Developmental Competence Of Human Embryos Research Articles

Multinucleation per se is not always sufficient as a marker of abnormality to decide against transferring human embryos

To assess the developmental competence of human embryos with multinucleation (MN). Experimental study. Private fertility center. Forty-four couples donating 143 zygotes for confocal imaging study, and 78 couples included in the retrospective clinical study. Time-lapse imaging study using confocal and light microscopes. Cytokinesis at first mitosis, MN, chromosomal behavior, euploidy, implantation, successful delivery of healthy baby. About 25% of the embryos showed abnormal cytokinesis (n = 34). All showed MN, and their development was greatly impaired. More than 75% of embryos that showed normal cytokinesis at first mitosis displayed MN (n = 81). However, the subsequent development of embryos with MN was similar to that of embryos without MN invitro and invivo. Most blastocysts were euploid. All chromosomes in several MNs took part in forming a bipolar spindle after the nuclear envelope breakdown followed by normal cleavage and development to the blastocyst stage. The implantation potential of embryos with MN was similar to that of embryos without MN, and healthy babies were born from the former group after transfer. The presence of MN after the first mitosis does not adversely affect the subsequent development of embryos if they showed normal cytokinesis at this stage. The poor development of embryos with MN is mainly caused by abnormal first cytokinesis.

Developmental competence of human embryos derived from in vitro maturation of immature oocytes retrieved during cesarean section

To investigate the developmental competence of human embryos that originated from in vitro matured oocytes retrieved during cesarean section. Immature oocytes were collected from 95 pregnant women, who underwent cesarean section at Buddhachinaraj Hospital Medical School and consented to participate in the study. Retrieved oocytes were cultured in blastocyst medium supplemented with 75 IU/L of human menopausal gonadotropin. Oocyte maturation was assessed at 30 and 48 h after culture. In vitro matured oocytes were inseminated by intracytoplasmic sperm injection and cultured up to 144 h. The fertilization, cleavage and blastocyst formation rates were observed. Maturation rate of oocytes after 30 h of culture was 67.9% compared with 13.1% at 48 h (P < 0.0001). Insemination of oocytes in both groups resulted in similar fertilization, cleavage and blastocyst formation rates. A large proportion of oocytes retrieved at the time of cesarean section exhibited the capacity to undergo maturation in vitro. They can be fertilized and developed into good-quality blastocyst stage.

A closed system supports the developmental competence of human embryos after vitrification : Closed vitrification of human embryos.

Closed-system vitrification may enable the risk of contamination to be minimised. We performed three studies to compare the developmental competence of human embryos vitrified using either a closed vitrification system (CVS; Rapid-i®) or an open vitrification system (OVS; Cryo-top®). The first study was performed in vitro using 66 zygotes previously vitrified at pronuclear stage. These were warmed and randomised 1:1 to revitrification using either the OVS or the CVS. After re-warming, embryo development and blastocyst cell number were assessed. For the second study, also performed in vitro, 60 vitrified-warmed blastocysts were randomised 1:1:1 into three groups (OVS or CVS revitrification, or no revitrification). The proportion of dead cells was assessed by staining. The third study was performed in vivo, using 263 high-grade blastocysts randomly assigned to vitrification using either the CVS (n = 100) or the OVS (n = 163). After warming, single blastocyst transfer was performed. There were no differences between the CVS and the OVS in survival rate (100% vs. 97%), blastulation rate (96h: 50% vs. 50%; 120h: 68% vs. 56%), proportion of good blastocysts (96h: 32% vs. 22%, 120h: 47% vs. 41%), or mean number of cells (137 vs. 138). The proportion of dead cells in blastocysts re-vitrified by CVS (31%) was similar to that for OVS (38%) and non-revitrification (32%). In vivo, the implantation rate for blastocysts vitrified using the CVS (54%) was similar to that with the OVS (53%). Our studies consistently indicate that human embryos may be vitrified using a CVS without impairment of developmental competence.

A closed vitrification system enables a safe and an aseptic vitrification without impairing the developmental competence of human embryos

To avoid the risk of contamination by bacteria, virus and prions, we compared the developmental competence of human embryos vitrified using a closed vitrification system (CVS) with that using an open vitrification system (OVS). Prospective randomized human study. This study was approved by a local IRB of IVF Namba Clinic. In experiment 1 and 2, vitrified embryos donated from patients who completed fertility treatment and gave informed consent were used. In experiment 1, 66 embryos at pronuclear stage were divided randomly into 2 groups after warming: CVS (Rapid-I, Vitrolife) and OVS (Cryotop, Kitazato medical) and were re-vitrified using CVS or OVS. After warming, embryos development and blastocysts cell number were assessed. In experiment 2, 60 vitrified-warmed blastocysts were divided randomly into 3 groups (CVS, OVS, and non-revitrified) and were assessed the proportion of dead cell by staining with Hoechst and Propidium iodide. In experiment 3, 27 high grade blastocysts were randomly divided into two groups and were vitrified using CVS (14) and OVS (13). After warming, single blastocyst transfer was performed. There were no differences between CVS and OVS in the survival rates (100% vs. 100%, respectively), the blastulation rates (Day 5: 50% vs. 50%; Day 6: 68% vs. 56%, respectively), the rate of good blastocyst (Day 5: 32% vs. 22%, Day 6: 47% vs. 41%, respectively), and the mean cell numbers (137 vs. 138) in experiment 1. In experiment 2, the proportion of dead cells in re-vitrified blastocysts were similar at 31%, 38% and 32% in the groups CVS, OVS and non-revitrified respectively. In experiment 3, the implantation rate of blastocysts vitrified using CVS (73%) was comparable to that for the OVS group (54%). The closed vitrification system overcomes the concerns associated with direct liquid nitrogen contact in the open system without impairing the developmental competence of human embryos.

Effect of vitrification and thawing on human oocyte ATP concentration

Vitrification/thawing has a significant negative impact on oocyte ATP concentration. However, incubating oocytes up to 180 minutes after thawing allowed oocytes to regain some ATP level.

A novel vitrification method using a microfiltration membrane (MFM) enables a simple manipulation of human embryos

OBJECTIVE: Vitrification requires a speedy manipulation skill. Therefore few embryologists always achieve high success rates. Recently, Takahashi et al. (2005) showed the high handleability of porcine embryos encapsulated in a microfiltration membrane (MFM) because embryos can be manipulated as a unit with MFM. We assessed the developmental competence of human embryos encapsulated in MFM after vitrification and thawing.

Medium without Ammonium Accumulation Supports the Developmental Competence of Human Embryos

L-Glutamine has been shown to play an important role during in vitro culture of mammalian embryos. However, it is easily decomposed into ammonium, which is believed to have deleterious effects on preimplantation embryos. In this study, we assessed prospectively the developmental competence of human embryos cultured in medium containing L-glutamine or a novel stable glutamine derivative and vitamins. The subjects of this study were 41 women who underwent IVF/ET treatment from September to November 2006 and from whom 6 or more oocytes were retrieved. Sibling oocytes were randomly divided into EA/BA (EmbryoAssyst and BlastAssyst containing a novel stable glutamine derivative and vitamins), and BAS groups (BlastAssyst system containing L-glutamine). There was no difference in pronuclear formation rate between EA/BA and BAS (74 vs. 69%). The blastulation rates of embryos based on the number of zygotes cultured in EA/BA on Days 5 (Day 0=insemination, 54%) and 6 (63%) were significantly higher (P<0.05) than those cultured in BAS (Day 5: 33% and Day 6: 45%, respectively). The present data indicate that a medium containing a novel stable glutamine derivative and vitamins supports the developmental competence of human embryos.

Novel stable glutamine derivative achieved dramatic improvement of developmental competence of human embryos

L-Glutamine has been shown to play an important role during in vitro culture of mammalian embryos. However, it is easily broken down into ammonium which is believed to be deleterious to pre-implantation embryos. Recently, it has been reported that heat-stable glutamine, including glycil-glutamine and alanyl-glutamine, generate very low levels of ammonium because of heat stable form of dipeptide and support the development of murine embryos. In this study, we assessed the developmental competence of human embryos cultured in medium containing novel stable glutamine derivative or L-glutamine supplied from Medicult Corporation.

Development of hatching blastocysts from immature human oocytes following in-vitro maturation and fertilization using a co-culture system.

Recently, in-vitro maturation (IVM) of immature human oocytes recovered from non-stimulated follicles has been applied in the treatment of infertility. However, in previous reports, very few embryos cultured in conventional medium have reached the expanded blastocyst stage following in-vitro maturation and fertilization (IVM/IVF). The objective of this study was to investigate whether the developmental competence of human embryos following IVM/IVF could be enhanced by the use of a human ampullary cell co-culture system. Immature human oocytes were aspirated from small follicles at Caesarean section and then cultured in medium containing human menopausal gonadotrophin for 36 to 48 h, followed by insemination. Zygotes were randomly cultured either in conventional culture medium alone or in the co-culture system. Of 48 embryos cultured in conventional medium alone, all arrested at the 2-16-cell stage on day 3 after insemination. Of 46 embryos cultured in the co-culture system, 26 embryos (56.5%) arrested at the 2-16-cell stage. Six embryos (13%) developed to the morula stage. Fourteen embryos (30.4%) developed to expanded blastocysts and two blastocysts were hatching on day 7 after insemination. We conclude that co-culture significantly enhances the development of blastocysts in embryos resulting from IVM/IVF.