| 1. |
- Asp, Michaela, et al.
(författare)
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A Spatiotemporal Organ-Wide Gene Expression and Cell Atlas of the Developing Human Heart
- 2019
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Ingår i: Cell. - : CELL PRESS. - 0092-8674 .- 1097-4172. ; 179:7, s. 1647-
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Tidskriftsartikel (refereegranskat)abstract
- The process of cardiac morphogenesis in humans is incompletely understood. Its full characterization requires a deep exploration of the organ-wide orchestration of gene expression with a single-cell spatial resolution. Here, we present a molecular approach that reveals the comprehensive transcriptional landscape of cell types populating the embryonic heart at three developmental stages and that maps cell-type-specific gene expression to specific anatomical domains. Spatial transcriptomics identified unique gene profiles that correspond to distinct anatomical regions in each developmental stage. Human embryonic cardiac cell types identified by single-cell RNA sequencing confirmed and enriched the spatial annotation of embryonic cardiac gene expression. In situ sequencing was then used to refine these results and create a spatial subcellular map for the three developmental phases. Finally, we generated a publicly available web resource of the human developing heart to facilitate future studies on human cardiogenesis.
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| 2. |
- Beljanski, Vladimir, et al.
(författare)
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Pleiotropic roles of autophagy in stem cell-based therapies
- 2019
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Ingår i: Cytotherapy. - : ELSEVIER SCI LTD. - 1465-3249 .- 1477-2566. ; 21:4, s. 380-392
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Forskningsöversikt (refereegranskat)abstract
- Stem cells (SCs) have been proven to possess regenerative and immunomodulatory properties and can be used to treat diseases that involve loss of cells due to tissue damage or inflammation. For this approach to succeed, SCs or their derivatives should be able to engraft in the target tissue at least for a short period of time. Unfortunately, once injected, therapeutic SCs will encounter a hostile environment, including hypoxia, lack of nutrients and stromal support, and cells may also be targeted and rejected by the immune system. Therefore, SC's stress-response mechanisms likely play a significant role in survival of injected cells and possibly contribute to their therapeutic efficacy. Autphagy, a stress-response pathway, is involved in many different cellular processes, such as survival during hypoxia and nutrient deprivation, cellular differentiation and de-differentiation, and it can also contribute to their immunovisibility by regulating antigen presentation and cytokine secretion. Autophagy machinery interacts with many proteins and signaling pathways that regulate SC properties, including PI3K/Akt, mammalian target of rapamycin (mTOR), Wnt, Hedgehog and Notch, and it is also involved in regulating intracellular reactive oxygen species (ROS) levels. In this review, we contend that autophagy is an important therapeutic target that can be used to improve the outcome of SC-based tissue repair and regeneration. Further research should reveal whether inhibition or stimulation of autophagy increases the therapeutic utility of SCs and it should also identify appropriate therapeutic regimens that can be applied in the clinic.
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| 3. |
- Chang, Ya-Ting, et al.
(författare)
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Antenatal imatinib treatment reduces pulmonary vascular remodeling in a rat model of congenital diaphragmatic hernia
- 2012
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Ingår i: American Journal of Physiology - Lung cellular and Molecular Physiology. - : American Physiological Society. - 1040-0605 .- 1522-1504. ; 302:11, s. L1159-L1166
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Tidskriftsartikel (refereegranskat)abstract
- The pathophysiology of congenital diaphragmatic hernia (CDH) is constituted by pulmonary hypoplasia and pulmonary hypertension (PH). We previously reported successful treatment with imatinib of a patient with CDH. This study examines the effect of antenatal imatinib administration on the pulmonary vasculature in a rat model of CDH. Pregnant rats were given nitrofen to induce CDH. Controls were given olive oil. Half of the CDH fetuses and half of the controls were treated with imatinib antenatally E17-E21, rendering four groups: Control, Control+Imatinib, CDH, and CDH+Imatinib. Lung sections were obtained for morphometry and immunohistochemistry, and protein was purified for Western blot. Effects of nitrofen and imatinib on Ki-67, caspase-3, PDGF-B, and PDGF receptors were analyzed. Imatinib significantly reduced medial wall thickness in pulmonary arteries of rats with CDH. It also normalized lumen area and reduced the proportion of fully muscularized arteries. Imatinib also caused medial thinning in the control group. Cell proliferation was increased in CDH, and this proliferation was significantly reduced by imatinib. PDGF-B and PDGFR-beta were upregulated in CDH, and imatinib treatment resulted in a downregulation. PDGFR-alpha remained unchanged in CDH but was significantly downregulated by imatinib. Antenatal imatinib treatment reduces development of medial wall thickness and restores lumen area in pulmonary arteries in nitrofen-induced CDH. The mechanism is reduced cell proliferation. Imatinib is an interesting candidate for antenatal therapy for PH in CDH, but potential side effects need to be investigated and more specific targeting of PDGF signaling is needed.
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| 4. |
- Corbascio, Matthias, et al.
(författare)
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Anti-lymphocyte function-associated antigen-1 monoclonal antibody inhibits CD40 ligand-independent immune responses and prevents chronic vasculopathy in CD40 ligand-deficient mice.
- 2002
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Ingår i: Transplantation. - 1534-6080. ; 74:1, s. 35-41
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Blockade of CD40 ligand (CD40L; CD154, gp39) is a potential treatment for autoimmune disease and allograft rejection. However, CD40L-/- mice are capable of mobilizing cellular immune responses to viral, parasitic, and intracellular bacterial infections as well as rejecting skin grafts with nearly the same efficiency as wild-type mice. CD40L-deficient mice (CD40L-/-) or wild-type mice treated with anti-CD40L develop chronic vasculopathy only 8 weeks after allogeneic heart transplantation. To overcome CD40L-independent immune responses, we used anti-lymphocyte function-associated antigen monoclonal antibody (LFA)-1, which has previously been shown to inhibit CD8+ immune responses. METHODS: We conducted mixed lymphocyte reactions, cytotoxicity assays, skin transplantation, and vascularized heterotopic heart transplantation in wild-type B6 and CD40L-deficient mice in the presence and absence of anti-LFA-1 to study the effects of anti-LFA-1 in the absence of CD40L signaling. RESULTS: Anti-LFA-1 inhibited proliferation of naïve CD40L-/- mixed leukocyte reactions and the lysis of donor targets by CD40L-/- cytotoxic T lymphocytes. Anti-LFA-1-treated CD40L-/- mice that received fully MHC-mismatched skin grafts showed significant prolongation of graft survival, with a median survival time of 55 days (mean 66 days) compared with 13 and 21 days in wild-type and CD40L-/- controls, respectively. CD40L-/- mice that received fully MHC-mismatched vascularized heart transplants treated with four doses of 200 microg of anti-LFA-1 at the time of transplantation did not develop any signs of chronic vasculopathy 150 days after transplantation. CONCLUSION: These results indicate that anti-LFA-1 can complement CD40L inhibition in the prevention of undesirable immune responses.
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| 5. |
- Corbascio, Matthias, et al.
(författare)
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CTLA4Ig combined with anti-LFA-1 prolongs cardiac allograft survival indefinitely.
- 2002
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Ingår i: Transplant Immunology. - 1878-5492. ; 10:1, s. 55-61
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Tidskriftsartikel (refereegranskat)abstract
- CTLA4Ig and anti-LFA-1 are members of a new generation of immunomodulatory drugs which inhibit important signaling pathways in T cell activation. Both substances target molecules which have pivitol functions in the activation of CD4+ and CD8+ T cells and have been theorized to have an interdependent relationship. These drugs have been used independently in various treatment regimens and have shown great promise in prolonging the survival of allografts. In order to test whether these substances have synergistic or potentiating effects when combined, we performed mixed lymphocyte reactions, skin transplantation and vascularised heterotopic heart transplantation in the Balb/c (H-2(d)) to C3H/HeJ (H-2(k)) strain combination. When anti-LFA-1 and CTLA4Ig were combined at low doses, there was a substantial inhibition of lymphocyte proliferation. When each drug was used as a mono-therapy in skin graft recipients, there was no significant effect on median graft survival (anti-LFA-1, 15 days; CTLA4Ig, 16 days) when compared to untreated controls (13 days), whereas a combination of anti-LFA-1 and CTLA4Ig extended graft survival significantly to 32 days. Untreated vascularised heart grafts rejected at a median of 8 days, CTLA4Ig-treated mice rejected at a median time of 79 days and anti-LFA-1-treated mice rejected at 43 days (n = 9). When CTLA4Ig and anti-LFA-1 were combined, all animals had functioning heart grafts at 100 days after transplantation. Histological analysis of combined-therapy hearts showed no signs or only minor changes associated with chronic rejection. In conclusion, these results indicate a synergistic effect of combining anti-LFA-1 with CTLA4Ig in inhibiting lymphocyte proliferation and prolonging the survival of fully MHC-mismatched allografts.
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| 6. |
- Cui, Hao, et al.
(författare)
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Heparanase expression upregulates platelet adhesion activity and thrombogenicity
- 2016
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:26, s. 39486-39496
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Tidskriftsartikel (refereegranskat)abstract
- Heparanase is an endo-glucuronidase that specifically cleaves heparan sulfate (HS) and heparin polysaccharides. The enzyme is expressed at low levels in normal tissues, but is often upregulated under pathological conditions such as cancer and inflammation. Normal human platelets express exceptionally high levels of heparanase, but the functional consequences of this feature remain unknown. We investigated functional roles of heparanase by comparing the properties of platelets expressing high (Hpa-tg) or low (Ctr) levels of heparanase. Upon activation, Hpa-tg platelets exhibited a much stronger adhesion activity as compared to Ctr platelets, likely contributing to a higher thrombotic activity in a carotid thrombosis model. Furthermore, we found concomitant upregulated expression of both heparanase and CD62P (P-selectin) upon activation of mouse and human platelets. As platelets play important roles in tumor metastasis, these findings indicate contribution of the platelet heparanase to hyper-thrombotic conditions often seen in patients with metastatic cancer.
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| 7. |
- Fux, Thomas, et al.
(författare)
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Synthetic tracheal grafts seeded with bone marrow cells fail to generate functional tracheae : First long-term follow-up study
- 2020
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : MOSBY-ELSEVIER. - 0022-5223 .- 1097-685X. ; 159:6, s. 2525-2537.e23
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Synthetic tracheal grafts seeded with autologous bone marrow-mononuclear cells (BM-MNCs) have been described as becoming living and functional grafts representing a promising option for tracheal replacement for pathologies unamenable by segmental resection or autologous repair. This study aimed to present the first long-term follow-up of these procedures in humans.Methods: We retrospectively analyzed 3 patients who received synthetic tracheal grafts seeded with BM-MNCs implanted.Results: Patient 1 was a 37-year-old man with mucoepidermoid carcinoma, the first-ever human to receive a synthetic tracheal graft seeded with BM-MNCs. Patient 2 was a 30-year-old man with adenoid cystic carcinoma, and patient 3 was a 22-year-old woman with an iatrogenic tracheal injury. All patients developed graft-related complications necessitating multiple surgical reinterventions. Patient 1 was hospitalized for 8 months before dying from respiratory failure secondary to graft dehiscence 32 months after implantation. Patient 2 died 3.5 months after implantation from undisclosed causes. Patient 3 received a second synthetic tracheal graft after 11 months and an allogeneic trachea and lung transplantation 45 months after the primary implantation. Patient 3 underwent 191 surgical interventions after the primary implantation and spent 55 months in the intensive care unit before dying from airway bleeding. All patients' bronchoscopic, histologic, and radiologic investigations demonstrated graft-associated complications, including anastomotic fistulae and obstructive granulation tissue, without graft vascularization, mucosal lining, or integration into adjacent tissues.Conclusions: Synthetic tracheal grafts seeded with BM-MNCs do not become living functional tracheal grafts and lead to debilitating complications and death.
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| 8. |
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| 9. |
- Granath, Carl, et al.
(författare)
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Characterization of Laminins in Healthy Human Aortic Valves and a Modified Decellularized Rat Scaffold
- 2020
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Ingår i: BioResearch Open Access. - : Mary Ann Liebert. - 2164-7844 .- 2164-7860. ; 9:1, s. 269-278
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Tidskriftsartikel (refereegranskat)abstract
- Aortic valve stenosis is one of the most common cardiovascular diseases in western countries and can only be treated by replacement with a prosthetic valve. Tissue engineering is an emerging and promising treatment option, but in-depth knowledge about the microstructure of native heart valves is lacking, making the development of tissue-engineered heart valves challenging. Specifically, the basement membrane (BM) of heart valves remains incompletely characterized, and decellularization protocols that preserve BM components are necessary to advance the field. This study aims to characterize laminin isoforms expressed in healthy human aortic valves and establish a small animal decellularized aortic valve scaffold for future studies of the BM in tissue engineering. Laminin isoforms were assessed by immunohistochemistry with antibodies specific for individual alpha, beta, and gamma chains. The results indicated that LN-411, LN-421, LN-511, and LN-521 are expressed in human aortic valves (n = 3), forming a continuous monolayer in the endothelial BM, whereas sparsely found in the interstitium. Similar results were seen in rat aortic valves (n = 3). Retention of laminin and other BM components, concomitantly with effective removal of cells and residual DNA, was achieved through 3 h exposure to 1% sodium dodecyl sulfate and 30 min exposure to 1% Triton X-100, followed by nuclease processing in rat aortic valves (n = 3). Our results provide crucial data on the microenvironment of valvular cells relevant for research in both tissue engineering and heart valve biology. We also describe a decellularized rat aortic valve scaffold useful for mechanistic studies on the role of the BM in heart valve regeneration.
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| 10. |
- Grinnemo, Karl-Henrik, et al.
(författare)
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Immunomodulatory effects of interferon-gamma on human fetal cardiac mesenchymal stromal cells
- 2019
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Ingår i: Stem Cell Research & Therapy. - : BMC. - 1757-6512. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Background: Mesenchymal stromal cells (MSCs), due to their regenerative and immunomodulatory properties, are therapeutically used for diseases, including heart failure. As early gestational-phase embryonic tissues exhibit extraordinary regenerative potential, fetal MSCs exposed to inflammation offer a unique opportunity to evaluate molecular mechanisms underlying preferential healing, and investigate their inherent abilities to communicate with the immune system during development. The principal aim of this study was to evaluate the effects of interferon-gamma (IFN gamma) on the immunomodulatory effects of first-trimester human fetal cardiac (hfc)-MSCs.Methods: hfcMSCs (gestational week 8) were exposed to IFN gamma, with subsequent analysis of the whole transcriptome, based on RNA sequencing. Exploration of surface-expressed immunoregulatory mediators and modulation of T cell responses were performed by flow cytometry. Presence and activity of soluble mediators were assessed by ELISA or high-performance liquid chromatography.Results: Stimulation of hfcMSCs with IFN gamma revealed significant transcriptional changes, particularly in respect to the expression of genes belonging to antigen presentation pathways, cell cycle control, and interferon signaling. Expression of immunomodulatory genes and associated functional changes, including indoleamine 2,3-dioxygenase activity, and regulation of T cell activation and proliferation via programmed cell death protein (PD)-1 and its ligands PD-L1 and PD-L2, were significantly upregulated. These immunoregulatory molecules diminished rapidly upon withdrawal of inflammatory stimulus, indicating a high degree of plasticity by hfcMSCs.Conclusions: To our knowledge, this is the first study performing a systematic evaluation of inflammatory responses and immunoregulatory properties of first-trimester cardiac tissue. In summary, our study demonstrates the dynamic responsiveness of hfcMSCs to inflammatory stimuli. Further understanding as to the immunoregulatory properties of hfcMSCs may be of benefit in the development of novel stromal cell therapeutics for cardiovascular disease.
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| 11. |
- Ljung, Karin, et al.
(författare)
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Human Fetal Cardiac Mesenchymal Stromal Cells Differentiate In Vivo into Endothelial Cells and Contribute to Vasculogenesis in Immunocompetent Mice
- 2019
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Ingår i: Stem Cells and Development. - : MARY ANN LIEBERT, INC. - 1547-3287 .- 1557-8534. ; 28:5, s. 310-318
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Tidskriftsartikel (refereegranskat)abstract
- Mesenchymal stromal cells (MSCs) have shown great potential as a treatment for systemic inflammatory diseases, but their local regenerative properties are highly tissue- and site specific. Previous studies have demonstrated that adult human MSCs respond to inflammatory cytokines through the release of paracrine factors that stimulate angiogenesis, but they do not themselves differentiate into vascular structures in vivo. In this study, we used human fetal cardiac MSCs (hfcMSCs) harvested during the first trimester of heart development and injected them into the subcutaneous tissue of normal immunocompetent mice treated with short-term costimulation blockade for tolerance induction. When hfcMSCs were transplanted subcutaneously together with Matrigel matrix, they contributed to vasculogenesis through differentiation into endothelial cells and generation of the basal membrane protein Laminin 4. These characteristics of hfcMSCs are similar to the mesodermal progenitors giving rise to the developing heart and they may be useful for treatment of ischemic injuries.
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| 12. |
- Malm, Helene, et al.
(författare)
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CTLA4ig induces long-term graft survival of allogeneic skin grafts and totally inhibits T-cell proliferation in LFA-1-deficient mice.
- 2002
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Ingår i: Transplantation. - 1534-6080. ; 73:2, s. 293-297
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: It was recently shown that some strains of mice are capable of rejecting transplants independently of B7 and CD40L signaling and that this rejection is mediated by CD8(+) T cells. LFA-1 is known to be important for CD8(+) T cell activation and cytotoxicity. Therefore, blockade of LFA-1 could be important in overcoming costimulation blockade, CD8(+) T-cell-mediated, resistant rejection. The purpose of this study was to define the effect of combined blockade of the LFA-1 and B7 costimulation pathways on the alloimmune response in mice. METHODS: Allogeneic skin transplantation was performed using BALB/c mice as donors and C57BL/6J wild-type or LFA-1-deficient (CD11a(-/-)) mice as recipients. CTLA4Ig or anti-LFA-1 was administered either as an induction or a prolonged therapy. Mixed lymphocyte reactions were conducted to study the effect of CTLA4Ig on T-cell proliferation in CD11a(-/-) mice. RESULTS AND CONCLUSIONS: Administration of CTLA4Ig completely inhibits CD11a(-/-) T-cell proliferation in response to alloantigens and significantly improved skin allograft survival in CD11a(-/-) mice. Prolonged treatment of wild-type recipient mice with CTLA4Ig and anti-LFA-1 increased median survival time to 45.5 days compared with 16 days after induction therapy, but it was not sufficient to induce indefinite allograft survival in this model.
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| 13. |
- Olesen, Kim, et al.
(författare)
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Diversity of respiratory parameters and metabolic adaptation to low oxygen tension in mesenchymal stromal cells
- 2022
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Ingår i: Metabolism Open. - : Elsevier. - 2589-9368. ; 13:March
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveCell metabolism has been shown to play an active role in regulation of stemness and fate decision. In order to identify favorable culture conditions for mesenchymal stromal cells (MSCs) prior to transplantation, this study aimed to characterize the metabolic function of MSCs from different developmental stages in response to different oxygen tension during expansion.Materials and methodsWe cultured human fetal cardiac MSCs and human adult bone-marrow MSCs for a week under hypoxia (3% O2) and normoxia (20% O2). We performed mitochondrial characterization and assessed oxygen consumption- and extracellular acidification-rates (OCR and ECAR) in addition to oxygen-sensitive respiration and mitochondrial complex activities, using both the Seahorse and Oroboros systems.ResultsAdult and fetal MSCs displayed similar basal respiration and mitochondrial amount, however fetal MSCs had lower spare respiratory capacity and apparent coupling efficiency. Fetal MSCs expanded in either hypoxia or normoxia demonstrated similar acidification rates, while adult MSCs downregulated their aerobic glycolysis in normoxia. Acute decrease in oxygen tension caused a higher respiratory inhibition in adult compared to fetal MSCs. In both sources of MSCs, minor changes in complex activities in normoxic and hypoxic cultures were found.ConclusionsIn contrast to adult MSCs, fetal MSCs displayed similar respiration and aerobic glycolysis at different O2 culture concentrations during expansion. Adult MSCs adjusted their respiration to glycolytic activities, depending on the culture conditions thus displaying a more mature metabolic function. These findings are relevant for establishing optimal in vitro culturing conditions, with the aim to maximize engraftment and therapeutic outcome.
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| 14. |
- Olesen, Kim
(författare)
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Extracellular factors for preservation and delivery of stromal cells
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modulating the immune response after a myocardial infarction seems like an appropriate strategy for reducing myocardial fibrosis. Mesenchymal Stromal Cells are immunomodulatory and have thus gained interest, but have so far not achieved the desired clinical outcomes. This is believed to due to the loss of their immunomodulatory and proliferative capacity during expansion and poor cell survival and retention upon delivery to the myocardium. The use of extracellular factors such as extracellular matrices, paracrine factors, nutrients as well as manipulation gas composition during culture might be used to overcome some of these shortcomings, which is further explored in this thesis.We demonstrated in Study I, that encapsulation of human cells by thermos-responsive microcapsules, which upon exposure to physiological temperature partially decompose and enable release of the cells. The hydrogel combination of agarose, gelatin and fibrinogen provided both thermos-responsive features and attachment points for the cells, preventing cell death. However, additional components can be used to support the encapsulated cells while retaining the thermo-responsiveness. In order to discover such components, we developed an in vitro model to study the cell- and extracellular matrix dynamics making use of the organ’s extracellular matrix and define anatomical regions that are capable of retaining the desired phenotype of the cell. To generate such a syngeneic model, naïve stromal cells were isolated from fetal rat hearts, and cultured on decellularized extracellular matrix sections of adult rat hearts. We found that when culturing cells with pericyte-like characteristics on the matrices, the surface marker expressions of CD146 and PDGFR-β were depending on the matrix composition, and especially of laminin alpha 4. Cells expressing CD146 were mainly located to the atrioventricular junction and to the perivascular niche, while PDGFR-β expression was more widespread. Since CD146 is also a potency marker for Mesenchymal Stromal Cells, these results indicate a matrix dependent niche for naïve stromal cells. These findings were next verified by immunohistochemistry of the native rat heart, where CD146 populations were mainly found in the atrioventricular and perivascular niche.In Study III, we explored the preferred metabolism of adult and fetal MSCs. It is known that proliferating stem-, progenitor cells utilize glycolysis, even in presence of oxygen. Therefore, we wanted to explore the metabolic profiles of human fetal (naïve) and MSCs during culture in either hypoxia 3% (close to physiological oxygen tension) or normoxia 20%. Adult MSCs grown in hypoxia retained oxidative phosphorylation and increased glycolytic activity, adapting a progenitor metabolic profile while in normoxia the adult MSCs down-regulated glycolysis and adapted an adult, or differentiated cell metabolic profile. Fetal MSCs demonstrated preserved oxidative phosphorylation and glycolytic activity regardless of oxygen tension, thus exhibiting a stem-, progenitor metabolic profile.The findings from these studies might help in designing future culture protocols and delivery systems for cell therapies.
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| 15. |
- Olesen, Kim, et al.
(författare)
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Spatiotemporal extracellular matrix modeling for in situ cell niche studies
- 2021
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Ingår i: Stem Cells. - : John Wiley & Sons. - 1066-5099 .- 1549-4918. ; 39:12, s. 1751-1765
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular matrix (ECM) components govern a range of cell functions such as migration, proliferation, maintenance of stemness and differentiation. Cell niches that harbor stem-/progenitor cells, with matching ECM, have been shown in a range of organs, although their presence in the heart is still under debate. Determining niches depends on a range of in vitro and in vivo models and techniques, where animal models are powerful tools for studying cell-ECM dynamics, however, they are costly and time-consuming to use. In vitro models based on recombinant ECM proteins lack the complexity of the in vivo ECM. To address these issues, we present the Spatiotemporal Extracellular Matrix Model (StEMM) for studies of cell-ECM dynamics, such as cell niches. This model combines gentle decellularization and sectioning of cardiac tissue, allowing retention of a complex ECM, with recellularization and subsequent image processing using image stitching, segmentation, automatic binning and generation of cluster maps. We have thereby developed an in situ representation of the cardiac ECM that is useful for assessment of repopulation dynamics and to study the effect of local ECM composition on phenotype preservation of reseeded mesenchymal progenitor cells. This model provides a platform for studies of organ-specific cell-ECM dynamics and identification of potential cell niches. © AlphaMed Press 2021 SIGNIFICANCE STATEMENT: Stem cells reside in adult organs within specific microenvironments called cell niches. The heart is a complex organ and so far, the presence and localization of stem-/progenitor cell niches are subject to constant debate. To address these issues, the authors have developed the Spatiotemporal Extracellular Matrix Model (StEMM), which combines a modified protocol for decellularization, with cryo-sectioning, recellularization, and subsequent image processing including automatic binning and generation of cluster maps. StEMM was developed within a cardiac context and validated using syngeneic mesenchymal progenitor cells. However, this model is not restricted with regard to species or organs.
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| 16. |
- Vlachonikola, Elisavet, et al.
(författare)
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T cell receptor gene repertoire profiles in subgroups of patients with chronic lymphocytic leukemia bearing distinct genomic aberrations
- 2023
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Ingår i: Frontiers in Oncology. - : Frontiers Media S.A.. - 2234-943X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: Microenvironmental interactions of the malignant clone with T cells are critical throughout the natural history of chronic lymphocytic leukemia (CLL). Indeed, clonal expansions of T cells and shared clonotypes exist between different CLL patients, strongly implying clonal selection by antigens. Moreover, immunogenic neoepitopes have been isolated from the clonotypic B cell receptor immunoglobulin sequences, offering a rationale for immunotherapeutic approaches. Here, we interrogated the T cell receptor (TR) gene repertoire of CLL patients with different genomic aberration profiles aiming to identify unique signatures that would point towards an additional source of immunogenic neoepitopes for T cells.Experimental design: TR gene repertoire profiling using next generation sequencing in groups of patients with CLL carrying one of the following copy-number aberrations (CNAs): del(11q), del(17p), del(13q), trisomy 12, or gene mutations in TP53 or NOTCH1.Results: Oligoclonal expansions were found in all patients with distinct recurrent genomic aberrations; these were more pronounced in cases bearing CNAs, particularly trisomy 12, rather than gene mutations. Shared clonotypes were found both within and across groups, which appeared to be CLL-biased based on extensive comparisons against TR databases from various entities. Moreover, in silico analysis identified TR clonotypes with high binding affinity to neoepitopes predicted to arise from TP53 and NOTCH1 mutations.Conclusions: Distinct TR repertoire profiles were identified in groups of patients with CLL bearing different genomic aberrations, alluding to distinct selection processes. Abnormal protein expression and gene dosage effects associated with recurrent genomic aberrations likely represent a relevant source of CLL-specific selecting antigens.
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| 17. |
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| 18. |
- Österholm, Cecilia
(författare)
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Tissue Factor in Transplantation -aspects on expression and inhibition
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Organ transplantation provides a treatment of end-stage disease primarily in the kidney, liver and heart. The immunosuppressive treatment regimens of today efficiently prevent early acute rejection; however the long-term survival has not improved to the same extent. Within months/years the majority of transplanted organs develop chronic allograft dysfunction (CAD), associated with fibrosis and intimal hyperplasia. Both alloantigen-dependent and -independent factors are suspected to affect the deteriorative process. Among the latter are ischemia and reperfusion (I/R) injury and also drug-induced nephrotoxicity. Tissue factor (TF) is the principal initiator of blood coagulation and triggers the coagulation cascade upon complex formation with FVIIa. TF is normally not expressed on cells in contact with blood, but can be induced as a response to a multitude of stimuli. Among those, many are associated with events occurring at transplantation, such as hypoxia and I/R injury. TF has also been implicated as a mediator of cellular adhesion, migration and proliferation, which are important features of vascular remodelling during CAD. By employing an isogenic aortic transplant model in the rat, the role of TF for development of intimal hyperplasia caused by long cold ischemia, was studied. Inhibition of TF reduced formation of neo-intima in treated animals as compared to controls. TF was further studied as a potential chemo-attractant for smooth muscle cells, monocytes and also endothelial precursor cells. Allthree cell types migrated towards TF in a migration assay. With the aim to decrease the pro-thrombotic and inflammatory properties of activated endothelium, RNA interference was used to down-regulate TF expression in these cells. The total antigen content and also TF expression on the cell surface were diminished, however this did not result in a decreased catalytic activity of TF/FVIIa. Efficient TF reduction was reflected in morphological alterations and decreased cell viability. Additionally we studied the presence of TF antigen in human renal allografts afflicted by rejection or cyclosporin (CsA) nephrotoxicity. Grafts with acute CsA nephrotoxicity displayed a marked TF staining in the tubular brush border, significantly increased in terms of intensity and spread, compared to allografts undergoing acute rejection. Vascular endothelial staining was present in grafts afflicted by chronic vasculopaty as well as chronic CsA nephrotoxicity. The results of these studies collectively imply that TF acts as a mediator in processes associated with chronic vascular remodelling after transplantation. Furthermore, TF may be used as a histological marker for acute CsA nephrotoxicity, a condition which is difficult to diagnose in a straightforward manner.
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