ABSTRACT
Creation of artificial gametes may provide a universal solution for these patients with no gametes. Stem cell technology may provide a way to obtain fully functional gametes. Retinoic acid [RA] can initiate meiosis. Several studies have demonstrated that RA can promote sperm cells differentiation from mouse embryonic stem cells [mESCs] and other cells from human embryonic stem cells [hESCs]. We sought to determine whether RA could promote differentiation of germ cells from hESCs. hESCs were differentiated as embryoid bodies [EBs] in suspension with all-trans RA [atRA] or without atRA for 0, 1, 3, 5 and 7 days, and then the expression of VASA, SCP3, GDF9 and TEKT1 were compared by real-time PCR. The statistical differences were evaluated by one way ANOVA. The expression of germ cell-specific markers including the gonocyte marker VASA, the meiotic marker SCP3, and post meiotic markers, GDF9 and TEKT1, all increased in the presence and absence of RA as EB differentiation progressed. In addition, the expression of these markers increased an average of 9.3, 6.9, 7.2 and 11.8 fold respectively in the presence of RA, compared to the absence of RA, over 5 days differentiation. Our results indicate that hESCs may have the potential to differentiate to primordial germ cells [PGCs] and early gametes. RA can improve germ cells differentiation from hESCs
Subject(s)
Embryonic Stem Cells , Germ Cells , TretinoinABSTRACT
To assess the relationship between pronuclear scoring and day-3 embryo quality and pregnancy outcome and to determine the clinical value of pronuclear stage scoring system in human in vitro fertilization-embryo transfer (WF-ET) program, a pronuclear scoring system was used to score zygotes 16-20 h after insemination during conventional WF or intracytoplasmic sperm injec- tion (ICS1). The embryos were classified into groups Z1, Z2, Z3 and Z4. Comparisons were made of the rates of arrested embryos and excellent embryos on day 3. Comparisons of pregnancy outcome were made only in those patients in whom cohorts of similarly Z-scored embryos were transferred. The results showed that there were less arrested embryos and more excellent embryos on day 3 in groups Z1 and Z2 than those in group Z3 and Z4. More embryos arrested and less excellent embryos developed in group Z4 than group Z3. The clinical pregnancy rates resulting from the transfer of single pronuclear score homologous embryo types were similar among groups Z1, Z2 and Z3. Implanta- tion rates of group Z1 were higher (P<0.05) than that of group Z3. These findings suggests that pro- nuclear scoring can predict developmental ability on day 3 and implantation potential. A evaluation that combines the Z-score and day 3 embryo morphology is useful in the determination of the most viable embryos and the number of embryos for transfer.