Application of iPS in assisted reproductive technology: sperm from somatic cells?

Estradiol modulated differentiation and dynamic growth of CD90+ spermatogonial stem cells toward Sertoli-like cells

Mouse CD90⁺ SSCs were enriched using the MACS technique and incubated with different doses of estradiol, ranging from 0.01 ng/mL to 500 μg/mL, for 7 days. The viability of SSCs was determined using an MTT assay. The combined effects of estradiol plus Sertoli cell differentiation medium on the orientation of SSCs toward Sertoli-like cells were also assessed. Using immunofluorescence imaging, we monitored protein levels of Oct3/4 after being exposed to estradiol. In addition, protein levels of testosterone, TF, and ABP were measured using ELISA. The expression of Sertoli cell-specific genes such as SOX9, GATA4, FSHR, TF, and ESR-1 and -2 was monitored using real-time PCR assay, and the effects of 14-day injection of estradiol on sperm parameters and Oct3/4 positive progenitor cells in a model of mouse were determined. Data showed that estradiol increased the viability of mouse SSCs in a dose-dependent manner compared to the control (p < 0.05). Along with these changes, cells displayed morphological changes and reduced Oct3/4 transcription factor levels compared to the control SSCs. 7-day incubation of SSCs with estradiol led to the up-regulation of SOX9, GATA4, FSHR, TF, and ESR-1 and -2, and levels of testosterone, TF, and ABP were increased compared to the control group (p < 0.05). The in-vivo examination noted that estradiol reduced sperm parameters coincided with morphological abnormalities (p < 0.05). Histological examination revealed pathological changes in seminiferous tubules and reduction of testicular Oct3/4⁺ progenitor cells. In conclusion, estradiol treatment probably can induce Sertoli cell differentiation of SSCs while exogenous administration leads to testicular progenitor cell depletion and infertility in long term.

Retinoic acid combined with spermatogonial stem cell conditions facilitate the generation of mouse germ-like cells

Spermatogenic lineage has been directly generated in spermatogonial stem cell (SSC) conditions from human pluripotent stem cells (PSCs). However, it remains unknown whether mouse embryonic stem cells (ESCs) can directly differentiate into advanced male germ cell lineage in the same conditions. Here, we showed rather low efficiency of germ-like cell generation from mouse ESCs in SSC conditions. Interestingly, addition of retinoic acid (RA) into SSC conditions enabled efficient differentiation of mouse ESCs into germ-like cells, as shown by the activation of spermatogenesis-associated genes such as Mvh, Dazl, Prdm14, Stella, Scp1, Scp3, Stra8 and Rec8. In contrast, for cells cultured in control medium, the activation of the above genes barely occurred. In addition, RA with SSC conditions yielded colonies of Acrosin-expressing cells and the positive ratio reached a peak at day 6. Our work thus establishes a simple and cost-efficient approach for male germ like cell differentiation from mouse PSCs and may propose a useful strategy for studying spermatogenesis in vitro.

The Current Status of Stem-Cell Therapy in Erectile Dysfunction: A Review

Stem cells are undifferentiated cells that are capable of renewal and repair of tissue due to their capacity for division and differentiation. The purpose of this review is to describe recent advances in the use of stem cell (SC) therapy for male erectile dysfunction (ED). We performed a MEDLINE database search of all relevant articles regarding the use of SCs for ED. We present a concise summary of the scientific principles behind the usage of SC for ED. We discuss the different types of SCs, delivery methods, current pre-clinical literature, and published clinical trials. Four clinical trials employing SC for ED have been published. These articles are summarized in this review. All four report improvements in ED after SC therapy. SC therapy remains under investigation for the treatment of ED. It is reassuring that clinical trials thus far have reported positive effects on erectile function and few adverse events. Safety and methodical concerns about SC acquisition, preparation and delivery remain and require continued investigation prior to wide-spread application of these methods.

Translational research-the need of a new bioethics approach

Translational research tries to apply findings from basic science to enhance human health and well-being. Many phases of the translational research may include non-medical tasks (information technology, engineering, nanotechnology, biochemistry, animal research, economy, sociology, psychology, politics, and so on). Using common bioethics principles to these areas might sometimes be not feasible, or even impossible. However, the whole process must respect some fundamental, moral principles. The purpose of this paper is to argument the need for a different approach to the morality in translational bioethics, and to suggest some directions that might be followed when constructing such a bioethics. We will show that a new approach is needed and present a few ethical issues that are specific to the translational research.

Stem cell treatment of erectile dysfunction

Erectile Dysfunction (ED) is a common disease that typically affects older men. While oral type-5 phosphodieserase inhibitors (PDE5Is) represent a successful first-line therapy, many patients do not respond to this treatment leading researchers to look for alternative treatment modalities. Stem cell (SC) therapy is a promising new frontier for the treatment of those patients and many studies demonstrated its therapeutic effects. In this article, using a Medline database search of all relevant articles, we present a summary of the scientific principles behind SCs and their use for treatment of ED. We discuss specifically the different types of SCs used in ED, the methods of delivery tested, and the methods attempted to enhance SC therapy effect. In addition, we review the current preclinical literature on SC therapy for ED and present a summary of its findings in addition to the single clinical trial published.

Direct differentiation of human pluripotent stem cells into haploid spermatogenic cells

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) have been shown to differentiate into primordial germ cells (PGCs) but not into spermatogonia, haploid spermatocytes, or spermatids. Here, we show that hESCs and hiPSCs differentiate directly into advanced male germ cell lineages, including postmeiotic, spermatid-like cells, in vitro without genetic manipulation. Furthermore, our procedure mirrors spermatogenesis in vivo by differentiating PSCs into UTF1-, PLZF-, and CDH1-positive spermatogonia-like cells; HIWI- and HILI-positive spermatocyte-like cells; and haploid cells expressing acrosin, transition protein 1, and protamine 1 (proteins that are uniquely found in spermatids and/or sperm). These spermatids show uniparental genomic imprints similar to those of human sperm on two loci: H19 and IGF2. These results demonstrate that male PSCs have the ability to differentiate directly into advanced germ cell lineages and may represent a novel strategy for studying spermatogenesis in vitro.

Specimen collection for induced pluripotent stem cell research: harmonizing the approach to informed consent

Induced pluripotent stem cells (iPSCs) have elicited excitement in both the scientific and ethics communities for their potential to advance basic and translational research. They have been hailed as an alternative to derivation from embryos that provides a virtually unlimited source of pluripotent stem cells for research and therapeutic applications. However, research with iPSCs is ethically complex, uniquely encompassing the concerns associated with genomics, immortalized cell lines, transplantation, human reproduction, and biobanking. Prospective donation of tissue specimens for iPSC research thus requires an approach to informed consent that is constructed for this context. Even in the nascent stages of this field, approaches to informed consent have been variable in ways that threaten the simultaneous goals of protecting donors and safeguarding future research and translation, and investigators are seeking guidance. We address this need by providing concrete recommendations for informed consent that balance the perspectives of a variety of stakeholders. Our work combines analysis of consent form language collected from investigators worldwide with a conceptual balancing of normative ethical concerns, policy precedents, and scientific realities. Our framework asks people to consent prospectively to a broad umbrella of foreseeable research, including future therapeutic applications, with recontact possible in limited circumstances. We argue that the long-term goals of regenerative medicine, interest in sharing iPSC lines, and uncertain landscape of future research all would be served by a framework of ongoing communication with donors. Our approach balances the goals of iPSC and regenerative medicine researchers with the interests of individual research participants.

Stem cells: novel players in the treatment of erectile dysfunction

Stem cells are defined by their capacity for both self-renewal and directed differentiation; thus, they represent great promise for regenerative medicine. Historically, stem cells have been categorized as either embryonic stem cells (ESCs) or adult stem cells (ASCs). It was previously believed that only ESCs hold the ability to differentiate into any cell type, whereas ASCs have the capacity to give rise only to cells of a given germ layer. More recently, however, numerous studies demonstrated the ability of ASCs to differentiate into cell types beyond their tissue origin. The aim of this review was to summarize contemporary evidence regarding stem cell availability, differentiation, and more specifically, the potential of these cells in the diagnosis and treatment of erectile dysfunction (ED) in both animal models and human research. We performed a search on PubMed for articles related to definition, localisation and circulation of stem cells as well as the application of stem cells in both diagnosis and treatment of ED. Strong evidence supports the concept that stem cell therapy is potentially the next therapeutic approach for ED. To date, a large spectrum of stem cells, including bone marrow mesenchymal stem cells, adipose tissue-derived stem cells and muscle-derived stem cells, have been investigated for neural, vascular, endothelial or smooth muscle regeneration in animal models for ED. In addition, several subtypes of ASCs are localized in the penis, and circulating endogenous stem cells can be employed to predict the outcome of ED and ED-related cardiovascular diseases.