Nitric oxide metabolite production in the human preimplantation embryo and successful blastocyst formation

Abstract

Eleven patients underwent controlled ovarian hyperstimulation yielding seventy-two embryos for evaluation. Mean nitric oxide metabolite (NOx) levels in the insemination media (IM) were 2.6 times higher in embryos that progressed to blastocysts by culture day (CD) 5 than those that did not (p=0.009). A comparison of the ROC curves between morphologic predictors and NOx levels revealed a trend toward a stronger association of IM NOx with blastocyst formation.Improvements in in vitro fertilization (IVF) outcomes have largely been due to the generation of supernumary embryos allowing for multiple embryo transfer (ET). The development of extended embryo culture has resulted in increased implantation rates and the potential for reductions in multiple births through single ET (1,2). One of the major disadvantages, however, has been the worry that in approximately 40% of patients, embryos would not be available for transfer (3).Unfortunately, culture day (CD) 3 morphologic assessment is not optimal for the prediction of blastocyst progression on CD 5 (4-5). Investigators have therefore sought quantifiable objective measures of embryonic health with a focus on metabolic activity (6-11). One such metabolic factor, nitric oxide (NO), has been implicated in a variety of biological and reproductive processes including oocyte maturation, fertilization and embryonic progression (12). Gouge et al. (13) demonstrated that NO production is essential for embryonic progression in the murine model. Chen and colleagues showed that blastocyst development in culture is inhibited by L-NAME, an NO inhibitor, in a concentration-dependent manner and SNP, an NO donor, can effectively reverse this effect (14). These studies highlight the potential importance of NO in embryogenesis.

Select nutrients and their effects on conceptus development in mammals

“…Nitric oxide regulates early-stage embryonic development in mice ( Chen et al, 2001 , Tranguch et al, 2003 ) and humans ( Lipari et al, 2009 ). Nitric oxide synthases 3 mRNA and protein are abundant in trophectoderm and endoderm of peri-implantation ovine conceptuses, whereas NOS1 mRNA and protein are expressed very weakly ( Gao et al, 2009e ).…”

Oxidative parameters of embryo culture media may predict treatment outcome in in vitro fertilization: a novel applicable tool for improving embryo selection

“…Oxidative stress is involved in numerous signal transduction pathways in cellular physiology and pathology (17,18) and in oxidative processes, which may be reflected in the culture media of the growing embryo during early development. Lipari et al (19) found an association between nitric oxide (a cytokine and pro-oxidant, involved in cellular physiology) metabolite production in the insemination media in IVF and successful blastocyst formation. The addition of certain nutrients to the culture media recently has been shown to improve the oxidative state of the early embryo (20,21).…”

Novel Insights on the Role of Nitric Oxide in the Ovary: A Review of the Literature

“…On the one side, Battaglia et al (2003) [55] and Lipari et al (2009) [56] found an association between the nitric oxide metabolites released in the embryo culture media with blastocyst formation progression [55] together with the pregnancy rates [56]. In detail, the mean NO metabolites in the insemination media were 2.6 higher in embryos that progressed to the blastocyst stage on day 5 of culture compared with those that did not [55], while the NO metabolite concentrations of the culture medium of each embryo were higher in the pregnant-resulting patients than those who did not become pregnant [56]. On the contrary, no association was found between NO metabolite production in a culture medium with the embryo cleavage rate in the study of Gallinelli et al, 2009 [57].…”