Electrostimulation induces cardiomyocyte predifferentiation of fibroblasts

Cardiac Regeneration Laboratories, Heart, Lung, and Esophageal Surgery Institute, University of Pittsburgh Medical Center and McGowan Institute for Regenerative Medicine, 3025 Carson Street, Pittsburgh, PA 15203, USA.
Biochemical and Biophysical Research Communications (Impact Factor: 2.3). 07/2008; 370(3):450-5. DOI: 10.1016/j.bbrc.2008.03.115
Source: PubMed


Stem-cell therapy has become a promising therapeutic tool for myocardial repair. Cardiac pre-committed cells, which complete their differentiation in the myocardium, may reduce fibrosis and restore muscle function. However, many questions concerning a precise, functional integration of injected cells remain unanswered. Fibroblasts regulate the cardiac extracellular matrix and are the most abundant cell population in an infarcted area. Electrostimulation is a well-known trophic factor and can induce phenotypic changes in myoblasts. The objective of this study was to evaluate the effectiveness of electrical stimulation to induce pre-commitment of fibroblasts into cardiomyocytes in vitro. Using short-time electrostimulation in a cytokine-free culture system, we induced pre-commitment of two fibroblast cell lines to a cardiomyocyte phenotype. This partial differentiation in vitro may facilitate further differentiation within the cardiac environment and result in better electro-mechanical integration of the therapeutically introduced cells.

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    • "Furthermore, cellular uptake of these electroactive nanoparticles [4] [5] provides a platform for the manipulation of MSC differentiation pathways using electrical stimulation. Previous studies have shown that electrical stimulation promotes a range of cell responses including reorientation and angiogenesis [6], muscle cell regeneration [7e9], myogenesis of fibroblasts [10] [11], cardiomyogenesis of embryonic stem cells [12e14] and enhanced cardiomyocyte phenotype [15e17]. Some of the initial attempts at promoting cardiomyogenesis using mesenchymal stem cells (MSC) involved the use of the controversial demethylating agent 5-azacytidine [18], which has been shown to induce apoptosis in vivo [19]. "
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    ABSTRACT: Once damaged, cardiac muscle has little intrinsic repair capability due to the poor regeneration potential of remaining cardiomyocytes. One method of overcoming this issue is to deliver functional cells to the injured myocardium to promote repair. To address this limitation we sought to test the hypothesis that electroactive carbon nanotubes (CNT) could be employed to direct mesenchymal stem cell (MSC) differentiation towards a cardiomyocyte lineage. Using a two-pronged approach, MSCs exposed to medium containing CNT and MSCs seeded on CNT based polylactic acid scaffolds were electrically stimulated in an electrophysiological bioreactor. After electrical stimulation the cells reoriented perpendicular to the direction of the current and adopted an elongated morphology. Using qPCR, an upregulation in a range of cardiac markers was detected, the greatest of which was observed for cardiac myosin heavy chain (CMHC), where a 40-fold increase was observed for the electrically stimulated cells after 14 days, and a 12-fold increase was observed for the electrically stimulated cells seeded on the PLA scaffolds after 10 days. Differentiation towards a cardioprogenitor cell was more evident from the western blot analysis, where upregulation of Nkx2.5, GATA-4, cardiac troponin t (CTT) and connexin43 (C43) was seen to occur. This was echoed in immunofluorescent staining, where increased levels of CTT, CMHC and C43 protein expression were observed after electrical stimulation for both cells and cell-seeded scaffolds. More interestingly, there was evidence of increased cross talk between the cells as shown by the pattern of C43 staining after electrical stimulation. These results establish a paradigm for nanoscale biomimetic cues that can be readily translated to other electroactive tissue repair applications.
    Biomaterials 06/2012; 33(26):6132-9. DOI:10.1016/j.biomaterials.2012.05.032 · 8.56 Impact Factor
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    • "Using 21 days of electrostimulation, cell proliferation was 40% higher than control non-stimulated cells (P=0.01). Previous studies showed a high incidence of cell death after electrostimulation.12–14 This is the first time that higher cell proliferation after three weeks of electrostimulation than control group has been demonstrated. "
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    ABSTRACT: Electrostimulation (ES) can be defined as a safe physical method to induce stem cell differentiation. The aim of this study is to evaluate the effectiveness of ES on bone marrow mesenchymal stem cells (BMSCs) seeded in collagen scaffolds in terms of proliferation and differentiation into cardiomyocytes. BMSCs were isolated from Wistar rats and seeded into 3D collagen type 1 templates measuring 25 × 25 × 6 mm. Bipolar in vitro ES was performed during 21 days. Electrical impedance and cell proliferation were measured. Expression of cardiac markers was assessed by immunocytochemistry. Viscoelasticity of collagen matrix was evaluated. Electrical impedance assessments showed a low resistance of 234±41 Ohms which indicates good electrical conductivity of collagen matrix. Cell proliferation at 570 nm as significantly increased in ES groups after seven day (ES 0.129±0.03 vs non-stimulated control matrix 0.06±0.01, P=0.002) and after 21 days, (ES 0.22±0.04 vs control 0.13±0.01, P=0.01). Immunocytoche mistry of BMSCs after 21 days ES showed positive staining of cardiac markers, troponin I, connexin 43, sarcomeric alpha-actinin, slow myosin, fast myosin and desmin. Staining for BMSCs marker CD29 after 21 days was negative. Electrostimulation of cell-seeded collagen matrix changed stem cell morphology and biochemical characteristics, increasing the expression of cardiac markers. Thus, MSC-derived differentiated cells by electrostimulation grafted in biological scaffolds might result in a convenient tissue engineering source for myocardial diseases.
    Heart International 06/2012; 7(2):e14. DOI:10.4081/hi.2012.e14
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    ABSTRACT: Stem cell therapy is a leading field of research worldwide given its promising potential for recovery or replacement of tissues and organs, especially for the treatment of cardiovascular pathologies. However, despite this enormous experimental effort and the reported positive results in different models, there is no conclusive demonstration of the mechanisms involved in tissue regeneration associated to adult stem cell treatment. This represents one of the major limitations for the clinical translation of stem cell therapy. A real regenerative medicine approach should consider the importance of the extracellular matrix (ECM) and the strong biological signals that it can provide. Connective tissue atmosphere in which cells are embedded exerts a number of actions affecting cells function and supporting their proliferation and differentiation. Polymeric electrospun matrices are among the most promising ECM-mimetic biomaterials, because of their physical structure closely resembling the fibrous proteins in native ECM. Moreover, electrospun materials can be easily functionalized with bioactive molecules providing localized biochemical stimuli to cells seeded therein. The idea of taking advantage of both stem cells plasticity and biomaterials that actively guide and provide the correct sequence of signals to allow ongoing lineage-specific differentiation is an attractive alternative and may represent a promising answer to the treatment limitations of cardiovascular severe diseases.
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