Human cardiac stem cells rejuvenated by modulating autophagy with MHY-1685 enhance the therapeutic potential for cardiac repair

AbstractStem cell-based therapies with clinical applications require millions of cells. Therefore, repeated subculture is essential for cellular expansion, which is often complicated by replicative senescence. Cellular senescence contributes to reduced stem cell regenerative potential as it inhibits stem cell proliferation and differentiation as well as the activation of the senescence-associated secretory phenotype (SASP). In this study, we employed MHY-1685, a novel mammalian target of rapamycin (mTOR) inhibitor, and examined its long-term priming effect on the activities of senile human cardiac stem cells (hCSCs) and the functional benefits of primed hCSCs after transplantation. In vitro experiments showed that the MHY-1685‒primed hCSCs exhibited higher viability in response to oxidative stress and an enhanced proliferation potential compared to that of the unprimed senile hCSCs. Interestingly, priming MHY-1685 enhanced the expression of stemness-related markers in senile hCSCs and provided the differentiation potential of hCSCs into vascular lineages. In vivo experiment with echocardiography showed that transplantation of MHY-1685‒primed hCSCs improved cardiac function than that of the unprimed senile hCSCs at 4 weeks post-MI. In addition, hearts transplanted with MHY-1685-primed hCSCs exhibited significantly lower cardiac fibrosis and higher capillary density than that of the unprimed senile hCSCs. In confocal fluorescence imaging, MHY-1685‒primed hCSCs survived for longer durations than that of the unprimed senile hCSCs and had a higher potential to differentiate into endothelial cells (ECs) within the infarcted hearts. These findings suggest that MHY-1685 can rejuvenate senile hCSCs by modulating autophagy and that as a senescence inhibitor, MHY-1685 can provide opportunities to improve hCSC-based myocardial regeneration.

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Cardiac Derived CD51-Positive Mesenchymal Stem Cells Enhance the Cardiac Repair Through SCF-Mediated Angiogenesis in Mice With Myocardial Infarction

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.642533 ◽

2021 ◽

Vol 9 ◽

Author(s):

Dong Mei Xie ◽

Yang Chen ◽

Yan Liao ◽

Wanwen Lin ◽

Gang Dai ◽

...

Keyword(s):

Myocardial Infarction ◽

Stem Cells ◽

Cardiac Fibrosis ◽

Therapeutic Potential ◽

Cardiac Repair ◽

Surface Proteins ◽

Differentiation Potential ◽

Cardiac Wall

Objective: Many tissues contained resident mesenchymal stromal/stem cells (MSCs) that facilitated tissue hemostasis and repair. However, there is no typical marker to identify the resident cardiac MSCs. We aimed to determine if CD51 could be an optimal marker of cardiac MSCs and assess their therapeutic potential for mice with acute myocardial infarction (AMI).Methods: Cardiac-derived CD51+CD31–CD45–Ter119– cells (named CD51+cMSCs) were isolated from C57BL/6 mice(7-day-old) by flow cytometry. The CD51+cMSCs were characterized by proliferation capacity, multi-differentiation potential, and expression of typical MSC-related markers. Adult C57BL/6 mice (12-week-old) were utilized for an AMI model via permanently ligating the left anterior descending coronary artery. The therapeutic efficacy of CD51+cMSCs was estimated by echocardiography and pathological staining. To determine the underlying mechanism, lentiviruses were utilized to knock down gene (stem cell factor [SCF]) expression of CD51+cMSCs.Results: In this study, CD51 was expressed in the entire layers of the cardiac wall in mice, including endocardium, epicardium, and myocardium, and its expression was decreased with age. Importantly, the CD51+cMSCs possessed potent self-renewal potential and multi-lineage differentiation capacity in vitro and also expressed typical MSC-related surface proteins. Furthermore, CD51+cMSC transplantation significantly improved cardiac function and attenuated cardiac fibrosis through pro-angiogenesis activity after myocardial infarction in mice. Moreover, SCF secreted by CD51+cMSCs played an important role in angiogenesis both in vivo and in vitro.Conclusions: Collectively, CD51 is a novel marker of cardiac resident MSCs, and CD51+cMSC therapy enhances cardiac repair at least partly through SCF-mediated angiogenesis.

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The therapeutic potential of stem cells

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2009.0149 ◽

2010 ◽

Vol 365 (1537) ◽

pp. 155-163 ◽

Cited By ~ 79

Author(s):

Fiona M. Watt ◽

Ryan R. Driskell

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Therapeutic Potential ◽

Patient Specific ◽

Religious Groups ◽

Differentiation Potential ◽

Cell Behaviour ◽

Different Types

In recent years, there has been an explosion of interest in stem cells, not just within the scientific and medical communities but also among politicians, religious groups and ethicists. Here, we summarize the different types of stem cells that have been described: their origins in embryonic and adult tissues and their differentiation potential in vivo and in culture. We review some current clinical applications of stem cells, highlighting the problems encountered when going from proof-of-principle in the laboratory to widespread clinical practice. While some of the key genetic and epigenetic factors that determine stem cell properties have been identified, there is still much to be learned about how these factors interact. There is a growing realization of the importance of environmental factors in regulating stem cell behaviour and this is being explored by imaging stem cells in vivo and recreating artificial niches in vitro . New therapies, based on stem cell transplantation or endogenous stem cells, are emerging areas, as is drug discovery based on patient-specific pluripotent cells and cancer stem cells. What makes stem cell research so exciting is its tremendous potential to benefit human health and the opportunities for interdisciplinary research that it presents.

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Are MSCs Stem Cells? Demonstration of in Vitro and in Vivo Stem Cell Properties of Highly Enriched linneg/CD45neg/CD271pos/CD140alow/Neg Mesenchymal Stromal Cells from Adult Human Bone Marrow

Blood ◽

10.1182/blood.v124.21.4374.4374 ◽

2014 ◽

Vol 124 (21) ◽

pp. 4374-4374

Author(s):

Roshanak Ghazanfari ◽

Hongzhe Li ◽

Dimitra Zacharaki ◽

Simón Méndez-Ferrer ◽

Stefan Scheding

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Human Bone ◽

Human Bone Marrow ◽

Differentiation Potential ◽

Self Renewal ◽

Adult Human

Abstract Human bone marrow contains a rare population of non-hematopoietic mesenchymal stromal cells (BM-MSC) with multilineage differentiation capacity, which are essential constituents of the hematopoietic microenvironment. Self-renewal and differentiation are the two key properties of somatic stem cells, however, stem cell properties of human adult BM-MSC have not been demonstrated conclusively yet. We have previously shown that low/negative expression of PDGFRα on linneg/CD45neg/CD271pos cells identified a highly enriched population of primary BM-MSC in adult human bone marrow (Li et al. Blood, 2013, 122:3699). Based on this work, the current study aimed to investigate the in-vitro and in-vivo stem cell properties of this putative stromal stem cell population. The in-vitro clonogenic potential of freshly sorted human linneg/CD45neg/CD271pos/PDGFRlow/neg cells was evaluated by utilizing the CFU-F assay as well as the recently-developed mesensphere assay, which enables MSC amplification while preserving an immature phenotype (Isern et al, Cell Reports 2013, 30: 1714-24). Comparable colony frequencies were obtained with both assays (19.3 ± 2 and 17.5 ± 2.3 CFU-F and spheres per 100 plated cells, respectively, n=6, p=0.19). In order to test whether both assays identified the same population of clonogenic cells, colonies and spheres were replated under both conditions for up to three generations. The results showed comparable capacities of CFU-F and mesenspheres to form secondary and tertiary CFU-F and spheres. In-vitro self-renewal as indicated by increasing numbers of CFU-F and spheres (416.6 ± 431.7-fold and 49.5 ± 65.7-fold, respectively, n=3) was observed up to the third generation and decreased thereafter. The total number of generations was five (CFU-F) and six (spheres). In-vitro differentiation assays with both, CFU-F- and sphere-derived cells (tested until passage three) demonstrated tri-lineage differentiation potential (adipocytes, osteoblasts, chondrocytes). In addition, CFU-Fs and spheres had comparable surface marker profiles (CD73, CD90, CD105, and HLA-ABC positive; CD31, CD34 and HLA-DR negative), except for CD90, which was higher expressed on CFU-Fs. To investigate in-vivo self-renewal and differentiation potential of the putative stromal stem cells, linneg/CD45neg/CD271pos/PDGFRlow/neg -derived CFU-F and spheres were serially transplanted s.c into NSG mice. After 8 weeks, implants were harvested, human cells were FACS-isolated (CD90 and CD105 expression), and re-assayed under CFU-F and sphere conditions. Whereas in-vivo self-renewal of CFU-F could not be shown (111.5 ± 36 –fold decrease in total CFU-F numbers after primary transplantation, n=3), sphere self-renewal was clearly demonstrated by increased numbers of spheres after primary as well as secondary transplantation (1.13 ± 0.05 and 2.06 ± 0.26 –fold, respectively, n=3), which is remarkable given the fact that the number of recovered human cells is underestimated due to the isolation approach. Here, confirming GFP-marking experiments are ongoing. Finally, preliminary data indicate that linneg/CD45neg/CD271pos/PDGFRlow/neg –derived spheres display full in-vivo differentiation capacity in primary and secondary transplantations. Taken together, our data demonstrate - for the first time - that primary human linneg/CD45neg/CD271pos/PDGFRlow/neg cells meet stringent stem cell criteria, i.e. in-vitro and in-vivo self-renewal and differentiation. These findings answer the long-open question of the potential stem cell properties of adult human MSC and will enable to better understand the properties of native BM-MSC and their biological role in the bone marrow. Disclosures No relevant conflicts of interest to declare.

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The Hypoxic Preconditioning Effect On Senescence Cell Process In Cultured Adipose-Derived Mesenchymal Stem Cells (AMSCs)

Indonesian Journal of Cardiology ◽

10.30701/ijc.v39i3.802 ◽

2019 ◽

Vol 39 (3) ◽

Author(s):

Nadiar Dwi Nuarisa ◽

I Gde Rurus Suryawan ◽

Andrianto Andrianto

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Stem Cell ◽

Life Span ◽

Hypoxic Preconditioning ◽

Differentiation Potential ◽

Hypoxic Precondition ◽

Significant Difference

Introduction : Stem cell therapy for myocardial regeneration is expected to increase cardiomyocyte proliferation and trigger neovascularization to improve cardiomyocytes. Mesenchymal Stem Cells (MSCs) are ideal candidates for regenerative medicine and immunotherapy. But low viability of MSCs is a major challenge in this alternative therapy. Therefore, a cytoprotective strategy is needed, one of them is hypoxic preconditioning which can significantly increase survival stem cells after being transplanted. MSCs are known to have a limited life span, after experiencing several splits MSC will enter the senescence process. It is known that hypoxia can also increase cell proliferation and differentiation potential in vitro and in vivo through the role of Octamer-4 (Oct-4) as a regulator of the pluripotency gene. Methods : Experimental laboratory studies (in vitro studies) using human-AMSCs which were given hypoxic preconditioning, observed as a immunocytochemistry. Results : The results showed that hypoxic precondition (1% O2) inhibited the senescence process. It can be seen in the lower expression of senescence in hypoxic conditions at P6, P7, P8, P9, P10 compared to normoxic ((p=0,004, p=0,001, p=0,009, p=0,013, p=0,024. There is a significant difference in the senescence expression of each passage in hypoxic and normoxic conditions with the highest expression at P10. In addition, we also observed AMSCs differentiation through the Oct-4 expression. It is showed that Oct-4 expression were higher in hypoxia compared to normoxia on P7, P8, P9, P10 (p=0,009, p=0,009, p=0,030, p=0,0001). Conclusions : Hypoxic preconditioning have the effect of inhibiting the senescence process on Adipose-derived MSCs (AMSCs) or prolonging their life span. The longer life span of AMSCs is also seen by higher cell differentiation potential from increased expression of Oct-4. However, the mechanism of inhibiting the senescence process in hypoxia in stem cells is still remain unknown. Keywords: human-Adipose derived Mesenchymal Stem Cell Cultures (h-AMSCs), Hypoxic Preconditioning, Senescence cell, Oct-4.

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Nanocarrier Mediated siRNA Delivery Targeting Stem Cell Differentiation

Current Stem Cell Research & Therapy ◽

10.2174/1574888x14666191202095041 ◽

2020 ◽

Vol 15 (2) ◽

pp. 155-172 ◽

Cited By ~ 1

Author(s):

Fiona Fernandes ◽

Pooja Kotharkar ◽

Adrija Chakravorty ◽

Meenal Kowshik ◽

Indrani Talukdar

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Viral Vectors ◽

Therapeutic Potential ◽

Transfection Efficiency ◽

Polymeric Nanoparticles ◽

Sirna Delivery ◽

Stem Cell Differentiation

Stem cell-based regenerative medicine holds exceptional therapeutic potential and hence the development of efficient techniques to enhance control over the rate of differentiation has been the focus of active research. One of the strategies to achieve this involves delivering siRNA into stem cells and exploiting the RNA interference (RNAi) mechanism. Transport of siRNA across the cell membrane is a challenge due to its anionic property, especially in primary human cells and stem cells. Moreover, naked siRNA incites immune responses, may cause off-target effects, exhibits low stability and is easily degraded by endonucleases in the bloodstream. Although siRNA delivery using viral vectors and electroporation has been used in stem cells, these methods demonstrate low transfection efficiency, cytotoxicity, immunogenicity, events of integration and may involve laborious customization. With the advent of nanotechnology, nanocarriers which act as novel gene delivery vehicles designed to overcome the problems associated with safety and practicality are being developed. The various nanomaterials that are currently being explored and discussed in this review include liposomes, carbon nanotubes, quantum dots, protein and peptide nanocarriers, magnetic nanoparticles, polymeric nanoparticles, etc. These nanodelivery agents exhibit advantages such as low immunogenic response, biocompatibility, design flexibility allowing for surface modification and functionalization, and control over the surface topography for achieving the desired rate of siRNA delivery and improved gene knockdown efficiency. This review also includes discussion on siRNA co-delivery with imaging agents, plasmid DNA, drugs etc. to achieve combined diagnostic and enhanced therapeutic functionality, both for in vitro and in vivo applications.

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Osteogenic Differentiation Potential of Human Bone Marrow and Amniotic Fluid-Derived Mesenchymal Stem Cells in Vitro & in Vivo

Open Access Macedonian Journal of Medical Sciences ◽

10.3889/oamjms.2019.124 ◽

2019 ◽

Vol 7 (4) ◽

pp. 507-515 ◽

Cited By ~ 4

Author(s):

Eman E. A. Mohammed ◽

Mohamed El-Zawahry ◽

Abdel Razik H. Farrag ◽

Nahla N. Abdel Aziz ◽

Wessam Sharaf-ElDin ◽

...

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Mesenchymal Stem Cells ◽

Stem Cell ◽

Amniotic Fluid ◽

Bone Regeneration ◽

Osteogenic Differentiation ◽

Differentiation Potential

BACKGROUND: Cell therapies offer a promising potential in promoting bone regeneration. Stem cell therapy presents attractive care modality in treating degenerative conditions or tissue injuries. The rationale behind this is both the expansion potential of stem cells into a large cell population size and its differentiation abilities into a wide variety of tissue types, when given the proper stimuli. A progenitor stem cell is a promising source of cell therapy in regenerative medicine and bone tissue engineering. AIM: This study aimed to compare the osteogenic differentiation and regenerative potentials of human mesenchymal stem cells derived from human bone marrow (hBM-MSCs) or amniotic fluid (hAF-MSCs), both in vitro and in vivo studies. SUBJECTS AND METHODS: Human MSCs, used in this study, were successfully isolated from two human sources; the bone marrow (BM) and amniotic fluid (AF) collected at the gestational ages of second or third trimesters. RESULTS: The stem cells derived from amniotic fluid seemed to be the most promising type of progenitor cells for clinical applications. In a pre-clinical experiment, attempting to explore the therapeutic application of MSCs in bone regeneration, Rat lumbar spines defects were surgically created and treated with undifferentiated and osteogenically differentiated MSCs, derived from BM and second trimester AF. Cells were loaded on gel-foam scaffolds, inserted and fixed in the area of the surgical defect. X-Ray radiography follows up, and histopathological analysis was done three-four months post- operation. The transplantation of AF-MSCs or BM-MSCs into induced bony defects showed promising results. The AF-MSCs are offering a better healing effect increasing the likelihood of achieving successful spinal fusion. Some bone changes were observed in rats transplanted with osteoblasts differentiated cells but not in rats transplanted with undifferentiated MSCs. Longer observational periods are required to evaluate a true bone formation. The findings of this study suggested that the different sources; hBM-MSCs or hAF-MSCs exhibited remarkably different signature regarding the cell morphology, proliferation capacity and osteogenic differentiation potential CONCLUSIONS: AF-MSCs have a better performance in vivo bone healing than that of BM-MSCs. Hence, AF derived MSCs is highly recommended as an alternative source to BM-MSCs in bone regeneration and spine fusion surgeries. Moreover, the usage of gel-foam as a scaffold proved as an efficient cell carrier that showed bio-compatibility with cells, bio-degradability and osteoinductivity in vivo.

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Regulation of sarcomagenesis by the empty spiracles homeobox genes EMX1 and EMX2

Cell Death and Disease ◽

10.1038/s41419-021-03801-w ◽

2021 ◽

Vol 12 (6) ◽

Author(s):

Manuel Pedro Jimenez-García ◽

Antonio Lucena-Cacace ◽

Daniel Otero-Albiol ◽

Amancio Carnero

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Transcription Factors ◽

Neural Crest ◽

Tumor Suppressors ◽

Homeobox Genes ◽

Neuronal Cell ◽

Cell Gene Expression

AbstractThe EMX (Empty Spiracles Homeobox) genes EMX1 and EMX2 are two homeodomain gene members of the EMX family of transcription factors involved in the regulation of various biological processes, such as cell proliferation, migration, and differentiation, during brain development and neural crest migration. They play a role in the specification of positional identity, the proliferation of neural stem cells, and the differentiation of certain neuronal cell phenotypes. In general, they act as transcription factors in early embryogenesis and neuroembryogenesis from metazoans to higher vertebrates. The EMX1 and EMX2’s potential as tumor suppressor genes has been suggested in some cancers. Our work showed that EMX1/EMX2 act as tumor suppressors in sarcomas by repressing the activity of stem cell regulatory genes (OCT4, SOX2, KLF4, MYC, NANOG, NES, and PROM1). EMX protein downregulation, therefore, induced the malignance and stemness of cells both in vitro and in vivo. In murine knockout (KO) models lacking Emx genes, 3MC-induced sarcomas were more aggressive and infiltrative, had a greater capacity for tumor self-renewal, and had higher stem cell gene expression and nestin expression than those in wild-type models. These results showing that EMX genes acted as stemness regulators were reproduced in different subtypes of sarcoma. Therefore, it is possible that the EMX genes could have a generalized behavior regulating proliferation of neural crest-derived progenitors. Together, these results indicate that the EMX1 and EMX2 genes negatively regulate these tumor-altering populations or cancer stem cells, acting as tumor suppressors in sarcoma.

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Cell Source-Dependent In Vitro Chondrogenic Differentiation Potential of Mesenchymal Stem Cell Established from Bone Marrow and Synovial Fluid of Camelus dromedarius

Animals ◽

10.3390/ani11071918 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1918

Author(s):

Young-Bum Son ◽

Yeon Ik Jeong ◽

Yeon Woo Jeong ◽

Mohammad Shamim Hossein ◽

Per Olof Olsson ◽

...

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Stem Cell ◽

Synovial Fluid ◽

Cartilage Regeneration ◽

Cartilage Tissue ◽

Chondrocyte Differentiation ◽

Differentiation Potential ◽

Proliferation Capacity

Mesenchymal stem cells (MSCs) are promising multipotent cells with applications for cartilage tissue regeneration in stem cell-based therapies. In cartilage regeneration, both bone marrow (BM-MSCs) and synovial fluid (SF-MSCs) are valuable sources. However, the cellular characteristics and chondrocyte differentiation potential were not reported in either of the camel stem cells. The in vitro chondrocyte differentiation competence of MSCs, from (BM and SF) sources of the same Camelus dromedaries (camel) donor, was determined. Both MSCs were evaluated on pluripotent markers and proliferation capacity. After passage three, both MSCs showed fibroblast-like morphology. The proliferation capacity was significantly increased in SF-MSCs compared to BM-MSCs. Furthermore, SF-MSCs showed an enhanced expression of transcription factors than BM-MSCs. SF-MSCs exhibited lower differentiation potential toward adipocytes than BM-MSCs. However, the osteoblast differentiation potential was similar in MSCs from both sources. Chondrogenic pellets obtained from SF-MSCs revealed higher levels of chondrocyte-specific markers than those from BM-MSCs. Additionally, glycosaminoglycan (GAG) content was elevated in SF-MSCs related to BM-MSCs. This is, to our knowledge, the first study to establish BM-MSCs and SF-MSCs from the same donor and to demonstrate in vitro differentiation potential into chondrocytes in camels.

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Adropin-based dual treatment enhances the therapeutic potential of mesenchymal stem cells in rat myocardial infarction

Cell Death and Disease ◽

10.1038/s41419-021-03610-1 ◽

2021 ◽

Vol 12 (6) ◽

Author(s):

HuiYa Li ◽

DanQing Hu ◽

Guilin Chen ◽

DeDong Zheng ◽

ShuMei Li ◽

...

Keyword(s):

Myocardial Infarction ◽

Stem Cells ◽

Mesenchymal Stem Cells ◽

Therapeutic Potential ◽

Left Ventricular ◽

Left Ventricular Ejection ◽

Paracrine Factors ◽

Dual Treatment

AbstractBoth weak survival ability of stem cells and hostile microenvironment are dual dilemma for cell therapy. Adropin, a bioactive substance, has been demonstrated to be cytoprotective. We therefore hypothesized that adropin may produce dual protective effects on the therapeutic potential of stem cells in myocardial infarction by employing an adropin-based dual treatment of promoting stem cell survival in vitro and modifying microenvironment in vivo. In the current study, adropin (25 ng/ml) in vitro reduced hydrogen peroxide-induced apoptosis in rat bone marrow mesenchymal stem cells (MSCs) and improved MSCs survival with increased phosphorylation of Akt and extracellular regulated protein kinases (ERK) l/2. Adropin-induced cytoprotection was blocked by the inhibitors of Akt and ERK1/2. The left main coronary artery of rats was ligated for 3 or 28 days to induce myocardial infarction. Bromodeoxyuridine (BrdU)-labeled MSCs, which were in vitro pretreated with adropin, were in vivo intramyocardially injected after ischemia, following an intravenous injection of 0.2 mg/kg adropin (dual treatment). Compared with MSCs transplantation alone, the dual treatment with adropin reported a higher level of interleukin-10, a lower level of tumor necrosis factor-α and interleukin-1β in plasma at day 3, and higher left ventricular ejection fraction and expression of paracrine factors at day 28, with less myocardial fibrosis and higher capillary density, and produced more surviving BrdU-positive cells at day 3 and 28. In conclusion, our data evidence that adropin-based dual treatment may enhance the therapeutic potential of MSCs to repair myocardium through paracrine mechanism via the pro-survival pathways.

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“Empowering” Cardiac Cells via Stem Cell Derived Mitochondrial Transplantation- Does Age Matter?

International Journal of Molecular Sciences ◽

10.3390/ijms22041824 ◽

2021 ◽

Vol 22 (4) ◽

pp. 1824

Author(s):

Matthias Mietsch ◽

Rabea Hinkel

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Treatment Strategies ◽

Cardiac Cells ◽

Aging Effects ◽

Beneficial Effects ◽

Micro Rnas ◽

New Treatment

With cardiovascular diseases affecting millions of patients, new treatment strategies are urgently needed. The use of stem cell based approaches has been investigated during the last decades and promising effects have been achieved. However, the beneficial effect of stem cells has been found to being partly due to paracrine functions by alterations of their microenvironment and so an interesting field of research, the “stem- less” approaches has emerged over the last years using or altering the microenvironment, for example, via deletion of senescent cells, application of micro RNAs or by modifying the cellular energy metabolism via targeting mitochondria. Using autologous muscle-derived mitochondria for transplantations into the affected tissues has resulted in promising reports of improvements of cardiac functions in vitro and in vivo. However, since the targeted treatment group represents mainly elderly or otherwise sick patients, it is unclear whether and to what extent autologous mitochondria would exert their beneficial effects in these cases. Stem cells might represent better sources for mitochondria and could enhance the effect of mitochondrial transplantations. Therefore in this review we aim to provide an overview on aging effects of stem cells and mitochondria which might be important for mitochondrial transplantation and to give an overview on the current state in this field together with considerations worthwhile for further investigations.

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