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Vassena R.,Clinica EUGIN | Eguizabal C.,Basque Center for Transfusion and Human Tissues | Heindryckx B.,Ghent University | Sermon K.,Free University of Brussels | And 7 more authors.
Human Reproduction | Year: 2015

STUDY QUESTION Are there effective and clinically validated stem cell-based therapies for reproductive diseases? SUMMARY ANSWER At the moment, clinically validated stem cell treatments for reproductive diseases and alterations are not available. WHAT IS KNOWN ALREADY Research in stem cells and regenerative medicine is growing in scope, and its translation to the clinic is heralded by the recent initiation of controlled clinical trials with pluripotent derived cells. Unfortunately, stem cell 'treatments' are currently offered to patients outside of the controlled framework of scientifically sound research and regulated clinical trials. Both physicians and patients in reproductive medicine are often unsure about stem cells therapeutic options. STUDY DESIGN, SIZE, DURATION An international working group was assembled to review critically the available scientific literature in both the human species and animal models. PARTICIPANTS/MATERIALS, SETTING, METHODS This review includes work published in English until December 2014, and available through Pubmed. MAIN RESULTS AND THE ROLE OF CHANCE A few areas of research in stem cell and reproductive medicine were identified: in vitro gamete production, endometrial regeneration, erectile dysfunction amelioration, vaginal reconstruction. The stem cells studied range from pluripotent (embryonic stem cells and induced pluripotent stem cells) to monopotent stem cells, such as spermatogonial stem cells or mesenchymal stem cells. The vast majority of studies have been carried out in animal models, with data that are preliminary at best. LIMITATIONS, REASONS FOR CAUTION This review was not conducted in a systematic fashion, and reports in publications not indexed in Pubmed were not analyzed. WIDER IMPLICATIONS OF THE FINDINGS A much broader clinical knowledge will have to be acquired before translation to the clinic of stem cell therapies in reproductive medicine; patients and physicians should be wary of unfounded claims of improvement of existing medical conditions; at the moment, effective stem cell treatment for reproductive diseases and alterations is not available. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. Source

Center For Regenerative Medicine Of Barcelona and Salk Institute for Biological Studies | Date: 2011-10-24

There are provided, inter alia, methods for forming (e.g. transgeneration of) hematopoietic stem cells from mesenchymal stem cells.

Rodrigues A.M.C.,Center for Regenerative Medicine of Barcelona | Christen B.,Center for Regenerative Medicine of Barcelona | Marti M.,Center for Regenerative Medicine of Barcelona | Izpisua Belmonte J.C.,Center for Regenerative Medicine of Barcelona | Izpisua Belmonte J.C.,Salk Institute for Biological Studies
BMC Developmental Biology | Year: 2012

Background: Mammals are not able to restore lost appendages, while many amphibians are. One important question about epimorphic regeneration is related to the origin of the new tissues and whether they come from mature cells via dedifferentiation and/or from stem cells. Several studies in urodele amphibians (salamanders) indicate that, after limb or tail amputation, the multinucleated muscle fibres do dedifferentiate by fragmentation and proliferation, thereby contributing to the regenerate. In Xenopus laevis tadpoles, however, it was shown that muscle fibres do not contribute directly to the tail regenerate. We set out to study whether dedifferentiation was present during muscle regeneration of the tadpole limb and zebrafish larval tail, mainly by cell tracing and histological observations. Results: Cell tracing and histological observations indicate that zebrafish tail muscle do not dedifferentiate during regeneration. Technical limitations did not allow us to trace tadpole limb cells, nevertheless we observed no signs of dedifferentiation histologically. However, ultrastructural and gene expression analysis of regenerating muscle in tadpole tail revealed an unexpected dedifferentiation phenotype. Further histological studies showed that dedifferentiating tail fibres did not enter the cell cycle and in vivo cell tracing revealed no evidences of muscle fibre fragmentation. In addition, our results indicate that this incomplete dedifferentiation was initiated by the retraction of muscle fibres. Conclusions: Our results show that complete skeletal muscle dedifferentiation is less common than expected in lower vertebrates. In addition, the discovery of incomplete dedifferentiation in muscle fibres of the tadpole tail stresses the importance of coupling histological studies with in vivo cell tracing experiments to better understand the regenerative mechanisms. © 2012 Cavaco Rodrigues et al; licensee BioMed Central Ltd. Source

Robles V.,Center for Regenerative Medicine of Barcelona | Robles V.,University of Leon | Marti M.,Center for Regenerative Medicine of Barcelona | Belmonte J.C.I.,Center for Regenerative Medicine of Barcelona | Belmonte J.C.I.,Salk Institute for Biological Studies
Zebrafish | Year: 2011

Targeted genomic manipulation using embryonic stem (ES) cells has not yet been achieved in zebrafish, although methods for zebrafish ES cell culture has been described in literature. The knowledge of pluripotency markers in this species is almost nonexistent and this is a very limiting factor in the definition of the ideal culture conditions for ES cells. Here, we studied the expression of several genes associated with pluripotency in zebrafish embryonic cells versus differentiated cells and the expression of some of these genes is recorded throughout embryonic development. Some of the commonly accepted pluripotency markers are also tested in embryonic cells, transient embryonic cell cultures, and differentiated cells. Our results support the hypothesis that stage-specific embryonic antigen 1 (SSEA1) is a marker that precedes the expression of pluripotency genes in a zebrafish embryonic cell colony, in the same way that SOX2 precedes nestin expression in those colonies that have already started differentiation toward neurons. We consider this study a step forward in the knowledge of zebrafish pluripotency markers and, therefore, an important tool for the monitoring of zebrafish embryonic cell cultures. © Mary Ann Liebert, Inc. Source

Christen B.,Center for Regenerative Medicine of Barcelona | Robles V.,Center for Regenerative Medicine of Barcelona | Robles V.,University of Leon | Raya M.,Center for Regenerative Medicine of Barcelona | And 3 more authors.
BMC Biology | Year: 2010

Background: Dedifferentiation occurs naturally in mature cell types during epimorphic regeneration in fish and some amphibians. Dedifferentiation also occurs in the induction of pluripotent stem cells when a set of transcription factors (Oct4, Sox2, Klf4 and c-Myc) is over expressed in mature cell types.Results: We hypothesised that there are parallels between dedifferentiation or reprogramming of somatic cells to induced pluripotent stem cells and the natural process of dedifferentiation during epimorphic regeneration. We analysed expression levels of the most commonly used pluripotency associated factors in regenerating and non-regenerating tissue and compared them with levels in a pluripotent reference cell. We found that some of the pluripotency associated factors (oct4/pou5f1, sox2, c-myc, klf4, tert, sall4, zic3, dppa2/4 and fut1, a homologue of ssea1) were expressed before and during regeneration and that at least two of these factors (oct4, sox2) were also required for normal fin regeneration in the zebrafish. However these factors were not upregulated during regeneration as would be expected if blastema cells acquired pluripotency.Conclusions: By comparing cells from the regeneration blastema with embryonic pluripotent reference cells we found that induced pluripotent stem and blastema cells do not share pluripotency. However, during blastema formation some of the key reprogramming factors are both expressed and are also required for regeneration to take place. We therefore propose a link between partially reprogrammed induced pluripotent stem cells and the half way state of blastema cells and suggest that a common mechanism might be regulating these two processes. © 2010 Christen et al; licensee BioMed Central Ltd. Source

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