Efficacy of dehydroepiandrosterone to overcome the effect of ovarian ageing (DITTO): a proof of principle randomised controlled trial protocol

Introduction: Dehydroepiandrosterone (DHEA) has been proposed to improve pregnancy rates in women with diminished ovarian reserve undergoing in vitro fertilisation (IVF) treatment. However, evidence regarding its efficacy is supported by a limited number of randomised controlled trials (RCTs). This doubleblinded RCT aims to measure the effect of DHEA supplementation prior to and during controlled ovarian hyperstimulation on ovarian response prior to IVF treatment in women predicted to have poor ovarian reserve. Methods and analysis: Sixty women with ovarian antral follicle count ≤10 and serum anti-Mullerian hormone ≤5 pmol/L undergoing IVF/intracytoplasmic sperm injection (ICSI) treatment at the Nurture fertility clinic, Nottingham will be recruited. They will be randomised to either receive DHEA capsule 75 mg/day or placebo for at least 12 weeks before egg collection. All participants will undergo standard long down regulation protocol using human menopausal gonadotropin 300 IU/day. Serum samples and follicular fluids at the time of egg collection will be collected for hormonal immunoassays. For ICSI participants, cumulus cells stripped from oocyte will be collected for cumulus gene expression analyses regarding oocyte competence. Microdrops of oocyte culture media before the time of ICSI will be assessed for glucose, pyruvate and lactate utilisation. Embryo transfer will be performed on day 2, 3 or 5 based on the number and quality of the embryos available. Pregnancy will be defined as urine pregnancy test positive (biochemical pregnancy) and 6–8 weeks ultrasound scan with fetal heart beat (clinical pregnancy) and live birth. It is planned to perform the molecular and nutritional fingerprint analyses in batches after finishing the clinical phase of the study. Ethics and dissemination: The approval of the study was granted by the NHS Research Ethics Committee (Ref number NRES 12/EM/0002), the Medicines and Healthcare products Regulatory Agency (MHRA), and the Nottingham University Hospitals Trust Research and Development department. All participants shall provide written informed consent before being randomised into allocated treatment groups

Bovine Sperm Sexing Alters Sperm Morphokinetics and Subsequent Early Embryonic Development

In artificial insemination the use of sex-sorted bovine sperm results in reduced conception, the causes of which are only partly understood. Therefore, we set out to investigate the effects of sexing on bovine sperm function and early embryonic development. Computer-assisted semen analysis (CASA) of sperm of the same bulls (n = 5), before and after sexing, demonstrated significantly reduced fast (A) and slow (B) progressively motile sperm (p [less than] 0.05) after sexing. Sexed-sperm also revealed significantly less hyperactivated sperm (p [less than] 0.05). As shown by time-lapse videomicroscopy of in vitro produced embryos (n = 360), embryos derived from sexed-sperm displayed significantly increased incidences of arrest at the 4-cell stage (p [less than] 0.05). The relative risk for shrinkage/fusion of blastomeres with subsequent lysis was 1.71 times higher in the embryos derived from sexed-sperm as compared to conventional embryos (p [less than] 0.05) resulting in significantly reduced blastocyst rates (p [less than] 0.001). The relative risk for cleavage was 2.36 times lower in the embryos derived from sex-sorted sperm (p [less than] 0.001). Additionally, sexed-sperm-derived embryos showed reduced survival times (hazard ratio HR = 1.54, p [less than] 0.001) which were bull dependent (p [less than] 0.001). However, the percentage of apoptotic cells was similar to conventional embryos. Furthermore, embryos derived from sexed-sperm were found to reach developmental stages at similar timings as conventional embryos. Our results suggest that reduced conception rates after sexing are due to altered sperm morphokinetics, decreasing the chance of sperm to reach and fertilise the oocyte, and aberrant early embryonic development

Nuclear transfer in ruminants

Ruminants were the first mammalian species to be cloned successfully by nuclear transplantation. Those experiments were designed to multiply high merit animals (Willadsen, Nature 320(6057):63–65, 1986; Prather et al., Biol Reprod 37(4):859–866, 1987; Wilmut et al., Nature 385(6619):810–813, 1997). Since then, cloning has provided us with a vast amount of knowledge and information on the reprogramming ability of somatic cells to different cell types which became an important basis for stem cell research and human medicine. Nowadays, the goals of most nuclear transfer work vary widely but in most cases the micromanipulation procedures remain the same. However, differences between species require different technical considerations. In this chapter, we describe in detail somatic cell nuclear transfer which is the foremost method for cloning ruminants with specific reference to sheep and cattle

Dissociated Fear and Spatial Learning in Mice with Deficiency of Ataxin-2

Mouse models with physiological and behavioral differences attributable to differential plasticity of hippocampal and amygdalar neuronal networks are rare. We previously generated ataxin-2 (Atxn2) knockout mice and demonstrated that these animals lacked obvious anatomical abnormalities of the CNS, but showed marked obesity and reduced fertility. We now report on behavioral changes as a consequence of Atxn2-deficiency. Atxn2-deficiency was associated with impaired long-term potentiation (LTP) in the amygdala, but normal LTP in the hippocampus. Intact hippocampal plasticity was associated behaviorally with normal Morris Water maze testing. Impaired amygdala plasticity was associated with reduced cued and contextual fear conditioning. Conditioned taste aversion, however, was normal. In addition, knockout mice showed decreased innate fear in several tests and motor hyperactivity in open cage testing. Our results suggest that Atxn2-deficiency results in a specific set of behavioral and cellular disturbances that include motor hyperactivity and abnormal fear-related behaviors, but intact hippocampal function. This animal model may be useful for the study of anxiety disorders and should encourage studies of anxiety in patients with spinocerebellar ataxia type 2 (SCA2)

Trichostatin A treatment of cloned mouse embryos improves constitutive heterochromatin remodeling as well as developmental potential to term

<p>Abstract</p> <p>Background</p> <p>Genome reprogramming in early mouse embryos is associated with nuclear reorganization and particular features such as the peculiar distribution of centromeric and pericentric heterochromatin during the first developmental stage. This zygote-specific heterochromatin organization could be observed both in maternal and paternal pronuclei after natural fertilization as well as in embryonic stem (ES) cell nuclei after nuclear transfer suggesting that this particular type of nuclear organization was essential for embryonic reprogramming and subsequent development.</p> <p>Results</p> <p>Here, we show that remodeling into a zygotic-like organization also occurs after somatic cell nuclear transfer (SCNT), supporting the hypothesis that reorganization of constitutive heterochromatin occurs regardless of the source and differentiation state of the starting material. However, abnormal nuclear remodeling was frequently observed after SCNT, in association with low developmental efficiency. When transient treatment with the histone deacetylase inhibitor trichostatin A (TSA) was tested, we observed improved nuclear remodeling in 1-cell SCNT embryos that correlated with improved rates of embryonic development at subsequent stages.</p> <p>Conclusion</p> <p>Together, the results suggest that proper organization of constitutive heterochromatin in early embryos is involved in the initial developmental steps and might have long term consequences, especially in cloning procedures.</p

Early epigenetic reprogramming in fertilized, cloned, and parthenogenetic embryos

Despite ongoing research in a number of species, the efficiency of embryo production by nuclear transfer remains low. Incomplete epigenetic reprogramming of the nucleus introduced in the recipient oocyte is one factor proposed to limit the success of this technique. Nonetheless, knowledge of reprogramming factors has increased—thanks to comparative studies on reprogramming of the paternal genome brought by sperm on fertilization—and will be reviewed here. Another valuable model of reprogramming is the one obtained in the absence of sperm fertilization through artificial activation—the parthenote—and will also be introduced. Altogether the objective of this review is to have a better understanding on the mechanisms responsible for the resistance to reprogramming, not only because it could improve embryonic development but also as it could benefit therapeutic reprogramming research

Steroids and miRNAs in assessment of ovarian tissue damage following cryopreservation

Ovarian cortical tissue cryopreservation is a relatively novel approach to preserving fertility in women diagnosed with cancer. However, the effects of freezing-thawing are not fully understood, mainly due to the lack of suitable methods to assess tissue’s survival after thawing. Disparities in steroid production have been associated with ovarian failure by disrupting folliculogenesis, ovulation and oocyte apoptosis. Moreover, specific miRNAs, identified in human ovarian follicles, are thought to play a fundamental role in folliculogenesis. In this study, we investigated the possible interplay between the ovariansteroidal production and miRNA expression patterns in spent culture media, as potential non-invasive markers for ovarian tissue damage after cryopreservation. Cryopreservation of ovarian cortical tissue decreased (P < 0.05) both steroid production (oestradiol and progesterone) and expression of miRNA-193b and 320A in spent culture media over 5 days; however, expression of miRNA-24 increased (P < 0.05). The number of primordial follicles was also reduced (P < 0.05) in fresh-cultured and cryopreserved-cultured cortical tissues when compared with fresh tissues. Downregulation of miRNA-193b and miRNA-320A together with upregulation of miRNA-24 could have a synergistic role in cell apoptosis, and consequently leading to reduced oestradiol and progesterone production.Thus, there appears to be an interplay between these miRNAs, ov arian steroid production and cell damage, which can be further explored as novel non-invasive markers of cell damage following cryopreservation

Partially-constrained sex allocation and the indirect effects of assisted reproductive technologies on the human sex ratio

Infertility affects around 15% of human couples and in many countries approximately 1–4% of babies are born following Assisted Reproductive Technologies (ART). Several ART techniques are used and these differentially affect the sex ratio of offspring successfully produced. These direct effects on sex ratio also have the potential to influence, indirectly, the sex ratios of offspring born to untreated couples. This is of concern because human sex ratio bias may adversely affect public health. Here the extent of indirect effects of ART that could operate, via Fisherian frequency-dependent natural selection, on the progeny sex ratio of unassisted members of a population is heuristically modelled. Given the degrees to which ART techniques bias sex ratios directly, it is predicted that well over 20% of couples would have to reproduce via ART for there to be any discernible effect on the sex ratios produced, in response, by the remainder of the population. This value is greater than the estimated prevalence of infertility problems among human couples. It is concluded that providing ART to couples with fertility problems does not currently generate significant ethical issues or public health concern in terms of indirect effects on the offspring sex ratios of untreated couples

Essential role of syntaxin-binding protein-1 in the regulation of glucagon-like peptide-1 secretion

Circadian secretion of the incretin, glucagon-like peptide-1 (GLP-1), correlates with expression of the core clock gene, Bmal1, in the intestinal L-cell. Several SNARE proteins known to be circadian in pancreatic α- and β-cells are also necessary for GLP-1 secretion. However, the role of the accessory SNARE, Syntaxin binding protein-1 (Stxbp1; also known as Munc18-1) in the L-cell is unknown. The aim of this study was to determine whether Stxbp1 is under circadian regulation in the L-cell and its role in the control of GLP-1 secretion. Stxbp1 was highly-enriched in L-cells, and STXBP1 was expressed in a subpopulation of L-cells in mouse and human intestinal sections. Stxbp1 transcripts and protein displayed circadian patterns in mGLUTag L-cells line, while chromatin-immunoprecipitation revealed increased interaction between BMAL1 and Stxbp1 at the peak time-point of the circadian pattern. STXBP1 recruitment to the cytosol and plasma membrane within 30 minutes of L-cell stimulation was also observed at this time-point. Loss of Stxbp1 in vitro and in vivo led to reduced stimulated GLP-1 secretion at the peak time-point of circadian release, and impaired GLP-1 secretion ex vivo. In conclusion, Stxbp1 is a circadian regulated exocytotic protein in the intestinal L-cell that is an essential regulatory component of GLP-1 secretion.Wellcome Trust MR