| 1. |
- Andersson, Henrik, et al.
(författare)
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Assaying cardiac biomarkers for toxicity testing using biosensing and cardiomyocytes derived from human embryonic stem cells
- 2010
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Ingår i: JOURNAL OF BIOTECHNOLOGY. - : Elsevier Science B.V., Amsterdam.. - 0168-1656 .- 1873-4863. ; 150:1, s. 175-181
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Tidskriftsartikel (refereegranskat)abstract
- Human embryonic stem cell (hESC) derived cardiomyocytes are in the present study being used for testing drug-induced cardiotoxicity in a biosensor set-up. The design of an in vitro testing alternative provides a novel opportunity to surpass previous methods based on rodent cells or cell lines due to its significantly higher toxicological relevance. In this report we demonstrate how hESC-derived cardiomyocytes release detectable levels of two clinically decisive cardiac biomarkers, cardiac troponin T and fatty acid binding protein 3, when the cardiac cells are exposed to the well-known cardioactive drug compound. doxorubicin. The release is monitored by the immuno-biosensor technique surface plasmon resonance, particularly appropriate due to its capacity for parallel and high-throughput analysis in complex media.
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| 2. |
- Asp, Julia, 1973, et al.
(författare)
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Cardiomyocyte clusters derived from human embryonic stem cells share similarities with human heart tissue.
- 2010
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Ingår i: Journal of molecular cell biology. - : Oxford University Press (OUP). - 1759-4685 .- 1674-2788. ; 2:5, s. 276-83
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Tidskriftsartikel (refereegranskat)abstract
- Cardiotoxicity testing is a key activity in the pharmaceutical industry in order to detect detrimental effects of new drugs. A reliable human in vitro model would both be beneficial in selection of lead compounds and be important for reducing animal experimentation. However, the human heart is a complex organ composed of many distinct types of cardiomyocytes, but cardiomyocyte clusters (CMCs) derived from human embryonic stem cells could be an option for a cellular model. Data on functional properties of CMCs demonstrate similarities to their in vivo analogues in human. However, development of an in vitro model requires a more thorough comparison of CMCs to human heart tissue. Therefore, we directly compared individually isolated CMCs to human fetal, neonatal, adult atrial and ventricular heart tissues. Real-time qPCR analysis of mRNA levels and protein staining of ion channels and cardiac markers showed in general a similar expression pattern in CMCs and human heart. Moreover, a significant decrease in beat frequency was noted after addition of Zatebradine, a blocker to I(f) involved in regulation of spontaneous contraction in CMCs. The results underscore the similarities of CMCs to human cardiac tissue, and further support establishment of novel cardiotoxicity assays based on the CMCs in drug discovery.
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| 3. |
- Chawade, Aakash, 1980, et al.
(författare)
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Development of a model system to identify differences in spring and winter oat
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Our long-term goal is to develop a Swedish winter oat (Avena sativa). To identify molecular differences that correlate with winter hardiness, a winter oat model comprising of both non-hardy spring lines and winter hardy lines is needed. To achieve this, we selected 294 oat breeding lines, originating from various Russian, German, and American winter oat breeding programs and tested them in the field in south- and western Sweden. By assaying for winter survival and agricultural properties during four consecutive seasons, we identified 14 breeding lines of different origins that not only survived the winter but also were agronomically better than the rest. Laboratory tests including electrolytic leakage, controlled crown freezing assay, expression analysis of the AsVrn1 gene and monitoring of flowering time suggested that the American lines had the highest freezing tolerance, although the German lines performed better in the field. Finally, six lines constituting the two most freezing tolerant lines, two intermediate lines and two spring cultivars were chosen to build a winter oat model system. Metabolic profiling of non-acclimated and cold acclimated leaf tissue samples isolated from the six selected lines revealed differential expression patterns of 245 metabolites including several sugars, amino acids, organic acids and 181 hitherto unknown metabolites. The expression patterns of 107 metabolites showed significant interactions with either a cultivar or a time-point. Further identification, characterisation and validation of these metabolites will lead to an increased understanding of the cold acclimation process in oats. Furthermore, by using the winter oat model system, differential sequencing of crown mRNA populations would lead to identification of various biomarkers to facilitate winter oat breeding. © 2012 Chawade et al.
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| 4. |
- Jonsson, Marianne, 1962, et al.
(författare)
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Novel 3D culture system with similarities to the human heart for studies of the cardiac stem cell niche.
- 2010
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Ingår i: Regenerative medicine. - : Future Medicine Ltd. - 1746-076X .- 1746-0751. ; 5:5, s. 725-36
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: The aim of this study was to develop a 3D culture system with similarities to the human heart, which was suitable for studies of adult cardiac stem or progenitor cells. MATERIALS & METHODS: Dissociated cells from human cardiac biopsies were placed in high-density pellet cultures and cultured for up to 6 weeks. Gene and protein expressions, analyzed by quantitative real-time PCR and immunohistochemistry, and morphology were studied in early and late pellets. RESULTS: Cells cultured in the 3D model showed similarities to human cardiac tissue. Moreover, markers for cardiac stem and progenitor cells were also detected after 6 weeks of culture, in addition to markers for signaling pathways active in stem cell niche regulation. CONCLUSIONS: The described 3D culture model could be a valuable tool when studying the influence of different compounds on proliferation and differentiation processes in cardiac stem or progenitor cells in cardiac regenerative research.
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| 5. |
- Sandstedt, Joakim, et al.
(författare)
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C-kit+ CD45- cells found in the adult human heart represent a population of endothelial progenitor cells.
- 2010
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Ingår i: Basic research in cardiology. - : Springer Science and Business Media LLC. - 1435-1803 .- 0300-8428. ; 105:4, s. 545-56
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Tidskriftsartikel (refereegranskat)abstract
- Although numerous reports support the existence of stem cells in the adult heart, few studies have been conducted using human cardiac tissue. Therefore, cells from human cardiac atrial biopsies were analyzed regarding progenitor properties. Expression of stem cell markers was analyzed using fluorescence-activated cell sorting. This identified a small population of C-kit+ cells, which could be further subdivided based on expression of CD45. The C-kit+ CD45+ population was determined to be of mast cell identity, while the C-kit+ CD45- population expressed mRNA of the endothelial lineage. Since the number of cells obtainable from biopsies was limited, a comparison between directly isolated and monolayer and explant cultured cells, respectively, was carried out. While both cultures retained a small population of mast cells, only monolayer culture produced a stable and relatively high percentage of C-kit+ CD45- cells. This population was found to co-express endothelial progenitor cell markers such as CD31, CD34, CXCR4, and FLK-1. The mRNA expression profile was similar to the one from directly isolated cells. When sorted cells were cultured in endothelial differentiation medium, the C-kit+ CD45- population retained its expression of endothelial markers to a large extent, but downregulated progenitor markers, indicating further differentiation into endothelial cells. We have confirmed that the human cardiac atrium contains a small C-kit+ CD45- population expressing markers commonly found on endothelial progenitor cells. The existence of an endothelial progenitor population within the heart might have future implications for developing methods of inducing neovascularization after myocardial infarction.
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| 6. |
- Sandstedt, Joakim, et al.
(författare)
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Human C-kit+CD45- cardiac stem cells are heterogeneous and display both cardiac and endothelial commitment by single-cell qPCR analysis.
- 2014
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Ingår i: Biochemical and biophysical research communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 443:1, s. 234-238
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Tidskriftsartikel (refereegranskat)abstract
- C-kit expressing cardiac stem cells have been described as multipotent. We have previously identified human cardiac C-kit+CD45- cells, but only found evidence of endothelial commitment. A small cardiac committed subpopulation within the C-kit+CD45- population might however be present. To investigate this at single-cell level, right and left atrial biopsies were dissociated and analyzed by FACS. Only right atrial biopsies contained a clearly distinguishable C-kit+CD45- population, which was single-cell sorted for qPCR. A minor portion of the sorted cells (1.1%) expressed early cardiac gene NKX2.5 while most of the cells (81%) expressed late endothelial gene VWF. VWF- cells were analyzed for a wider panel of genes. One group of these cells expressed endothelial genes (FLK-1, CD31) while another group expressed late cardiac genes (TNNT2, ACTC1). In conclusion, human C-kit+CD45- cells were predominantly localized to the right atrium. While most of these cells expressed endothelial genes, a minor portion expressed cardiac genes.
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| 7. |
- Sandstedt, Joakim, et al.
(författare)
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Left atrium of the human adult heart contains a population of side population cells.
- 2012
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Ingår i: Basic research in cardiology. - : Springer Science and Business Media LLC. - 1435-1803 .- 0300-8428. ; 107:2
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Tidskriftsartikel (refereegranskat)abstract
- Cardiac "side population" (SP) cells have previously been found to differentiate into both endothelial cells and cardiomyocytes in mice and rats, but there are no data on SP cells in the human adult heart. Therefore, human cardiac atrial biopsies were dissociated, stained for SP cells and analyzed with FACS. Identified cell populations were analyzed for gene expression by quantitative real-time PCR and subjected to in vitro differentiation. Only biopsies from the left atrium contained a clearly distinguishable population of SP cells (0.22±0.08%). The SP population was reduced by co-incubation with MDR1 inhibitor Verapamil, while the ABCG2 inhibitor FTC failed to decrease the number of SP cells. When the gene expression was analyzed, SP cells were found to express significantly more MDR1 than non-SP cells. For ABCG2, there was no detectable difference. SP cells also expressed more of the stem cell-associated markers C-KIT and OCT-4 than non-SP cells. On the other hand, no significant difference in the expression of endothelial and cardiac genes could be detected. SP cells were further subdivided based on CD45 expression. The CD45-SP population showed evidence of endothelial commitment at gene expression level. In conclusion, the results show that a SP population of cells is present also in the human adult heart.
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| 8. |
- Sandstedt, Joakim, et al.
(författare)
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SSEA-4+ CD34- Cells in the Adult Human Heart Show the Molecular Characteristics of a Novel Cardiomyocyte Progenitor Population.
- 2014
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Ingår i: Cells, tissues, organs. - : S. Karger AG. - 1422-6421 .- 1422-6405. ; 199:2-3, s. 103-116
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Tidskriftsartikel (refereegranskat)abstract
- Stage-specific embryonic antigen (SSEA) expression is used to describe the differentiation state of an embryonic stem cell (ESC). In human ESCs, SSEA-3 and SSEA-4 are highly expressed in undifferentiated cells and downregulated upon differentiation. SSEA-4 has also been described as a marker for adult stem cells in various tissues, including human neonatal cardiac tissue. However, there is currently little data on the expression of SSEAs in human adult cardiac tissue. We obtained right and left atrial biopsies from patients undergoing cardiac surgery. These were dissociated, stained for SSEAs and other cardiac stem cell markers and analyzed by flow cytometry. Directly isolated cells expressed variable levels of SSEA-1, SSEA-3 and SSEA-4. The SSEA-1+ population was established as contaminating hematopoietic cells. The SSEA-4+ population, on the other hand, could be subdivided based on the endothelial progenitor marker CD34. The SSEA-4+ CD34- population in the right atrium had a high gene expression of both early (TBX5, NKX2.5) and late (TNNT2) cardiomyocyte markers. The SSEA-4+ CD34+ population, on the other hand, overlapped with previously described C-kit+ CD45- cardiac stem cells. Primary monolayer-cultured cells retained expression of SSEAs while the cardiomyogenic specification in the SSEA-4+ CD34- population was lost. In tissue sections, SSEA-4+ cells could be identified both within and outside the myocardium. Within the myocardium, some SSEA-4+ cells coexpressed cardiomyogenic markers. In conclusion, the results show that the adult human heart expresses SSEAs and that there is a subpopulation of SSEA-4+ CD34- cells that show features of a cardiomyocyte progenitor population. © 2014 S. Karger AG, Basel.
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| 9. |
- Vukusic, Kristina, 1979, et al.
(författare)
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High Density Sphere Culture of Adult Cardiac Cells Increases the Levels of Cardiac and Progenitor Markers and Shows Signs of Vasculogenesis
- 2013
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Ingår i: Biomed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141.
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Tidskriftsartikel (refereegranskat)abstract
- 3D environment and high cell density play an important role in restoring and supporting the phenotypes of cells represented in cardiac tissues.. e aim of this study was therefore to investigate the suitability of high density sphere (HDS) cultures for studies of cardiomyocyte-, endothelial-, and stem-cell biology. Primary adult cardiac cells from nine human biopsies were cultured using different media for up to 9 weeks.. e possibilities to favor a certain cell phenotype and induce production of extra cellular matrix (ECM) were studied by histology, immunohistochemistry, and uantitative real-time PCR. Defined media gave significant increase in both cardiac-and progenitor-specific markers and also an intraluminal position of endothelial cells over time. Cardiac media showed indication of differentiation and maturity of HDS considering the ECM production and activities within NOTCH regulation but no additional cardiac differentiation. Endothelial media gave no positive effects on endothelial phenotype but increased proliferation without fibroblast overgrowth. In addition, indications for early vasculogenesis were found. It was also possible to affect the Wnt signaling in HDS by addition of a glycogen synthase kinase 3 (GSK3) inhibitor. In conclusion, these findings show the suitability of HDS as in vitro model for studies of cardiomyocyte-, endothelial-, and stem-cell biology.
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| 10. |
- Asp, Julia, 1973, et al.
(författare)
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Comparison of human cardiac gene expression profiles in paired samples of right atrium and left ventricle collected in vivo
- 2012
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 44:1, s. 89-98
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Tidskriftsartikel (refereegranskat)abstract
- Studies of expressed genes in human heart provide insight into both physiological and pathophysiological mechanisms. This is of importance for extended understanding of cardiac function as well as development of new therapeutic drugs. Heart tissue for gene expression studies is generally hard to obtain, particularly from the ventricles. Since different parts of the heart have different functions, expression profiles should likely differ between these parts. The aim of the study was therefore to compare the global gene expression in cardiac tissue from the more accessible auricula of the right atrium to expression in tissue from the left ventricle. Tissue samples were collected from five men undergoing aortic valve replacement or coronary artery bypass grafting. Global gene expression analysis identified 542 genes as differentially expressed between the samples extracted from these two locations, corresponding to similar to 2% of the genes covered by the microarray; 416 genes were identified as abundantly expressed in right atrium, and 126 genes were abundantly expressed in left ventricle. Further analysis of the differentially expressed genes according to available annotations, information from curated pathways and known protein interactions, showed that genes with higher expression in the ventricle were mainly associated with contractile work of the heart. Transcription in biopsies from the auricula of the right atrium on the other hand indicated a wider area of functions, including immunity and defense. In conclusion, our results suggest that biopsies from the auricula of the right atrium may be suitable for various genetic studies, but not studies directly related to muscle work.
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