Comparison of senescence phenotype of short- and long- term cultured rat mesenchymal stem cells in vitro.

Mesenchymal stem cells present clinical potential to recover and regenerate injured tissues in diverse pathologies. The in vitro expansion and characterization of these cells contribute to elucidation of the mechanisms of senescence and strategies involving cell therapies. This study aimed to compare specific characteristics between initial and advanced passages of mesenchymal stem cells derived from adipose tissue and bone marrow. Both cell types were characterized according to immunophenotype, osteogenic differentiation, genomic instability, migration assay, doubling population time and colony forming ability. Our results demonstrated that both cell types were able to maintain an immunophenotypic profile typical of mesenchymal stem cells during increasing passages. Adipose stem cells at initial passage presented greater migration capacity compared to advanced passage cells, and advanced passage cells proliferated faster than initial passage cells. Bone marrow stem cells at early passages presented higher osteogenic potential than advanced. At advanced passages they presented higher colony forming capacity and genetic damage than those at initial passage. These results suggest that mesenchymal stem cells maintained in culture presented characteristics of senescence that should be monitored prior the use in regenerative medicine and cells derived from bone marrow at initial passage have better potential for therapeutic use in bone tissue engineering.

Improvement of human pancreatic islet quality after co-culture with human adipose-derived stem cells.

The aim of this study was to investigate whether co-culture of human islets with adipose-derived stem cells (ASCs) can improve islet quality and to evaluate which factors play a role in the protective effect of ASCs against islet dysfunction. Islets and ASCs were cultured in three experimental groups for 24 h, 48 h, and 72 h: 1) indirect co-culture of islets with ASC monolayer (Islets/ASCs); 2) islets alone; and 3) ASCs alone. Co-culture with ASCs improved islet viability and function in all culture time-points analyzed. VEGFA, HGF, IL6, IL8, IL10, CCL2, IL1B, and TNF protein levels were increased in supernatants of islet/ASC group compared to islets alone, mainly after 24 h. Moreover, VEGFA, IL6, CCL2, HIF1A, XIAP, CHOP, and NFKBIA genes were differentially expressed in islets from the co-culture condition compared to islets alone. In conclusion, co-culture of islets with ASCs promotes improvements in islet quality.

Transamidase site-targeted agents alter the conformation of the transglutaminase cancer stem cell survival protein to reduce GTP binding activity and cancer stem cell survival.

Type 2 transglutaminase (TG2) is an important cancer stem cell survival protein that exists in open and closed conformations. The major intracellular form is the closed conformation that functions as a GTP-binding GTPase and is required for cancer stem cell survival. However, at a finite rate, TG2 transitions to an open conformation that exposes the transamidase catalytic site involved in protein-protein crosslinking. The activities are mutually exclusive, as the closed conformation has GTP binding/GTPase activity, and the open conformation transamidase activity. We recently showed that GTP binding, but not transamidase activity, is required for TG2-dependent cancer stem cell invasion, migration and tumour formation. However, we were surprised that transamidase site-specific inhibitors reduce cancer stem cell survival. We now show that compounds NC9, VA4 and VA5, which react exclusively at the TG2 transamidase site, inhibit both transamidase and GTP-binding activities. Transamidase activity is inhibited by direct inhibitor binding at the transamidase site, and GTP binding is blocked because inhibitor interaction at the transamidase site locks the protein in the extended/open conformation to disorganize/inactivate the GTP binding/GTPase site. These findings suggest that transamidase site-specific inhibitors can inhibit GTP binding/signalling by driving a conformation change that disorganizes the TG2 GTP binding to reduce TG2-dependent signalling, and that drugs designed to target this site may be potent anti-cancer agents.

VEGF gene therapy cooperatively recruits molecules from the immune system and stimulates cell homing and angiogenesis in refractory angina.

BACKGROUND: New vessels are formed in response to stimuli from angiogenic factors, a process in which paracrine signaling is fundamental. OBJECTIVE: To investigate the cooperative paracrine signaling profile in response to Vascular Endothelial Growth Factor (VEGF) gene therapy in patients with coronary artery disease (CAD) and refractory angina. METHOD: A cohort study was conducted in which plasma was collected from patients who underwent gene therapy with a plasmid expressing VEGF 165 (10) and from surgical procedure controls (4). Blood samples were collected from both groups prior to baseline and on days 3, 9 and 27 after the interventions and subjected to systemic analysis of protein expression (Interleukin-6, IL-6; Tumor Necrosis Factor-α, TNF-α; Interleukin-10, IL-10; Stromal Derived Factor-1 α, SDF-1α; VEGF; Angiopoietin-1, ANGPT-1; and Endothelin-1, ET-1) using the enzyme-linked immunosorbent assay (ELISA). RESULTS: Analysis showed an increase in proinflammatory IL-6 (p=0.02) and ET-1 (p=0.05) on day 3 after gene therapy and in VEGF (p=0.02) on day 9. A strong positive correlation was found between mobilization of endothelial progenitor cells and TNF-α on day 9 (r=0.71; p=0.03). Furthermore, a strong correlation between ß-blockers, antiplatelets, and vasodilators with SDF-1α baseline in the group undergoing gene therapy was verified (r=0.74; p=0.004). CONCLUSION: Analysis of cooperative paracrine signaling after VEGF gene therapy suggests that the immune system cell and angiogenic molecule expression as well as the endothelial progenitor cell mobilization are time-dependent, influenced by chronic inflammatory process and continuous pharmacological treatment.

Role of the autologous mesenchymal stem cells compared with platelet rich plasma on cicatrization of cutaneous wounds in diabetic mice / Papel das células-tronco mesenquimais autólogas em comparação com plasma rico em plaquetas na cicatrização de feridas cutâneas em camundongos diabéticos

Chronic cutaneous lesions affect 15% of diabetic human patients and represent a risk 15 to 46 times larger of limb amputations compared to people with normal glycemia. It is assumed that half of these amputations could be prevented by early treatment of wounds, for example, with proper cell therapy. Objectives: In this study, the action of the autologous transplant of mesenchymal stem-cells (MSC) was evaluated compared to the treatment with autologous platelet rich plasma (PRP) in the cicatrization of cutaneous lesions induced in diabetic mice. These animals were previously treated with streptozootocin to induce diabetes mellitus and round wounds of 1.5cm in diameter were created in the posterior region. Diameters of the wounds and healing time were evaluated during 30 days and the results were submitted to variance analysis and Tukey's test average. It was noticed that the animals treated with MSC presented a more accelerated cicatrization of the cutaneous lesion than the animals treated with PRP. However, the treatment with PRP presented better results than just the daily asepsis of the lesions with saline or covering them with semi-permeable bandage. Besides, the use of semi-permeable bandage kept the cutaneous lesions of diabetic mice did not interfere negatively with cicatrization, proved to be harmless to use, but kept the cutaneous lesions more hydrated than the ones exposed to the environment.(AU)

Lesões cutâneas crônicas afetam 15% dos pacientes diabéticos e humanos representam um risco 15 a 46 vezes maior de amputações de membros em comparação com as pessoas com a glicemia normal. Supõe-se que a metade destas amputações poderia ser evitada por meio do tratamento precoce das feridas cutâneas com, por exemplo, uma adequada terapia celular. Objetivos: Neste estudo, a ação do transplante autólogo de células estaminais mesenquimais (MSC) foi avaliada em comparação com o tratamento com plasma rico em plaquetas autólogo (PRP) na cicatrização de lesões cutâneas induzidas em camundongos diabéticos. Estes animais foram previamente tratados com estreptozotocina para induzir diabetes mellitus e feridas redondas de 1,5 cm de diâmetro foram criadas na região posterior. Os diâmetros dos ferimentos e tempo de cicatrização foram avaliados durante 30 dias e os resultados foram submetidos à análise de variância e média pelo teste de Tukey. Verificou-se que os animais tratados com MSC apresentam uma cicatrização mais acelerada da lesão cutânea que do que os animais tratados com PRP. No entanto, o tratamento com PRP apresentou melhores resultados do que apenas a assepsia das lesões diariamente com solução salina ou cobrindo-os com atadura semi-permeável. Além disso, a utilização de atadura semi-permeável mantidas as lesões cutâneas de camundongos diabéticos não interfere negativamente com a cicatrização, provou ser inofensiva para usar, mas manteve as lesões cutâneas hidratadas mais do que os expostos ao meio ambiente.(AU)

Direct intramyocardial transthoracic transplantation of bone marrow mononuclear cells for non-ischemic dilated cardiomyopathy: INTRACELL, a prospective randomized controlled trial.

OBJECTIVE: We tested the hypothesis that direct intramyocardial injection of bone marrow mononuclear cells in patients with non-ischemic dilated cardiomyopathy can improve left ventricular function and physical capacity. METHODS: Thirty non-ischemic dilated cardiomyopathy patients with left ventricular ejection fraction <35% were randomized at a 1:2 ratio into two groups, control and treated. The bone marrow mononuclear cells group received 1.06±108 bone marrow mononuclear cells through mini-thoracotomy. There was no intervention in the control group. Assessment was carried out through clinical evaluations as well as a 6-min walk test, nuclear magnectic resonance imaging and echocardiogram. RESULTS: The bone marrow mononuclear cells group showed a trend toward left ventricular ejection fraction improvement, with magnectic resonance imaging - at 3 months, showing an increase from 27.80±6.86% to 30.13±9.06% (P=0.08) and returning to baseline at 9 months (28.78%, P=0.77). Magnectic resonance imaging showed no changes in left ventricular ejection fraction during follow-up of the control group (28.00±4.32%, 27.42±7.41%, and 29.57±4.50%). Echocardiogram showed left ventricular ejection fraction improved in the bone marrow mononuclear cells group at 3 months, 25.09±3.98 to 30.94±9.16 (P=0.01), and one year, 30.07±7.25% (P=0.001). The control group showed no change (26.1±4.4 vs 26.5±4.7 and 30.2±7.39%, P=0.25 and 0.10, respectively). Bone marrow mononuclear cells group showed improvement in New York Heart Association functional class, from 3.40±0.50 to 2.41±0.79 (P=0.002); patients in the control group showed no change (3.37±0.51 to 2.71±0.95; P=0.17). Six-minute walk test improved in the bone marrow mononuclear cells group (348.00±93.51m at baseline to 370.41±91.56m at 12 months, P=0.66) and there was a non-significant decline in the control group (361.25±90.78m to 330.00±123.42m after 12 months, P=0.66). Group comparisons were non-significant. CONCLUSION: The trend of intragroup functional and subjective improvement was not confirmed when compared to the control group. Direct intramyocardial application of bone marrow mononuclear cells in non-ischemic dilated cardiomyopathy was not associated with significant changes in left ventricular function. Differences observed within the bone marrow mononuclear cells group could be due to placebo effect or low statistical power.

Direct intramyocardial transthoracic transplantation of bone marrow mononuclear cells for non-ischemic dilated cardiomyopathy: INTRACELL, a prospective randomized controlled trial / Ensaio clínico prospectivo randomizado sobre terapia com células mononucleares da medula óssea para cardiomiopatia dilatada idiopática: INTRACELL

Objective: We tested the hypothesis that direct intramyocardial injection of bone marrow mononuclear cells in patients with non-ischemic dilated cardiomyopathy can improve left ventricular function and physical capacity. Methods: Thirty non-ischemic dilated cardiomyopathy patients with left ventricular ejection fraction <35% were randomized at a 1:2 ratio into two groups, control and treated. The bone marrow mononuclear cells group received 1.06±108 bone marrow mononuclear cells through mini-thoracotomy. There was no intervention in the control group. Assessment was carried out through clinical evaluations as well as a 6-min walk test, nuclear magnectic resonance imaging and echocardiogram. Results: The bone marrow mononuclear cells group showed a trend toward left ventricular ejection fraction improvement, with magnectic resonance imaging - at 3 months, showing an increase from 27.80±6.86% to 30.13±9.06% (P=0.08) and returning to baseline at 9 months (28.78%, P=0.77). Magnectic resonance imaging showed no changes in left ventricular ejection fraction during follow-up of the control group (28.00±4.32%, 27.42±7.41%, and 29.57±4.50%). Echocardiogram showed left ventricular ejection fraction improved in the bone marrow mononuclear cells group at 3 months, 25.09±3.98 to 30.94±9.16 (P=0.01), and one year, 30.07±7.25% (P=0.001). The control group showed no change (26.1±4.4 vs 26.5±4.7 and 30.2±7.39%, P=0.25 and 0.10, respectively). Bone marrow mononuclear cells group showed improvement in New York Heart Association functional class, from 3.40±0.50 to 2.41±0.79 (P=0.002); patients in the control group showed no change (3.37±0.51 to 2.71±0.95; P=0.17). Six-minute walk test improved in the bone marrow mononuclear cells group (348.00±93.51m at baseline to 370.41±91.56m at 12 months, P=0.66) and there was a non-significant decline in the control group ...

Objetivo: Testamos a hipótese de que a injeção intramiocárdica direta de células mononucleares de medula óssea em pacientes portadores de cardiomiopatia dilatada não-isquêmica pode melhorar a função ventricular e a capacidade física. Métodos: Trinta pacientes com cardiomiopatia dilatada não isquêmica e fração de ejeção 35% foram randomizados na razão 1:2 em grupos controle e tratado. Grupo células mononucleares de medula óssea recebeu 1,06 ± 108 células mononucleares de medula óssea por mini-toracotomia. Grupo controle não recebeu intervenção. Avaliação foi feita clinicamente e por teste de caminhada 6 minutos (T6m), ressonância magnética e ecocardiogramas. Resultados: Grupo células mononucleares de medula óssea mostrou tendência de melhora da Fração de ejeção - ressonância magnética aos 3 meses, 27,80±6,86% para 30,13±9,06% (P=0,08), retornando ao basal aos 9 meses (28,78%, P=0,77). Grupo controle não apresentou variação (28,00±4,32%; 27,42±7,41% e 29,57±4,50%). Ecocardiogramas - fração de ejeção melhorou no grupo células mononucleares de medula óssea aos 3 meses: 25,09±3,98 para 30,94±9,16 (P=0,01) e aos 12 meses (30,07±7,25%, P=0,001), enquanto o controle não variou: 26,1±4,4 vs. 26,5±4,7 e 30,2±7,39%, P=0,25 e 0,10, respectivamente). Células mononucleares de medula óssea melhorou classe funcional New York Heart Association: 3,40±0.50 para 2,41±0,79 (P=0,002); controles não mudaram (3,37±0,51 para 2,71±0,95; P=0,17). T6m melhorou no grupo células mononucleares de medula óssea (348,00±93,51 m inicial para 370,41±91,56 m aos 12 m, P=0,66) e declinou sem significância no ...

Mesenchymal stem cells from different murine tissues have differential capacity to metabolize extracellular nucleotides.

Mesenchymal stem cells (MSCs) have shown a great potential for cell-based therapy and many different therapeutic purposes. Despite the recent advances in the knowledge of MSCs biology, their biochemical and molecular properties are still poorly defined. Ecto-nucleoside triphosphate diphosphohydrolases (E-NTPDases) and ecto-5'-nucleotidase (eNT/CD73) are widely expressed enzymes that hydrolyze extracellular nucleotides, generating an important cellular signaling cascade. Currently, studies have evidenced the relationship between the purinergic system and the development, maintenance, and differentiation of stem cells. The objective of this study is to identify the NTPDases and eNT/CD73 and compare the levels of nucleotide hydrolysis on MSCs isolated from different murine tissues (bone marrow, lung, vena cava, kidney, pancreas, spleen, skin, and adipose tissue). MSCs from all tissues investigated expressed the ectoenzymes at different levels. In MSCs from pancreas and adipose tissue, the hydrolysis of triphosphonucleosides was significantly higher when compared to the other cells. The diphosphonucleosides were hydrolyzed at a higher rate by MSC from pancreas when compared to MSC from other tissues. The differential nucleotide hydrolysis activity and enzyme expression in these cells suggests that MSCs play different roles in regulating the purinergic system in these tissues. Overall MSCs are an attractive adult-derived cell population for therapies, however, the fact that ecto-nucleotide metabolism can affect the microenvironment, modulating important events, such as immune response, makes the assessment of this metabolism an important part of the characterization of MSCs to be applied therapeutically.

High doses of vascular endothelial growth factor 165 safely, but transiently, improve myocardial perfusion in no-option ischemic disease.

UNLABELLED: Gene therapy can induce angiogenesis in ischemic tissues. The aim of this study was to assess safety, feasibility, and results, both clinical and on myocardial perfusion, of gene therapy in refractory angina. This was a phase I/II, prospective, temporal-controlled series, clinical trial. Thirteen patients were maintained for minimum 6 months under optimized clinical management, and then received intramyocardial injections of 2000 µg plasmid vascular endothelial growth factor 165 and were followed by single-photon emission computed tomography (SPECT), treadmill tests, Minnesota quality of life questionnaire (QOL), and New York Heart Association (NYHA) functional plus Canadian Cardiovascular Society (CCS) angina classifications. There were no deaths, early or late. During the optimized clinical treatment, we observed worsening of rest ischemia scores on SPECT (p<0.05). After treatment, there was a transitory increase in myocardial perfusion at the third-month SPECT under stress (pre-operative [pre-op] 18.38 ± 7.51 vs. 3 months 15.31 ± 7.30; p<0.01) and at the sixth month under rest (pre-op 13.23 ± 7.98 vs. 6 months: 16.92 ± 7.27; p<0.01). One year after, there were improvements in treadmill test steps (pre-op 2.46 ± 2.07 vs.12 months 4.15 ± 2.23; p<0.01) and oxygen consumption (pre-op 7.66 ± 4.47 vs.12 months 10.89 ± 4.65; p<0.05), QOL (pre-op 48.23 ± 18.35 vs.12 months 28.31 ± 18.14; p<0.01) scores, and CCS (pre-op 3 [3-3.5] vs.12 months 2 [1-2.5]; p<0.01) and NYHA (pre-op 3 [3-3] vs. 2 [2-2] vs. 12 months 2 [1-2]; p<0.01) classes. Gene therapy demonstrated to be feasible and safe in this advanced ischemic cardiomyopathy patient sample. There were improvements in clinical evaluation parameters, and a transitory increase in myocardial perfusion detectable by SPECT scintigraphy. CLINICAL TRIAL REGISTRATION: NCT00744315 http://clinicaltrials.gov/

Mesenchymal stem cells combined with an artificial dermal substitute improve repair in full-thickness skin wounds.

Autografts represent the gold standard for the treatment of full thickness burns. Factors such as lack of suitable donor sites and poor skin quality, however, have led to the development of artificial dermal substitutes. The investigation of mechanisms leading to enhanced functionality of these skin substitutes has been attracting great attention. This study aimed to investigate the effect of autologous stem cells on the integration and vascularization of a dermal substitute in full-thickness skin wounds, in a murine model. Two cell populations were compared, whole bone marrow cells and cultivated mesenchymal stem cells, isolated from mice transgenic for the enhanced green fluorescent protein, which allowed tracking of the transplanted cells. The number of cells colonizing the dermal substitute, as well as vascular density, were higher in mice receiving total bone marrow and particularly mesenchymal stem cells, than in control animals. The effect was more pronounced in animals treated with mesenchymal stem cells, which located primarily in the wound bed, suggesting a paracrine therapeutic mechanism. These results indicate that combining mesenchymal stem cells with artificial dermal substitutes may represent an important potential modality for treating full thickness burns, even in allogeneic combinations due to the immunoregulatory property of these cells.

Treatment of critical defects produced in calvaria of mice with mesenchymal stem cells.

Mesenchymal stem cells (MSC) are present in specialized niches in perivascular regions of adult tissues and are able to differentiate into various cell types, such as those committed to repairing. Bone marrow derived MSC from eight young mice C57BL/ 6 gfp(+) were expanded in culture for repairing critical defects in calvarial bone produced in twenty-four young isogenic adult C57BL/6 mice. The animals were subjected to a cranial defect of 6.0mm diameter and divided into two equal experimental groups. Control group did not receive any treatment and the treated group received a MSC pellet containing 1.0 x 10(7) cells/mL into the defects. The group treated with MSC showed increased angiogenesis and amount of new bone deposited on the defect limits than that observed in the control group. The results demonstrated that transplantation of bone marrow-derived MSC of C57BL/6 gfp(+) mice to bone critical defects produced in mice calvarial contributes positively to the bone repair process. MSC presets ability to influence the correct functioning of osteoblasts, increases the amount of mobilized cells for the repairing process, speeds up growth, and increases deposition of bone matrix.

Terapia gênica para cardiopatia isquêmica: revisão de ensaios clínicos / Gene therapy for ischemic heart disease: review of clinical trials

Cardiopatia isquêmica grave com angina refratária a formas convencionais de tratamento apresenta-se em uma crescente incidência. Para tratar angina refratária, terapias alternativas na tentativa de redução da isquemia miocárdica e alívio de sintomas têm sido estudadas. Neste contexto, a terapia gênica representa uma opção, pela possibilidade de induzir angiogênese, estabelecer circulação colateral e reperfundir miocárdio isquêmico. Diversos ensaios clínicos têm sido conduzidos e, com exceção de casos isolados e específicos de efeitos adversos, há indicação de segurança, viabilidade e potencial eficácia da terapia. O benefício clínico não está bem definido. Neste artigo, revisamos os ensaios clínicos que utilizaram terapia gênica para tratamento de pacientes cardiopatas isquêmicos. A abordagem inclui: (1) isquemia miocárdica e angiogênese, sobre os aspectos fisiopatológicos envolvidos; (2) fatores de crescimento, tratando sobre aspectos específicos e justificando a utilização em pacientes cardiopatas isquêmicos sem opções pela terapêutica convencional; (3) ensaios clínicos controlados, onde é apresentado um resumo dos principais estudos envolvendo terapia gênica para tratamento da cardiopatia isquêmica grave; (4) nossa experiência, especialmente sobre resultados preliminares do primeiro ensaio clínico de terapia gênica do Brasil e (5) perspectivas.

Severe ischemic heart disease with refractory angina, occurs in increasing incidence. Alternative forms of treatment, in an attempt to reduce myocardial ischemia and relief of symptoms has been studied. In this context, gene therapy is an option, for the possibility of inducing angiogenesis, establish collateral circulation and reperfuse ischemic myocardium. Several clinical trials have been conducted and, except for specific cases of adverse effects, there is indication of safety, feasibility and potential effectiveness of therapy. The clinical benefit, however, is not yet well established. In this article we review the clinical trials of gene therapy for patients with ischemic heart disease. The approach includes: (1) myocardial ischemia and angiogenesis on the pathophysiological aspects involved, (2) growth factors, dealing with specific aspects and justifying the use in cardiac patients with no option for conventional therapy, (3) controlled clinical trials, where a summary of the main studies involving gene therapy for severe ischemic heart disease is presented, (4) our experience, especially on preliminary results of the first gene therapy clinical trial in Brazil and (5) future prospects.

Evaluation of scaffolds based on α-tricalcium phosphate cements for tissue engineering applications.

Growth of cells in 3-D porous scaffolds has gained importance in the field of tissue engineering. The scaffolds guide cellular growth, synthesize extracellular matrix and other biological molecules, and make the formation of tissues and functional organs easier. The aim of this study is to use α-tricalcium phosphate cement in order to obtain new types of scaffolds with the aid of paraffin spheres as pore generators. The porosity of the scaffolds produced with paraffin spheres was analyzed and compared to the literature, and the study of scaffold permeability using the Forchheimer equation allowed the analysis of pore interconnectivity. In vitro tests showed the behavior of scaffolds in solutions of simulated body fluid, and viability and cell proliferation were also evaluated. The results show the potential use of the materials developed for scaffolds for use in tissue engineering applications.

Gene therapy for ischemic heart disease: review of clinical trials.

Severe ischemic heart disease with refractory angina, occurs in increasing incidence. Alternative forms of treatment, in an attempt to reduce myocardial ischemia and relief of symptoms has been studied. In this context, gene therapy is an option, for the possibility of inducing angiogenesis, establish collateral circulation and reperfuse ischemic myocardium. Several clinical trials have been conducted and, except for specific cases of adverse effects, there is indication of safety, feasibility and potential effectiveness of therapy. The clinical benefit, however, is not yet well established. In this article we review the clinical trials of gene therapy for patients with ischemic heart disease. The approach includes: (1) myocardial ischemia and angiogenesis on the pathophysiological aspects involved, (2) growth factors, dealing with specific aspects and justifying the use in cardiac patients with no option for conventional therapy, (3) controlled clinical trials, where a summary of the main studies involving gene therapy for severe ischemic heart disease is presented, (4) our experience, especially on preliminary results of the first gene therapy clinical trial in Brazil and (5) future prospects.

Biology of stem cells: an overview.

Stem cells are defined as precursor cells that have the capacity to self-renew and to generate multiple mature cell types. Only after collecting and culturing tissues is it possible to classify cells according to this operational concept. This difficulty in identifying stem cells in situ, without any manipulation, limits the understanding of their true nature. This review aims at presenting, to health professionals interested in this area, an overview on the biology of embryonic and adult stem cells, and their therapeutic potential.

Global contractility increment in nonischemic dilated cardiomyopathy after free wall-only intramyocardial injection of autologous bone marrow mononuclear cells: an insight over stem cells clinical mechanism of action.

Bone marrow mononuclear cells (BMMC) effects have been investigated in small series of nonischemic dilated cardiomyopathy (NIDC). Left ventricular myocardial contractility improvements occur, but doubt remains about their mechanism of action. We compared contractility changes in areas treated (free wall) and nontreated (septal wall) with BMMC, in selected patients who have showed significant ventricular improvement after free wall-only intramyocardial stem cells injection. From 15 patients with functional class III/IV (NYHA) and LVEF inferior to 35%, who received 9.6 ± 2.6 × 10(7) BMMC divided into 10 points over the left ventricular free wall, 7 (46.7%) showed LVEF relative improvement greater than 15%. Those patients were selected for further contractility study. BMMC were collected from iliac bone and isolated with Ficoll-Hypaque. Magnetic resonance imaging was used to measure the systolic thickening of the septal (nontreated) and free wall (treated) before injection and 3 months postoperatively. Mean systolic septal wall thickening increased from 0.46 to 1.23 mm (an absolute 0.77 ± 1.3 mm and relative 167.4% increase) and in the free wall from 1.13 to 1.87 mm (an absolute 0.74 ± 1.5 mm and relative increase of 65.5%). There was no difference in the rate of absolute or relative systolic thickening between the two walls (p = 0.866 and 1.0, respectively), when cells were injected only in the left ventricular free wall. BMMC transplantation in nonischemic dilated cardiomyopathy can improve ventricular function by an overall effect, even in areas that are not directly injected. This finding favors the existence of a diffuse mechanism of action, rather than a local effect, and should be reminded when the pathophysiology of stem cells is considered.

Expression of mdr isoforms in mice during estrous cycle and under hormone stimulation

The multidrug resistance (MDR) phenotype is associated with the expression of P-glycoprotein (Pgp), coded by the multigenic mdr family. Mice present the isoforms mdr1 and mdr3, which are responsible for multidrug resistance, and mdr2, that is involved in the transport of phospholipids. mdr1 expression has more recently been associated also with the secretion of steroid hormones. This work presents an RT-PCR analysis of the expression of mdr isoforms, in several organs of mice during different phases of the estrous cycle. Additionally, females were ovariectomized, submitted to different hormone treatments, and their uterus was analyzed for the expression of mdr isoforms. The results show that in the adrenal gland and ovaries mdr1 is the main isoform during proestrus, and that progesterone or a combination of progesterone and estrogen induce the expression of all mdr isoforms in the uterus of ovariectomized females. We suggest that the functions of mdr1 and mdr3 are overlapping, that mdr3 may be the more efficient isoform in the detoxification function, and that mdr1 may be more closely related to the secretion of steroid hormones.