| 51. |
- 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
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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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| 52. |
- 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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| 53. |
- 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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| 54. |
- Sandstedt, Mikael, 1990, et al.
(författare)
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Intracellular flow cytometry may be combined with good quality and high sensitivity RT-qPCR analysis.
- 2015
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Ingår i: Cytometry. Part A : the journal of the International Society for Analytical Cytology. - : Wiley. - 1552-4930. ; 87:12
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Tidskriftsartikel (refereegranskat)abstract
- Flow cytometry (FCM) has become a well-established method for analysis of both intracellular and cell-surface proteins, while quantitative RT-PCR (RT-qPCR) is used to determine gene expression with high sensitivity and specificity. Combining these two methods would be of great value. The effects of intracellular staining on RNA integrity and RT-qPCR sensitivity and quality have not, however, been fully examined. We, therefore, intended to assess these effects further. Cells from the human lung cancer cell line A549 were fixed, permeabilized and sorted by FCM. Sorted cells were analyzed using RT-qPCR. RNA integrity was determined by RNA quality indicator analysis. A549 cells were then mixed with cells of the mouse cardiomyocyte cell line HL-1. A549 cells were identified by the cell surface marker ABCG2, while HL-1 cells were identified by intracellular cTnT. Cells were sorted and analyzed by RT-qPCR. Finally, cell cultures from human atrial biopsies were used to evaluate the effects of fixation and permeabilization on RT-qPCR analysis of nonimmortalized cells stored prior to analysis by FCM. A large amount of RNA could be extracted even when cells had been fixed and permeabilized. Permeabilization resulted in increased RNA degradation and a moderate decrease in RT-qPCR sensitivity. Gene expression levels were also affected to a moderate extent. Sorted populations from the mixed A549 and HL-1 cell samples showed gene expression patterns that corresponded to FCM data. When samples were stored before FCM sorting, the RT-qPCR analysis could still be performed with high sensitivity and quality. In summary, our results show that intracellular FCM may be performed with only minor impairment of the RT-qPCR sensitivity and quality when analyzing sorted cells; however, these effects should be considered when comparing RT-qPCR data of not fixed samples with those of fixed and permeabilized samples. © 2015 International Society for Advancement of Cytometry.
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| 55. |
- Sandstedt, Mikael, 1990, et al.
(författare)
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Regional transcriptomic profiling reveals immune system enrichment in nonfailing atria as well as all chambers of the failing human heart
- 2023
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Ingår i: American Journal of Physiology. Heart and Circulatory Physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 325:6, s. H1430-H1445
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Tidskriftsartikel (refereegranskat)abstract
- The different chambers of the human heart demonstrate regional physiological traits and may be differentially affected during pathologic remodeling, resulting in heart failure. Few previous studies have, however, characterized the different chambers at a transcriptomic level. We therefore conducted whole-tissue RNA sequencing and gene set enrichment analysis of biopsies collected from the four chambers of adult failing (n = 8) and nonfailing (n = 11) human hearts. Atria and ventricles demonstrated distinct transcriptional patterns. Compared to nonfailing ventricles, the transcriptional pattern of nonfailing atria was enriched for a large number of gene sets associated with cardiogenesis, the immune system and bone morphogenetic protein (BMP), transforming growth factor beta (TGF beta), MAPK/JNK and Wnt signaling. Differences between failing and nonfailing hearts were also determined. The transcriptional pattern of failing atria was distinct compared to that of nonfailing atria and enriched for gene sets associated with the innate and adaptive immune system, TGF beta/SMAD signaling, and changes in endothelial, smooth muscle cell and cardiomyocyte physiology. Failing ventricles were also enriched for gene sets associated with the immune system. Based on the transcriptomic patterns, upstream regulators associated with heart failure were identified. These included many immune response factors predicted to be similarly activated for all chambers of failing hearts. In summary, the heart chambers demonstrate distinct transcriptional patterns that differ between failing and nonfailing hearts. Immune system signaling may be a hallmark of all four heart chambers in failing hearts, and could constitute a novel therapeutic target.
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| 56. |
- Sjölin, Jacob, et al.
(författare)
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Expression of Stem Cell Niche-Related Biomarkers at the Base of the Human Tricuspid Valve
- 2023
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Ingår i: Stem Cells and Development. - : Mary Ann Liebert Inc. - 1547-3287 .- 1557-8534. ; 32:5-6, s. 140-151
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Tidskriftsartikel (refereegranskat)abstract
- Stem cell niches have been thoroughly investigated in tissue with high regenerative capacity but not in tissues where cell turnover is slow, such as the human heart. The left AtrioVentricular junction (AVj), the base of the mitral valve, has previously been proposed as a niche region for cardiac progenitors in the adult human heart. In the present study, we explore the right side of the human heart, the base of the tricuspid valve, to investigate the potential of this region as a progenitor niche. Paired biopsies from explanted human hearts were collected from multi-organ donors (N = 12). The lateral side of the AVj, right atria (RA), and right ventricle (RV) were compared for the expression of stem cell niche-related biomarkers using RNA sequencing. Gene expression data indicated upregulation of genes related to embryonic development and extracellular matrix (ECM) composition in the proposed niche region, that is, the AVj. In addition, immunohistochemistry showed high expression of the fetal cardiac markers MDR1, SSEA4, and WT1 within the same region. Nuclear expression of HIF1 alpha was detected suggesting hypoxia. Rare cells were found with the co-staining of the proliferation marker PCNA and Ki67 with cardiomyocyte nuclei marker PCM1 and cardiac Troponin T (cTnT), indicating proliferation of small cardiomyocytes. WT1+/cTnT+ and SSEA4+/cTnT+ cells were also found, suggesting cardiomyocyte-specific progenitors. The expression of the stem cell markers gradually decreased with distance from the tricuspid valve. No expression of these markers was observed in the RV tissue. In summary, the base of the tricuspid valve is an ECM-rich region containing cells with expression of several stem cell niche-associated markers. Co-expression of stem cell markers with cTnT indicates cardiomyocyte-specific progenitors. We previously reported similar data from the base of the mitral valve and thus propose that human adult cardiomyocyte progenitors reside around both atrioventricular valves.
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| 57. |
- Stattin, Eva-Lena, et al.
(författare)
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A missense mutation in the aggrecan C-type lectin domain disrupts extracellular matrix interactions and causes dominant familial osteochondritis dissecans
- 2010
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 86:2, s. 126-137
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Tidskriftsartikel (refereegranskat)abstract
- Osteochondritis dissecans is a disorder in which fragments of articular cartilage and subchondral bone dislodge from the joint surface. We analyzed a five-generation family in which affected members had autosomal-dominant familial osteochondritis dissecans. A genome-wide linkage analysis identified aggrecan (ACAN) as a prime candidate gene for the disorder. Sequence analysis of ACAN revealed heterozygosity for a missense mutation (c.6907G > A) in affected individuals, resulting in a p.V2303M amino acid substitution in the aggrecan G3 domain C-type lectin, which mediates interactions with other proteins in the cartilage extracellular matrix. Binding studies with recombinant mutated and wild-type G3 proteins showed loss of fibulin-1, fibulin-2, and tenascin-R interactions for the V2303M protein. Mass spectrometric analyses of aggrecan purified from patient cartilage verified that V2303M aggrecan is produced and present in the tissue. Our results provide a molecular mechanism for the etiology of familial osteochondritis dissecans and show the importance of the aggrecan C-type lectin interactions for cartilage function in vivo.
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| 58. |
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| 59. |
- Suserud, Björn-Ove, et al.
(författare)
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Caring for patients at high speed
- 2013
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Ingår i: Emergency Nurse. - : RCNI. - 1354-5752 .- 2047-8984. ; 21:7, s. 14-18
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The aim of this article is to explore whether ambulance clinicians in Sweden perceive their working environment to be safe. Method: Twenty four ambulance nurses and nine paramedics at five ambulance stations in urban and rural areas of Sweden were interviewed. Findings: After transcripts of the interviews had been analysed, nine issues that affect how participants perceive the safety of patient care in ambulances emerged: planning before departure; use of safety belts; driving at high speeds; patient first, safety second; equipment design and placement; noise; driving styles; presence of relatives; documentation. Conclusion: Ambulance personnel should have greater involvement in the design of ambulance care spaces and drivers should be given more regular training.
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| 60. |
- Synnergren, Jane, et al.
(författare)
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Transcriptional sex and regional differences in paired human atrial and ventricular cardiac biopsies collected in vivo
- 2020
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 52:2, s. 110-120
-
Tidskriftsartikel (refereegranskat)abstract
- Transcriptional studies of the human heart provide insight into physiological and pathophysiological mechanisms, essential for understanding the fundamental mechanisms of normal cardiac function and how they are altered by disease. To improve the understanding of why men and women may respond differently to the same therapeutic treatment it is crucial to learn more about sex-specific transcriptional differences. In this study the transcriptome of right atrium and left ventricle was compared across sex and regional location. Paired biopsies from five male and five female patients undergoing aortic valve replacement or coronary artery bypass grafting were included. Gene expression analysis identified 620 differentially expressed transcripts in atrial and ventricular tissue in men and 471 differentially expressed transcripts in women. In total 339 of these transcripts overlapped across sex but notably, 281 were unique in the male tissue and 162 in the female tissue, displaying marked sex differences in the transcriptional machinery. The transcriptional activity was significantly higher in atrias than in ventricles as 70% of the differentially expressed genes were upregulated in the atrial tissue. Furthermore, pathway- and functional annotation analyses performed on the differentially expressed genes showed enrichment for a more heterogeneous composition of biological processes in atrial compared with the ventricular tissue, and a dominance of differentially expressed genes associated with infection disease was observed. The results reported here provide increased insights about transcriptional differences between the cardiac atrium and ventricle but also reveal transcriptional differences in the human heart that can be attributed to sex.
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