| 1. |
- Helenius, Gisela, 1973, et al.
(författare)
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Effect of shear stress on the expression of coagulation and fibrinolytic factors in both smooth muscle and endothelial cells in a co-culture model.
- 2008
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Ingår i: European surgical research. Europ?ische chirurgische Forschung. Recherches chirurgicales europ?ennes. - : S. Karger AG. - 1421-9921 .- 0014-312X. ; 40:4, s. 325-32
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Tidskriftsartikel (refereegranskat)abstract
- Blood vessels are subjected to forces due to the flow. Endothelial cells (EC) are recipients, cross-talk with smooth muscle cells (SMC), and regulate physiology. It was hypothesized that both EC and SMC respond to shear stress, which alters the expression of factors in coagulation and fibrinolysis. METHODS: A co-culture of human saphenous vein EC (HSVEC) and human saphenous vein SMC (HSVSMC) was exposed to shear, following which the cells were separated. Gene expression of tissue factor, thrombomodulin (TM), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) were analyzed with real-time RT-PCR. Protein expression was studied with ELISA. In HSVEC, the expression of PAI-1 (x2.1), tPA (x1.8), uPA (x1.6), tissue factor (x2.5) and TM (x1.9) was upregulated after 4 h of shear compared to controls. After 24 h of shear, expression was still upregulated in tPA (x2.3) and TM (x1.6). In HSVSMC, change in expression of PAI-1 (x2.1) was present after 4 h and in uPA (x2.1), and TM (x0.4) after 24 h. Both HSVEC and HSVSMC responded to shear, which led to altered expression of coagulation and fibrinolytic factors. This indicates that SMC, and interactions between EC and SMC, are more important in the regulation of vascular wall hemostasis than earlier studies have reported.
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| 2. |
- Helenius, Gisela, 1973, et al.
(författare)
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Expression of fibrinolytic and coagulation factors in cocultured human endothelial and smooth muscle cells
- 2004
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Ingår i: Tissue engineering. - 1076-3279. ; 10:3-4, s. 353-60
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Tidskriftsartikel (refereegranskat)abstract
- Interactions between endothelial cells and smooth muscle cells are interesting from a tissue-engineering point of view. We have developed a coculture system that allows direct contact between these two cell types. The fibrinolytic factors PAI-1, tPA, and uPA and the coagulation factor TF, were studied at the gene level by RT-PCR and at the protein level by ELISA. Significant changes of all studied factors were seen at the gene level in cocultured endothelial cells. tPA and TF were upregulated 4- and 7-fold, respectively, and PAI-1 and uPA were downregulated 4- and 1.5-fold, respectively, compared with single-cultured controls. In cocultured smooth muscle cells alterations of PAI-1 and TF were significant, with a 1.5-fold upregulation of PAI-1 and a 2.5-fold downregulation of TF. Results at the protein level mirrored the gene expression results. These findings indicate that cocultured endothelial cells are rendered both hypercoagulative and hyperfibrinolytic.
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| 3. |
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| 4. |
- Heydarkhan-Hagvall, Sepideh, 1969, et al.
(författare)
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DNA microarray study on gene expression profiles in co-cultured endothelial and smooth muscle cells in response to 4- and 24-h shear stress
- 2006
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Ingår i: Molecular and cellular biochemistry. - : Springer Science and Business Media LLC. - 0300-8177 .- 1573-4919. ; 281:1-2, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Shear stress, a major hemodynamic force acting on the vessel wall, plays an important role in physiological processes such as cell growth, differentiation, remodelling, metabolism, morphology, and gene expression. We investigated the effect of shear stress on gene expression profiles in co-cultured vascular endothelial cells (ECs) and smooth muscle cells (SMCs). Human aortic ECs were cultured as a confluent monolayer on top of confluent human aortic SMCs, and the EC side of the co-culture was exposed to a laminar shear stress of 12 dyn/cm(2) for 4 or 24 h. After shearing, the ECs and SMCs were separated and RNA was extracted from the cells. The RNA samples were labelled and hybridized with cDNA array slides that contained 8694 genes. Statistical analysis showed that shear stress caused the differential expression (p < or = 0.05) of a total of 1151 genes in ECs and SMCs. In the co-cultured ECs, shear stress caused the up-regulation of 403 genes and down-regulation of 470. In the co-cultured SMCs, shear stress caused the up-regulation of 152 genes and down-regulation of 126 genes. These results provide new information on the gene expression profile and its potential functional consequences in co-cultured ECs and SMCs exposed to a physiological level of laminar shear stress. Although the effects of shear stress on gene expression in monocultured and co-cultured EC are generally similar, the response of some genes to shear stress is opposite between these two types of culture (e.g., ICAM-1 is up-regulated in monoculture and down-regulated in co-culture), which strongly indicates that EC-SMC interactions affect EC responses to shear stress.
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| 5. |
- Heydarkhan-Hagvall, Sepideh, 1969, et al.
(författare)
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Production of extracellular matrix components in tissue-engineered blood vessels
- 2006
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Ingår i: Tissue engineering. - : Mary Ann Liebert Inc. - 1076-3279 .- 1557-8690. ; 12:4, s. 831-42
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Tidskriftsartikel (refereegranskat)abstract
- Morphology and compliance of tissue-engineered blood vessels (TEBV) are dependent on the culture period and production of extracellular matrix (ECM) components in order to increase the strength of the developing tissue. The aim of the present study was to evaluate the potential of TEBVs to produce an ECM similar to native arteries and veins. Human smooth muscle cells (SMC) were seeded onto the poly(glycolic acid) (PGA) scaffold and placed in bioreactors filled with DMEM supplemented with growth factors. After 6 weeks, the vessels were harvested from the bioreactors and seeded with human endothelial cells at the lumen for another 3 days. Then, the TEBVs were harvested for RNA and protein isolation for further RT-PCR and Western blot. TEBVs had a similar macroscopic appearance to that of native vessels with no visible evidence of the original PGA. Histological and immunohistochemical analyses indicated the presence of high cell density and development of a highly organized structure of ECM. After 6 weeks of culture, there were significantly lower gene expression of SMC-specific markers, such as alpha-actin, caldesmon, and vimentin, and proteoglycans, such as biglycan, decorin, and versican, and other ECM components, such as collagen I and elastin, in TEBVs, with and without pulsatile conditions, compared to that of native arteries. Gene expression of fibronectin was significantly lower in TEBVs grown during pulsatile conditions compared to that of native arteries. No difference was observed in TEBVs grown during non-pulsatile conditions. The presence of alpha-actin, collagen I, decorin, and fibronectin at protein level was demonstrated in TEBVs with and without pulsatile conditions after 6 weeks and in native veins and arteries as well. How this deviation translates into mechanical properties remains to be explored.
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| 6. |
- Heydarkhan-Hagvall, Sepideh, 1969
(författare)
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Toward a tissue engineered blood vessel. Cell cultivation, hemodynamic influences and matrix production
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cardiovascular diseases are the leading causes of mortality in the western world. Thereplacement or repair of diseased blood vessels with human autografts (vein or arteries) orsynthetic vascular grafts (ePTFE or Dacron) has become a routine treatment. Autologous graftsare not always available in all patients. Synthetic substitutes are not able to grow or remodel andare prone to complications like stenosis, thrombosis, calcification and infection. Tissueengineered blood vessels (TEBVs) could offer a promising approach to reduce the limitations insmall vessel grafting by creating viable constructs with repair and remodelling capabilities.The aim of this thesis is to form biologically active TEBVs in vitro. In particular, the importanceof a cell-cell contact in expression of angiogenic factors in the vascular wall was studied in a coculturesystem of endothelial cells (ECs) and smooth muscle cells (SMCs). Also, the effects ofthe physiological level of laminar shear stress on vascular cells in the co-culture wereinvestigated. Furthermore, the production of extracellular matrix (ECM) components in TEBVswas evaluated. Finally, mesenchymal stem cells were compared to vascular SMCs when appliedto cyclic strains in order to investigate if these cells can be an alternative cell source for vasculartissue engineering.Direct cell-cell interactions of vascular ECs and SMCs were found to affect the gene and proteinexpression of angiogenic factors. Shear stress modulated the expression profiles of genes relatedto cytoskeleton/ECM modelling, cell proliferation, signal transduction, and immuneresponses/inflammation in co-cultured ECs and SMCs. The gene expression and proteinproduction of different SMCs' specific markers and ECM components in tissue engineeredconstruct were lower in the constructs compared to native veins and arteries after a period of 6weeks. Human MSCs were demonstrated to be capable of responding to mechanical stress, andthey hold great potential as a cell source of autologous vascular cells.To increase the success of engineered vascular grafts, the blood vessel constructs should bedesigned to mimic the properties of native blood vessels. Therefore, understanding theimportance of ECM and regulation of cellular behaviour is particularly necessary.
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