Kid depletion in mouse oocytes associated with multinucleated blastomere formation and inferior embryo development.

This study investigated the knockdown (KD) of Kid on maturation developmental competence and multinucleation of mouse germinal vesicle (GV) oocytes after parthenogenetic activation. Data revealed that Kid messenger RNA (mRNA) was expressed in GV and MII stage oocyte and 1- and 2-cell embryos. Additionally, Kid mRNA expression in the Kid KD group decreased by nearly 46% compared to the control small interfering RNA (siRNA) groups. The rate of multinucleated embryos in the Kid KD group (52.4%) was significantly higher (P < 0.05) than the control siRNA group (4.7%). Finally, the developmental rates were significantly lower in the Kid siRNA group at > 4-cell stage (28.6% vs. 53.5%) and the blastocyst stage (2.4% vs. 23.3%) compared to the control siRNA groups. Suppression of Kid using siRNA caused multinucleation in early embryos with high frequency and it may increase 2- to 4-cell arrested embryos and reduce the developmental competence to blastocyst.

Developmental capacity and implantation potential of the embryos with multinucleated blastomeres.

The presence of multinucleated blastomeres (MNBs) in embryos is associated with poor developmental competence in assisted reproductive technologies. This phenomenon is observed not only in humans but also in other animal species. The purpose of the present study was to investigate the characteristics of embryos with MNBs (MNB embryos) that could be utilized in embryo transfer. The developmental rate of MNB embryos to the blastocyst stage (50.8%) was significantly lower than that of normal embryos (73.3%) (P < 0.05). The clinical pregnancy rates of fresh embryo transfer (ET) using day 2 or day 3 embryos were significantly lower in MNB embryos (5.1%) compared with normal embryos (24.0%) (P < 0.05). In the case of frozen-thawed ET using a single vitrified/warmed blastocyst, however, the clinical pregnancy rate of MNB embryos was close to that of normal embryos (59.1% vs. 52.8%). Thus, the findings of the present study suggest that the frozen-thawed ET of MNB embryos might improve the potential for implantation followed by successful pregnancy.

Perinatal outcomes for transfer of blastocysts vitrified and warmed in defined solutions with recombinant human albumin: 374 babies born after 898 embryo transfers.

PURPOSE: To assess the efficacy of a novel, defined vitrification procedure using recombinant human albumin (rHA) for cryopreservation of human blastocysts. DESIGN: Retrospective study. SETTING: Private IVF clinic. PATIENTS: 1,496 patients received vitrified/warmed embryo transfer (ET). METHODS: Surplus blastocysts, and blastocysts from patients undergoing elective embryo cryopreservation, were vitrified/warmed using Cryotop carriers in homemade solutions containing either human serum albumin (HSA) or rHA. MAIN OUTCOME MEASURES: Clinical and neonatal outcomes regarding the vitrified/warmed ET procedures. RESULTS: The HSA and rHA groups had a total of 1,163 and 898 vitrified/warmed cycles, respectively. Embryo survival rates (98.7% vs. 98.9%, respectively) and the number of embryos transferred (1.08 ± 0.01 vs. 1.06 ± 0.01, respectively) were similar in the HSA and rHA groups. Clinical pregnancy rates/ET were higher (P < 0.05) in the rHA group (56.0%) than in the HSA group (51.5%). The HSA and rHA groups had similar live delivery rates/pregnancy (72.2% vs. 72.3%, respectively) and perinatal outcomes, including birth weight (2,988 ± 28 vs. 3,046 ± 26 g, respectively). Birth defects occurred in 0.9% and 1.6% of neonates in the HSA and rHA groups, respectively. CONCLUSIONS: rHA effectively replaced HSA for human embryo vitrification procedures, and yielded high rates of pregnancy and live births after vitrified/warmed ET. This new approach will support the development of defined ART systems, which will eliminate the variation and risks associated with the use of blood-derived products.

Perinatal outcome of twice-frozen-thawed embryo transfers: a clinical follow-up study.

We evaluated our clinical data on refrozen-thawed ETs (92 cycles) and found that human embryos were capable of withstanding two freeze-thaw cycles, resulting in normal live births after transfer at a rate similar to that of primary frozen-thawed embryos. This is the first follow-up study to present perinatal outcomes of children born after embryo re-cryopreservation, and our results should encourage clinicians to explore the possibility of performing the refreezing procedure.

A successful pregnancy and live birth after intracytoplasmic sperm injection with globozoospermic sperm and electrical oocyte activation.

OBJECTIVE: To present the effectiveness of intracytoplasmic sperm injection (ICSI) using globozoospermic sperm and assisted oocyte activation by electrical stimulation. DESIGN: A case report. SETTING: A private IVF center in Japan. PATIENT(S): A man with globozoospermia. INTERVENTION(S): Acridine orange (AO) test, mouse oocyte activation test, and ICSI with electrical oocyte activation. MAIN OUTCOME MEASURE(S): Fertilization, pregnancy, and live birth. RESULT(S): In the first ICSI attempt, neither of the two injected oocytes fertilized. Staining of the patient's sperm with AO showed that only 2.9% of the sperm emitted a green fluorescence at the characteristic round head (sperm with native DNA content). The mouse oocyte activation test using the roundheaded sperm showed that the normal fertilization rate was 78.9% when SrCl(2) was used for assisted oocyte activation; however, it was 6.0% without assisted oocyte activation. We confirmed that the sperm had defective ability to activate oocytes. In the second ICSI attempt, human oocytes were activated electrically with use of a single square direct current pulse after microinjection. All the seven injected oocytes fertilized normally, and two eight-cell embryos were transferred on day 3. Clinical pregnancy was confirmed, and a healthy girl weighing 2362 g was delivered at 37 weeks of gestation by cesarean section. CONCLUSION(S): This is the first successful outcome of ICSI using globozoospermic sperm and electrical oocyte activation. The electroactivation obviates the need for the use of potentially harmful drugs for activation.

Selected single blastocyst transfers maintained pregnancy outcome and eliminated multiple pregnancies.

Background: Transfer of more than one embryo following in vitro fertilization/intracytoplasmic sperm injection cycles have increased pregnancy rate at the cost of increasing the incidence of triplets and twins. It has been proposed that prolonged culture to the blastocyst stage would automatically result in the selection of good quality embryos for transfer and minimize the incidence of triplets and twins. Methods and Results: The objectives of the present retrospective analysis were to examine the pregnancy outcome, multiple pregnancy and related data following: (i) single blastocyst transfer (BT) and double BT; (ii) single BT in patients belonging to different age groups; and (iii) good, fair or poor quality of BT. A total of 260 BT were carried out between August 1998 and July 2002 and they are included in the current study. Sixty of the 260 BT patients received a single BT, and 41 of them received selected single good quality BT (SSBT). The implantation rate has no significant difference between following single BT (53.3%) and double BT (42.8%). No multiple pregnancy occurred following single BT, while significantly higher (P < 0.05) multiple pregnancy rate was observed following a double BT (45.8%). The clinical pregnancy and implantation rates following a single BT were similar (P > 0.05) in patients belonging to <30 years (62.5%), 30-34 years (57.9%) and 35-39 years old (35.8%). Conclusion: Selected single good quality BT maintained pregnancy and avoided multiple pregnancies. It is recommended for patients with a risk for high-order multiple pregnancy. (Reprod Med Biol 2004; 3: 13-18).