApoE(-/-) mice following transient overexpression of VEGF is further increased by additional simvastatin treatment. These effects occurred concurrently with simvastatin-induced stimulation of the VEGF system, increased eNOS production and reduction in p38 MAPK phosphorylation.
    Journal of Molecular and Cellular Cardiology 01/2005; 37(6):1235-44. · 5.15 Impact Factor
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    ABSTRACT: Therapeutic angiogenesis is a potential treatment modality for myocardial ischemia. phVEGF-A(165), phPDGF-BB, or a combination of the two were injected into the myocardial infarct border zone in rats 7 days after ligation of the coronary left anterior descending artery. Cardiac function was measured by echocardiography. Hearts were harvested 1 and 4 weeks after plasmid injection. phVEGF-A(165) increased capillary density more than phPDGF-BB, and phPDGF-BB preferentially stimulated arteriolar growth. The combination increased both capillaries and arterioles but did not enhance angiogenesis any more than single plasmid treatments did. VEGF-A(165) and the combination of phVEGF-A(165) and phPDGF-BB counteracted left ventricular dilatation after 1 week but did not counteract further deterioration.
    Biochemical and Biophysical Research Communications 10/2004; 322(1):292-6. · 2.41 Impact Factor
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    ABSTRACT: Therapeutic effects of combination of angiogenic growth factors for the treatment of ischemia after myocardial infarction are largely unknown. Plasmids expressing basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF-BB) or their combination with a 1:1 mass ratio were injected into hearts with 7-day-old myocardial infarction. Hearts were harvested after 1 and 4 weeks after gene transfer. The major findings in this chronic myocardial infarction model were that bFGF, PDGF-BB and their combination all had a more pronounced angiogenic effect on the arteriolar than the capillary level. bFGF stimulated both capillary and arteriolar growth while PDGF-BB preferentially stimulated arterioles. The combination increased the amount of both capillaries and arterioles and in addition gave rise to stable capillaries compared to single factor transfer but did not further enhance angiogenesis. No cardiovascular side effects were observed after gene transfer.
    Biochemical and Biophysical Research Communications 04/2004; 315(4):1058-63. · 2.41 Impact Factor
  • Lakartidningen 110(49-50):2242-3.

Publication Stats

279 Citations
334 Downloads
703 Views
44.94 Total Impact Points

Institutions

  • 2005–2008
    • Karolinska Institutet
      • Department of Cardiology
      Stockholm, Stockholm, Sweden
  • 2004–2007
    • Karolinska University Hospital
      • Department of Cardiology
      Stockholm, Stockholm, Sweden
    • Stockholm University
      • Division of Clinical Psychology
      Stockholm, Stockholm, Sweden