Adipose-derived stem cells for the regeneration of damaged tissues

Repair and tissue engineering techniques for articular cartilage

Chondral and osteochondral lesions due to injury or other pathology commonly result in the development of osteoarthritis, eventually leading to progressive total joint destruction. Although current progress suggests that biologic agents can delay the advancement of deterioration, such drugs are incapable of promoting tissue restoration. The limited ability of articular cartilage to regenerate renders joint arthroplasty an unavoidable surgical intervention. This Review describes current, widely used clinical repair techniques for resurfacing articular cartilage defects; short-term and long-term clinical outcomes of these techniques are discussed. Also reviewed is a developmental pipeline of acellular and cellular regenerative products and techniques that could revolutionize joint care over the next decade by promoting the development of functional articular cartilage. Acellular products typically consist of collagen or hyaluronic-acid-based materials, whereas cellular techniques use either primary cells or stem cells, with or without scaffolds. Central to these efforts is the prominent role that tissue engineering has in translating biological technology into clinical products; therefore, concomitant regulatory processes are also discussed.

Transplantation of human adipose-derived stem cells enhances remyelination in lysolecithin-induced focal demyelination of rat spinal cord

Adipose-derived stem cells (ADSCs) are a desirable stem cell source in neurodegenerative diseases treatment due to their ability to differentiate into different cell lineages. In this study, we transplanted human ADSCs (hADSCs) into a lysophosphatidylcholine (lysolecithin) model of multiple sclerosis (MS) and determined the efficiency of these cells in remyelination process. Forty adult rats were randomly divided into control, lysolecithin, vehicle, and transplantation groups, and focal demyelination was induced by lysolecithin injection into spinal cord. To assess motor performance, all rats were examined weekly with a standard EAE scoring scale. Four weeks after cell transplantation, to assess the extent of demyelination and remyelination, Luxol Fast Blue staining was used. In addition, immunohistochemistry technique was used for assessment of the presence of oligodendrocyte phenotype cells in damaged spinal cord. Our results indicated that hADSCs had ability to differentiate into oligodendrocyte phenotype cells and improved remyelination process. Moreover, the evaluation of rat motor functions showed that animals which were treated with hADSC compared to other groups had significant improvement (P < 0.001). Our finding showed that hADSCs transplantation for cell-based therapies may play a proper cell source in the treatment of neurodegenerative diseases such as MS.

Therapeutic potential of human adipose-derived stem cells in neurological disorders

Stem cell therapy has been noted as a novel strategy to various diseases including neurological disorders such as Alzheimer's disease, Parkinson's disease, stroke, amyotrophic lateral sclerosis, and Huntington's disease that have no effective treatment available to date. The adipose-derived stem cells (ASCs), mesenchymal stem cells (MSCs) isolated from adipose tissue, are well known for their pluripotency with the ability to differentiate into various types of cells and immuno-modulatory property. These biological features make ASCs a promising source for regenerative cell therapy in neurological disorders. Here we discuss the recent progress of regenerative therapies in various neurological disorders utilizing ASCs.

Menstrual blood-derived stromal stem cells inhibit optimal generation and maturation of human monocyte-derived dendritic cells

INTRODUCTION

Menstrual blood stromal stem Cells (MenSCs) have shown promising potential for future clinical settings. Nonetheless, data regarding their interaction with immune cells is still scarce. Here, we investigated whether MenSCs could affect the generation and/or maturation of human blood monocyte-derived dendritic cells (DCs).

MATERIALS AND METHODS

MenSCs were isolated from menstrual blood of normal women through culture of adherent mononuclear cells. Magnetically-isolated peripheral blood monocytes were differentiated toward immature DCs (iDC) and mature DCs (mDCs) in the presence or absence of MenSCs. Monocyte-derived cells were assessed for the percentage of monocyte-, iDC-, and mDC-specific markers as well as the expression of costimulatory molecules. IL-6 and IL-10 levels were also determined in supernatants of MenSC-monocytes cocultures.

RESULTS

Optimal phenotypic differentiation of monocytes into iDCs was inhibited upon coculture with MenSCs. Moreover, higher levels of IL-6 and IL-10 were detected in these settings. Even though addition of MenSCs to iDC cultures could not prevent iDC maturation, coculture of MenSCs with monocytes from the beginning of differentiation process could effectively hinder generation of fully mature DCs.

CONCLUSION

This is the first study to address the inhibitory impact of MenSCs on generation and maturation of DCs. IL-6 and IL-10 could be partly held responsible for this effect. Given the central roles of DCs in regulation of immune responses, these results highlight the importance of further research on the potential modulatory impacts of MenSCs, as rather easily accessible and expandable stem cells, on the immune system-related cells.

Adipose tissue-derived stem cells suppress acute cellular rejection by TSG-6 and CD44 interaction in rat kidney transplantation

BACKGROUND

In addition to its abundance and easy accessibility, adipose tissue yields more potent immunoregulatory stem cells (adipose tissue-derived stem cells, ADSCs) than does bone marrow. However, the beneficial effects of ADSCs on alloreactivity are scarcely known. This study evaluated the beneficial effects of ADSCs in rat kidney transplantation and analyzed the underlying molecular mechanism.

METHODS

Dark Agouti rat kidneys were transplanted into Lewis rats. Autologous ADSCs (2×10) were injected through the left renal artery of the donors before the nephrectomy (ADSCs group). Graft survival, histologic changes, and the expression of several cytokines and proteins were assessed. In an in vitro experiment, the immunosuppressive capacity of ADSCs was tested in a mixed lymphocyte reaction.

RESULTS

Histologic findings of the ADSCs group revealed a reduced rejection grade, whereas the number of infiltrated CD4/CD8 T cells was also significantly decreased as compared to the control. Relative to these findings, injection of ADSCs led to a significantly prolonged mean graft survival compared with the control. In vitro, autologous ADSCs dose-dependently suppressed alloreactive lymphocytes. Moreover, ADSCs increased the level of tumor necrosis factor-inducible gene 6 protein (TSG-6) in mixed lymphocyte reaction, which has an anti-inflammatory capacity. Recombinant TSG-6 markedly suppressed alloreactive T cells through downregulating CD44, which may lead to the suppression of T-cell activation and infiltration into allografts.

CONCLUSION

Our findings clearly showed that ADSCs attenuated acute rejection by secreting TSG-6 as well as through direct cell interaction. These findings contribute to the clinical application of these cells in solid organ transplantation.

Immunological barriers to stem cell therapy in the central nervous system

The central nervous system is vulnerable to many neurodegenerative disorders such as Alzheimer's disease that result in the extensive loss of neuronal cells. Stem cells have the ability to differentiate into many types of cells, which make them ideal for treating such disorders. Although stem cell therapy has shown some promising results in animal models for many brain disorders it has yet to translate into the clinic. A major hurdle to the translation of stem cell therapy into the clinic is the immune response faced by stem cell transplants. Here, we focus on immunological and related hurdles to stem cell therapies for central nervous system disorders.

Mesenchymal stem cells as a potent cell source for articular cartilage regeneration

Since articular cartilage possesses only a weak capacity for repair, its regeneration potential is considered one of the most important challenges for orthopedic surgeons. The treatment options, such as marrow stimulation techniques, fail to induce a repair tissue with the same functional and mechanical properties of native hyaline cartilage. Osteochondral transplantation is considered an effective treatment option but is associated with some disadvantages, including donor-site morbidity, tissue supply limitation, unsuitable mechanical properties and thickness of the obtained tissue. Although autologous chondrocyte implantation results in reasonable repair, it requires a two-step surgical procedure. Moreover, chondrocytes expanded in culture gradually undergo dedifferentiation, so lose morphological features and specialized functions. In the search for alternative cells, scientists have found mesenchymal stem cells (MSCs) to be an appropriate cellular material for articular cartilage repair. These cells were originally isolated from bone marrow samples and further investigations have revealed the presence of the cells in many other tissues. Furthermore, chondrogenic differentiation is an inherent property of MSCs noticed at the time of the cell discovery. MSCs are known to exhibit homing potential to the damaged site at which they differentiate into the tissue cells or secrete a wide spectrum of bioactive factors with regenerative properties. Moreover, these cells possess a considerable immunomodulatory potential that make them the general donor for therapeutic applications. All of these topics will be discussed in this review.

Comprehensive characterization of four different populations of human mesenchymal stem cells as regards their immune properties, proliferation and differentiation

In the present study, we compared mesenchymal stem cells (MSCs) derived from 4 different sources, human bone marrow (BM), adipose tissue (AT), umbilical cord Wharton's Jelly (WJ) and the placenta (PL), in order to determine which population of MSCs displayed the most prominent immunosuppressive effects on phytohemagglutinin-induced T cell proliferation, and which one had the highest proliferative and differentiation potential. MSC and T lymphocyte co-culture (mixed culture) was used to determine whether the MSCs inhibit T cell proliferation, as well as which population of MSCs has the strongest inhibitory ability. The expression of immune-related genes was analyzed by RT-PCR and RT-qPCR. The proliferation and differentiation potential of the MSCs were determined using standard methods. Following MSC and T cell co-culture, mitogen-induced T cell proliferation was effectively suppressed by all 4 populations of MSCs. This occurred through soluble factors rather than direct contact inhibition. Among the 4 populations of MSCs, the WJ-MSC has the strongest suppression effects. On immune related genes, WJ-MSC has the weakest expression of MHC II genes, TLR4, TLR3, JAG1, NOTCH2 and NOTCH3. To compare the proliferation potential, WJ-MSCs showed the most rapid growth rate followed by the AT-, PL- and BM-MSCs. As regards differentiation potential, the WJ-MSCs had the strongest osteogenetic ability followed by PL, AT and BM-MSC. AT-MSC has the strongest adipogenetic ability followed by the WJ-, BM- and PL-MSCs. These data indicated that the WJ-MSCs had the strongest immunomodulatory and immunosuppressive potential. In light of these observations, we suggest that WJ-MSCs are the most attractive cell population for use in immune cellular therapy when immunosuppressive action is required.

Bone tissue engineering by using a combination of polymer/Bioglass composites with human adipose-derived stem cells

Translational research in bone tissue engineering is essential for "bench to bedside" patient benefit. However, the ideal combination of stem cells and biomaterial scaffolds for bone repair/regeneration is still unclear. The aim of this study is to investigate the osteogenic capacity of a combination of poly(DL-lactic acid) (PDLLA) porous foams containing 5 wt% and 40 wt% of Bioglass particles with human adipose-derived stem cells (ADSCs) in vitro and in vivo. Live/dead fluorescent markers, confocal microscopy and scanning electron microscopy showed that PDLLA/Bioglass porous scaffolds supported ADSC attachment, growth and osteogenic differentiation, as confirmed by enhanced alkaline phosphatase (ALP) activity. Higher Bioglass content of the PDLLA foams increased ALP activity compared with the PDLLA only group. Extracellular matrix deposition after 8 weeks in the in vitro cultures was evident by Alcian blue/Sirius red staining. In vivo bone formation was assessed by using scaffold/ADSC constructs in diffusion chambers transplanted intraperitoneally into nude mice and recovered after 8 weeks. Histological and immunohistochemical assays indicated significant new bone formation in the 40 wt% and 5 wt% Bioglass constructs compared with the PDLLA only group. Thus, the combination of a well-developed biodegradable bioactive porous PDLLA/Bioglass composite scaffold with a high-potential stem cell source (human ADSCs) could be a promising approach for bone regeneration in a clinical setting.

Familial occurrence of pulmonary embolism after intravenous, adipose tissue-derived stem cell therapy

The therapeutic potential of human multipotent mesenchymal stromal cells, especially human adipose tissue-derived stem cells (hASC), is promising. However, there are concerns about the safety of infusion of hASC in human. Recently, we have experienced pulmonary embolism and infarct among family members who have taken multiple infusions of intravenous autologous hASC therapy. A 41-year-old man presented with chest pain for one month. Chest CT showed multiple pulmonary artery embolism and infarct at right lung. Serum D-dimer was 0.8 μg/mL (normal; 0-0.5 μg/mL). He had received intravenous autologous adipose tissue-derived stem cell therapy for cervical herniated intervertebral disc three times (one, two, and three months prior to the visit). His parents also received the same therapy five times and their chest CT also showed multiple pulmonary embolism. These cases represent artificial pulmonary embolisms and infarct after IV injection of hASC. Follow-up chest CT showed spontaneous resolution of lesions in all three patients.

Photo-mediated internalization of nanocomplex for effective gene delivery to adipose tissue-derived stem cells

To deliver efficiently osteogenic, chondrogenic or adipogenic induction genes, such as Runx2, SOX9 and C/EBP-α, to adipose tissue-derived stem cells (ADSCs), a photo-mediated nanocomplex internalization gene delivery system was designed using chlorin e6 as a photosensitizer (PS) and polyethyleneimine (PEI) as a gene delivery carrier. In this system, gene delivery efficacy was significantly increased in ADSCs by photo irradiation. The gene transfection efficiency of Runx2, SOX9 and C/EBP-α was increased by 8.6-, 6.7- and 9.3-fold, respectively, by applying 0.7J/cm(2) of irradiation. Osteogenic, chondrogenic and adipogenic differentiation was confirmed by differentiation-related markers and histological analysis. ADSCs transfected with Runx2, SOX9 and C/EBP-α genes via photo irradiation indicated enhanced differentiation in comparison to the non-irradiated cells. These findings demonstrate that photo-mediated internalization is a promising system for efficient gene delivery and differentiation in ADSCs.

Stem cell therapy in veterinary dermatology

BACKGROUND

Adult stem cells come from many sources and have the capacity to differentiate into many cell types, including those of the skin. The most commonly studied stem cells are those termed mesenchymal stem cells (MSCs), which are easily isolated from bone marrow and adipose tissue. Mesenchymal stem cells are known to produce a wide array of cytokines that modulate the regeneration process. The ease of collection, propagation and use of these MSCs in therapy of traumatic, ischaemic and immune-mediated skin conditions is emerging.

APPROACH AND EVIDENCE

In traumatic and ischaemic skin damage, MSCs are used in tissue-engineered skin and by direct injection into damaged tissue. For immune-mediated diseases, systemic administration of stem cells can modulate the immune system. The earliest clinical work has been with autologous stem cell sources, such as adipose tissue and bone marrow. In immune-mediated diseases, the MSCs are used to downregulate production of inflammatory cytokines and to block T-cell activation. Cells are generally given intravenously. Multiple sclerosis, rheumatoid arthritis and lupus have been successfully treated in human clinical trials. Mesenchymal stem cells can also stimulate resident local cells, such as keratinocytes and progenitor cells, to proliferate, migrate and repair skin injury and disease.

LOOKING AHEAD

The discovery of the MSC in adipose tissue has spawned a global effort to utilize these cells in therapy of a wide range of diseases of the skin. Reconstructive surgery, scar blocking and resolution and skin regeneration have all been shown to be possible in human and animal studies.

Strategies to improve recovery in acute ischemic stroke patients: Iberoamerican Stroke Group Consensus

Stroke is not only a leading cause of death worldwide but also a main cause of disability. In developing countries, its burden is increasing as a consequence of a higher life expectancy. Whereas stroke mortality has decreased in developed countries, in Latin America, stroke mortality rates continue to rise as well as its socioeconomic dramatic consequences. Therefore, it is necessary to implement stroke care and surveillance programs to better describe the epidemiology of stroke in these countries in order to improve therapeutic strategies. Advances in the understanding of the pathogenic processes of brain ischemia have resulted in development of effective therapies during the acute phase. These include reperfusion therapies (both intravenous thrombolysis and interventional endovascular approaches) and treatment in stroke units that, through application of management protocols directed to maintain homeostasis and avoid complications, helps to exert effective brain protection that decreases further cerebral damage. Some drugs may enhance protection, and besides, there is increasing knowledge about brain plasticity and repair mechanisms that take place for longer periods beyond the acute phase. These mechanisms are responsible for recovery in certain patients and are the focus of basic and clinical research at present. This paper discusses recovery strategies that have demonstrated clinical effect, or that are promising and need further study. This rapidly evolving field needs to be carefully and critically evaluated so that investment in patient care is grounded on well-proven strategies.

Role of Wnt signaling on proliferation of menstrual blood derived stem cells

AIM

Menstrual blood derived stem cells (MenSCs) are unique stem cells that have been isolated and identified recently. The special traits of MenSCs can be related to the cell signaling pathways. In this study, in order to find out the role of Wnt signaling on MenSCs proliferation, we evaluated ß-catenin expression as a key participant in Wnt signaling pathway in response to Lithium chloride (LiCl).

METHODS

MenSCs were isolated from healthy women by combining gradient density centrifugation with plastic adherence. After characterization of the isolated cells, cell proliferation of MenSCs in presence of 10-15 mM LiCl was evaluated by MTT assay. ß-catenin expression of the treated cells was examined using immunofluorescence technique.

RESULTS

Flow cytometric analysis revealed that both mesenchymal and embryonic stem cell markers are expressed on menstrual blood stem cells. MTT value decreased depending on the LiCl concentration. The proliferation of MenSCs cultivated in culture media containing 15mM LiCl was approximately two fold less than those grown without LiCl (p<0.01). Moreover, nuclear accumulation of ß-catenin protein in cells treated by LiCl was greater than cells without LiCl.

CONCLUSION

The MenSCs are stem cell populations with high proliferation ability and unique immunophenotyping properties. Our results demonstrated that Wnt signaling pathway regulates MenSCs proliferation via trans-localization of activated-ß-catenin protein.

Autologous fat grafting: use of closed syringe microcannula system for enhanced autologous structural grafting

OBJECTIVES

Provide background for use of acquiring autologous adipose tissue as a tissue graft and source of adult progenitor cells for use in cosmetic plastic surgery. Discuss the background and mechanisms of action of closed syringe vacuum lipoaspiration, with emphasis on accessing adipose-derived mesenchymal/stromal cells and the stromal vascular fraction (SVF) for use in aesthetic, structural reconstruction and regenerative applications. Explain a proven protocol for acquiring high-quality autologous fat grafts (AFG) with use of disposable, microcannula systems.

DESIGN

Explain the components and advantage of use of the patented super luer-lock and microcannulas system for use with the closed-syringe system. A sequential explanation of equipment selection for minimally traumatic lipoaspiration in small volumes is presented, including use of blunt injection cannulas to reduce risk of embolism.

RESULTS

Thousands of AFG have proven safe and efficacious for lipoaspiration techniques for large and small structural fat grafting procedures. The importance and advantages of gentle harvesting of the adipose tissue complex has become very clear in the past 5 years. The closed-syringe system offers a minimally invasive, gentle system with which to mobilize subdermal fat tissues in a suspension form. Resulting total nuclear counting of undifferentiated cells of the adipose-derived -SVF suggests that the yield achieved is better than use of always-on, constant mechanical pump applied vacuum systems.

CONCLUSION

Use of a closed-syringe lipoaspiration system featuring disposable microcannulas offers a safe and effective means of harvesting small volumes of nonmanipulated adipose tissues and its accompanying progenitor cells within the SVF. Closed syringes and microcannulas are available as safe, sterile, disposable, compact systems for acquiring high-quality AFG. Presented is a detailed, step-by-step, proven protocol for performing quality autologous structural adipose transplantation.

Regeneration of articular cartilage by adipose tissue derived mesenchymal stem cells: perspectives from stem cell biology and molecular medicine

Adipose-derived stem cells (ASCs) have been discovered for more than a decade. Due to the large numbers of cells that can be harvested with relatively little donor morbidity, they are considered to be an attractive alternative to bone marrow derived mesenchymal stem cells. Consequently, isolation and differentiation of ASCs draw great attention in the research of tissue engineering and regenerative medicine. Cartilage defects cause big therapeutic problems because of their low self-repair capacity. Application of ASCs in cartilage regeneration gives hope to treat cartilage defects with autologous stem cells. In recent years, a lot of studies have been performed to test the possibility of using ASCs to re-construct damaged cartilage tissue. In this article, we have reviewed the most up-to-date articles utilizing ASCs for cartilage regeneration in basic and translational research. Our topic covers differentiation of adipose tissue derived mesenchymal stem cells into chondrocytes, increased cartilage formation by co-culture of ASCs with chondrocytes and enhancing chondrogenic differentiation of ASCs by gene manipulation.

Prospective biomarkers of stem cells of human endometrium and fallopian tube compared with bone marrow

The applicability of stem cells from the human endometrium and fallopian tube for regeneration is a fascinating area of research because of the role of these cells in dynamic tissue remodelling and their cyclical regenerative property during the menstrual cycle and pregnancy. Nevertheless, studies on the identity of biomarkers of these stem cells are limited and need to be extended. The present study has aimed at exploring the tissue-specific biomarkers of stem cells derived from the human endometrium and fallopian tube compared with those from bone marrow. Cells were isolated from human endometrium and fallopian tubes and characterized for biomarkers, including CD34, CD133, CD117, CD90, CD105, CD73, nestin, CD29, CD44, CD31, CD54, CD166, CD106, CD49d, CD45, ABCG2, SSEA4, OCT4, SOX2, CD140b and CD146, by flowcytometry. Both endometrium and fallopian tube sources exhibited positivity over a wide range of markers, as did bone marrow. In particular, they exhibited pluripotency, perivascular and mesenchymal stem cell markers and cell adhesion molecules, thereby suggesting their relevance in tissue repair and regeneration. Overall, the results of this study provide evidence for the presence of stem cells in the human endometrium and fallopian tube, which could thus represent additional stem cell sources for regenerative medicine.

Platelet-Rich Plasma Enhances the Dermal Regeneration Efficacy of Human Adipose-Derived Stromal Cells Administered to Skin Wounds

The administration of human adipose-derived stromal cells (hASCs) enhances skin wound healing. However, poor survival of hASCs that are administered to avascular wound regions may limit the therapeutic efficacy of the hASCs. The aim of this study was to determine whether the coadministration of platelet-rich plasma (PRP) and hASCs enhanced the skin wound-healing efficacy of hASCs. Skin regeneration was examined in skin wounds of athymic mice that were either untreated or treated with hASCs, PRP, or both hASCs and PRP. Coadministration of PRP and hASCs resulted in better skin regeneration than hASC administration alone in part by significantly improving the proliferation of administered hASCs by the angiogenic growth factor secretion of the hASCs and surrounding mouse host cells in the wound areas and by promoting neovascularization in the wound beds.

Human adipose tissue-derived mesenchymal stem cells improve cognitive function and physical activity in ageing mice

Brain ageing leads to atrophy and degeneration of the cholinergic nervous system, resulting in profound neurobehavioral and cognitive dysfunction from decreased acetylcholine biosynthesis and reduced secretion of growth and neurotrophic factors. Human adipose tissue-derived mesenchymal stem cells (ADMSCs) were intravenously (1 × 10(6) cells) or intracerebroventricularly (4 × 10(5) cells) transplanted into the brains of 18-month-old mice once or four times at 2-week intervals. Transplantation of ADMSCs improved both locomotor activity and cognitive function in the aged animals, in parallel with recovery of acetylcholine levels in brain tissues. Transplanted cells differentiated into neurons and, in part, into astrocytes and produced choline acetyltransferase proteins. Transplantation of ADMSCs restored microtubule-associated protein 2 in brain tissue and enhanced Trk B expression and the concentrations of brain-derived neurotrophic factor and nerve growth factor. These results indicate that human ADMSCs differentiate into neural cells in the brain microenvironment and can restore physical and cognitive functions of aged mice not only by increasing acetylcholine synthesis but also by restoring neuronal integrity that may be mediated by growth/neurotrophic factors. © 2013 Wiley Periodicals, Inc.

Unravelling the retention of proliferation and differentiation potency in extensive culture of human subcutaneous fat-derived mesenchymal stem cells in different media

OBJECTIVES

This study has intended to investigate longevity of subcutaneous fat-derived mesenchymal stem cells (SF-MSCs) under extensive culturing. It has also focused on optimization of culture media for them over prolonged periods in vitro.

MATERIALS AND METHODS

We evaluated SF-MSCs with reference to phenotypic characterization, proliferative ability, karyotype stability and differentiation potency with early (P3) and late passage (P20) conditions, using four different media, DMEM-LG, ALPHA-MEM, DMEM-F12 and DMEM-KO.

RESULTS

This study unravels retention of SF-MSC characteristics in facets of phenotypic expression profile (CD 90, CD 105, CD 73, CD 34, CD 29, CD 54, CD 49d, CD 117, HLA-DR, CD 166, CD 31, CD 44), proliferative characteristics, karyotyping and differentiation potency prolonged culturing to P25 in all media. Population doubling time (PDT) in Alpha MEM, DMEM LG, DMEM F 12, DMEM KO were identified to be (1.81, 1.84, 1.9, 2.08 days) at early passage and (2.93, 2.94, 3.12, 3.06 days) at late passage. As a corollary, Alpha MEM and DMEM LG serve as appropriate basal media for SF-MSC when proliferative potency is considered.

CONCLUSIONS

In research, it is imperative that SF-MSC uphold their expansion potency in the aforesaid attributes in all media over extensive culturing, thereby transforming their colossal in vitro potency, with the aim of curing a wide horizon of diseases.

Implications of adipose-derived stromal cells in a 3D culture system for osteogenic differentiation: an in vitro and in vivo investigation

BACKGROUND CONTEXT

Healthy mammalian cells in normal tissues are organized in complex three-dimensional (3D) networks that display nutrient and signaling gradients. Conventional techniques that grow cells in a 2D monolayer fail to reproduce the environment that is observed in vivo. In recent years, 3D culture systems have been used to mimic tumor microenvironments in cancer research and to emulate embryogenesis in stem cell cultures. However, there have been no studies exploring the ability for adipose-derived stromal (ADS) cells in a 3D culture system to undergo osteogenic differentiation.

PURPOSE

To characterize and investigate the in vitro and in vivo potential for human ADS cells in a novel 3D culture system to undergo osteogenic differentiation.

STUDY DESIGN

Basic science and laboratory study.

METHODS

Human ADS cells were isolated and prepared as either a 2D monolayer or 3D multicellular aggregates (MAs). Multicellular aggregates were formed using the hanging droplet technique. Cells were treated in osteogenic medium in vitro, and cellular differentiation was investigated using gene expression, histology, and microCT at 1-, 2-, and 4-week time points. In vivo investigation involved creating a muscle pouch by developing the avascular muscular interval in the vastus lateralis of male athymic rats. Specimens were then pretreated with osteogenic medium and surgically implanted as (1) carrier (Matrigel) alone (control), (2) carrier with human ADS cells in monolayer, or (3) human ADS cells as MAs. In vivo evidence of osteogenic differentiation was evaluated with micro computed tomography and histologic sectioning at a 2-week time point.

RESULTS

Human ADS cells cultured by the hanging droplet technique successfully formed MAs at the air-fluid interface. Adipose-derived stromal cells cultured in monolayer or as 3D MAs retain their ability to self-replicate and undergo multilineage differentiation as confirmed by increased runx2/Cbfa2, ALP, and OCN and increased matrix mineralization on histologic sectioning. Multicellular aggregate cells expressed increased differentiation potential and extracellular matrix production over the same human ADS cells cultured in monolayer. Furthermore, MAs reseeded onto monolayer retained their stem cell capabilities. When implanted in vivo, significantly greater bone volume and extracellular matrix were present in the implanted specimens of MAs confirmed on both microCT and histological sectioning.

CONCLUSIONS

This is the first study to investigate the capability of human ADS cells in a 3D culture system to undergo osteogenic differentiation. The results confirm that MAs maintain their stem cell characteristics. Compared with analogous cells in monolayer culture, the human ADS cells as MAs exhibit elevated levels of osteogenic differentiation and increased matrix mineralization. Furthermore, the creation of uniform spheroids allows for improved handling and manipulation during transplantation. These findings strongly support the concept that 3D culture systems remain not only a viable option for stem cell culture but also possibly a more attractive alternative to traditional culture techniques to improve the osteogenic potential of human adipose stem cells.

Genipin-Cross-Linked Microencapsulated Human Adipose Stem Cells Augment Transplant Retention Resulting in Attenuation of Chronically Infarcted Rat Heart Fibrosis and Cardiac Dysfunction

Stem cell transplantation has been widely acknowledged for their immense potential in regenerative medicine. In these procedures, the implanted cells need to maintain both their viability and functional properties for effective therapeutic outcomes. This has long been a subject of major concern and intensive studies. Microencapsulation of stem cells within polymeric microcapsules can be an efficient approach to achieve this goal, particularly for heart diseases. This study reports the use of biocompatible, fluorogenic genipin-cross-linked alginate chitosan (GCAC) microcapsules in delivery of human adipose stem cells (hASCs) with an aim to increase the implant retention in the infarcted myocardium for maximum clinical benefits. In vitro results show, under hypoxic conditions, the microencapsulated cells overexpressed significantly higher amount of biologically active vascular endothelial growth factor (VEGF). We investigated on the in vivo potential using immunocompetent female rats after induction of myocardial infarction. For this, animal groups ( n = 8) received empty control microcapsules, 1.5 × 106 free male hASCs, or 1.5 × 106 microencapsulated male hASCs. Results show significant retention (3.5 times higher) of microencapsulated hASCs compared to free hASCs after 10 weeks of transplantation. Microencapsulated hASCs showed significantly attenuated infarct size compared to free hASCs and empty microcapsule group (21.6% ± 1.1% vs. 27.2% ± 3.1% vs. 33.3% ± 3.2%; p < 0.05), enhanced vasculogenesis, and improved cardiac function (fractional shortening: 24.2% ± 2.1% vs. 19.1% ± 0.5% vs. 12.0% ± 4.0%; p < 0.05). These data suggest that microencapsulated hASCs can contribute significantly to the improvement in cardiac functions. Their greater retentions exhibit reduced fibrosis and cardiac dysfunction in experimental animals. However, further research is needed to fully comprehend the underlying biological and immunological effects of microencapsulated hASCs, which jointly play important roles in cardiac repair.

Trophic factors and cell therapy to stimulate brain repair after ischaemic stroke

Brain repair involves a compendium of natural mechanisms that are activated following stroke. From a therapeutic viewpoint, reparative therapies that encourage cerebral plasticity are needed. In the last years, it has been demonstrated that modulatory treatments for brain repair such as trophic factor- and stem cell-based therapies can promote neurogenesis, gliogenesis, oligodendrogenesis, synaptogenesis and angiogenesis, all of which having a beneficial impact on infarct volume, cell death and, finally, and most importantly, on the functional recovery. However, even when promising results have been obtained in a wide range of experimental animal models and conditions these preliminary results have not yet demonstrated their clinical efficacy. Here, we focus on brain repair modulatory treatments for ischaemic stroke, that use trophic factors, drugs with trophic effects and stem cell therapy. Important and still unanswered questions for translational research ranging from experimental animal models to recent and ongoing clinical trials are reviewed here.

Comparison of in vitro hepatogenic differentiation potential between various placenta-derived stem cells and other adult stem cells as an alternative source of functional hepatocytes

Mesenchymal stem cells (MSCs) are powerful sources for cell therapy in regenerative medicine. The capability to obtain effective stem cell-derived hepatocytes would improve cell therapy for liver diseases. Recently, various placenta-derived stem cells (PDSCs) depending on the localization of placenta have been suggested as alternative sources of stem cells are similar to bone marrow-derived MSC (BM-MSCs) and adipose-derived MSC (AD-MSCs). However, comparative studies for the potentials of the hepatogenic differentiation among various MSCs largely lacking. Therefore, we investigated to compare the potentials for hepatogenic differentiation of PDSCs with BM-MSCs, AD-MSCs, and UCB-MSCs. Several MSCs were isolated from human term placenta, adipose tissue, and umbilical cord blood and characterized isolated MSCs and BM-MSCs was performed by quantitative reverse transcription-PCR (RT-PCR) and special stains after mesodermal differentiation. The hepatogenic potential of PDSCs was compared with AD-MSCs, UCB-MSCs, and BM-MSCs using RT-PCR, PAS stain, ICG up-take assays, albumin expression, urea production, and cytokine assays. MSCs isolated from different tissues all presented similar characteristics of MSCs. However, the proliferative potential of PDSCs and the expression of hepatogenic markers in differentiated PDSCs were higher than other MSCs. Interestingly, the expression of hepatocyte growth factor (HGF) increased in PDSCs after hepatogenic differentiation. Interestingly, stem cell factor (SCF) expression in chorionic plate-derived MSCs, one of the PDSCs, was significantly higher than in the other PDSCs. Taken together, the results of the present study suggest that MSCs isolated from various adult tissues can be induced to undergo hepatogenic differentiation in vitro, and that PDSCs may have the greatest potential for hepatogenic differentiation and proliferation. Therefore, PDSCs could be used as a stem cell source for cell therapy in liver diseases.

Intracoronary artery transplantation of cardiomyoblast-like cells from human adipose tissue-derived multi-lineage progenitor cells improve left ventricular dysfunction and survival in a swine model of chronic myocardial infarction

Transplantation of human cardiomyoblast-like cells (hCLCs) from human adipose tissue-derived multi-lineage progenitor cells improved left ventricular function and survival of rats with myocardial infarction. Here we examined the effect of intracoronary artery transplantation of human CLCs in a swine model of chronic heart failure. Twenty-four pigs underwent balloon-occlusion of the first diagonal branch followed by reperfusion, with a second balloon-occlusion of the left ascending coronary artery 1 week later followed by reperfusion. Four weeks after the second occlusion/reperfusion, 17 of the 18 surviving animals with severe chronic MI (ejection fraction <35% by echocardiography) were immunosuppressed then randomly assigned to receive either intracoronary artery transplantation of hCLCs hADMPCs or placebo lactic Ringer's solution with heparin. Intracoronary artery transplantation was followed by the distribution of DiI-stained hCLCs into the scarred myocardial milieu. Echocardiography at post-transplant days 4 and 8 weeks showed rescue and maintenance of cardiac function in the hCLCs transplanted group, but not in the control animals, indicating myocardial functional recovery by hCLCs intracoronary transplantation. At 8 week post-transplantation, 7 of 8 hCLCs transplanted animals were still alive compared with only 1 of the 5 control (p=0.0147). Histological studies at week 12 post-transplantation demonstrated engraftment of the pre DiI-stained hCLCs into the scarred myocardium and their expression of human specific alpha-cardiac actin. Human alpha cardiac actin-positive cells also expressed cardiac nuclear factors; nkx2.5 and GATA-4. Our results suggest that intracoronary artery transplantation of hCLCs is a potentially effective therapeutic strategy for future cardiac tissue regeneration.

Superior osteogenic capacity of different mesenchymal stem cells for bone tissue engineering

OBJECTIVE

We evaluated the effect of human bone marrow stromal cells (hBMSCs), human adipose tissue-derived mesenchymal stem cells (hAD-MSCs), and umbilical cord-derived mesenchymal stem cells (hUC-MSCs) in bone tissue engineering and identified a reliable cell source.

STUDY DESIGN

Alkaline phosphatase (ALP) activity and quantitative polymerase chain reaction were used to evaluate osteogenic in vitro, X-ray and histologic analysis in vivo.

RESULTS

hBMSCs exhibited strongest ALP staining, followed by hAD-MSCs and hUC-MSCs. At 7 days, hUC-MSCs and hAD-MSCs had higher expression of collagen type I and Runt-related transcription factor 2 than hBMSCs, and hUC-MSCs showed higher osteopontin expression. Bone structure was observed in the hUC-MSC group. Defects showed good healing in the hBMSC and hAD-MSC groups. Enhanced green fluorescent protein and osteopontin were detected in newly formed bone at 8 weeks.

CONCLUSIONS

Our results suggested that hUC-MSCs and hAD-MSCs could be used for bone tissue engineering effectively; hUC-MSCs could serve as a new alternative cell source.

Layer-shaped alginate hydrogels enhance the biological performance of human adipose-derived stem cells

BACKGROUND

The reconstruction of adipose tissue defects is often challenged by the complications that may occur following plastic and reconstructive surgery, including donor-site morbidity, implant migration and foreign body reaction. To overcome these problems, adipose tissue engineering (ATE) using stem cell-based regeneration strategies has been widely explored in the last years. Mounting evidence has shown that adipose-derived stem cells (ADSCs) represent a promising cell source for ATE. In the context of a small number of reports concerning adipose tissue regeneration using three-dimensional (3-D) systems, the present study was designed to evaluate the biological performance of a novel alginate matrix that incorporates human ADSCs (hADSCs).

RESULTS

Culture-expanded cells isolated from the stromal vascular fraction (SVF), corresponding to the third passage which showed the expression of mesenchymal stem cell (MSC) markers, were used in the 3-D culture systems. The latter represented a calcium alginate hydrogel, obtained by the diffusion of calcium gluconate (CGH matrix), and shaped as discoid-thin layer. For comparative purposes, a similar hADSC-laden alginate hydrogel cross-linked with calcium chloride was considered as reference hydrogel (RH matrix). Both hydrogels showed a porous structure under scanning electron microscopy (SEM) and the hADSCs embedded displayed normal spherical morphologies, some of them showing signs of mitosis. More than 85% of the entrapped cells survived throughout the incubation period of 7 days. The percentage of viable cells was significantly higher within CGH matrix at 2 days post-seeding, and approximately similar within both hydrogels after 7 days of culture. Moreover, both alginate-based hydrogels stimulated cell proliferation. The number of hADSC within hydrogels has increased during the incubation period of 7 days and was higher in the case of CGH matrix. Cells grown under adipogenic conditions for 21 days showed that both analyzed 3-D culture systems support adipogenic differentiation in terms of neutral lipid accumulation and perillipin expression. Furthermore, the cells encapsulated in CGH matrix displayed a more differentiated phenotype.

CONCLUSIONS

The results of this study suggest that both CGH and RH matrices successfully support the survival and adipogenesis of hADSC. An enhancement of biological performance was detected in the case of CGH matrix, suggesting its promising application in ATE.

Production of canine mesenchymal stem cells from adipose tissue and their application in dogs with chronic osteoarthritis of the humeroradial joints

Autologous AD-MSC [adipose-derived MSC (mesenchymal stem cell)] therapy involves harvesting fat from the patient by isolating the stem and regenerative cells and administering the cells back to the patient. This study evaluated the production of canine AD-MSCs and their possible application in cellular therapy for dogs. To assess whether cellular therapy can replace drug therapy, the clinical effect of a single intra-articular injection of AD-MSCs was evaluated on 4 dogs with lameness associated with OA (osteoarthritis) of the humeroradial joints. MSCs were readily isolated from adult dog adipose tissue, and their ability to form colony and differentiate into various phenotypes was confirmed. AD-MSCs expressed OCT4, NANOG and SOX2 at the mRNA level, pluripotency markers usually ascribed to embryonic stem cells. The results suggest the stemness of the cells isolated from canine fat, and good quality control made them available for both experimental and clinical use. Follow-up studies to evaluate the effects of AD-MSC therapy showed that OA of the elbow joints improved with time, indicating significant potential for clinical use in the treatment of lameness, particularly when administered before the injury becomes severe.

Alteration of gene expression levels during osteogenic induction of human adipose derived stem cells in long-term culture

Adipose tissue is a source of multipotent stem cells and it has the ability to differentiate into several types of cell lineages such as neuron cells, osteogenic and adipogenic cells. Most studies on human adipose-derived stem cells (ASCs) have been carried out at the early passages. For clinical usage, ASCs need to be expanded in vitro for a period of time to get sufficient cells for transplantation into patients. However, the impact of long-term culture on ASCs molecular characteristics has not been established yet. Several studies have also shown that osteogenic and adipogenic cells have the ability to switch pathways during in vitro culture as they share the same progenitor cells. This data is important to ensure their functionality and efficacy before being used clinically in the treatment of bone diseases. Therefore, we aim to investigate the effect of long-term culture on the adipogenic, stemness and osteogenic genes expression during osteogenic induction of ASCs. In this study, the molecular characteristics of ASCs during osteogenic induction in long-term culture was analysed by observing their morphological changes during induction, analysis of cell mineralization using Alizarin Red staining and gene expression changes using quantitative RT-PCR. Morphologically, cell mineralization at P20 was less compared to P5, P10 and P15. Adipogenesis was not observed as negative lipid droplets formation was recorded during induction. The quantitative PCR data showed that adipogenic genes expression e.g. LPL and AP2 decreased but PPAR-γ was increased after osteogenic induction in long-term culture. Most stemness genes decreased at P5 and P10 but showed no significant changes at P15 and P20. While most osteogenic genes increased after osteogenic induction at all passages. When compared among passages after induction, Runx showed a significant increased at P20 while BSP, OSP and ALP decreased at later passage (P15 and P20). During long-term culture, ASCs were only able to differentiate into immature osteogenic cells.

Human adipose-derived mesenchymal stem cells systemically injected promote peripheral nerve regeneration in the mouse model of sciatic crush

Mesenchymal stem cells (MSCs) represent a promising therapeutic approach in nerve tissue engineering. To date, the local implantation of MSC in injured nerves has been the only route of administration used. In case of multiple sites of injury, the systemic administration of cells capable of reaching damaged nerves would be advisable. In this regard, we found that an intravenous administration of adipose-derived MSC (ASC) 1 week after sciatic nerve crush injury, a murine model of acute axonal damage, significantly accelerated the functional recovery. Sciatic nerves from ASC-treated mice showed the presence of a restricted number of undifferentiated ASC together with a significant improvement in fiber sprouting and the reduction of inflammatory infiltrates for up to 3 weeks. Besides the immune modulatory effect, our results show that ASC may contribute to peripheral nerve regeneration because of their ability to produce in culture neuroprotective factors such as insulin-like growth factor I, brain-derived neurotrophic factor, or basic fibroblast growth factor. In addition to this production in vitro, we interestingly found that the concentration of glial-derived neurotrophic factor (GDNF) was significantly increased in the sciatic nerves in mice treated with ASC. Since no detectable levels of GDNF were observed in ASC cultures, we hypothesize that ASC induced the local production of GDNF by Schwann cells. In conclusion, we show that systemically injected ASC have a clear therapeutic potential in an acute model of axonal damage. Among the possible mechanisms promoting nerve regeneration, our results rule out a process of trans-differentiation and rather suggest the relevance of a bystander effect, including the production of in situ molecules, which, directly or indirectly through a cross-talk with local glial cells, may modulate the local environment with the down-regulation of inflammation and the promotion of axonal regeneration.

Effect of menstrual blood-derived stromal stem cells on proliferative capacity of peripheral blood mononuclear cells in allogeneic mixed lymphocyte reaction

AIM

Menstrual blood stromal stem cells (MBSCs) have been demonstrated to exhibit stem cell properties such as the capability for self-renewal and multipotency, allowing for multilineage differentiation. In addition, this cell type has various immunomodulatory effects. In this study, we examined the potential effect of MBSCs on proliferation of peripheral blood mononuclear cells (PBMCs) in allogeneic mixed lymphocyte reaction (MLR).

MATERIALS AND METHODS

Menstrual blood was collected from healthy donors after menstrual blood flow initiated and its mononuclear cell fraction was separated. Cells were subsequently cultured and adherent cells were allowed to propagate and used as stem cells. Flowcytometric immunophenotyping was performed using a panel of monoclonal antibodies including CD44, CD45, CD34, CD9, CD29, CD10, CD38, CD105, CD73, CD133, STRO-1 and Oct-4A. For functional analysis, PBMCs were co-cultured with MBSCs, collected after 4 days and added to allogeneic PBMCs. 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay was carried out to evaluate cell proliferation.

RESULTS

MBSCs showed surface and intracellular markers of mesenchymal stem cells with the exception of the high expression of Oct-4A. MBSCs affected the proliferative response of PBMC in a dose-dependent manner. At ratio of 1:1 to 1:2, MBSCs inhibited, while at lower ratios (1:32 to 1:64) stimulated the proliferative capacity of allogeneic PBMCs.

CONCLUSION

According to the present study, MBSCs exert their immunoregulatory effects on allogeneic PBMCs in a dose-dependent manner. This finding can be considered as a valuable point in future cell therapy strategies, when this cell population is used.

Once fat was fat and that was that: our changing perspectives on adipose tissue

Abstract

Past civilisations saw excess body fat as a symbol of wealth and prosperity as the general population struggled with food shortages and famine. Nowadays it is recognised that obesity is associated with co-morbidities such as cardiovascular disease and diabetes. Our views on the roll of adipose tissue have also changed, from being solely a passive energy store, to an important endocrine organ that modulates metabolism, immunity and satiety. The relationship between increased visceral adiposity and obesity-related co-morbidities has lead to the recognition that variation in fat distribution contributes to ethnic differences in the prevalence of obesity-related diseases. Our current negative view of adipose tissue may change with the use of pluripotent adipose-derived stromal cells, which may lead to future autologous stem cell therapies for bone, muscle, cardiac and cartilage disorders. Here, we briefly review the concepts that adipose tissue is an endocrine organ, that differences in body fat distribution underline the aetiology of obesity-related co-morbidities, and the use of adipose-derived stem cells for future therapies.

Transdifferentiation: why and how?

Cell therapy is based on the replacement of damaged cells in order to restore injured tissues. The first consideration is that an abundant source of cells is needed; second, these cells should be immunologically compatible with the guest and third, there should be no real threat of these cells undergoing malignant transformation in the future. Given these requirements, already differentiated adult cells or adult stem cells obtained from the body of the patient appear to be the ideal candidates to meet all of these demands. The utilization of somatic cells also avoids numerous ethical and political drawbacks and concerns. Transdifferentiation is the phenomenon by which an adult differentiated cell switches to another differentiated cell. This paper reviews the importance of transdifferentiation, discussing the cells that are suitable for this process and the methods currently employed to induce the change in cell type.

Tissue engineering solutions for tendon repair

Tendon injuries range from acute traumatic ruptures and lacerations to chronic overuse injuries, such as tendinosis. Even with improved nonsurgical, surgical, and rehabilitation techniques, outcomes following tendon repair are inconsistent. Primary repair remains the standard of care. However, repaired tendon tissue rarely achieves functionality equal to that of the preinjured state. Poor results have been linked to alterations in cellular organization within the tendon that occur at the time of injury and throughout the early stages of healing. Enhanced understanding of the biology of tendon healing is needed to improve management and outcomes. The use of growth factors and mesenchymal stem cells and the development of biocompatible scaffolds could result in enhanced tendon healing and regeneration. Recent advances in tendon bioengineering may lead to improved management following tendon injury.