The Effects of Hypoxic Preconditioned Murine Mesenchymal Stem Cells on Post-Infarct Arrhythmias in the Mouse Model.

Ventricular arrhythmias associated with myocardial infarction (MI) have a significant impact on mortality in patients following heart attack. Therefore, targeted reduction of arrhythmia represents a therapeutic approach for the prevention and treatment of severe events after infarction. Recent research transplanting mesenchymal stem cells (MSC) showed their potential in MI therapy. Our study aimed to investigate the effects of MSC injection on post-infarction arrhythmia. We used our murine double infarction model, which we previously established, to more closely mimic the clinical situation and intramyocardially injected hypoxic pre-conditioned murine MSC to the infarction border. Thereafter, various types of arrhythmias were recorded and analyzed. We observed a homogenous distribution of all types of arrhythmias after the first infarction, without any significant differences between the groups. Yet, MSC therapy after double infarction led to a highly significant reduction in simple and complex arrhythmias. Moreover, RNA-sequencing of samples from stem cell treated mice after re-infarction demonstrated a significant decline in most arrhythmias with reduced inflammatory pathways. Additionally, following stem-cell therapy we found numerous highly expressed genes to be either linked to lowering the risk of heart failure, cardiomyopathy or sudden cardiac death. Moreover, genes known to be associated with arrhythmogenesis and key mutations underlying arrhythmias were downregulated. In summary, our stem-cell therapy led to a reduction in cardiac arrhythmias after MI and showed a downregulation of already established inflammatory pathways. Furthermore, our study reveals gene regulation pathways that have a potentially direct influence on arrhythmogenesis after myocardial infarction.

Therapeutic potential of menstrual blood-derived endometrial stem cells in cardiac diseases.

Despite significant developments in medical and surgical strategies, cardiac diseases remain the leading causes of morbidity and mortality worldwide. Numerous studies involving preclinical and clinical trials have confirmed that stem cell transplantation can help improve cardiac function and regenerate damaged cardiac tissue, and stem cells isolated from bone marrow, heart tissue, adipose tissue and umbilical cord are the primary candidates for transplantation. During the past decade, menstrual blood-derived endometrial stem cells (MenSCs) have gradually become a promising alternative for stem cell-based therapy due to their comprehensive advantages, which include their ability to be periodically and non-invasively collected, their abundant source material, their ability to be regularly donated, their superior proliferative capacity and their ability to be used for autologous transplantation. MenSCs have shown positive therapeutic potential for the treatment of various diseases. Therefore, aside from a brief introduction of the biological characteristics of MenSCs, this review focuses on the progress being made in evaluating the functional improvement of damaged cardiac tissue after MenSC transplantation through preclinical and clinical studies. Based on published reports, we conclude that the paracrine effect, transdifferentiation and immunomodulation by MenSC promote both regeneration of damaged myocardium and improvement of cardiac function.

Nkx2.5 Based Ventricular Programming of Murine ESC-Derived Cardiomyocytes.

BACKGROUND/AIMS: The availability of truly maturated cardiomyocytic subtypes is a major prerequisite for cardiovascular cell replacement therapies. Pluripotent stem cells provide a suitable source for the development of new strategies to overcome enormous hurdles such as yield, purity and safety of in vitro generated cells. METHODS: To address these issues, we have refined existing forward programming protocols by combining forced exogenous overexpression of the early cardiovascular transcription factor Nkx2.5 with a αMHC-promoter-based antibiotic selection step. Additionally, we applied small molecules such as ascorbic acid to enhance cardiomyogenic differentiation efficiency. Subsequently, we evaluated the cell fate of the resulting cardiomyocytes on the mRNA as well as protein levels. The latter was performed using high-resolution confocal microscopy. Furthermore, we examined the response of the cells` beating activities to pharmacological substance administration. RESULTS: Our results reveal an apparent influence of Nkx2.5 on the cell fate of ESC-derived cardiomyocytes. Resulting single cells exhibit characteristics of early ventricular cardiomyocytes, such as sarcomeric marker expression, spontaneous beating frequency, and distinct L-type calcium channel occurrence. CONCLUSION: Therefore, we demonstrate cardiovascular subtype forward programming of ESCs using a combination of transcription factors along with small molecule administration. However, our findings also underline current assumptions, that a terminal maturation of PSC derived cardiomyocytes in vitro is still an unsolved problem which urgently needs to be addressed in the field.

Vimentin-Induced Cardiac Mesenchymal Stem Cells Proliferate in the Acute Ischemic Myocardium.

In-depth knowledge of the mechanisms induced by early postischemic cardiac endogenous mesenchymal stem cells (MSCs) in the acutely ischemic heart could advance our understanding of cardiac regeneration. Herein, we aimed to identify, isolate, and initially characterize the origin, kinetics and fate of cardiac MSCs. This was facilitated by in vivo genetic cell fate mapping through green fluorescent protein (GFP) expression under the control of vimentin induction after acute myocardial infarction (MI). Following permanent ligation of the left anterior descending coronary artery in CreER+ mTom/mGFP+ mice, vimentin/GFP+ cells revealed ischemia-responsive activation, survival, and local enrichment inside the peri-infarction border zone. Fluorescence-activated cell sorting (FACS)-isolated vimentin/GFP+ cells could be strongly expanded in vitro with clonogenic precursor formation and revealed MSC-typical cell morphology. Flow-cytometric analyses demonstrated an increase in cardiac vimentin/GFP+ cells in the ischemic heart, from a 0.6% cardiac mononuclear cell (MNC) fraction at 24 h to 1.6% at 72 h following MI. Sca-1+CD45- cells within the vimentin/GFP+ subtype of this MNC fraction increased from 35.2% at 24 h to 74.6% at 72 h after MI. The cardiac postischemic vimentin/GFP+ MNC subtype showed multipotent adipogenic, chondrogenic, and osteogenic differentiation potential, which is distinctive for MSCs. In conclusion, we demonstrated a seemingly proliferative first response of vimentin- induced cardiac endogenous MSCs in the acutely ischemic heart. Genetically, GFP-targeted in vivo cell tracking, isolation, and in vitro expansion of this cardiac MSC subtype could help to clarify their reparative status in inflammation, fibrogenesis, cell turnover, tissue homeostasis, and myocardial regeneration.

Safety of Simultaneous Coronary Artery Bypass Grafting and Carotid Endarterectomy Versus Isolated Coronary Artery Bypass Grafting: A Randomized Clinical Trial.

BACKGROUND AND PURPOSE: The optimal operative strategy in patients with severe carotid artery disease undergoing coronary artery bypass grafting (CABG) is unknown. We sought to investigate the safety and efficacy of synchronous combined carotid endarterectomy and CABG as compared with isolated CABG. METHODS: Patients with asymptomatic high-grade carotid artery stenosis ≥80% according to ECST (European Carotid Surgery Trial) ultrasound criteria (corresponding to ≥70% NASCET [North American Symptomatic Carotid Endarterectomy Trial]) who required CABG surgery were randomly assigned to synchronous carotid endarterectomy+CABG or isolated CABG. To avoid unbalanced prognostic factor distributions, randomization was stratified by center, age, sex, and modified Rankin Scale. The primary composite end point was the rate of stroke or death at 30 days. RESULTS: From 2010 to 2014, a total of 129 patients were enrolled at 17 centers in Germany and the Czech Republic. Because of withdrawal of funding after insufficient recruitment, enrolment was terminated early. At 30 days, the rate of any stroke or death in the intention-to-treat population was 12/65 (18.5%) in patients receiving synchronous carotid endarterectomy+CABG as compared with 6/62 (9.7%) in patients receiving isolated CABG (absolute risk reduction, 8.8%; 95% confidence interval, -3.2% to 20.8%; PWALD=0.12). Also for all secondary end points at 30 days and 1 year, there was no evidence for a significant treatment-group effect although patients undergoing isolated CABG tended to have better outcomes. CONCLUSIONS: Although our results cannot rule out a treatment-group effect because of lack of power, a superiority of the synchronous combined carotid endarterectomy+CABG approach seems unlikely. Five-year follow-up of patients is still ongoing. CLINICAL TRIAL REGISTRATION: URL: https://www.controlled-trials.com. Unique identifier: ISRCTN13486906.

Cardiac Cell Therapies for the Treatment of Acute Myocardial Infarction: A Meta-Analysis from Mouse Studies.

AIMS: Stem cell-based regenerative therapies for the treatment of ischemic myocardium are currently a subject of intensive investigation. A variety of cell populations have been demonstrated to be safe and to exert some positive effects in human Phase I and II clinical trials, however conclusive evidence of efficacy is still lacking. While the relevance of animal models for appropriate pre-clinical safety and efficacy testing with regard to application in Phase III studies continues to increase, concerns have been expressed regarding the validity of the mouse model to predict clinical results. Against the background that hundreds of preclinical studies have assessed the efficacy of numerous kinds of cell preparations - including pluripotent stem cells - for cardiac repair, we undertook a systematic re-evaluation of data from the mouse model, which initially paved the way for the first clinical trials in this field. METHODS AND RESULTS: A systematic literature screen was performed to identify publications reporting results of cardiac stem cell therapies for the treatment of myocardial ischemia in the mouse model. Only peer-reviewed and placebo-controlled studies using magnet resonance imaging (MRI) for left ventricular ejection fraction (LVEF) assessment were included. Experimental data from 21 studies involving 583 animals demonstrate a significant improvement in LVEF of 8.59%+/- 2.36; p=.012 (95% CI, 3.7-13.8) compared with control animals. CONCLUSION: The mouse is a valid model to evaluate the efficacy of cell-based advanced therapies for the treatment of ischemic myocardial damage. Further studies are required to understand the mechanisms underlying stem cell based improvement of cardiac function after ischemia.

Therapeutic progenitor cell application for tissue regeneration: Analyzing the impact of toll-like receptor signaling on c-kit+ cell migration following ischemia-reperfusion injury in vivo.

OBJECTIVES: Toll-like-receptor (TLR) mediated immune response has been shown to regulate myocardial damage following cardiac ischemia-reperfusion (IR). It has not been described conclusively so far whether migration of therapeutically applied progenitor cells following an IR event depends on TLR-signaling. METHODS: In vivo migratory capacity murine c-kit+ cells following IR injury was quantified by intravital fluorescence microscopy, utilizing the mouse cremaster muscle model and analyzing early (rolling) and late (adhesion) c-kit+ cell interaction with the local endothelium. The role of TLR-2 and TLR-4, as well as MyD88 and TRIF was analyzed by applying specific knock-out models. RESULTS: A sequence of 15min ischemia followed by 15min of reperfusion induced firm endothelial c-kit+ cell adhesion (5.6±1.3cells/mm2 in Control vs. 30.2±10.1cells/mm2 in IR, p<0.05). Knock-out of TLR-2 and TLR-4 diminished both IR induced early c-kit+ cell-endothelial cell interactions (67.6±2.3% c-kit+ cell rolling in IR vs. 46.3±4.8% c-kit+ cell rolling in IR-TLR-2-ko vs. 45.3±4.8% c-kit+ cell rolling in IR-TLR-4-ko, p<0.05) as well as firm endothelial c-kit+ cell adhesion (30.2±10.1cells/mm2 in IR vs. 16.3±3.9cells/mm2 in IR-TLR-2-ko vs. 14.5±4.4cells/mm2 in IR-TLR-4-ko, p<0.05). Adaptor protein knock-out resulted in a significantly decreased firm endothelial c-kit+ cell adhesion only in MyD88 knock-out but not in TRIF knock-out (9.2±2.2cells/mm2 in IR-MyD88-ko vs. 30.1±9.9cells/mm2 in IR-WT, p<0.05). CONCLUSION: Artificially applied c-kit+ cells interact with the target organ endothelium following IR injury. This interaction seems to depend on TLR-MyD88 signaling. Therapeutic blockade of TLR signaling for anti-inflammatory purposes might interfere with regenerative cell-based therapy protocols.

Clinical outcomes of conventional surgery versus MitraClip® therapy for moderate to severe symptomatic mitral valve regurgitation in the elderly population: an institutional experience.

BACKGROUND: The aim of this study was to compare treatment of moderate to severe symptomatic mitral regurgitation (MR) with either conventional surgery or the mitral valve edge-to-edge device (MitraClip®) in very elderly patients. The newly introduced MitraClip device has demonstrated promising acute results in treating this patient cohort. Also noteworthy is the fact that patients who otherwise would have been denied surgery are increasingly referred for treatment with the MitraClip device. We sought to review our institutional experience, comparing outcomes in both surgical and MitraClip arms of treatment in the elderly population with symptomatic MR. METHODS: From October 2008 through October 2014, 136 consecutive patients aged ≥ 80 with moderate to severe symptomatic MR were scheduled for either conventional surgery or MitraClip intervention. 56 patients ≥ 80 were operated for symptomatic MR and 80 patients ≥ 80 were treated with the mitraClip device. Patients suitable for this study were identified from our hospital database. Patients ≥80 with moderate/severe symptomatic MR treated with either conventional surgery or the MitraClip device were eligible for our analysis. We compared the surgical patient cohort with the mitraClip patient cohort after eliminating patients that did not meet our inclusion criteria. Forty-two patients were identified from the conventional cohort who were then compared with 42 patients from the mitraClip cohort. Forty-two patients (50%) underwent mitral valve repair or replacement (40.5% functional MR, 59.5% organic/mixed MR) and 42 patients (50%) underwent MitraClip intervention (50% functional MR, 50% organic/mixed MR). Associated procedures in the conventional surgical group were myocardial revascularization 38%, pulmonary vein ablation 23.8%, left atrial appendage resection 52.4% and PFO occlusion 11.9%. RESULTS: Patients who underwent MitraClip treatment were though slightly older but the differences did not attain statistical significance (mean, 82.2 ± 1.65 vs 81.7 ± 1.35 years, p = 0,100), had lower LVEF (mean, 47.6 ± 14.2 vs 53.4 ± 14.3, p = 0.072), lower logistic EuroScore II (mean, 11.3 ± 5.63 vs 12.1 ± 10.6, p = 0.655) but higher STS risk score (mean, 11.8 ± 6.7 vs 8.1 ± 5.6, p = 0.008) respectively compared to surgical patients. Procedural success was 100% vs 96% in surgery and MitraClip groups respectively. Thirty -day mortality was 7.1% vs 4.8% (p = 1.000) in surgery and MitraClip group respectively. Residual postoperative MR ≥2 at discharge was present in none of the patients treated surgically, whereas this was the case in 10 (23.8%) patients treated with the MitraClip device. At 1 year a cumulative number of four (9.52%) patients died in the surgical group vs 9 (21.4%) patients who died in the MitraClip group. CONCLUSIONS: Elderly patients presenting with moderate to severe symptomatic MR may either be treated by conventional surgery or with the MitraClip device with acceptable acute outcomes. The decision for treatment with the MitraClip device should not depend on age alone rather on cumulative risk of conventional surgery. Concomitant cardiac pathologies, often times treated simultaneously during surgery for symptomatic MR may be omitted, if patients are scheduled outright to MitraClip treatment. The effect of concomitant cardiac pathologies left untreated at the time of interventional mitral valve repair on outcome after MitraClip therapy remain widely unknown.

Cardiac Mesenchymal Stem Cells Proliferate Early in the Ischemic Heart.

BACKGROUND/PURPOSE: Cardiac mesenchymal stem cells (MSCs) could stimulate cell-specific regenerative mechanisms after myocardial infarction (MI) depending on spatial origin, distribution, and niche regulation. We aimed at identifying and isolating tissue-specific cardiac MSCs that could contribute to regeneration. METHODS: Following permanent ligation of the left anterior descending coronary artery in rats (n = 16), early cardiac tissues and cardiac mononuclear cells (MNCs) were analyzed by immunohistology, confocal laser scanning microscopy, and flow cytometry, respectively. Early postischemic specific MSCs were purified by fluorescence-activated cell sorting, cultivated under standardized culture conditions, and tested for multipotent differentiation in functional identification kits. RESULTS: Cardiac MSC niches were detected intramyocardially in cell clusters after MI and characterized by positive expression for vimentin, CD29, CD44, CD90, CD105, PDGFRα, and DDR2. Following myocardial ischemia, proliferation was induced early and proliferation density was approximately 11% in intramyocardial MSC clusters of the peri-infarction border zone. Cluster sizes increased by 157 and 64% in the peri-infarction and noninfarcted areas of infarcted hearts compared with noninfarcted hearts 24 h following MI, respectively. Coincidentally, flow cytometry analyses illustrated postischemic moderate enrichments of CD45-CD44+ and CD45-DDR2+ cardiac MNCs. We enabled isolation of early postischemic culturable cardiac CD45-CD44+DDR2+ MSCs that demonstrated typical clonogenicity with colony-forming unit-fibroblast formation as well as adipogenic, chondrogenic, and osteogenic differentiation. CONCLUSIONS: MI triggered early proliferation in specific cardiac MSC niches that were organized in intramyocardial clusters. Following targeted isolation, early postischemic cardiac CD45-CD44+DDR2+ MSCs exhibited typical characteristics with multipotent differentiation capacity and clonogenic expansion.

Conventional Surgery for Early and Late Symptomatic Mitral Valve Stenosis After MitraClip® Intervention: An Institutional Experience With Four Consecutive Patients.

BACKGROUND: Surgical mitral valve repair is the gold standard for treatment of mitral regurgitation. Recently, the transcatheter treatment of mitral regurgitation with the MitraClip® device (Abbot Vascular Structural Heart, Menlo Park, CA) has demonstrated promising results in treating patients not amenable for surgical correction of mitral valve regurgitation. Most patients reported in the literature requiring surgical bailout after MitraClip treatment presented with residual or recurrent mitral valve regurgitation. Mitral valve stenosis after MitraClip treatment has been rarely reported. METHODS: From February 2010 to December 2014, four patients out of 165 patients who underwent MitraClip therapy developed symptomatic mitral valve stenosis (2.4%) and needed surgical correction. Data of the four patients were reviewed retrospectively. Follow-up data were obtained from each patient's general practitioner/cardiologist by phone calls and facsimile and were complete in all patients. RESULTS: All four patients were treated with ≥ 2 MitraClip (MC) devices during their initial presentation. All four patients underwent MV replacement with a tissue valve. The postoperative course was uneventful and there was no 30-day mortality. At 6-month follow-up, all patients were alive and in NYHA class I-III. CONCLUSION: Placement of multiple clip devices may lead to slightly elevated transmitral gradients. This may not necessarily interpret into symptomatic mitral stenosis. However, in some cases this is possible. Caution should be exercised at this phase of the learning curve of the percutaneous MC treatment, especially in use of multiple MC devices.

Applying 3D-FRAP microscopy to analyse gap junction-dependent shuttling of small antisense RNAs between cardiomyocytes.

Small antisense RNAs like miRNA and siRNA are of crucial importance in cardiac physiology, pathology and, moreover, can be applied as therapeutic agents for the treatment of cardiovascular diseases. Identification of novel strategies for miRNA/siRNA therapy requires a comprehensive understanding of the underlying mechanisms. Emerging data suggest that small RNAs are transferred between cells via gap junctions and provoke gene regulatory effects in the recipient cell. To elucidate the role of miRNA/siRNA as signalling molecules, suitable tools are required that will allow the analysis of these small RNAs at the cellular level. In the present study, we applied 3 dimensional fluorescence recovery after photo bleaching microscopy (3D-FRAP) to visualise and quantify the gap junctional exchange of small RNAs between neonatal cardiomyocytes in real time. Cardiomyocytes were transfected with labelled miRNA and subjected to FRAP microscopy. Interestingly, we observed recovery rates of 21% already after 13min, indicating strong intercellular shuttling of miRNA, which was significantly reduced when connexin43 was knocked down. Flow cytometry analysis confirmed our FRAP results. Furthermore, using an EGFP/siRNA reporter construct we demonstrated that the intercellular transfer does not affect proper functioning of small RNAs, leading to marker gene silencing in the recipient cell. Our results show that 3D-FRAP microscopy is a straightforward, non-invasive live cell imaging technique to evaluate the GJ-dependent shuttling of small RNAs with high spatio-temporal resolution. Moreover, the data obtained by 3D-FRAP confirm a novel pathway of intercellular gene regulation where small RNAs act as signalling molecules within the intercellular network.

TRAPLINE: a standardized and automated pipeline for RNA sequencing data analysis, evaluation and annotation.

BACKGROUND: Technical advances in Next Generation Sequencing (NGS) provide a means to acquire deeper insights into cellular functions. The lack of standardized and automated methodologies poses a challenge for the analysis and interpretation of RNA sequencing data. We critically compare and evaluate state-of-the-art bioinformatics approaches and present a workflow that integrates the best performing data analysis, data evaluation and annotation methods in a Transparent, Reproducible and Automated PipeLINE (TRAPLINE) for RNA sequencing data processing (suitable for Illumina, SOLiD and Solexa). RESULTS: Comparative transcriptomics analyses with TRAPLINE result in a set of differentially expressed genes, their corresponding protein-protein interactions, splice variants, promoter activity, predicted miRNA-target interactions and files for single nucleotide polymorphism (SNP) calling. The obtained results are combined into a single file for downstream analysis such as network construction. We demonstrate the value of the proposed pipeline by characterizing the transcriptome of our recently described stem cell derived antibiotic selected cardiac bodies ('aCaBs'). CONCLUSION: TRAPLINE supports NGS-based research by providing a workflow that requires no bioinformatics skills, decreases the processing time of the analysis and works in the cloud. The pipeline is implemented in the biomedical research platform Galaxy and is freely accessible via www.sbi.uni-rostock.de/RNAseqTRAPLINE or the specific Galaxy manual page (https://usegalaxy.org/u/mwolfien/p/trapline---manual).

Non-viral magnetic engineering of endothelial cells with microRNA and plasmid-DNA-An optimized targeting approach.

Genetic modulation of angiogenesis is a powerful tool for the treatment of multiple disorders. Here, we describe a strategy to produce modified endothelial cells, which can be efficiently magnetically guided. First, we defined optimal transfection conditions with both plasmid and microRNA, using a polyethyleneimine/magnetic nanoparticle-based vector (PEI/MNP), previously designed in our group. Further, two approaches were assessed in vitro: direct vector guidance and magnetic targeting of transfected cells. Due to its higher efficiency, including simulated dynamic conditions, production of miR/PEI/MNP-modified magnetically responsive cells was selected for further detailed investigation. In particular, we have studied internalization of transfection complexes, functional capacities and intercellular communication of engineered cells and delivery of therapeutic miR. Moreover, we demonstrated that 104 miRNA/PEI/MNP-modified magnetically responsive cells loaded with 0.37pg iron/cell are detectable with MRI. Taken together, our in vitro findings show that PEI/MNP is highly promising as a multifunctional tool for magnetically guided angiogenesis regulation.

Do oral bacteria alter the regenerative potential of stem cells? A concise review.

Mesenchymal stem cells (MSCs) are widely recognized as critical players in tissue regeneration. New insights into stem cell biology provide evidence that MSCs may also contribute to host defence and inflammation. In case of tissue injury or inflammatory diseases, e.g. periodontitis, stem cells are mobilized towards the site of damage, thus coming in close proximity to bacteria and bacterial components. Specifically, in the oral cavity, complex ecosystems of commensal bacteria live in a mutually beneficial state with the host. However, the formation of polymicrobial biofilm communities with pathogenic properties may trigger an inadequate host inflammatory-immune response, leading to the disruption of tissue homoeostasis and development of disease. Because of their unique characteristics, MSCs are suggested as crucial regulators of tissue regeneration even under such harsh environmental conditions. The heterogeneous effects of bacteria on MSCs across studies imply the complexity underlying the interactions between stem cells and bacteria. Hence, a better understanding of stem cell behaviour at sites of inflammation appears to be a key strategy in developing new approaches for in situ tissue regeneration. Here, we review the literature on the effects of oral bacteria on cell proliferation, differentiation capacity and immunomodulation of dental-derived MSCs.

The CD4(+) AT2R(+) T cell subpopulation improves post-infarction remodelling and restores cardiac function.

Myocardial infarction (MI) is a major condition causing heart failure (HF). After MI, the renin angiotensin system (RAS) and its signalling octapeptide angiotensin II (Ang II) interferes with cardiac injury/repair via the AT1 and AT2 receptors (AT1R, AT2R). Our study aimed at deciphering the mechanisms underlying the link between RAS and cellular components of the immune response relying on a rodent model of HF as well as HF patients. Flow cytometric analyses showed an increase in the expression of CD4(+) AT2R(+) cells in the rat heart and spleen post-infarction, but a reduction in the peripheral blood. The latter was also observed in HF patients. The frequency of rat CD4(+) AT2R(+) T cells in circulating blood, post-infarcted heart and spleen represented 3.8 ± 0.4%, 23.2 ± 2.7% and 22.6 ± 2.6% of the CD4(+) cells. CD4(+) AT2R(+) T cells within blood CD4(+) T cells were reduced from 2.6 ± 0.2% in healthy controls to 1.7 ± 0.4% in patients. Moreover, we characterized CD4(+) AT2R(+) T cells which expressed regulatory FoxP3, secreted interleukin-10 and other inflammatory-related cytokines. Furthermore, intramyocardial injection of MI-induced splenic CD4(+) AT2R(+) T cells into recipient rats with MI led to reduced infarct size and improved cardiac performance. We defined CD4(+) AT2R(+) cells as a T cell subset improving heart function post-MI corresponding with reduced infarction size in a rat MI-model. Our results indicate CD4(+) AT2R(+) cells as a promising population for regenerative therapy, via myocardial transplantation, pharmacological AT2R activation or a combination thereof.

Exploiting AT2R to Improve CD117 Stem Cell Function In Vitro and In Vivo--Perspectives for Cardiac Stem Cell Therapy.

BACKGROUND/AIMS: CD117(+) stem cell (SC) based therapy is considered an alternative therapeutic option for terminal heart disease. However, controversies exist on the effects of CD117(+) SC implantation. In particular, the link between CD117(+) SC function and angiotensin-II-type-2 receptor (AT2R) after MI is continuously discussed. We therefore asked whether 1) AT2R stimulation influences CD117(+) SC properties in vitro and, 2) which effects can be ascribed to AT2R stimulation in vivo. METHODS: We approached AT2R stimulation with Angiotensin II while simultaneously blocking its opponent receptor AT1 with Losartan. CD117 effects were dissected using a 2D-Matrigel assay and HL-1 co-culture in vitro. A model of myocardial infarction, in which we implanted EGFP(+) CD117 SC, was further applied. RESULTS: While we found indications for AT2R driven vasculogenesis in vitro, co-culture experiments revealed that CD117(+) SC improve vitality of cardiomyocytes independently of AT2R function. Likewise, untreated CD117(+) SC had a positive effect on cardiac function and acted cardioprotective in vivo. CONCLUSIONS: Therefore, our data show that transient AT2R stimulation does not significantly add to the beneficial actions of CD117(+) SC in vivo. Yet, exploiting AT2R driven vasculogenis via an optimized AT2R stimulation protocol may become a promising tool for cardiac SC therapy.

Defining optimized properties of modified mRNA to enhance virus- and DNA- independent protein expression in adult stem cells and fibroblasts.

BACKGROUND: By far, most strategies for cell reprogramming and gene therapy are based on the introduction of DNA after viral delivery. To avoid the high risks accompanying these goals, non-viral and DNA-free delivery methods for various cell types are required. METHODS: Relying on an initially established PCR-based protocol for convenient template DNA production, we synthesized five differently modified EGFP mRNA (mmRNA) species, incorporating various degrees of 5-methylcytidine-5'-triphosphate (5mC) and pseudouridine-5'-triphosphate (Ψ). We then investigated their effect on i) protein expression efficiencies and ii) cell viability for human mesenchymal stem cells (hMSCs) and fibroblasts from different origins. RESULTS: Our protocol allows highly efficient mmRNA production in vitro, enabling rapid and stable protein expression after cell transfection. However, our results also demonstrate that the terminally optimal modification needs to be defined in pilot experiments for each particular cell type. Transferring our approach to the conversion of fibroblasts into skeletal myoblasts using mmRNA encoding MyoD, we confirm the huge potential of mmRNA based protein expression for virus- and DNA-free reprogramming strategies. CONCLUSION: The achieved high protein expression levels combined with good cell viability not only in fibroblasts but also in hMSCs provides a promising option for mmRNA based modification of various cell types including slowly proliferating adult stem cells. Therefore, we are confident that our findings will substantially contribute to the improvement of efficient cell reprogramming and gene therapy approaches.

Arthralgia and blood culture-negative endocarditis in middle Age Men suggest tropheryma whipplei infection: report of two cases and review of the literature.

BACKGROUND: Whipple's disease is a rare, often multisystemic chronic infectious disease caused by the rod-shaped bacterium Tropheryma whipplei. Very rarely the heart is involved in the process of the disease, leading to culture-negative infective endocarditis. Up to 20 % of all infective endocarditis are blood culture-negative and therefore a diagnostic challenge. We present two unusual cases of culture-negative infective endocarditis encountered in two different patients with prior history of arthralgia. A history of rheumatic arthritis or even a transient arthralgia should put Tropheryma whipplei on the top of differentials in patients of this age group presenting with culture-negative infective endocarditis, especially in cases of therapy resistance to antirheumatic agents. CASE PRESENTATION: The first patient was a 55 year-old Caucasian male with culture-negative Whipple-related adhesive pericarditis and endocarditis of the aortic valve. Importantly, the patient reported a 15-year history of therapy resistant sero-negative migratory polyarthritis. Aortic valve endocarditis developed during treatment with tocilizumab. The second patient was a 65-year-old male patient with no prior history of the classic Whipple's disease who presented with a culture-negative aortic valve endocarditis. His past medical history revealed episodes of transient arthralgia, which he was not treated for however, due to the self-limiting nature of the symptoms. Both patients underwent aortic valve replacement surgery. During surgery, pericardectomy was necessary in the first patient due to adhesive pericarditis. Post surgery both patients were started on long-term treatment with trimetoprim-sulfamethoxazol. At 1-year follow-up of both patients, echocardiographic and clinical assessment revealed no signs of persistent infection. Both men reported negative history of arthralgia during the one year period post surgery. CONCLUSION: Tropheryma whipplei culture negative-infective endocarditis is an emerging clinical entity, predominantly found in middle-aged and older men with a history of arthralgia. These data highlight the need for ruling out Whipple's disease in patients with a history of arthralgia prior to initiation of biological agents in treatment of rheumatoid arthritis. There is also a need to assess for Tropheryma whipplei in all patients with culture- negative infective endocarditis.

Awake extracorporeal membrane oxygenation (ECMO) as bridge to recovery after left main coronary artery occlusion: a promising concept of haemodynamic support in cardiogenic shock.

Cardiogenic shock following acute myocardial infarction is associated with high mortality rate. Different management concepts including fluid management, inotropic support, intra aortic balloon counterpulsation (IABP) and extracorporeal membrane oxygenation (ECMO) mainly in mechanically ventilated patients have been used as cornerstones of management. However, success rates have been disappointing. Few reports suggested that ECMO when performed under circumvention of mechanical ventilation, may offer some survival benefits. We herein present our experience with the use of veno-arterial ECMO as bridge to recovery in an awake and spontaneously breathing patient after left main coronary artery occlusion complicated by cardiogenic shock.

Dental follicle progenitor cells responses to Porphyromonas gingivalis LPS.

Periodontitis is a bacterially induced chronic inflammatory disease. Dental follicle progenitor cells (DFPCs) have been proposed as biological graft for periodontal regenerative therapies. The potential impact of bacterial toxins on DFPCs properties is still poorly understood. The aim of this study was to investigate whether DFPCs are able to sense and respond to lipopolysaccharide (LPS) from Porphyromonas gingivalis, a major periopathogenic bacterium. Specifically, we hypothesized that LPS could influence the migratory capacity and IL-6 secretion of DFPCs. DFPCs properties were compared to bone marrow mesenchymal stem cells (BMSCs), a well-studied class of adult stem cells. The analysis by flow cytometry indicated that DFPCs, similar to BMSCs, expressed low levels of both toll-like receptor (TLR) 2 and 4. The TLR4 mRNA expression was down-regulated in response to LPS in both cell populations, while on protein level TLR4 was significantly up-regulated on BMSCs. The TLR2 expression was not influenced by the LPS treatment in both DFPCs and BMSCs. The migratory efficacy of LPS-treated DFPCs was evaluated by in vitro scratch wound assays and found to be significantly increased. Furthermore, we assayed the secretion of interleukin-6 (IL-6), a potent stimulator of cell migration. Interestingly, the levels of IL-6 secretion of DFPCs and BMSCs remained unchanged after the LPS treatment. Taken together, these results suggest that DFPCs are able to sense and respond to P. gingivalis LPS. Our study provides new insights into understanding the physiological role of dental-derived progenitor cells in sites of periodontal infection.