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This corrects the article DOI: 10.1038/nature24675.
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The number of clinical trials using human pluripotent stem cells (hPSC)-both embryonic and induced pluripotent stem cells (hESC/iPSC)-has expanded in the last several years beyond expectations. By the end of 2021, a total of 90 trials had been registered in 13 countries with more than 3000 participants. However, only US, Japan, China, and the UK are conducting both hESC- and hiPSC-based trials. Together US, Japan, and China have registered 78% (70 out of 90) of all trials worldwide. More than half of all trials (51%) are focused on the treatment of degenerative eye diseases and malignancies, enrolling nearly 2/3 of all participants in hPSC-based trials. Although no serious adverse events resulting in death or morbidity due to hPSC-based cellular therapy received have been reported, information about safety and clinical efficacy are still very limited. With the availability of novel technologies for precise genome editing, a new trend in the development of hPSC-based cellular therapies seems to be emerging. Engineering universal donor hPSC lines has become a holy grail in the field. Indeed, because of its effectiveness and simplicity nanomedicine and in vivo delivery of gene therapy could become more advantageous than cellular therapies for the treatment of multiple diseases. In the future, for the best outcome, hPSC-based cellular therapy might be combined with other technological advancements, such as biomimetic epidural electrical stimulation that can restore trunk and leg motor functions after complete spinal injury.
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Células-Tronco Embrionárias Humanas , Células-Tronco Pluripotentes Induzidas , Células-Tronco Pluripotentes , Diferenciação Celular , Linhagem Celular , Terapia Baseada em Transplante de Células e Tecidos , HumanosRESUMO
Human pluripotent stem cells (hPS cells) can self-renew indefinitely, making them an attractive source for regenerative therapies. This expansion potential has been linked with the acquisition of large copy number variants that provide mutated cells with a growth advantage in culture. The nature, extent and functional effects of other acquired genome sequence mutations in cultured hPS cells are not known. Here we sequence the protein-coding genes (exomes) of 140 independent human embryonic stem cell (hES cell) lines, including 26 lines prepared for potential clinical use. We then apply computational strategies for identifying mutations present in a subset of cells in each hES cell line. Although such mosaic mutations were generally rare, we identified five unrelated hES cell lines that carried six mutations in the TP53 gene that encodes the tumour suppressor P53. The TP53 mutations we observed are dominant negative and are the mutations most commonly seen in human cancers. We found that the TP53 mutant allelic fraction increased with passage number under standard culture conditions, suggesting that the P53 mutations confer selective advantage. We then mined published RNA sequencing data from 117 hPS cell lines, and observed another nine TP53 mutations, all resulting in coding changes in the DNA-binding domain of P53. In three lines, the allelic fraction exceeded 50%, suggesting additional selective advantage resulting from the loss of heterozygosity at the TP53 locus. As the acquisition and expansion of cancer-associated mutations in hPS cells may go unnoticed during most applications, we suggest that careful genetic characterization of hPS cells and their differentiated derivatives be carried out before clinical use.
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Genes Dominantes/genética , Genes p53 , Células-Tronco Embrionárias Humanas/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Mutação/genética , Seleção Genética , Proteína Supressora de Tumor p53/genética , Alelos , Contagem de Células , Diferenciação Celular/genética , Divisão Celular/genética , Linhagem Celular , DNA/metabolismo , Análise Mutacional de DNA , Exoma/genética , Células-Tronco Embrionárias Humanas/citologia , Humanos , Perda de Heterozigosidade/genética , Mosaicismo , Neoplasias/genética , Domínios Proteicos , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/metabolismoRESUMO
The foundations of mammalian development lie in a cluster of embryonic epiblast stem cells. In response to extracellular matrix signalling, these cells undergo epithelialization and create an apical surface in contact with a cavity, a fundamental event for all subsequent development. Concomitantly, epiblast cells transit through distinct pluripotent states, before lineage commitment at gastrulation. These pluripotent states have been characterized at the molecular level, but their biological importance remains unclear. Here we show that exit from an unrestricted naive pluripotent state is required for epiblast epithelialization and generation of the pro-amniotic cavity in mouse embryos. Embryonic stem cells locked in the naive state are able to initiate polarization but fail to undergo lumenogenesis. Mechanistically, exit from naive pluripotency activates an Oct4-governed transcriptional program that results in expression of glycosylated sialomucin proteins and the vesicle tethering and fusion events of lumenogenesis. Similarly, exit of epiblasts from naive pluripotency in cultured human post-implantation embryos triggers amniotic cavity formation and developmental progression. Our results add tissue-level architecture as a new criterion for the characterization of different pluripotent states, and show the relevance of transitions between these states during development of the mammalian embryo.
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Embrião de Mamíferos/citologia , Morfogênese , Células-Tronco Pluripotentes/citologia , Âmnio/citologia , Animais , Padronização Corporal , Colágeno , Combinação de Medicamentos , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Camadas Germinativas/citologia , Glicosilação , Células-Tronco Embrionárias Humanas/citologia , Humanos , Laminina , Masculino , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Fator 3 de Transcrição de Octâmero/metabolismo , Proteoglicanas , Sialomucinas/metabolismo , Esferoides Celulares/citologiaRESUMO
Thyroid hormones are regarded as the major controllers of metabolic rate and oxygen consumption in mammals. Although it has been demonstrated that thyroid hormone supplementation improves bovine embryo development in vitro, the cellular mechanisms underlying these effects are so far unknown. In this study, we investigated the role of thyroid hormone in development of human preimplantation embryos. Embryos were cultured in the presence or absence of 10-7 M triiodothyronine (T3) till blastocyst stage. Inner cell mass (ICM) and trophectoderm (TE) were separated mechanically and subjected to RNAseq or quantification of mitochondrial DNA copy number. Analyses were performed using DESeq (v1.16.0 on R v3.1.3), MeV4.9 and MitoMiner 4.0v2018 JUN platforms. We found that the exposure of human preimplantation embryos to T3 had a profound impact on nuclear gene transcription only in the cells of ICM (1178 regulated genes-10.5% of 11 196 expressed genes) and almost no effect on cells of TE (38 regulated genes-0.3% of expressed genes). The analyses suggest that T3 induces in ICM a shift in ribosome and oxidative phosphorylation activity, as the upregulated genes are contributing to the composition and organization of the respiratory chain and associated cofactors involved in mitoribosome assembly and stability. Furthermore, a number of genes affecting the citric acid cycle energy production have reduced expression. Our findings might explain why thyroid disorders in women have been associated with reduced fertility and adverse pregnancy outcome. Our data also raise a possibility that supplementation of culture media with T3 may improve outcomes for women undergoing in vitro fertilization.
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Blastocisto/metabolismo , Mitocôndrias/metabolismo , Hormônios Tireóideos/metabolismo , Feminino , Humanos , Fosforilação Oxidativa , GravidezRESUMO
To effectively study the skin and its pathology, various platforms have been used to date, with in vitro 3D skin models being considered the future gold standard. These models have generally been engineered from primary cell lines. However, their short life span leading to the use of various donors, imposes issues with genetic variation. Human pluripotent stem cell (hPSC)-technology holds great prospects as an alternative to the use of primary cell lines to study the pathophysiology of human skin diseases. This is due to their potential to generate an unlimited number of genetically identical skin models that closely mimic the complexity of in vivo human skin. During the past decade, researchers have therefore started to use human embryonic and induced pluripotent stem cells (hESC/iPSC) to derive skin resident-like cells and components. These have subsequently been used to engineer hPSC-derived 3D skin models. In this review, we focus on the advantages, recent developments, and future perspectives in using hPSCs as an alternative cell source for modelling human skin diseases in vitro.
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Técnicas de Cultura de Células em Três Dimensões , Células-Tronco Pluripotentes , Dermatopatias/patologia , Linhagem Celular , Humanos , Modelos BiológicosRESUMO
Differentiation of normal human keratinocytes (NHK) grown in vitro as a monolayer to confluency can be triggered with an acute increase in concentration of extracellular Ca++ . Over several days, induced by Ca++ , the cells form pseudostratified sheets that somewhat resemble the basic organization of the intact skin. This experimental system is widely used in studies of keratinocyte biology and skin pathology. However, expression pattern of the genes considered as markers for cells in specific layers of epidermis in vivo does not always match the specific pattern observed in vitro and might lead to misinterpretation of data. Here, we demonstrate that among 18 markers of terminally differentiated keratinocytes of stratum granulosum (SG) and stratum corneum (SC) in vivo, only four (CDSN, KPRP, LCE1C and SPRR4) have reproduced their expression pattern in vitro. Our data suggest that findings based on two-dimensional (2D) Ca++ -induced terminal differentiation of NHK in vitro should be subjected to additional scrutiny before conclusions could be made and, if possible, verified in other experimental system that might more faithfully represent the in vivo microenvironment.
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Cálcio/farmacologia , Diferenciação Celular/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Queratinócitos/fisiologia , Biomarcadores/metabolismo , Células Cultivadas , Proteínas Ricas em Prolina do Estrato Córneo/genética , Epiderme/metabolismo , Humanos , Técnicas In Vitro , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Queratinócitos/metabolismo , Proteínas/genética , RNA Mensageiro/metabolismo , Proteína da Zônula de Oclusão-1/metabolismoRESUMO
BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB) is a hereditary blistering disorder due to a lack of type VII collagen. At present, treatment is mainly supportive. OBJECTIVES: To determine whether intravenous allogeneic bone marrow-derived mesenchymal stromal/stem cells (BM-MSCs) are safe in RDEB adults and if the cells improve wound healing and quality of life. METHODS: We conducted a prospective, phase I/II, open-label study recruiting 10 RDEB adults to receive 2 intravenous infusions of BM-MSCs (on day 0 and day 14; each dose 2-4 × 106 cells/kg). RESULTS: BM-MSCs were well tolerated with no serious adverse events to 12 months. Regarding efficacy, there was a transient reduction in disease activity scores (8/10 subjects) and a significant reduction in itch. One individual showed a transient increase in type VII collagen. LIMITATIONS: Open-label trial with no placebo. CONCLUSIONS: MSC infusion is safe in RDEB adults and can have clinical benefits for at least 2 months.
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Epidermólise Bolhosa Distrófica/terapia , Transplante de Células-Tronco Mesenquimais/métodos , Prurido/terapia , Adolescente , Adulto , Idoso , Epidermólise Bolhosa Distrófica/complicações , Epidermólise Bolhosa Distrófica/diagnóstico , Feminino , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Prurido/diagnóstico , Prurido/etiologia , Qualidade de Vida , Índice de Gravidade de Doença , Transplante Homólogo/métodos , Resultado do Tratamento , Cicatrização , Adulto JovemRESUMO
STUDY QUESTION: Can miRNAs be reliably detected in the spent blastocyst media (SBM) after IVF as putative biomarkers of the implantation potential of euploid embryos? SUMMARY ANSWER: Adjustment of the data for blastocyst quality and the day of full-expansion hinders the predictive power of a fast, inexpensive, reproducible and user-friendly protocol based on the detection of 10 selected miRNAs from SBM. WHAT IS KNOWN ALREADY: Euploidy represents so far the strongest predictor of blastocyst competence. Nevertheless, ~50% of the euploid blastocysts fail to implant. Several studies across the years have suggested that a dialogue exists between the embryo and the endometrium aimed at the establishment of a pregnancy. MicroRNAs have been proposed as mediators of such a dialogue and investigated in this respect. Several expensive, time-consuming and complex protocols have been adopted and promising results have been produced, but conclusive evidence from large clinical studies is missing. STUDY DESIGN, SIZE, DURATION: This study was conducted in two phases from September 2015 to December 2017. In Phase 1, the human blastocyst miRNome profile was defined from the inner cell mass (ICM) and the corresponding whole-trophectoderm (TE) of six donated blastocysts. Two different protocols were adopted to this end. In parallel, 6 pools of 10 SBM each were run (3 from only implanted euploid blastocysts, IEBs; and 3 from only not-implanted euploid blastocysts, not-IEBs). A fast, inexpensive and user-friendly custom protocol for miRNA SBM profiling was designed. In Phase 2, 239 SBM from IEB and not-IEB were collected at three IVF centres. After 18 SBM from poor-quality blastocysts were excluded from the analysis, data from 107 SBM from not-IEB and 114 from IEB were produced through the previously developed custom protocol and compared. The data were corrected through logistic regressions. PARTICIPANT/MATERIALS, SETTINGS, METHODS: Donated blastocysts underwent ICM and whole-TE isolation. SBM were collected during IVF cycles characterized by ICSI, blastocyst culture in a continuous media, TE biopsy without zona pellucida opening in Day 3, quantitative PCR (qPCR)-based aneuploidy testing and vitrified-warmed single euploid embryo transfer. Not-IEB and IEB were clustered following a negative pregnancy test and a live birth, respectively. The Taqman Low Density Array (TLDA) cards and the Exiqon microRNA human panel I+II qPCR analysis protocols were adopted to analyse the ICM and whole-TE. The latter was used also for SBM pools. A custom protocol and plate was then designed based on the Exiqon workflow, validated and finally adopted for SBM analysis in study Phase 2. This custom protocol allows the analysis of 10 miRNAs from 10 SBM in 3 hours from sample collection to data inspection. MAIN RESULTS AND ROLE OF THE CHANCE: The TLDA cards protocol involved a higher rate of false positive results (5.6% versus 2.8% with Exiqon). There were 44 miRNAs detected in the ICM and TE from both the protocols. One and 24 miRNAs were instead detected solely in the ICM and the TE, respectively. Overall, 29 miRNAs were detected in the pooled SBM: 8 only from not-IEB, 8 only from IEB and 13 from both. Most of them (N = 24/29, 82.7%) were also detected previously in both the ICM and TE with the Exiqon protocol; two miRNAs (N = 2/29, 6.9%) were previously detected only in the TE, and three (N = 3/29, 10.3%) were never detected previously. In study Phase 2, significant differences were shown between not-IEB and IEB in terms of both miRNA detection and relative quantitation. However, when the data were corrected for embryo morphology and day of full development (i.e. SBM collection), no significant association was confirmed. LIMITATIONS, REASONS FOR CAUTION: This study did not evaluate specifically exosomal miRNAs, thereby reducing the chance of identifying the functional miRNAs. Ex-vivo experiments are required to confirm the role of miRNAs in mediating the dialogue with endometrial cells, and higher throughput technologies need to be further evaluated for miRNA profiling from clinical SBM samples. WIDER IMPLICATIONS OF THE FINDINGS: Although no clinical predictive power was reported in this study, the absence of invasiveness related with SBM analysis and the evidence that embryonic genetic material can be reliably detected and analysed from SBM make this waste product of IVF an important source for further investigations aimed at improving embryo selection. STUDY FUNDING/COMPETING INTEREST(S): This project has been financially supported by Merck KgaA (Darmstadt, Germany) with a Grant for Fertility Innovation (GFI) 2015. The authors have no conflict of interest to declare related with this study. TRIAL REGISTRATION NUMBER: None.
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Aneuploidia , Massa Celular Interna do Blastocisto/metabolismo , Meios de Cultura/química , Técnicas de Cultura Embrionária/métodos , Implantação do Embrião , Fertilização in vitro/métodos , MicroRNAs/genética , Diagnóstico Pré-Implantação/métodos , Adulto , Biomarcadores , Feminino , Humanos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Gravidez , Diagnóstico Pré-Implantação/economia , Reprodutibilidade dos Testes , Transferência de Embrião Único , VitrificaçãoRESUMO
The transcriptional profile induced by hypoxia plays important roles in the chondrogenic differentiation of marrow stromal/stem cells (MSC) and is mediated by the hypoxia inducible factor (HIF) complex. However, various compounds can also stabilize HIF's oxygen-responsive element, HIF-1α, at normoxia and mimic many hypoxia-induced cellular responses. Such compounds may prove efficacious in cartilage tissue engineering, where microenvironmental cues may mediate functional tissue formation. Here, we investigated three HIF-stabilizing compounds, which each have distinct mechanisms of action, to understand how they differentially influenced the chondrogenesis of human bone marrow-derived MSC (hBM-MSC) in vitro. hBM-MSCs were chondrogenically-induced in transforming growth factor-ß3-containing media in the presence of HIF-stabilizing compounds. HIF-1α stabilization was assessed by HIF-1α immunofluorescence staining, expression of HIF target and articular chondrocyte specific genes by quantitative polymerase chain reaction, and cartilage-like extracellular matrix production by immunofluorescence and histochemical staining. We demonstrate that all three compounds induced similar levels of HIF-1α nuclear localization. However, while the 2-oxoglutarate analog dimethyloxalylglycine (DMOG) promoted upregulation of a selection of HIF target genes, desferrioxamine (DFX) and cobalt chloride (CoCl2 ), compounds that chelate or compete with divalent iron (Fe2+ ), respectively, did not. Moreover, DMOG induced a more chondrogenic transcriptional profile, which was abolished by Acriflavine, an inhibitor of HIF-1α-HIF-ß binding, while the chondrogenic effects of DFX and CoCl2 were more limited. Together, these data suggest that HIF-1α function during hBM-MSC chondrogenesis may be regulated by mechanisms with a greater dependence on 2-oxoglutarate than Fe2+ availability. These results may have important implications for understanding cartilage disease and developing targeted therapies for cartilage repair. Stem Cells 2018;36:1380-1392.
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Células da Medula Óssea/efeitos dos fármacos , Hipóxia Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Prolina Dioxigenases do Fator Induzível por Hipóxia/antagonistas & inibidores , Células-Tronco Mesenquimais/efeitos dos fármacos , Aminoácidos Dicarboxílicos/farmacologia , Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Diferenciação Celular/efeitos dos fármacos , Hipóxia Celular/fisiologia , Criança , Condrogênese/efeitos dos fármacos , Cobalto/farmacologia , Desferroxamina/farmacologia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Prolina Dioxigenases do Fator Induzível por Hipóxia/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismoRESUMO
Human pluripotent stem cells possess remarkable proliferative and developmental capacity and thus have great potential for advancement of cellular therapy, disease modeling, and drug discovery. Twelve years have passed since the first reported isolation of human embryonic stem cell lines (hESC), followed in October 2010 by the first treatment of a patient with hESC-based cellular therapy at the Shepherd Center in Atlanta. Despite seemingly insurmountable challenges and obstacles in the early days, hESC clinical potential reached application in an extraordinarily short time. Eight currently ongoing clinical trials are yielding encouraging results, and these are likely to lead to new trials for other diseases. However, with the discovery of induced pluripotent stem cells (iPSC), disease-specific hESC lines derived from patients undergoing preimplantation genetic diagnosis for single gene disorders fell short of expectations. Lack of ethical controversy made human iPSC (hiPSC) with specific genotypes/phenotypes more appealing than hESC for drug discovery and toxicology-related studies, and in time, lines from HLA-homologous hiPSC banks are likely to take over from hESC in clinical applications. Currently, hESC are indispensable; the results of hESC-based clinical trials will set a gold standard for future iPSC-based cellular therapy. Stem Cells 2017;35:17-25.
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Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/metabolismo , Blastômeros/citologia , Ensaios Clínicos como Assunto , Doença/genética , Humanos , Mutação/genética , Pesquisa com Células-Tronco/éticaRESUMO
BACKGROUND: Human amniotic membrane (HAM) has been embraced as a natural wound dressing almost exclusively in ophthalmology. Only recently, emergence of commercial HAM products prompted its use in growing range of indications, especially treatment of chronic non-healing wounds. SOURCES OF DATA: ClinicalTrials.gov database and International Clinical Trials Registry Platform searched with key words 'human amniotic membrane' and 'chronic wounds'. AREAS OF AGREEMENT: HAM can be successfully used as a natural wound dressing to promote healing. AREAS OF CONTROVERSY: It is still unclear, which preparation is more advantageous, cryopreserved HAM or dehydrated HAM. GROWING POINTS: There are an increasing number of commercial HAM products and clinical trials for a variety of dermatological diagnoses. AREAS TIMELY FOR DEVELOPING RESEARCH: In spite of easy procurement and low production costs, to our knowledge, there are currently only a few manufacturers of commercial HAM products tested in clinical trials for cutaneous wounds and all of them are located in the USA.
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Âmnio/transplante , Curativos Biológicos , Pele/lesões , Cicatrização/fisiologia , Doença Crônica/terapia , Ensaios Clínicos como Assunto , Pé Diabético/terapia , Humanos , Úlcera da Perna/terapia , Pele ArtificialRESUMO
Biological processes require close cooperation of multiple transcription factors that integrate different signals. Thyroid hormone receptors (TRs) induce Krüppel-like factor 9 (KLF9) to regulate neurogenesis. Here, we show that triiodothyronine (T3) also works through TR to induce KLF9 in HepG2 liver cells, mouse liver, and mouse and human primary hepatocytes and sought to understand TR/KLF9 network function in the hepatocyte lineage and stem cells. Knockdown experiments reveal that KLF9 regulates hundreds of HepG2 target genes and modulates T3 response. Together, T3 and KLF9 target genes influence pathways implicated in stem cell self-renewal and differentiation, including Notch signaling, and we verify that T3 and KLF9 cooperate to regulate key Notch pathway genes and work independently to regulate others. T3 also induces KLF9 in human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSC) and this effect persists during differentiation to definitive endoderm and hiPSC-derived hepatocytes. Microarray analysis reveals that T3 regulates hundreds of hESC and hiPSC target genes that cluster into many of the same pathways implicated in TR and KLF9 regulation in HepG2 cells. KLF9 knockdown confirms that TR and KLF9 cooperate to regulate Notch pathway genes in hESC and hiPSC, albeit in a partly cell-specific manner. Broader analysis of T3 responsive hESC/hiPSC genes suggests that TRs regulate multiple early steps in ESC differentiation. We propose that TRs cooperate with KLF9 to regulate hepatocyte proliferation and differentiation and early stages of organogenesis and that TRs exert widespread and important influences on ESC biology.
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Diferenciação Celular/fisiologia , Hepatócitos/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , Células-Tronco Pluripotentes/metabolismo , Receptores dos Hormônios Tireóideos/metabolismo , Transdução de Sinais/fisiologia , Animais , Feminino , Células Hep G2 , Hepatócitos/citologia , Humanos , Fatores de Transcrição Kruppel-Like/genética , Masculino , Camundongos , Células-Tronco Pluripotentes/citologia , Receptores Notch/genética , Receptores Notch/metabolismo , Receptores dos Hormônios Tireóideos/genética , Tri-Iodotironina/genética , Tri-Iodotironina/metabolismoRESUMO
The mammalian epidermis provides both an interface and a protective barrier between the organism and its environment. Lipid, processed into water-impermeable bilayers between the outermost layers of the epidermal cells, forms the major barrier that prevents water from exiting the organism, and also prevents toxins and infectious agents from entering. The secretory phospholipase 2 (sPLA2) enzymes control important processes in skin and other organs, including inflammation and differentiation. sPLA2 activity contributes to epidermal barrier formation and homeostasis by generating free fatty acids, which are required both for formation of lamellar membranes and also for acidification of the stratum corneum (SC). sPLA2 is especially important in controlling SC acidification and establishment of an optimum epidermal barrier during the first postnatal week. Several sPLA2 isoforms are present in the epidermis. We find that two of these isoforms, sPLA2 IIA and sPLA2 IIF, localize to the upper stratum granulosum and increase in response to experimental barrier perturbation. sPLA2F(-/-) mice also demonstrate a more neutral SC pH than do their normal littermates, and their initial recovery from barrier perturbation is delayed. These findings confirm that sPLA2 enzymes perform important roles in epidermal development, and suggest that the sPLA2IIF isoform may be central to SC acidification and barrier function. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.
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Epiderme/enzimologia , Ácidos Graxos/metabolismo , Metabolismo dos Lipídeos/fisiologia , Fosfolipases A2 Secretórias/metabolismo , Animais , Ácidos Graxos/genética , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Camundongos , Camundongos Knockout , Fosfolipases A2 Secretórias/genéticaRESUMO
BACKGROUND: Human embryonic and induced pluripotent stem cells (hESC and hiPSC) have tremendous potential for clinical implementation. In spite of all hurdles and controversy, clinical trials in treatment of spinal cord injury, macular degeneration of retina, type 1 diabetes and heart failure are already ongoing. SOURCES OF DATA: ClinicalTrials.gov database, International Clinical Trials Registry Platform, PubMed and press releases and websites of companies and institutions working on hESC- and iPSC-based cellular therapy. AREAS OF AGREEMENT: The initial results from multiple clinical trials demonstrate that hESC-based therapies are safe and promising. AREAS OF CONTROVERSY: Are iPSC cells safe in the clinical application? Is there a room for both hESC and iPSC in the future clinical applications? GROWING POINTS: Increasing number of new clinical trials. AREAS TIMELY FOR DEVELOPING RESEARCH: Development of hESC- and/or iPSC-based cellular therapy for other diseases.
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Terapia Baseada em Transplante de Células e Tecidos/métodos , Células-Tronco Embrionárias/transplante , Células-Tronco Pluripotentes Induzidas/transplante , Ensaios Clínicos como Assunto/métodos , Diabetes Mellitus Tipo 1/terapia , Insuficiência Cardíaca/terapia , Humanos , Degeneração Macular/terapia , Traumatismos da Medula Espinal/terapiaRESUMO
STUDY QUESTION: Is the quality of the human embryos generated by twinning in vitro comparable to the quality of the embryos created by fertilization? SUMMARY ANSWER: Our data suggest that the human twin embryos created in vitro are unsuitable not only for clinical use but also for research purposes. WHAT IS KNOWN ALREADY: Pregnancy from in vitro generated monozygotic twins by embryo splitting or twinning leads to live birth of healthy animals. Similar strategies, however, have been less successful in primates. Recent reports suggest that the splitting of human embryos might result in viable, morphologically adequate blastocysts, although the qualitative analyses of the embryos created in such a way have been very limited. STUDY DESIGN, SIZE, DURATION: This study was a comparative analysis of embryos generated by twinning in vitro and the embryos created by in vitro fertilization. PARTICIPANTS/MATERIALS, SETTING, METHODS: We analysed morphokinetics and developmental competence of 176 twin embryos created by splitting of 88 human embryos from either early (2-5 blastomeres, n = 43) or late (6-10 blastomeres, n = 45) cleavage stages. We compared the data with morphometrics of embryos created by in vitro fertilization and resulting in pregnancy and live birth upon single blastocyst transfer (n = 42). MAIN RESULTS AND THE ROLE OF CHANCE: The morphokinetic data suggested that the human preimplantation development is subjected to a strict temporal control. Due to a 'developmental clock', the size of twin embryos was proportionate to the number of cells used for their creation. Furthermore, the first fate decision was somewhat delayed; the inner cell mass (ICM) became distinguishable later in the twin than in the normal blastocysts obtained through fertilization. If an ICM was present at all, it was small and of poor quality. The majority of the cells in the twin embryos expressed ICM and trophectoderm markers simultaneously. LIMITATIONS, REASONS FOR CAUTION: We created monozygotic twins by blastomere separation from cleavage stage embryos. Embryo twinning by blastocyst bisection may circumvent limitations set by the developmental clock. WIDER IMPLICATIONS OF THE FINDINGS: Taken together, our data suggest that the human twin embryos created in vitro are unsuitable not only for clinical use but also for research purposes.
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Blastocisto/citologia , Blastômeros/citologia , Transferência Embrionária/métodos , Desenvolvimento Embrionário/fisiologia , Gêmeos Monozigóticos , Feminino , Fertilização in vitro , Humanos , GravidezRESUMO
The main purpose of this study was to explore the cause-and-effect relation of maximal muscle strength (MSmax) on the optimum drop height (DHopt) that maximizes power output in drop jump. In total, 30 physically active male students participated in this study, whereas the 16 subjects were selected according to their resistance strength training background (i.e., level of MSmax) and allocated into 2 equal subgroups: strong (n = 8) and weak (n = 8). The main testing session consisted of drop jumps performed from 8 different drop heights (i.e., from 0.12 to 0.82 m). The individual DHopt was determined based on the maximal value power output across applied ranges of drop heights. The tested relationships between DHopt and MSmax were moderate (r = 0.39-0.50, p ≤ 0.05). In addition, the stronger individuals, on average, showed maximal values of power output on the higher drop height compared with the weaker individuals (0.62 vs. 0.32 m). Finally, significant differences in the individual DHopt between groups were detected (p < 0.01). The present findings suggest that drop height should be adjusted based on a subject's neuromuscular capacity to produce MSmax. Hence, from the perspective of strength and conditioning practitioners, MSmax should be considered as an important factor that could affect the DHopt, and therefore should be used for its adjustment in terms of optimizing athlete's testing, training, or rehabilitation intervention.
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Teste de Esforço/métodos , Extremidade Inferior/fisiologia , Força Muscular/fisiologia , Humanos , Masculino , Adulto JovemRESUMO
Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in September 2023.
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Medicina Regenerativa , Pesquisa com Células-Tronco , Indústria FarmacêuticaRESUMO
Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in July 2024.
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Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in April 2024.