Publications by authors named "Karl-Henrik Grinnemo"

47 Publications

Characterization of Laminins in Healthy Human Aortic Valves and a Modified Decellularized Rat Scaffold.

Biores Open Access 2020 7;9(1):269-278. Epub 2020 Dec 7.

Division of Clinical Genetics, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.

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 α, β, and γ chains. The results indicated that LN-411, LN-421, LN-511, and LN-521 are expressed in human aortic valves ( = 3), forming a continuous monolayer in the endothelial BM, whereas sparsely found in the interstitium. Similar results were seen in rat aortic valves ( = 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 ( = 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/biores.2020.0018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7757704PMC
December 2020

Differences and similarities between cancer and somatic stem cells: therapeutic implications.

Stem Cell Res Ther 2020 11 18;11(1):489. Epub 2020 Nov 18.

NSU Cell Therapy Institute, Nova Southeastern University, 3301 College Ave, 3200 South University Drive, Fort Lauderdale, FL, 33328, USA.

Over the last decades, the cancer survival rate has increased due to personalized therapies, the discovery of targeted therapeutics and novel biological agents, and the application of palliative treatments. Despite these advances, tumor resistance to chemotherapy and radiation and rapid progression to metastatic disease are still seen in many patients. Evidence has shown that cancer stem cells (CSCs), a sub-population of cells that share many common characteristics with somatic stem cells (SSCs), contribute to this therapeutic failure. The most critical properties of CSCs are their self-renewal ability and their capacity for differentiation into heterogeneous populations of cancer cells. Although CSCs only constitute a low percentage of the total tumor mass, these cells can regrow the tumor mass on their own. Initially identified in leukemia, CSCs have subsequently been found in cancers of the breast, the colon, the pancreas, and the brain. Common genetic and phenotypic features found in both SSCs and CSCs, including upregulated signaling pathways such as Notch, Wnt, Hedgehog, and TGF-β. These pathways play fundamental roles in the development as well as in the control of cell survival and cell fate and are relevant to therapeutic targeting of CSCs. The differences in the expression of membrane proteins and exosome-delivered microRNAs between SSCs and CSCs are also important to specifically target the stem cells of the cancer. Further research efforts should be directed toward elucidation of the fundamental differences between SSCs and CSCs to improve existing therapies and generate new clinically relevant cancer treatments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13287-020-02018-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7672862PMC
November 2020

Cardiac Arrest after a Transatlantic Flight in a Patient with a Large Left Atrial Myxoma.

CASE (Phila) 2020 Feb 25;4(1):28-32. Epub 2019 Nov 25.

Department of Surgical Sciences, Cardiothoracic Surgery and Anesthesia, Uppsala University Hospital, Uppsala, Sweden.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.case.2019.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7026534PMC
February 2020

Compared with matched controls, patients with postoperative atrial fibrillation (POAF) have increased long-term AF after CABG, and POAF is further associated with increased ischemic stroke, heart failure and mortality even after adjustment for AF.

Clin Res Cardiol 2020 Oct 8;109(10):1232-1242. Epub 2020 Feb 8.

Department of Surgical Sciences, Cardiothoracic Surgery, Uppsala University, Uppsala, Sweden.

Objective: To analyze (1) associations between postoperative atrial fibrillation (POAF) after CABG and long-term cardiovascular outcome, (2) whether associations were influenced by AF during follow-up, and (3) if morbidities associated with POAF contribute to mortality.

Methods: An observational cohort study of 7145 in-hospital survivors after isolated CABG (1996-2012), with preoperative sinus rhythm and without AF history. Incidence of AF was compared with matched controls. Time-updated covariates were used to adjust for POAF-related morbidities during follow-up, including AF.

Results: Thirty-one percent of patients developed POAF. Median follow-up was 9.8 years. POAF patients had increased AF compared with matched controls (HR 3.03; 95% CI 2.66-3.49), while AF occurrence in non-POAF patients was similar to controls (1.00; 0.89-1.13). The observed AF increase among POAF patients compared with controls persisted over time (> 10 years 2.73; 2.13-3.51). Conversely, the non-POAF cohort showed no AF increase beyond the first postoperative year. Further, POAF was associated with long-term AF (adjusted HR 3.20; 95% CI 2.73-3.76), ischemic stroke (1.23; 1.06-1.42), heart failure (1.44; 1.27-1.63), overall mortality (1.21; 1.11-1.32), cardiac mortality (1.35; 1.18-1.54), and cerebrovascular mortality (1.54; 1.17-2.02). These associations remained after adjustment for AF during follow-up. Adjustment for other POAF-associated morbidities weakened the association between POAF and overall mortality, which became non-significant.

Conclusions: Patients with POAF after CABG had three times the incidence of long-term AF compared with both non-POAF patients and matched controls. POAF was associated with long-term ischemic stroke, heart failure, and corresponding mortality even after adjustment for AF during follow-up. The increased overall mortality was partly explained by morbidities associated with POAF.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00392-020-01614-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7515855PMC
October 2020

Synthetic tracheal grafts seeded with bone marrow cells fail to generate functional tracheae: First long-term follow-up study.

J Thorac Cardiovasc Surg 2020 06 31;159(6):2525-2537.e23. Epub 2019 Oct 31.

Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Heart and Vascular Division, Karolinska University Hospital, Stockholm, Sweden.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jtcvs.2019.09.185DOI Listing
June 2020

Immunomodulatory effects of interferon-γ on human fetal cardiac mesenchymal stromal cells.

Stem Cell Res Ther 2019 12 4;10(1):371. Epub 2019 Dec 4.

Department of Molecular Medicine and Surgery, Karolinska Institutet, BioClinicum J10:20, SE-171 64, Solna, Sweden.

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-γ (IFNγ) on the immunomodulatory effects of first-trimester human fetal cardiac (hfc)-MSCs.

Methods: hfcMSCs (gestational week 8) were exposed to IFNγ, 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 IFNγ 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13287-019-1489-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6894330PMC
December 2019

[Bicuspid aortic valve - a common congenital cardiac malformation associated with serious complications].

Lakartidningen 2019 May 15;116. Epub 2019 May 15.

Uppsala Universitet Institutionen for kirurgiska vetenskaper - Uppsala, Sweden Uppsala Universitet Institutionen for kirurgiska vetenskaper - Uppsala, Sweden.

Bicuspid aortic valve (BAV) is the most common congenital cardiac malformation, affecting 1-2% of the general population. BAV is associated with an increased morbidity and mortality related to diseases of the aortic valve (aortic stenosis and aortic regurgitation) and the thoracic aorta (aortic aneurysm and aortic dissection). These conditions can often be treated surgically to prevent adverse events and reduce mortality. However, optimal management of BAV patients requires knowledge about the natural history of common clinical complications and involved pathological mechanisms. The aim of this article is to present common complications associated with BAV and to summarize the recently published evidence-based guidelines focusing solely on BAV patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
May 2019

Pleiotropic roles of autophagy in stem cell-based therapies.

Cytotherapy 2019 04 12;21(4):380-392. Epub 2019 Mar 12.

Department of Molecular Medicine and Surgery, Division of Cardiothoracic Surgery and Anesthesiology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcyt.2019.02.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6538418PMC
April 2019

Dual roles of heparanase in human carotid plaque calcification.

Atherosclerosis 2019 04 5;283:127-136. Epub 2019 Jan 5.

Department of Molecular Medicine and Surgery, Bioclinicum J8:20, Karolinska Institutet, 171 64, Solna, Sweden.

Background And Aims: Calcification is a hallmark of advanced atherosclerosis and an active process akin to bone remodeling. Heparanase (HPSE) is an endo-β-glucuronidase, which cleaves glycosaminoglycan chains of heparan sulfate proteoglycans. The role of HPSE is controversial in osteogenesis and bone remodeling while it is unexplored in vascular calcification. Previously, we reported upregulation of HPSE in human carotid endarterectomies from symptomatic patients and showed correlation of HPSE expression with markers of inflammation and increased thrombogenicity. The present aim is to investigate HPSE expression in relation to genes associated with osteogenesis and osteolysis and the effect of elevated HPSE expression on calcification and osteolysis in vitro.

Methods: Transcriptomic and immunohistochemical analyses were performed using the Biobank of Karolinska Endarterectomies (BiKE). In vitro calcification and osteolysis were analysed in human carotid smooth muscle cells overexpressing HPSE and bone marrow-derived osteoclasts from HPSE-transgenic mice respectively.

Results: HPSE expression correlated primarily with genes coupled to osteoclast differentiation and function in human carotid atheromas. HPSE was expressed in osteoclast-like cells in atherosclerotic lesions, and HPSE-transgenic bone marrow-derived osteoclasts displayed a higher osteolytic activity compared to wild-type cells. Contrarily, human carotid SMCs with an elevated HPSE expression demonstrated markedly increased mineralization upon osteogenic differentiation.

Conclusions: We suggest that HPSE may have dual functions in vascular calcification, depending on the stage of the disease and presence of inflammatory cells. While HPSE plausibly enhances mineralization and osteogenic differentiation of vascular smooth muscle cells, it is associated with inflammation-induced osteoclast differentiation and activity in advanced atherosclerotic plaques.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.atherosclerosis.2018.12.027DOI Listing
April 2019

Human Fetal Cardiac Mesenchymal Stromal Cells Differentiate In Vivo into Endothelial Cells and Contribute to Vasculogenesis in Immunocompetent Mice.

Stem Cells Dev 2019 03 5;28(5):310-318. Epub 2019 Feb 5.

1 Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.

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 α4. 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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/scd.2018.0198DOI Listing
March 2019

Wnt/β-Catenin Stimulation and Laminins Support Cardiovascular Cell Progenitor Expansion from Human Fetal Cardiac Mesenchymal Stromal Cells.

Stem Cell Reports 2016 Apr 24;6(4):607-617. Epub 2016 Mar 24.

Division of Cardiothoracic Surgery and Anesthesiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, 17177 Stockholm, Sweden; Cell Therapy Institute, Nova Southeastern University, Fort Lauderdale, FL 33314, USA. Electronic address:

The intrinsic regenerative capacity of human fetal cardiac mesenchymal stromal cells (MSCs) has not been fully characterized. Here we demonstrate that we can expand cells with characteristics of cardiovascular progenitor cells from the MSC population of human fetal hearts. Cells cultured on cardiac muscle laminin (LN)-based substrata in combination with stimulation of the canonical Wnt/β-catenin pathway showed increased gene expression of ISL1, OCT4, KDR, and NKX2.5. The majority of cells stained positive for PDGFR-α, ISL1, and NKX2.5, and subpopulations also expressed the progenitor markers TBX18, KDR, c-KIT, and SSEA-1. Upon culture of the cardiac MSCs in differentiation media and on relevant LNs, portions of the cells differentiated into spontaneously beating cardiomyocytes, and endothelial and smooth muscle-like cells. Our protocol for large-scale culture of human fetal cardiac MSCs enables future exploration of the regenerative functions of these cells in the context of myocardial injury in vitro and in vivo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.stemcr.2016.02.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4834052PMC
April 2016

Human fetal cardiac progenitors: The role of stem cells and progenitors in the fetal and adult heart.

Best Pract Res Clin Obstet Gynaecol 2016 Feb 10;31:58-68. Epub 2015 Sep 10.

Department of Molecular Medicine and Surgery, Division of Cardiothoracic Surgery and Anesthesiology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden; Center for Diseases of Aging (CDA) at Vaccine and Gene Therapy Institute (VGTI), Port St Lucie, FL, USA.

The human fetal heart is formed early during embryogenesis as a result of cell migrations, differentiation, and formative blood flow. It begins to beat around gestation day 22. Progenitor cells are derived from mesoderm (endocardium and myocardium), proepicardium (epicardium and coronary vessels), and neural crest (heart valves, outflow tract septation, and parasympathetic innervation). A variety of molecular disturbances in the factors regulating the specification and differentiation of these cells can cause congenital heart disease. This review explores the contribution of different cardiac progenitors to the embryonic heart development; the pathways and transcription factors guiding their expansion, migration, and functional differentiation; and the endogenous regenerative capacity of the adult heart including the plasticity of cardiomyocytes. Unfolding these mechanisms will become the basis for understanding the dynamics of specific congenital heart disease as well as a means to develop therapy for fetal as well as postnatal cardiac defects and heart failure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bpobgyn.2015.08.008DOI Listing
February 2016

In Vivo Effects of Mesenchymal Stromal Cells in Two Patients With Severe Acute Respiratory Distress Syndrome.

Stem Cells Transl Med 2015 Oct 18;4(10):1199-213. Epub 2015 Aug 18.

Departments of Molecular Medicine and Surgery, Cardiothoracic Surgery and Anesthesia, and Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden; Department of Internal Medicine, Hematology and Oncology, University of Erlangen-Nuremberg, Erlangen, Germany; Stem Cell Research Laboratory, Section of Hematology, Department of Medicine, University of Verona, Verona, Italy; Cancer Proteomics Mass Spectrometry, Science for Life Laboratory, Department of Oncology-Pathology, Department of Medical Biochemistry and Biophysics, and Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden; Center for Diseases of Aging, Vaccine and Gene Therapy Institute Florida, Port St. Lucie, Florida, USA; Exosome Diagnostics Inc., New York, New York, USA; Departments of Cardiothoracic Surgery, Hematology, and Immunology, Genetics and Pathology, Uppsala University Hospital, Uppsala, Sweden; Ludwig Institute for Cancer Research, Stockholm, Sweden; Health Sciences Research Facility, Department of Medicine, University of Vermont, Burlington, Vermont, USA

Unlabelled: Mesenchymal stromal cells (MSCs) have been investigated as a treatment for various inflammatory diseases because of their immunomodulatory and reparative properties. However, many basic questions concerning their mechanisms of action after systemic infusion remain unanswered. We performed a detailed analysis of the immunomodulatory properties and proteomic profile of MSCs systemically administered to two patients with severe refractory acute respiratory distress syndrome (ARDS) on a compassionate use basis and attempted to correlate these with in vivo anti-inflammatory actions. Both patients received 2×10(6) cells per kilogram, and each subsequently improved with resolution of respiratory, hemodynamic, and multiorgan failure. In parallel, a decrease was seen in multiple pulmonary and systemic markers of inflammation, including epithelial apoptosis, alveolar-capillary fluid leakage, and proinflammatory cytokines, microRNAs, and chemokines. In vitro studies of the MSCs demonstrated a broad anti-inflammatory capacity, including suppression of T-cell responses and induction of regulatory phenotypes in T cells, monocytes, and neutrophils. Some of these in vitro potency assessments correlated with, and were relevant to, the observed in vivo actions. These experiences highlight both the mechanistic information that can be gained from clinical experience and the value of correlating in vitro potency assessments with clinical effects. The findings also suggest, but do not prove, a beneficial effect of lung protective strategies using adoptively transferred MSCs in ARDS. Appropriate randomized clinical trials are required to further assess any potential clinical efficacy and investigate the effects on in vivo inflammation.

Significance: This article describes the cases of two patients with severe refractory adult respiratory syndrome (ARDS) who failed to improve after both standard life support measures, including mechanical ventilation, and additional measures, including extracorporeal ventilation (i.e., in a heart-lung machine). Unlike acute forms of ARDS (such in the current NIH-sponsored study of mesenchymal stromal cells in ARDS), recovery does not generally occur in such patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5966/sctm.2015-0021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4572899PMC
October 2015

Percutaneous Fluoroscopic-Guided Endomyocardial Delivery in an Experimental Model of Left Ventricular Assist Device Support.

J Cardiovasc Transl Res 2015 Aug 7;8(6):381-4. Epub 2015 Jul 7.

Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden,

Endomyocardial delivery in the setting of active left ventricular assist device (LVAD) support has rarely been studied. The objective was to establish a protocol for endomyocardial injections during LVAD support without compromising mechanical circulation. LVAD implantation was performed in four pigs. A curved needle catheter was percutaneously inserted into the right carotid artery and positioned into the left ventricle under fluoroscopic guidance. In the setting of increasing LVAD flows (2.3-3.1 l/min), percutaneous methylene blue dye administration into the myocardium proceeded without complications in all pigs. Transection of excised hearts revealed an anterior, lateral, inferior, and septal wall distribution of methylene blue documenting injections in all four regions of the left ventricle. Ex vivo, the catheter could be maneuvered close to the LVAD inflow cannula despite augmentation of LVAD flow up to 5 l/min. Endomyocardial injections during LVAD support was found to be feasible and safe with the curved needle catheter.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12265-015-9642-4DOI Listing
August 2015

Sublethal caspase activation promotes generation of cardiomyocytes from embryonic stem cells.

PLoS One 2015 12;10(3):e0120176. Epub 2015 Mar 12.

Division of Cardiothoracic Surgery and Anesthesiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.

Generation of new cardiomyocytes is critical for cardiac repair following myocardial injury, but which kind of stimuli is most important for cardiomyocyte regeneration is still unclear. Here we explore if apoptotic stimuli, manifested through caspase activation, influences cardiac progenitor up-regulation and cardiomyocyte differentiation. Using mouse embryonic stem cells as a cellular model, we show that sublethal activation of caspases increases the yield of cardiomyocytes while concurrently promoting the proliferation and differentiation of c-Kit+/α-actininlow cardiac progenitor cells. A broad-spectrum caspase inhibitor blocked these effects. In addition, the caspase inhibitor reversed the mRNA expression of genes expressed in cardiomyocytes and their precursors. Our study demonstrates that sublethal caspase-activation has an important role in cardiomyocyte differentiation and may have significant implications for promoting cardiac regeneration after myocardial injury involving exogenous or endogenous cell sources.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0120176PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4357377PMC
May 2016

HeartWare left ventricular assist device thrombosis in aspirin non-responder.

Asian Cardiovasc Thorac Ann 2014 Feb 11;22(2):203-4. Epub 2013 Jul 11.

Department of Molecular Medicine and Surgery, Department of Cardiothoracic Surgery and Anesthesiology, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden.

Patient characteristics that increase the risk of continuous-flow left ventricular assist device thrombosis have not been well established. We report a case of HeartWare thrombosis in a patient with aspirin hyporesponsiveness, and discuss the role of platelet function testing in preventing this severe complication. There is a need for clinical trials determining optimal antiplatelet therapy in patients supported with left ventricular assist devices, and consensus regarding modification of antiplatelet therapy after device thrombosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0218492312467993DOI Listing
February 2014

[Minimally invasive implantation of left ventricular assist devices. Good results in the first procedure in Sweden].

Lakartidningen 2013 Dec 4-17;110(49-50):2242-3

Karolinska universitetssjukhuset och Karolinska institutet, Stockholm.

View Article and Find Full Text PDF

Download full-text PDF

Source
February 2014

Clonal culturing of human embryonic stem cells on laminin-521/E-cadherin matrix in defined and xeno-free environment.

Nat Commun 2014 ;5:3195

1] Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm SE-171 77, Sweden [2] Cardiovascular and Metabolic Disorders Program, Duke-NUS, Singapore City 169857, Singapore.

Lack of robust methods for establishment and expansion of pluripotent human embryonic stem (hES) cells still hampers development of cell therapy. Laminins (LN) are a family of highly cell-type specific basement membrane proteins important for cell adhesion, differentiation, migration and phenotype stability. Here we produce and isolate a human recombinant LN-521 isoform and develop a cell culture matrix containing LN-521 and E-cadherin, which both localize to stem cell niches in vivo. This matrix allows clonal derivation, clonal survival and long-term self-renewal of hES cells under completely chemically defined and xeno-free conditions without ROCK inhibitors. Neither LN-521 nor E-cadherin alone enable clonal survival of hES cells. The LN-521/E-cadherin matrix allows hES cell line derivation from blastocyst inner cell mass and single blastomere cells without a need to destroy the embryo. This method can facilitate the generation of hES cell lines for development of different cell types for regenerative medicine purposes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ncomms4195DOI Listing
October 2015

Emergency parallel mechanical circulatory support for ventricular fibrillation.

Circ Heart Fail 2014 Jan;7(1):229-30

Department of Medicine, Unit of Cardiology and Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; and Department of Cardiology and Department of Cardiothoracic Surgery and Anesthesiology, Karolinska University Hospital, Stockholm, Sweden.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1161/CIRCHEARTFAILURE.113.001012DOI Listing
January 2014

Costimulation blockade induces foxp3(+) regulatory T cells to human embryonic stem cells.

Biores Open Access 2013 Dec;2(6):455-8

Department of Cardiothoracic Surgery & Anesthesiology (Solna), Karolinska University Hospital , Stockholm, Sweden .

Transplantation of human embryonic stem cells (hESCs), like other allogeneic cellular transplants, require immunomodulation or immunosuppression in order to be maintained in the recipient. Costimulation blockade applied at the time of transplantation inhibits costimulatory signals in the immunological synapse leading to a state of anergy in the donor reactive T-cell population and a state of immunological tolerance in the host. In models of solid organ transplantation, tolerance is maintained by the infiltration of Foxp3(+) regulatory T cells into the graft. In order to study if regulatory T cells could be generated to hESC transplants, costimulation blockade (CTLA4Ig, anti-CD40L, anti-LFA-1) was administered for the first week after transplantation of two different hESC lines implanted under the kidney capsule of wild-type mice. hESC transplants were maintained indefinitely, and when harvested at long-term follow-up, Foxp3(+) T-cells were found surrounding the graft, implying the maintenance of tolerance through the induction of regulatory T cells. These results imply that costimulation blockade could be a useful treatment strategy for the induction of tolerance to hESC transplants and may down-modulate immune responses locally around the graft.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/biores.2013.0039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3869426PMC
December 2013

Whole organ and tissue reconstruction in thoracic regenerative surgery.

Mayo Clin Proc 2013 Oct;88(10):1151-66

Advanced Center for Translational Regenerative Medicine, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden.

Development of novel prognostic, diagnostic, and treatment options will provide major benefits for millions of patients with acute or chronic respiratory dysfunction, cardiac-related disorders, esophageal problems, or other diseases in the thorax. Allogeneic organ transplant is currently available. However, it remains a trap because of its dependency on a very limited supply of donated organs, which may be needed for both initial and subsequent transplants. Furthermore, it requires lifelong treatment with immunosuppressants, which are associated with adverse effects. Despite early clinical applications of bioengineered organs and tissues, routine implementation is still far off. For this review, we searched the PubMed, MEDLINE, and Ovid databases for the following keywords for each tissue or organ: tissue engineering, biological and synthetic scaffold/graft, acellular and decelluar(ized), reseeding, bioreactor, tissue replacement, and transplantation. We identified the current state-of-the-art practices in tissue engineering with a focus on advances during the past 5 years. We discuss advantages and disadvantages of biological and synthetic solutions and introduce novel strategies and technologies for the field. The ethical challenges of innovation in this area are also reviewed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mayocp.2013.03.011DOI Listing
October 2013

Peripheral extracorporeal membrane oxygenation as short-term right ventricular support after HeartWare left ventricular assist device implantation.

ASAIO J 2013 Sep-Oct;59(5):523-5

Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.

Left ventricular assist device (LVAD) implantation is associated with the risk of early postoperative right heart dysfunction, which may require urgent institution of mechanical right ventricular support. This is conventionally achieved by cannulation of the femoral vein or right atrial appendage for the inflow and the pulmonary artery for the outflow. However, this requires resternotomy with increased risk of wound and device infection, as well as excessive bleeding. We describe the use of peripheral venoarterial extracorporeal membrane oxygenation as a short-term treatment of right heart failure after HeartWare LVAD implantation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAT.0b013e31829be043DOI Listing
April 2014

The international translational regenerative medicine center.

Regen Med 2012 Nov;7(6 Suppl):74-5

International Translational Regenerative Medicine Center, Beckman Research Institute at City of Hope, CA, USA.

The International Translational Regenerative Medicine Center, an organizing sponsor of the World Stem Cell Summit 2012, is a global initiative established in 2011 by founding partners Karolinska Institutet (Stockholm, Sweden) and Beckman Research Institute at City of Hope (CA, USA) with a mission to facilitate the acceleration of translational research and medicine on a global scale. Karolinska Institutet, home of the Nobel Prize in Medicine or Physiology, is one of the most prestigious medical research institutions in the world. The Beckman Research Institute/City of Hope is ranked among the leading NIH-designated comprehensive cancer research and treatment institutions in the USA, has the largest academic GMP facility and advanced drug discovery capability, and is a pioneer in diabetes research and treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2217/rme.12.72DOI Listing
November 2012

Local control of nuclear calcium signaling in cardiac myocytes by perinuclear microdomains of sarcolemmal insulin-like growth factor 1 receptors.

Circ Res 2013 Jan 1;112(2):236-45. Epub 2012 Nov 1.

Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chile, Santiago, Chile.

Rationale: The ability of a cell to independently regulate nuclear and cytosolic Ca(2+) signaling is currently attributed to the differential distribution of inositol 1,4,5-trisphosphate receptor channel isoforms in the nucleoplasmic versus the endoplasmic reticulum. In cardiac myocytes, T-tubules confer the necessary compartmentation of Ca(2+) signals, which allows sarcomere contraction in response to plasma membrane depolarization, but whether there is a similar structure tunneling extracellular stimulation to control nuclear Ca(2+) signals locally has not been explored.

Objective: To study the role of perinuclear sarcolemma in selective nuclear Ca(2+) signaling.

Methods And Results: We report here that insulin-like growth factor 1 triggers a fast and independent nuclear Ca(2+) signal in neonatal rat cardiac myocytes, human embryonic cardiac myocytes, and adult rat cardiac myocytes. This fast and localized response is achieved by activation of insulin-like growth factor 1 receptor signaling complexes present in perinuclear invaginations of the plasma membrane. The perinuclear insulin-like growth factor 1 receptor pool connects extracellular stimulation to local activation of nuclear Ca(2+) signaling and transcriptional upregulation through the perinuclear hydrolysis of phosphatidylinositol 4,5-biphosphate inositol 1,4,5-trisphosphate production, nuclear Ca(2+) release, and activation of the transcription factor myocyte-enhancing factor 2C. Genetically engineered Ca(2+) buffers--parvalbumin--with cytosolic or nuclear localization demonstrated that the nuclear Ca(2+) handling system is physically and functionally segregated from the cytosolic Ca(2+) signaling machinery.

Conclusions: These data reveal the existence of an inositol 1,4,5-trisphosphate-dependent nuclear Ca(2+) toolkit located in direct apposition to the cell surface, which allows the local control of rapid and independent activation of nuclear Ca(2+) signaling in response to an extracellular ligand.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1161/CIRCRESAHA.112.273839DOI Listing
January 2013

Intentional ABO-incompatible heart transplantation: a case report of 2 adult patients.

J Heart Lung Transplant 2012 Dec 26;31(12):1307-10. Epub 2012 Oct 26.

Department of Transplantation Surgery, Karolinska University Hospital, Stockholm, Sweden.

Background: In 2009, we started to screen all patients on the heart transplant waiting list for the presence of blood group anti-A or anti-B antibodies. From our experience with ABO-incompatible kidney transplantation, we know that transplantation can safely be performed if the antibody level is reduced to a titer of immunoglobulin G (IgG) 1:8.

Methods: We decided to accept all patients with anti-A or anti-B antibody titer ≤1:8 for ABO-incompatible heart transplantation without any special pre-treatment and patients with antibody titers of IgG 1:16 and 1:32, provided 1 apheresis session could be performed immediately before transplantation.

Results: We found 6 of 13 patients were suitable for this program, and 2 ABO incompatible patients underwent successful transplantation with a follow-up of 1 year.

Conclusion: In heart transplant candidates where there are problems obtaining a compatible heart and who are not suitable for ventricular assist device support, ABO-incompatible heart transplantations can be considered using our protocol, provided that the levels of anti-A or anti-B antibodies are low.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.healun.2012.09.011DOI Listing
December 2012

Exploration of human, rat, and rabbit embryonic cardiomyocytes suggests K-channel block as a common teratogenic mechanism.

Cardiovasc Res 2013 Jan 20;97(1):23-32. Epub 2012 Sep 20.

Department of Cardiology, Karolinska University Hospital, Huddinge, SE-141 86, Stockholm, Sweden.

Aims: Several drugs blocking the rapidly activating potassium (K(r)) channel cause malformations (including cardiac defects) and embryonic death in animal teratology studies. In humans, these drugs have an established risk for acquired long-QT syndrome and arrhythmia. Recently, associations between cardiac defects and spontaneous abortions have been reported for drugs widely used in pregnancy (e.g. antidepressants), with long-QT syndrome risk. To investigate whether a common embryonic adverse-effect mechanism exists in the human, rat, and rabbit embryos, we made a comparative study of embryonic cardiomyocytes from all three species.

Methods And Results: Patch-clamp and quantitative-mRNA measurements of K(r) and slowly activating K (K(s)) channels were performed on human, rat, and rabbit primary cardiomyocytes and cardiac samples from different embryo-foetal stages. The K(r) channel was present when the heart started to beat in all species, but was, in contrast to human and rabbit, lost in rats in late organogenesis. The specific K(r)-channel blocker E-4031 prolonged the action potential in a species- and development-dependent fashion, consistent with the observed K(r)-channel expression pattern and reported sensitive periods of developmental toxicity. E-4031 also increased the QT interval and induced 2:1 atrio-ventricular block in multi-electrode array electrographic recordings of rat embryos. The K(s) channel was expressed in human and rat throughout the embryo-foetal period but not in rabbit.

Conclusion: This first comparison of mRNA expression, potassium currents, and action-potential characteristics, with and without a specific K(r)-channel blocker in human, rat, and rabbit embryos provides evidence of K(r)-channel inhibition as a common mechanism for embryonic malformations and death.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/cvr/cvs296DOI Listing
January 2013

Ischemia-reperfusion injury and pregnancy initiate time-dependent and robust signs of up-regulation of cardiac progenitor cells.

PLoS One 2012 9;7(5):e36804. Epub 2012 May 9.

Division of Cardiology, Department of Medicine, Karolinska Institutet, Stockholm, Sweden.

To explore how cardiac regeneration and cell turnover adapts to disease, different forms of stress were studied for their effects on the cardiac progenitor cell markers c-Kit and Isl1, the early cardiomyocyte marker Nkx2.5, and mast cells. Adult female rats were examined during pregnancy, after myocardial infarction and ischemia-reperfusion injury with/out insulin like growth factor-1(IGF-1) and hepatocyte growth factor (HGF). Different cardiac sub-domains were analyzed at one and two weeks post-intervention, both at the mRNA and protein levels. While pregnancy and myocardial infarction up-regulated Nkx2.5 and c-Kit (adjusted for mast cell activation), ischemia-reperfusion injury induced the strongest up-regulation which occurred globally throughout the entire heart and not just around the site of injury. This response seems to be partly mediated by increased endogenous production of IGF-1 and HGF. Contrary to c-Kit, Isl1 was not up-regulated by pregnancy or myocardial infarction while ischemia-reperfusion injury induced not a global but a focal up-regulation in the outflow tract and also in the peri-ischemic region, correlating with the up-regulation of endogenous IGF-1. The addition of IGF-1 and HGF did boost the endogenous expression of IGF and HGF correlating to focal up-regulation of Isl1. c-Kit expression was not further influenced by the exogenous growth factors. This indicates that there is a spatial mismatch between on one hand c-Kit and Nkx2.5 expression and on the other hand Isl1 expression. In conclusion, ischemia-reperfusion injury was the strongest stimulus with both global and focal cardiomyocyte progenitor cell marker up-regulations, correlating to the endogenous up-regulation of the growth factors IGF-1 and HGF. Also pregnancy induced a general up-regulation of c-Kit and early Nkx2.5+ cardiomyocytes throughout the heart. Utilization of these pathways could provide new strategies for the treatment of cardiac disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0036804PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3348899PMC
September 2012

Myocardial recovery in peri-partum cardiomyopathy after continuous flow left ventricular assist device.

J Cardiothorac Surg 2011 Nov 14;6:150. Epub 2011 Nov 14.

Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.

Left ventricular assist devices (LVADs) offer effective therapy for severe heart failure (HF) as bridge to transplantation or destination therapy. Rarely, the sustained unloading provided by the LVAD has led to cardiac reverse remodelling and recovery, permitting explantation of the device. We describe the clinical course of a patient with severe peri-partum cardiomyopathy (PPCM) rescued with a continuous flow LVAD, who experienced recovery and explantation. We discuss assessment of and criteria for recovery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1749-8090-6-150DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256109PMC
November 2011