MatrigelBD, a biocompatible scaffold that improves gingival mesenchymal stem cells proliferation / MatrigelBD, un andamiaje biocompatible que estimula la proliferación de celulas troncales mesenquimales derivadas del tejido gingival

MatrigelBD is a hydrogel scaffold with three-dimensional intercrossed networks of hydrophilic polymers with high water content. Human gingival tissue might represent a better source of MSCs, allowing these cells to be easily obtained in a relatively non-invasive way. The objective of this study was to evaluate the biocompatibility of MatrigelBD with GMSCs in vitro. Gingival connective tissue samples were obtained from healthy donors. Fresh tissue was minced and cultured during two weeks, after which cells at passage fourth were analyzed for their immune phenotype by flow cytometry. Differentiation into osteogenic, chondrogenic, and adipogenic lineages was induced and evaluated by culture staining. The "construct" was made of MatrigelBD with GMSC. To assess the biocompatibility, an MTT cellular proliferation assay was performed. The differentiation potential of the cells toward the osteogenic, adipogenic, and chondrogenic lineages was analyzed after 21 days of growth in MatrigelBD with induction differentiation media. The MTT analysis showed that MatrigelBD stimulated cell proliferation; the GMSCs maintained the expression of MSC markers. Importantly, the growth of GMSCs within the MatrigelBD did not interfere with the cell differentiation potential. These findings indicate that MatrigelBD is biocompatible with GMSCs, and this matrix improves cell proliferation in vitro.

MatrigelBD es un andamiaje de hidrogel con redes tridimensionales entrecruzadas de polímeros hidrófilos con un alto contenido de agua. El tejido gingival humano podría representar una mejor fuente de MSCs, estas células pueden obtenerse fácilmente de una manera relativamente no invasiva. El objetivo de este estudio fue evaluar la biocompatibilidad de MatrigelBD con GMSCs in vitro. Muestras gingivales de tejido conectivo se obtuvieron de donantes sanos. El tejido se trituró y se cultivó durante dos semanas, y cuando las células se encontraban en el cuarto pasaje se les analizó su fenotipo inmunológico utilizando citometría de flujo. Se indujo la diferenciación hacia los linajes osteogénico, condrogénico y adipogénico, evaluandose con tinciones. El "constructo" se hizo de MatrigelBD con GMSC. Para evaluar la biocompatibilidad, se realizó un ensayo de proliferación celular: MTT. Se analizó el potencial de diferenciación de las células hacia los linajes osteogénico, adipogénico y condrogénico después de 21 días de cultivo en MatrigelBD con medio de diferenciación de inducción. El análisis de MTT mostró que MatrigelBD estimula la proliferación celular; GMSCs mantiene la expresión de marcadores de MSC. Es importante destacar que el crecimiento de GMSCs en MatrigelBD no interfirió con el potencial de diferenciación celular. Estos hallazgos indican que MatrigelBD es biocompatible con GMSCs, y esta matriz mejora la proliferación celular in vitro.

Human Urine-derived Stem Cells Seeded Surface Modified Composite Scaffold Grafts for Bladder Reconstruction in a Rat Model

We conducted this study to investigate the synergistic effect of human urine-derived stem cells (USCs) and surface modified composite scaffold for bladder reconstruction in a rat model. The composite scaffold (Polycaprolactone/Pluronic F127/3 wt% bladder submucosa matrix) was fabricated using an immersion precipitation method, and heparin was immobilized on the surface via covalent conjugation. Basic fibroblast growth factor (bFGF) was loaded onto the heparin-immobilized scaffold by a simple dipping method. In maximal bladder capacity and compliance analysis at 8 weeks post operation, the USCs-scaffold(heparin-bFGF) group showed significant functional improvement (2.34 ± 0.25 mL and 55.09 ± 11.81 microL/cm H2O) compared to the other groups (2.60 ± 0.23 mL and 56.14 ± 9.00 microL/cm H2O for the control group, 1.46 ± 0.18 mL and 34.27 ± 4.42 microL/cm H2O for the partial cystectomy group, 1.76 ± 0.22 mL and 35.62 ± 6.69 microL/cm H2O for the scaffold group, and 1.92 ± 0.29 mL and 40.74 ± 7.88 microL/cm H2O for the scaffold(heparin-bFGF) group, respectively). In histological and immunohistochemical analysis, the USC-scaffold(heparin-bFGF) group showed pronounced, well-differentiated, and organized smooth muscle bundle formation, a multi-layered and pan-cytokeratin-positive urothelium, and high condensation of submucosal area. The USCs seeded scaffold(heparin-bFGF) exhibits significantly increased bladder capacity, compliance, regeneration of smooth muscle tissue, multi-layered urothelium, and condensed submucosa layers at the in vivo study.

Advanced Properties of Urine Derived Stem Cells Compared to Adipose Tissue Derived Stem Cells in Terms of Cell Proliferation, Immune Modulation and Multi Differentiation

Adipose tissue stem cells (ADSCs) would be an attractive autologous cell source. However, ADSCs require invasive procedures, and has potential complications. Recently, urine stem cells (USCs) have been proposed as an alternative stem cell source. In this study, we compared USCs and ADSCs collected from the same patients on stem cell characteristics and capacity to differentiate into various cell lineages to provide a useful guideline for selecting the appropriate type of cell source for use in clinical application. The urine samples were collected via urethral catheterization, and adipose tissue was obtained from subcutaneous fat tissue during elective laparoscopic kidney surgery from the same patient (n = 10). Both cells were plated for primary culture. Cell proliferation, colony formation, cell surface markers, immune modulation, chromosome stability and multi-lineage differentiation were analyzed for each USCs and ADSCs at cell passage 3, 5, and 7. USCs showed high cell proliferation rate, enhanced colony forming ability, strong positive for stem cell markers expression, high efficiency for inhibition of immune cell activation compared to ADSCs at cell passage 3, 5, and 7. In chromosome stability analysis, both cells showed normal karyotype through all passages. In analysis of multi-lineage capability, USCs showed higher myogenic, neurogenic, and endogenic differentiation rate, and lower osteogenic, adipogenic, and chondrogenic differentiation rate compared to ADSCs. Therefore, we expect that USC can be an alternative autologous stem cell source for muscle, neuron and endothelial tissue reconstruction instead of ADSCs.

Adipose-derived stem cells (ADSC) in the viability of a random pattern dorsal skin flap in rats

PURPOSE: To evaluate the viability of random pattern dorsal skin flaps in rats after injection of adipose-derived stem cells (ADSC). METHODS: Thirty five adult male Wistar EPM rats (weight 250-300 g) were distributed, at random, in two groups. I- Control (flap elevation with injection of saline solution) with fifteen animals and II- Experimental (flap elevation with injection of ADSC ) with fifteen animal. The ADSC were isolated from others five adult male rats. A dorsal skin flap measuring 10x4 cm was raised and a plastic barrier was placed between the flap and its bed in both groups and the injection (cells or saline solution) were perfomed immediately after the surgery. The percentage of flap necrosis was measured on the seventh postoperative day. RESULTS: The ADSC were able to replicate in our culture conditions. We also induced their adipogenic, osteogenic and chondrogenic differentiation to verify their mesenchymal stem cells potentiality in vitro. The results were statistically significant showing that the ADSC decreased the area of necrosis (p<0.05). CONCLUSIONS: The cells demonstrated adipogenic, osteogenic and chondrogenic differentiation potential in vitro. The administration of adipose-derived stem cells was effective to increase the viability of the random random pattern dorsal skin flaps in rats. .

Characterization of human adipose-derived stem cells / Caracterização de células-tronco do tecido adiposo humano

PURPOSE: There is a growing scientific interest in the plasticity and therapeutic potential of adipose-derived stem cells (ASCs), which are multipotent and abundant in adipose tissue and can differentiate in vitro into multiple lineages, including adipocytes, chondrocytes, osteoblasts, neural cells, endothelial cells and cardiomyocytes. The aim of this study was to isolate, cultivate and identify ASCs. METHODS: Human adipose precursor cells were obtained from subcutaneous abdominal tissue. Recently dispersed cells were separated by density centrifugation gradient, cultured and then analyzed. RESULTS: Human ASCs were able to replicate in our culture conditions. The cells maintained their phenotypes throughout the studied period on different passages confirming they suitability for in vitro cultivation. We also induced their adipogenic, osteogenic and chondrogenic differentiation, verifying their mesenchymal stem cells potentiality in vitro. Flow cytometry results showed that these cells expressed CD73, CD90 and CD105, (mesenchymal stem-cells markers), contrasting with the lack of expression of CD16, CD34 and CD45 (hematopoietic cells markers). CONCLUSION: It was possible to isolate human adipose-derived stem cells by in vitro cultivation without adipogenic induction, maintaining their functional integrity and high proliferation levels. The cells demonstrated adipogenic, osteogenic and chondrogenic differentiation potential in vitro.

OBJETIVO: Há um interesse científico crescente na plasticidade e potencial terapêutico das células-tronco do tecido adiposo humano, células multipotentes e abundantes no tecido adiposo que podem se diferenciar in vitro em múltiplas linhagens celulares, incluindo adipócitos, condrócitos, osteoblastos, células neurais, endoteliais e cardiomiócitos. O objetivo deste estudo foi isolar, cultivar e identificar células-tronco do tecido adiposo humano. MÉTODOS: Células precursoras humanas do tecido adiposo foram obtidas de tecido abdominal subcutâneo. As células recém-dispersas foram separadas por gradiente de centrifugação por densidade, cultivadas e então analisadas. RESULTADOS: As células-tronco do tecido adiposo humano foram capazes de se replicar nas nossas condições de cultivo e mantiveram seu fenótipo em diferentes passagens durante o estudo, confirmando sua adequabilidade para cultivo in vitro. A diferenciação adipogênica, osteogênica e condrogênica também foi induzida, confirmando seu potencial de células-tronco mesenquimais in vitro. Os resultados de citometria de fluxo evidenciaram a expressão dos marcadores de células-tronco mesenquimais CD73, CD90 e CD105, contrastando com a falta de expressão dos marcadores de células hematopoiéticas CD16, CD34 e CD45. CONCLUSÃO: Foi possível isolar células-tronco do tecido adiposo humano por cultivo in vitro sem indução adipogênica, mantendo sua integridade funcional e altos níveis de proliferação. As células demonstraram potencial de diferenciação adipogênico, osteogênico e condrogênico in vitro.

Stem cell therapy: A challenge to periodontist.

Periodontitis is an inflammatory disease which manifests clinically as loss of supporting periodontal tissues including periodontal ligament, cementum, and alveolar bone, and periodontal therapy is aimed at achieving complete regeneration of these structures. To date, this goal has been tried to accomplish using various bone grafts, growth factors, and barrier membranes. Stem cells are the most fascinating area of biology today and have been used clinically in the field of medicine to treat many incurable diseases. Various human and animal studies have confirmed the presence of stem cells in dental tissues including periodontal ligament. This has opened new avenues aiming toward complete periodontal regeneration using cell-based therapies. This review provides an overview of various types of stem cells in medicine and dentistry and their potential uses especially pertaining to periodontal regeneration.

Stem Cell Properties of Therapeutic Potential / 대한소화기학회지

Stem cell research is a innovative technology that focuses on using undifferentiated cells able to self-renew through the asymmetrical or symmetrical divisions. Three types of stem cells have been studied in laboratory including embryonic stem cell, adult stem cells and induced pluripotent stem cells. Embryonic stem cells are pluripotent stem cells derived from the inner cell mass and it can give rise to any fetal or adult cell type. Adult stem cells are multipotent, have the ability to differentiate into a limited number of specialized cell types, and have been obtained from the bone marrow, umbilical cord blood, placenta and adipose tissue. Stem cell therapy is the most promising therapy for several degenerative and devastating diseases including digestive tract disease such as liver failure, inflammatory bowel disease, Celiac sprue, and pancreatitis. Further understanding of biological properties of stem cells will lead to safe and successful stem cell therapies.

Preclinical Experience in Stem Cell Therapy for Digestive Tract Diseases / 대한소화기학회지

Adult stem cells are multipotent and self-renewing cells that contain several functions; i) migration and homing potential: stem cells can migrate to injured and inflamed tissues. ii) differentiation potential: stem cells which migrated to injured tissues can be differentiated into multiple cell types for repairing and regenerating the tissues. iii) immunomodulatory properties: stem cells, especially mesenchymal stem cells can suppress immune system such as inflammation. All those characteristics might be useful for the treatment of the digestive tract diseases which are complex and encompass a broad spectrum of different pathogenesis. Preclinical stem cell therapy showed some promising results, especially in liver failure, pancreatitis, sepsis, and inflammatory bowel disease. If we can understand more about the mechanism of stem cell action, stem cell therapy can become a promising alternative treatment for refractory digestive disease in the near future. In this review, we summarized current preclinical experiences in diseases of the digestive tract using stem cells.

Células-tronco derivadas de tecido adiposo humano: desafios atuais e perspectivas clínicas / Human adipose-derived stem cells: current challenges and clinical perspectives

As células-tronco adultas ou somáticas detêm grande promessa para a reparação e regeneração de tecidos. Atualmente, o interesse dos cientistas é contínuo na investigação da biologia de células-tronco mesenquimais, tanto em aspectos básicos, quanto no potencial de aplicações terapêuticas. As células-tronco adultas derivadas do estroma do tecido adiposo, em comparação com as células-tronco derivadas do estroma da medula óssea, apresentam como vantagem o método fácil de obtenção da fonte tecidual. As células-tronco adultas derivadas do estroma do tecido adiposo apresentam potencial para se diferenciarem em células de tecidos mesodérmicos, como os adipócitos, as cartilagens, os ossos e o músculo esquelético e não mesodérmicos, como os hepatócitos, as células pancreáticas endócrinas, os neurônios, os hepatócitos e as células endoteliais vasculares. Entretanto, os dados disponíveis na literatura científica sobre as características das células-tronco adultas derivadas do estroma do tecido adiposo e os procedimentos para sua obtenção e manipulação no laboratório são inconsistentes. É necessário o desenvolvimento de metodologias e procedimentos eficazes de isolamento dessas células para obtenção de células em quantidade e qualidade suficientes para aplicação terapêutica. Nesta revisão, são discutidos os métodos correntes de coleta de tecido adiposo, isolamento e caracterização de células-tronco adultas derivadas do estroma do tecido adiposo, com ênfase na futura aplicação em medicina regenerativa e nos possíveis desafios nesse recente campo da ciência.

Adult or somatic stem cells hold great promise for tissue regeneration. Currently, one major scientific interest is focused on the basic biology and clinical application of mesenchymal stem cells. Adipose tissue-derived stem cells share similar characteristics with bone marrow mesenchymal stem cells, but have some advantages including harvesting through a less invasive surgical procedure. Moreover, adipose tissue-derived stem cells have the potential to differentiate into cells of mesodermal origin, such as adipocytes, cartilage, bone, and skeletal muscle, as well as cells of non-mesodermal lineage, such as hepatocytes, pancreatic endocrine cells, neurons, cardiomyocytes, and vascular endothelial cells. There are, however, inconsistencies in the scientific literature regarding methods for harvesting adipose tissue and for isolating, characterizing and handling adipose tissue-derived stem cells. Future clinical applications of adipose tissue-derived stem cells rely on more defined and widespread methods for obtaining cells of clinical grade quality. In this review, current methods in adipose tissue-derived stem cell research are discussed with emphasis on strategies designed for future applications in regenerative medicine and possible challenges along the way.

Células-tronco: a resposta para os enigmas da patogênese da endometriose / Stem cells: the answer to the puzzles of the pathogenesis of endometriosis

A endometriose é uma doença crônica caracterizada pela presença de tecido endometrial ectópico. Esta doença frequentemente resulta em alta morbidade, incluindo dor pélvica crônica e infertilidade. A causa da endometriose é provavelmente multifatorial, sendo ainda objeto de muitos estudos. Fatores genéticos, ambientais e imunes estão possivelmente envolvidos na etiopatogenia desta doença, sendo especulada a associação com outros mecanismos. Nos últimos anos, alguns trabalhos têm demonstrado a presença de células-tronco/progenitoras no endométrio sadio; tais células possivelmente estão envolvidas na capacidade regenerativa desse tecido, assim como na patogênese de doenças ginecológicas proliferativas, como endometriose e carcinoma endometrial. Esta revisão avaliou as evidências disponíveis sobre a existência de células tronco/progenitoras endometriais e agrupou os resultados em uma hipótese de envolvimento dessas células na patogênese da endometriose. Foram selecionados os artigos mais relevantes sobre o tema. A identificação de células-tronco nos tecidos humanos e animais é presumida a partir da identificação de label retaining cells, células side population, marcadores de indiferenciação, potencial de clonogenicidade e diferenciação celular. A presença de supostas células-tronco no endométrio normal e ectópico foi demonstrada por alguns pesquisadores. Células endometriais no endométrio eutópico e em implantes endometrióticos, originadas a partir de células-tronco derivadas de medula óssea transplantada em humanos e de animais, também foram identificadas. Esses resultados sugerem que as células-tronco/progenitoras podem estar envolvidas na gênese da endometriose. No entanto, mais estudos são necessários para corroborar esta hipótese.

Endometriosis is a chronic disease characterized by the presence of ectopic endometrial tissue. This disease often results in high degree of morbidity, including chronic pelvic pain and infertility. Probably, the cause of endometriosis is multifactorial and it has been the object of many studies. Genetic, environmental and immune factors are possibly involved in the pathogenesis of this disease, and it is speculated that there are other mechanisms associated. In recent years, some studies have shown the presence of adult stem cells in the healthy endometrium. These cells are possible involved in the regenerative capability of endometrium and in the pathogenesis of proliferative gynecological diseases, such as endometriosis and endometrial carcinoma. This review evaluated the available evidence on the existence of stem/progenitor cells in the endometrium and gathered the results in an hypothesis of involvement of these cells in the pathogenesis of endometriosis. The most relevant articles about this subject were selected. The identification of stem cells in animal and human tissues is presumed from the identification of label retaining cells, side population cells, undifferentiation markers, besides the potential of clonogenesis and cellular differentiation. The presence of putative stem cells in the normal and ectopic endometrium was demonstrated by some researches. Endometrial cells in eutopic endometrium and endometriotic implants, originated from bone marrow-derived stem cells transplanted into humans and animals, have also been identified. These results suggest that stem/progenitor cells may be involved in the genesis of endometriosis. However, more studies are necessary to this hypothesis

Isolation, culture, characterization and optimization of human corneal stem cells

The effects of human versus mouse EGF on cell growth and culture duration were studied to optimize a human limbal stem cells culture method for therapeutical autologous transplantation. Limbal cells were obtained by trypsin digestion and transferred to a culture medium. The time needed to reach full confluence in culture was determined. Specific antibodies to corneal stem cell marker (P63) versus corneal epithelial differentiation marker (K3) were used for histochemical determinations. A high proportion of P63 positive cells (85 +/- 4.6%), and a correspondingly low proportion K3 positive cells (15 +/- 3.8%) indicated that most cultured cells remained undifferentiated and were considered as stem cells (mean +/- SE, n=10). Cultures reached full confluency after 17.3 +/- 1.2 days when the medium was supplemented with human EGF, while 21.7 +/- 1.5 days were needed when the medium was supplemented with mouse EGF. The results showed that limbal stem cells proliferate more easily and reach to full confluency in a shorter time if the medium is supplemented with hEGF rather than with mEGF.

Comparative study of technique to obtain stem cells from bone marrow collection between the iliac crest and the femoral epiphysis in rabbits / Estudo comparativo da técnica para a obtenção de células tronco pela coleta de medula óssea entre a crista ilíaca e epífise do fêmur em coelhos

PURPOSE: To assess the technique for the collection of rabbit bone marrow stem cells from different regions to be used as an experimental model in regenerative medicine. METHODS: Thirty rabbits were allocated into 2 groups: GROUP A, n=8, animals that underwent bone marrow blood (BMB) harvesting from the iliac crest; and GROUP B: including 22 rabbits that underwent BMB harvesting from the femur epiphysis. After harvesting, mononuclear cells were isolated by density gradient centrifugation (Ficoll - Histopaque). The number of mononuclear cells per ml was counted in a Neubauer chamber and cell viability was checked through Tripan Blue method. RESULTS: Harvesting from the iliac crest yielded an average of 1 ml of BMB and 3,6.10(6) cells/ml over 1 hour of surgery, whereas an average of 3ml of BMB and 11,79.10(6) cells./ml were obtained in 30 min from the femur epiphysis with a reduced animal death rate. CONCLUSION: The analysis for the obtention of a larger number of mononuclear cells/ml from rabbit bone marrow blood was more satisfactory in the femur epiphysis than in the iliac crest.

OBJETIVO: Avaliar a técnica mais promissora para a coleta de células tronco adultas de medula óssea de coelhos para a utilização do mesmo como modelo experimental na medicina regenerativa. MÉTODOS: Foram utilizados 30 coelhos divididos em 2 grupos: GRUPO A, n=8, onde realizamos a coleta de sangue de medula óssea (MO) da crista ilíaca e grupo B, n=22, onde realizamos a coleta de sangue da medula óssea da epífise do fêmur. Após as coletas, realizamos a separação das células mononucleadas através do gradiente de densidade (Ficoll-Hystopaque). Através da câmara de Neubauer realizamos a contagem das células mononucleadas por ml. Testamos a viabilidade celular através do método Tripan Blue. RESULTADOS: Na coleta de sangue de MO na crista ilíaca obtivemos a média de 1 ml durante 1 hora de procedimento cirúrgico, obtendo a quantidade de 3,6 .10(6) células/ml, enquanto que a punção na epífise do fêmur obtivemos a média de 3 ml durante 30 minutos de procedimento cirúrgico obtendo a quantidade de 11,79.10(6) cél./ml diminuindo o óbito dos animais. CONCLUSÃO: A análise para a obtenção de maior número de células mononucleadas/ml de sangue de medula óssea de coelho foi mais satisfatória na região da epífise do fêmur em comparação com a crista ilíaca.

DNA Methylation and Expression Patterns of Key Tissue-specific Genes in Adult Stem Cells and Stomach Tissues

CpG-island margins and non-island-CpG sites round the transcription start sites of CpG-island-positive and -negative genes are methylated to various degrees in a tissue-specific manner. These methylation-variable CpG sites were analyzed to delineate a relationship between the methylation and transcription of the tissue-specific genes. The level of tissue-specific transcription was estimated by counting the number of the total transcripts in the SAGE (serial analysis of gene expression) database. The methylation status of 12 CpG-island margins and 21 non-island CpG sites near the key tissue-specific genes was examined in pluripotent stromal cells obtained from fat and bone marrow samples as well as in lineage-committed cells from marrow bulk, stomach, colon, breast, and thyroid samples. Of the 33 CpG sites examined, 10 non-island-CpG sites, but none of the CpG-island margins were undermethylated concurrent with tissue-specific expression of their nearby genes. The net methylation of the 33 CpG sites and the net amount of non-island-CpG gene transcripts were high in stomach tissues and low in stromal cells. The present findings suggest that the methylation of the non-island-CpG sites is inversely associated with the expression of the nearby genes, and the concert effect of transitional-CpG methylation is linearly associated with the stomach-specific genes lacking CpG-islands.

Lesión de médula espinal y medicina regenerativa: [revisión] / Spinal cord injury and regenerative medicine: [review]

La lesión medular (LM) es un problema que afecta sobre todo a la población en edad laboral y, por lo tanto, sus repercusiones rebasan el ámbito familiar. La LM es irreversible para la mitad de las víctimas y en la actualidad los tratamientos existentes consisten en la asistencia y la estabilización espinal. Con el reconocimiento de la existencia de células madre (CM), el tratamiento de la LM ha recibido otro enfoque. Las CM se encargan de la renovación de los tejidos durante la vida del individuo y su reparación en caso de lesión. Las CM más atractivas desde el punto de vista terapéutico son las capaces de generar diversos tejidos, obtenibles con facilidad, y cuya manipulación es aceptable en términos éticos. En este artículo se presentan algunos de los estudios realizados con CM de diversos orígenes y su aplicación al tratamiento de la LM.

Spinal cord injury (SCI) is a trauma problem striking mainly working age adults, therefore affecting society beyond the victim’s family circle. Most of the victims of SCI will never recover; therapy for this type of injury consists basically on spinal cord support and stabilization. With the discovery of stem cells (SC), SCI treatment has been given another chance. Stem cells are responsible for tissue renewal throughout the individual’s life, as well as tissue repair when needed. From the therapeutic point of view, the most appealing SC are those capable of generating a variety of tissues, those easily harvested, and finally, those ethically unquestioned. This article summarizes some studies carried with SC of various origins and their application to SCI treatment.

Regulation of stem cell fate in hematopoietic development.

Stem cells are broadly classified into two categories; embryonic stem cell and somatic stem cell. Both types of stem cells can be differentiated into many cell types of the body with a different capability. Blood cells are examples of the cells that can be derived from both embryonic and somatic stem cells, both in vivo and in vitro. In adults, blood cells are mainly derived from hematopoietic stem cells (HSC) in the bone marrow. HSC growth and differentiation is tightly regulated which require both intrinsic and extrinsic signals. In this regard, transcription factors are critical for the development of HSC and specific cell lineages, in part, by regulating the expression of hematopoietic growth factor (HGF) receptors, other transcription factors and lineage specific genes transcription. This review will focus on the role of Id transcription factors in stem cell fate regulation.

Células troncales (stem cells) y regeneración cardíaca / Stem cells and cardiac regeneration

Las células troncales carecen de marcadores de diferenciación, tienen gran capacidad proliferativa, pueden automantener la población, producen progenies de células progenitoras y participan en la regeneración de tejidos. Los tejidos de un individuo tienen capacidad de regeneración, que a veces está ligada a la presencia de células troncales. La medicina regenerativa plantea la terapia celular como una alternativa para el tratamiento de diversas enfermedades, incluyendo las cardíacas (cardiomioplastia celular). Las células a usar pueden provenir de distintas fuentes, entre ellas las células troncales de origen cardíaco o extracardíaco. La médula ósea es una de las fuentes más importantes de células troncales extracardíacas, que podrían contribuir a obtener células cardíacas por diversos mecanismos (transdiferenciación, fusión o transferencia a través de estructuras nanotubulares). En los últimos años, diversas publicaciones refieren la existencia de células troncales nativas cardíacas, caracterizadas por la presencia de distintos marcadores. Se plantea también la alternativa del uso de factores de crecimiento para producir la movilización de células troncales. El individuo adulto posee células con alta potencialidad, surgidas en estadios embrionarios antes o después de la determinación en las capas germinales, y mantenidas hasta la adultez que, bajo condiciones apropiadas de manipulación, permita su utlización en la medicina regenerativa

Stem cells are defined by virtue of their functional attributes: absence of tissue specific differentitated markers, capable of proliferation, able to self-maintain the population, able to produce a large number of differentiated, functional progeny, able to regenerate the tissue after injury. Cell therapy is an alternative for the treatment of several diseases, like cardiac diseases (cell cardiomyoplasty). A variety of stem cells could be used for cardiac repair: from cardiac and extracardiac sources. Each cell type has its own profile of advantages, limitations, and practicability issues in specific clinical settings. Differentiation of bone marrow stem cells to cardiomyocyte-like cells have been observed under different culture conditions. The presence of resident cardiac stem cell population capable of differentiation into cardiomyocyte or vascular lineage suggests that these cells could be used for cardiac tissue repair, and represent a great promise for clinical application. Stem cells mobilization by cytokines may also offer a strategy for cardiac regeneration. The use of stem cells (embryonic and adult) may hold the key to replacing cells lost in many devastating diseases. This potential benefit is a major focus for stem cell research