[Show abstract][Hide abstract] ABSTRACT: The therapeutic efficiency of bone marrow mononuclear cells (BMMNCs) autologous transplantation for myocardial infarction (MI) remains low. Here we developed a novel strategy to improve cardiac repair by preconditioning BMMNCs via angiotensin II type 2 receptor (AT2R) stimulation.
Acute MI in rats led to a significant increase of AT2R expression in BMMNCs. Preconditioning of BMMNCs via AT2R stimulation directly with an AT2R agonist CGP42112A or indirectly with angiotensin II plus AT1R antagonist valsartan led to ERK activation and increased eNOS expression as well as subsequent nitric oxide generation, ultimately improved cardiomyocyte protection in vitro as measured by co-culture approach. Intramyocardial transplantation of BMMNCs preconditioned via AT2R stimulation improved survival of transplanted cells in ischemic region of heart tissue and reduced cardiomyocyte apoptosis and inflammation at 3 days after MI. At 4 weeks after transplantation, compared to DMEM and non-preconditioned BMMNCs group, AT2R stimulated BMMNCs group showed enhanced vessel density in peri-infarct region and attenuated infarct size, leading to global heart function improvement.
Preconditioning of BMMNCs via AT2R stimulation exerts protective effect against MI. Stimulation of AT2R in BMMNCs may provide a new strategy to improving therapeutic efficiency of stem cells for post MI cardiac repair.
PLoS ONE 12/2013; 8(12):e82997. DOI:10.1371/journal.pone.0082997 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objectives: Dental follicle progenitor cells (DFPCs) are promising candidates for cell-based periodontal regenerative therapies. Thus, the exposure of DFPCs to the bacterial milieu of periodontal pockets would be highly possible. Nucleotide-binding Oligomerization Domain (NOD) 1 and NOD2 are able to induce host immune responses by recognizing fragments of bacterial components. Aim of this pilot study was to investigate the profile of NOD1 and NOD2 gene expression by DFPCs.
Methods: DFPCs were first isolated from healthy impacted wisdom teeth by their ability to adhere to plastic. After assaying their multipotent potential, DFPCs were examined for gene expression of NOD1 and NOD2 by RT-PCR. Then, DFPCs were treated with LPS in order to evaluate the fold change in NOD1 and NOD2 gene expression. Cell viability of LPS-treated cells was tested by MTT assay. NODs gene expression by DFPCs was compared to bone marrow mesenchymal stem cells (BMSCs), a well-studied class of adult stem cells.
Results: DFPCs, as BMSCs, possessed typical stem cell-like properties. Both cell populations showed low NOD1 and NOD2 gene expression levels. Interestingly, the expression of NOD1 was significantly higher than NOD2 in both cell populations. After LPS treatment, NOD1 gene expression was down-regulated in DFPCs, whereas the expression of NOD2 was not significantly affected. LPS-treated BMSCs showed higher expression of NOD2 mRNA compared to untreated controls. Noticeably, NOD1 gene expression in BMSCs was highly variable after the LPS treatment. Finally, LPS provoked no cytotoxic effects on cells.
Conclusion: Our findings demonstrate gene expression of NOD1 and NOD2 by DFPCs, as well as BMSCs. LPS treatment may provoke changes in NODs expression profile in both cell populations. Further studies are needed to unveil the possible role of NOD1 and NOD2 in human dental-derived progenitor cells being exposed to bacterial toxin-rich environments.
Annual Meeting of the IADR Continental European Division 2013; 09/2013
[Show abstract][Hide abstract] ABSTRACT: Objectives CD133pos cells are currently evaluated for use in cardiac cell therapy. We hypothesized that they exert their beneficial effects in a paracrine manner and investigated this in a cell culture ischaemia model. Furthermore, we checked whether purified CD133pos cells perform better than non-fractionated mononuclear cells (MNC). Methods CD133pos cells were isolated from bone marrow MNC and conditioned medium was prepared from CD133pos and non-fractionated MNC. HL-1 cardiomyocytes were subjected to simulated ischaemia in the respective conditioned media or in control medium. After treatment, total remaining cells, apoptotic cells and nuclear shrinking were quantified using an automated imaging system. Furthermore, metabolic activity and phosphorylation of kinases Akt, Erk1/2, GSK3b and transcription factor Stat3 were investigated. Results After simulated ischaemia, the rate of detached dead cells was lowest in CD133pos conditioned medium (26 ± 6%) and highest in control medium (36 ± 6%). In CD133pos conditioned medium, the fraction of non-apoptotic cells was most enhanced and nuclear shrinking as a consequence of apoptosis was reduced. Cell viability was also highest in CD133pos conditioned medium (109.4 ± 8.8% in relation to control). In both conditioned media, phosphorylation of Akt, Erk1/2, and GSK3b was lower than in control medium. Stat3 phosphorylation was sustained on the level of control. Conclusions Factors released from purified CD133pos bone marrow cells exhibit more pronounced protective effects on HL-1 cardiomyocytes under simulated ischaemia than from non-fractionated MNC. These effects are not associated with the phosphorylation of cell survival promoting kinases Akt, Erk1/2, GSK3b and transcription factor Stat3. Although the molecular mechanism of cardioprotection by CD133pos cells requires further investigation, our results reinforce the advantage of enriching CD133pos cells for cardiac cell therapy. Conflict of interest and funding No conflict of interest declared. This work was supported by the German Ministry of Education and Research [BMBF FKZ 0312138A].
Interactive cardiovascular and thoracic surgery; 02/2013
[Show abstract][Hide abstract] ABSTRACT: As research institutions prepare roadmaps for "systems medicine", we ask how this differs from applications of systems biology approaches in medicine and what we (should) have learned from about one decade of funding in systems biology. After surveying the area, we conclude that systems medicine is the logical next step and necessary extension of systems biology with a focus on clinically relevant applications. We specifically discuss three related notions. First, more interdisciplinary collaborations are needed to face the challenges of integrating basic research and clinical practice: integration, analysis, and interpretation of clinical and non-clinical data for diagnosis, prognosis, and therapy require advanced statistical, computational and mathematical tools. Second, strategies are required to (a) develop and maintain computational platforms for integration of clinical and non-clinical data, (b) to further develop technologies for quantitative and time-resolved tracking of changes in gene expression, cell signaling, and metabolism in relation with environmental and lifestyle influences, (c) to develop methodologies for mathematical and statistical analyses of integrated data sets and multilevel models. Third, interdisciplinary collaborations represent a major challenge and are difficult to implement. For an efficient and successful initiation of interdisciplinary systems medicine programmes, we argue that epistemological, ontological, and sociological aspects require attention.Pediatric Research (2013); doi:10.1038/pr.2013.4.
Pediatric Research 01/2013; 73(4). DOI:10.1038/pr.2013.4 · 2.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Manufacturing life-long functional cardiovascular (CV) implants is the ultimate goal for researchers and clinicians in the cardiothoracic field. Tissue engineering (TE) is an opportunity to create ideal prostheses that are vital, growing, adaptive, autologous and functionally optimally performing. Today, initial translation from basic science to first clinical trials has begun. The article depicts the state of the art in TE techniques for CV products and describes milestones in the ongoing development of tissue-engineered myocardial, valvular and vascular devices from an experimental and clinical point of view. Artificial CV implants still reveal remarkable limitations but promising advances regarding optimal structural design, the prevention of intimal hyperplasia and the reduction of antigenicity and thrombogenicity. Where applicable, the implantation of vascularized autografts should still be preferred. Apart from that, decellularized allogen bioprostheses currently represent most promising matrix scaffolds that can be autologously cellularized in vitro prior to or in vivo after implantation. Capable biologic alternatives have been described like the decellularized porcine small intestinal submucosa. Rising evidence suggests that in vitro endothelialization might be the minimal requirement for improved long-term results of biological tissue-engineered CV grafts.
European Surgical Research 07/2012; 49(1):44-52. DOI:10.1159/000339606 · 2.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To evaluate the short-term outcome of patients predominantly at high risk treated with the MitraClip® device for severe mitral valve regurgitation (MR) using one or more clips.
We prospectively analyzed patients with highly symptomatic MR classified as inoperable (logistic EuroSCORE 24.16 ± 13.64%; STS-score 29.9 ± 14.5%) but subject to mitral valve repair with MitraClip® between May 2010 and January 2011. Thirty-three consecutive patients (57.6% male; age 77.8 ± 6.7 years) were enrolled and treated with either 1 (n = 7; 21.2%), 2 (n = 20; 60.6%), 3 (n = 4; 12.1%), or 4 (n = 2, 6.1%) clips. Grading of MR was performed by two-dimensional transesophageal echocardiography (2D-TEE) prior to TEE-guided clipping and before discharge.
MR was classified as functional in 23 (69.7%) and organic in 10 (30.3%) of the patients with MR-grade ≥ 3+ in 32 (97%) and = 4 in 1 patients (3%) before repair. Reduction in MR grade to grade ≤1+ was achieved in 81.7% and to 2 in 12.1% (P = 0.00072). Invasive pulmonary artery systolic pressure (PAPsyst) and pulmonary capillary wedge pressure (PCWP) v-wave decreased from 59.2 ± 18.6 to 46.9 ± 15.3 mmHg (P = 0.00014) and 21.2 ± 6.7 to 8.0 ± 3.3 mmHg (P = 0.0093), respectively, as measured immediately after clipping. Functional NYHA class improved from mean 3 (range 3 [90.9%] to 4 [9.1%]) to 2 in 84.9% (P = 0.00081) as obtained at discharge.
Mitral valve repair with MitraClip® using multiple clips is appropriate and safe in unselected patients resulting in reduced MR with positive impact on short-term functional capacity.
[Show abstract][Hide abstract] ABSTRACT: The identification of dental follicle progenitor cells (DFPCs) has stimulated interest in their potential use in stem cell-based therapies to treat periodontitis. However, the inflammatory state of periodontal disease displays a major challenge to such therapeutical approaches. Objectives: In this study, we challenged human DFPCs with Porphyromonas gingivalis lipopolysaccharide (P.g-LPS) - a major etiological factor in periodontitis - and assayed the response of DFPCs in terms of viability and secretion of interleukin-6 (IL-6), a pleiotropic cytokine that is considered as an osteolytic factor involved in periodonitis. Methods: Human DFPCs were obtained from extracted wisdom teeth and characterized. Second passage cells were subsequently stimulated with different concentrations of P.g.-LPS (0 μg/ml, 1 μg/ml, 10 μg/ml and 50 μg/ml) respectively. After 24 hours of incubation cytotoxicity assays (MTT) were performed and concentration of secreted IL-6 in culture supernatants was determined by a specific enzyme-linked immunosorbent assay (ELISA). Human mesenchymal stem cells (MSCs) were used as a control group. Results: DFPCs were able to attach onto plastic surface, showed a typical fibroblast-like morphology and formed single-cell colonies. Furthermore, DFPCs could differentiate into adipocytes, osteoblasts and chondrocytes and were strongly positive to typical stem cell markers (CD29, CD44, CD73, CD90 and CD105). Interestingly, after LPS challenge no secretion of IL-6 was detected in the supernatants of DFPCs, while ELISA demonstrated the secretion of IL-6 by MSCs in a concentration-dependent manner. In terms of cytotoxicity, the challenge with LPS showed no statistically significant influence on both cell populations. Conclusion: The findings of this study indicate that P.g.-LPS do not affect DFPCs regarding their viability and IL-6 secretion.
45th Meeting of the Continental European Division of the International Association of Dental Research (CED-IADR) with the Scandinavian Division (NOF) 2011; 09/2011
[Show abstract][Hide abstract] ABSTRACT: Die chirurgische Korrektur kongenitaler Herzfehler kann heute mit exzellenten Resultaten durchgeführt werden. Postoperative,
chronische kardiale Belastungszustände sind insbesondere bei komplexen Anomalien nicht immer vermeidbar. Regenerative Therapiekonzepte
stellen zur komplementären Behandlung kongenitaler Herzfehler eine aussichtsreiche Option dar. In unseren Arbeiten wurden
in zwei experimentellen Modellen an Lämmern zur Druck- und Volumenbelastung der rechten Herzkammer jeweils autologe, mononukleäre
Nabelschnurblutzellen und Erythropoietin eingesetzt. Die Effekte der intramyokardial applizierten mononukleären Zellen im
Volumenbelastungsmodell scheinen in erster Linie in einer Verbesserung der diastolischen rechtsventrikulären Funktion nach
3Monaten durch eine Erhöhung der Kapillardichte zu bestehen. Intramyokardial und systemisch verabreichtes Erythropoietin
hat nach unseren Ergebnissen einen positiven Einfluss auf Kapillardichte, Fibrosegrad und Proliferationsrate des Herzmuskels.
Weiterhin fanden wir eine niedrigere Aktivität von myokardialen Proteinen, welche die Apoptoseaktivität und die Inflammation
triggern. Die Elastizität des chronisch druckbelasteten rechten Ventrikels war nach 3Monaten in der Behandlungsgruppe signifikant
besser. Diese Daten stützen das Potenzial regenerativer Therapien in der komplementären Behandlung angeborener Herzfehler.
Nowadays surgical treatment of congenital heart disease can be performed with excellent outcome. However, chronic postoperative
cardiac overload cannot always be obviated especially with more complex anomalies. Therefore, regenerative therapeutic concepts
may offer promising options for complementary management of congenital heart disease. In this study umbilical cord blood mononuclear
cells and erythropoietin were employed in two different models for volume and pressure overload of the right ventricle, respectively.
Enhancement of myocardial capillary density seems to be the most significant effect of the intramyocardial application of
umbilical cord mononuclear cells for a significant improvement of diastolic properties of the right ventricle after 3 months
chronic volume overload. Erythropoietin, which was administered via an intramyocardial and systemic route, has positive effects
by enhancing capillary density, limiting fibrosis and augmenting proliferation activity of the myocardium. In addition lower
apoptosis and inflammation could be observed at the level of myocardial protein expression. Hence, the elasticity of the chronically
pressure overloaded ventricle was superior with erythropoietin treatment than in the control group 3 months postoperatively.
These data support the potential of regenerative therapies in the complementary therapy of congenital heart disease.
SchlüsselwörterMyokardiale Regeneration–Nabelschnurblut–Zelltherapie–Erythropoietin–Angeborene Herzfehler
KeywordsMyocardial regeneration–Umbilical cord blood–Cell therapy–Erythropoietin–Congenital heart disease
Zeitschrift für Herz- Thorax- und Gefäßchirurgie 08/2011; 25(4):235-240. DOI:10.1007/s00398-011-0862-x
[Show abstract][Hide abstract] ABSTRACT: In cardiac stem cell therapy, the past decade has been interesting with respect to preclinical and clinical research. The high diversity of applied stem cell populations and evaluation methods represent a challenge to fully understand the impact of stem cell administration, leaving uncertain answers to the questions that have been dealt with thus far. In the present work, registered studies in cardiac stem cell therapy are summarized and the study aims are highlighted. Furthermore, preliminary data on the additional intramyocardial administration of CD133+ stem cells in patients undergoing mitral valve surgery are presented.
[Show abstract][Hide abstract] ABSTRACT: Numerous studies have confirmed that stem cell therapy has significant potential for the regeneration of congenital and acquired heart diseases. The utilization of embryonic stem cells and induced pluripotent stem cells promises a possible generation and regeneration of all cardiovascular structures. On the one hand fetal and adult stem cells, e.g. endothelial progenitors, mesenchymal, hematopoietic, cardiac stem cells and myoblasts, possess limited potential for multilinear differentiation. On the other hand these cells have high paracrin activity and support with well-confirmed safety the reconstruction and formation of cardiovascular structures. On the visionary track towards an autonomously functioning autologous heart generated by tissue engineering, vascular, valvular and myocardial tissues have already been successfully created. This manuscript describes the possible stem cell sources for cardiovascular tissue engineering and evaluates their potency and safety from a medical and ethical point of view employing the data from systematic reviews (Medline database) and own investigations.
Der Chirurg 03/2011; 82(4):295-302. DOI:10.1007/s00104-010-2030-3 · 0.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chronic ischemic heart disease remains one of the most important causes of morbidity and mortality worldwide. Although revascularisation procedures and conventional drug therapy may delay ventricular remodelling, there is no basic therapeutic regime available to prevent or even reverse this process. Chronic coronary artery disease and heart failure impair quality of life and are associated with subsequent worsening of left ventricular function. In the recent past experimental and clinical studies have demonstrated the capacity of bone marrow stem cells in cardiac repair and regeneration of compromised heart muscle. Several clinical trials showed the safety and efficacy of autologous bone marrow stem cell transplantation in the patients with acute myocardial infarction or chronic ischemic heart disease. Today the therapeutic strategy of cell administration during cardiac surgery or coronary artery intervention is entering the clinical practice. Biological as well as methodological backgrounds, indications and clinical results of cardiac stem cell therapy for the treatment of acute myocardial infarction and chronic ischemic heart disease are reviewed.
[Show abstract][Hide abstract] ABSTRACT: Coronary heart disease and chronic heart failure are common and have an increasing frequency. Although revascularisation procedures and conventional drug therapy may delay ventricular remodelling, there is no basic therapeutic regime available for preventing or even reversing this process. Chronic coronary artery disease and heart failure impair quality of life and are associated with subsequent worsening of the cardiac pump function. Numerous studies within the past few years have been demonstrated, that cardiac stem cell therapy has to be considered a safe therapeutic procedure in heart disease, when destroyed and/or compromised heart muscle must be regenerated. Different autologous or allogenic progenitor cell populations have been addressed for cardiac cell therapy. This kind of cell therapy with autologous bone marrow cells is completely justified ethical, except for the small numbers of patients with direct or indirect bone marrow disease (e.g. myeloma, leukaemic infiltration) in whom there would be intrinsic lesions of mononuclear cells. Several preclinical as well as clinical trials have shown that transplantation of autologous bone marrow stem cells or precursor cells improve cardiac function after myocardial infarction and in chronic ischemic heart disease. The age of infarction seems to be irrelevant to regenerative potency of stem cells, since stem cell therapy in old infarctions (many years old) is almost equally effective in comparison to previous infarcts. Further indications are non-ischemic and diabetic cardiomyopathy (dilated cardiomyopathy) as well as heart failure due to an infectious cause like Chagas heart disease. Further clinical development is aimed to modify cardiac inflammation and cardiogenesis by stem cell modification and to test other stem cell sources.
[Show abstract][Hide abstract] ABSTRACT: Zusammenfassung Erythropoietin (EPO) ist ein hypoxieinduziertes Wachstumshormon mit pleiotropischem Wirkungsprofil. Die EPO-vermittelten Haupteffekte
nach myokardialer Ischämie umfassen Apoptoseinhibition, Entzündungsmodifikation, Angiogenese und Reverse Remodeling. Darüber
hinaus erscheinen Synergismen mit stammzellassoziierter Kardioregeneration sowie die Induktion intrakardialer Proliferation
therapeutisch nutzbar. Infolge wiederholten Nachweises therapeutischer Effizienz tritt EPO zunehmend in den Fokus des klinischen
Interesses. Nachfolgender Beitrag erläutert mögliche Indikationen, translationale Richtlinien sowie Risiken während präklinischer
und klinischer Studien. Applikationsdosierungen, -zeitpunkte, -routen und EPO-Derivate wurden entsprechend mittels systematischer
Literaturrecherche (Medline Datenbank) und eigener Studien gegeneinander evaluiert.
Zeitschrift für Herz- Thorax- und Gefäßchirurgie 12/2010; 24(6). DOI:10.1007/s00398-010-0806-x
[Show abstract][Hide abstract] ABSTRACT: Die regulierenden Signalwege, welche die Migration von therapeutisch applizierten Stammzellen („homing“) beispielsweise in
ein ischämisch geschädigtes Myokard vermitteln, sind bisher nur in Ansätzen untersucht. In unserer Arbeitsgruppe haben wir
die Interaktionen von Knochenmarkstammzellen und Gefäßendothel, in Abhängigkeit von lokaler Inflammation sowie endothelialer
Stickoxid(NO)produktion, in der Mikrozirkulation einer Maus untersucht. Hierzu wurden ein etabliertes Tiermodell sowie die
intravitale Fluoreszenzmikroskopie angewandt. Es konnte gezeigt werden, dass die Präsenz des Chemokins SDF-1α in Kombination
mit lokaler Stimulation durch TNF-α selektiv die Interaktion von c-kit+-Knochenmarkstammzellen mit dem Gefäßendothel in extramedullärem Gewebe verstärkt. Weiterhin konnte gezeigt werden, dass sowohl
die Expression als auch die Funktion der endothelialen NO-Synthase für diesen adhäsionsverstärkenden Effekt von SDF-1α bei
einer entzündlichen Gewebssituation unabdingbar sind. Therapieprotokolle, die eine intravaskuläre Stammzellapplikation vorsehen,
sollten die lokale endotheliale NO-Produktion als limitierenden Faktor der Zellmigration berücksichtigen.
The underlying mechanisms of stem cell migration after therapeutic application to non-marrow tissue, e.g., in ischemia-damaged
myocardium, have not been clarified. In order to analyzse the role of stromal cell-derived factor-1α (SDF-1α) and endothelial
nitric oxide synthase next toassociated with a local inflammatory response, we studied peripheral c-kit+ stem cell interactions with the local vascular endothelium in vivo using a mouse model of intravital microscopy. We were
able to showIn this study, it was shown that besides the presence of SDF-1α, an inflammatory response induced by local tumor
necrosis factor-α (TNF-α) treatment is needed for relevant stem cell interactions with the vascular endothelium in vivo. Moreover,
the presence of endothelial nitric oxide synthase (eNOS) appears to be a crucial factor for firm c-kit+ stem cell adhesion to the vascular endothelium.
KeywordsMyocardial infarction-Ischemic heart disease-Stem cells-Cell migration-Stromal cell-derived factor-1α
Zeitschrift für Herz- Thorax- und Gefäßchirurgie 10/2010; 24(5):317-323. DOI:10.1007/s00398-010-0800-3