[Show abstract][Hide abstract] ABSTRACT: A multitude of stem cell types has been extensively studied and used for myocardial regenerative therapy. Amongst these endothelial progenitor cells form a promising source. In our present study, we investigated a one-staged approach for isolation and application of autologous endothelial progenitor cells in a pig model of myocardial infarction. Endothelial progenitor cell isolation was performed by immediately preprocedural bone marrow aspiration and consecutive positive selection by aptamer-based magnetic cell sorting. Animals were divided in three groups receiving endothelial progenitor cells, saline, or no intramyocardial injection respectively. Postprocedural follow-up consisted of weekly echocardiographic evaluations. Postmortem histological analysis after four weeks focused on detection of transplanted PKH26-positive endothelial progenitor cells and neovascularization within the infarcted myocardium. A significant difference in left ventricular ejection fraction could not be shown between the three groups. PKH26-stained endothelial progenitor cells could be found in the endothelial progenitor cells transplanted group, although detection was scarce. Large-sized capillaries were found to be significantly more in endothelial progenitor cells treated myocardium. The one-stage approach of endothelial progenitor cells isolation and application presented herein offers a new therapeutic concept. Even though a beneficial impact on myocardial function could not be assessed, increased neovascularization may indicate positive effects on remodeling processes. Being able to harvest endothelial progenitor cells right before application provides a wider scope of action in urgent cases.
[Show abstract][Hide abstract] ABSTRACT: Enterococci are among the major pathogens implicated in cardiac infections and biofilm formation. E. faecalis has been shown to play an important role in infectious endocarditis. Several distinct mechanisms for biofilm formation have been identified in E. faecalis. Our group has previously characterized two distinct bacterial glucosyltransferases playing key roles in the production of the major cell wall glycolipids and leading to reduced biofilm production. To assess if this mechanism is involved in the pathogenesis of enterococcal endocarditis we compared the wild-type strain of E. faecalis 12030 with two mutants in gene EF2891 and EF2890 respectively in a rat model of infective endocarditis. The results showed less endocarditic lesions and reduced colony counts per vegetation in the two mutants. indicating that the modification of bacterial surface lipids results in significantly reduced virulence in infective endocarditis. These results underscore the important role of biofilm formation in the pathogenicity of enterococcal endocarditis and may indicate an interesting target for novel therapeutic strategies.
PLoS ONE 03/2014; 9(3):e91863. DOI:10.1371/journal.pone.0091863 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this protocol we provide a method to isolate dendritic cells (DC) and epithelial cells (TEC) from the human thymus. DC and TEC are the major antigen presenting cell (APC) types found in a normal thymus and it is well established that they play distinct roles during thymic selection. These cells are localized in distinct microenvironments in the thymus and each APC type makes up only a minor population of cells. To further understand the biology of these cell types, characterization of these cell populations is highly desirable but due to their low frequency, isolation of any of these cell types requires an efficient and reproducible procedure. This protocol details a method to obtain cells suitable for characterization of diverse cellular properties. Thymic tissue is mechanically disrupted and after different steps of enzymatic digestion, the resulting cell suspension is enriched using a Percoll density centrifugation step. For isolation of myeloid DC (CD11c(+)), cells from the low-density fraction (LDF) are immunoselected by magnetic cell sorting. Enrichment of TEC populations (mTEC, cTEC) is achieved by depletion of hematopoietic (CD45(hi)) cells from the low-density Percoll cell fraction allowing their subsequent isolation via fluorescence activated cell sorting (FACS) using specific cell markers. The isolated cells can be used for different downstream applications.
Journal of Visualized Experiments 10/2013; DOI:10.3791/50951 · 1.33 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Cold Ischemia-Reperfusion Injury (CIRI) is regarded as the major cause of early graft dysfunction after cardiac transplantations and is associated with rejection episodes. Consequently, it is one of the main therapeutic targets in order to improve survival after heart transplantation. The aim of this study was to evaluate hemodynamic effects of milrinone and its influence on the markers of myocardial damage when used in a piglet working heart model with a cold ischemia-reperfusion setting.
Methods: Hearts of 18 piglets were examined in a homologous blood-perfused, working heart model to get baseline measurements. After hypothermic cardioplegic arrest and storage on ice for 60 minutes, the hearts received either milrinone or served as controls. All hearts were examined for 45 minutes in the working heart model. Hemodynamic parameter changes, h-FABP levels and myocardial oxygen consumption were assessed.
Results: Significant difference between the groups was observed in cardiac output (MIL +14% vs. CON -33%; p<0.05), coronary sinus blood flow (MIL +84% vs. CON +17%; p<0.05) and relaxation (MIL +5% vs. CON -22%; p<0.01). In addition, significantly higher h-FABP (heart fatty acid binding proteine) levels after cold ischemia were measured in CON group (CON: 18.75 ng/ml; MIL 6.29 ng/ml; p<0.01).
Conclusions: Milrinone has a positive effect on cardiac function after cardioplegic cardiac arrest with following cold-ischemia period in an isolated piglet heart model. Its use in a heart transplantation setting induces an improved hemodynamic performance and a better preservation from reperfusion injury.
[Show abstract][Hide abstract] ABSTRACT: A driveline exit site infection is a serious and common complication in long-term left ventricular assist device (LVAD) support. To reduce the incidence and severity of late driveline infections, we modified our surgical technique (double tunnel), and compared it to the conventional short and straight driveline tunnel technique (conventional). We analyzed 43 consecutive patients (37 HeartMate II; 6 Ventrassist) regarding late onset driveline exit site infections after using the surgical driveline tunnel technique after successful LVAD implantation. Of these 43 patients, 11 were treated with the conventional short and straight driveline tunnel technique (conventional), while 32 patients were treated with the modified long subfascial, C-shaped technique (double tunnel). We observed slightly fewer superficial driveline exit site infections in the double tunnel group, even though the difference was not statistically significant (0.638 vs. 1.148 infections/1,000 patient-days; P = 0.22). There were also insignificantly fewer surgical interventions because of exit site infections in the double tunnel group (0.159 vs. 0.581 revisions/1,000 patient-days; P = 0.18). The double tunnel technique offers more surgical options in the case of driveline exit site infections. Due to the long subfascial tunnel, the infected site can be separated from the new driveline exit site, and vacuum-assisted closure therapy can be applied to the infected area. In conclusion, we recommend using the double tunnel driveline technique because of the low infection rate and better treatment options in the case of driveline exit site infection.