Reproductive biomedicine online最新文献

Research question: Will ultra-fast vitrification (UFV) and rapid elution of mature human oocytes retain the reliable, high survival rates and meiotic spindle normality seen in the germinal vesicle model, and will these oocytes maintain their developmental competence to form blastocyst-stage embryos following artificial oocyte activation (AOA)?

Design: Conventional vitrification treatment was compared with UFV treatment in mature, germinal-vesicle-derived oocytes (Phase 2, Expt. 2, n = 50) and substandard donor oocytes, metaphase I-metaphase II (MII) oocytes and poor-quality MII oocytes (n = 222). Post-warming survival, the integrity of the meiotic spindle and AOA-related development were assessed.

Results: Overall survival rates were higher (P = 0.003) for UFV/rapid elution treatment (94-100%, mean = 98%) compared with conventional vitrification/control dilution treatment (80-90%, mean = 83.3%). MII oocytes derived from immature germinal vesicles following conventional vitrification/control dilution or UFV/rapid elution treatments proved to be capable of activated development (54-71% cleavage rate), with four blastocysts produced. AOA treatment with DMAP exposure yielded optimal activated development. When vitrifying mature oocytes, both UFV and conventional vitrification treatments exhibited normal activated development and blastocyst production (34.9% and 31.7%, respectively).

Conclusions: Considering that oocyte freezing was deemed non-experimental based primarily on healthy live births from frozen-oocyte-derived embryo transfer the validation of normal blastocyst formation using the novel UFV approach is a critical accomplishment. The UFV method for oocyte cryopreservation represents a strategic deviation from traditional semi-equilibration vitrification protocols. UFV is a more time-efficient approach that consistently yields a higher survival rate, and thus has the potential to create more embryos. These findings justify proceeding with strategic clinical trial applications.

Research question: Can GV-oocytes serve as an effective model to test the efficacy of ultra-fast vitrification (UFV)/ rapid elution (RE) treatments to support reliable, high survival rates and sustained functionality?

Design: Prospective pilot cohort studies were performed to investigate the feasibility of non-equilibration, UFV to sustain cellular integrity and development in contrast to control vitrification (CV: 10-15min ES/ 1min VS). In Phase 1, we applied a 2 × 2 factorial design (n=25-30 eggs/group) to evaluate post-warming dilution treatments: conventional multi-step (CD) versus rapid elution (RE; one-step), including an apriori fresh egg control group. Phase 1/2 focused on survival and maturation assessments, including meiotic spindle formation (Phase 2).

Results: The survival of EG/DMSO treated UFV oocytes in Phase 1 and 2 was not different to spontaneous degeneration seen in the fresh IVM control groups (3.2%) but was higher than CV treated oocytes immediately post-warming (p<0.03). Of the intact GVs, no difference in IVM-MII development was detected (52.6 -58.3%) at +48h IVM across all groups. Meiotic spindle integrity of MII oocytes was normal in all treatment groups.

Conclusions: As originally reported by Gallardo (2019), non-equilibrated dehydrated human oocytes can effectively vitrify after UFV/CD treatment. We further verified the resiliency of oocytes to withstand RE treatment and continue to develop normally, like fresh GV-matured oocytes. Furthermore, we confirmed that the meiotic spindle formation and density of UFV/RE-treated GV oocytes was similar to fresh controls. Overall, the GV-model proved to be a useful resource to substantiate the promising potential of UFV technology to reliably achieve high survival and normal developmental competence in a more time efficient manner.

With a new Netflix film Joy telling the dramatic story of IVF, Dr Kamal Ahuja recalls the inspirational role that the late Sir Robert Edwards played in his own career and in the foundation of the London Women's Clinic.

Research question: To what extent do legislative measures impact standard reproductive outcome parameters?

Design: Retrospective cohort study using data from the Swiss national IVF registry analysing the outcomes of 13,908 women undergoing embryo transfers resulting from their first lifetime oocyte retrieval before (2014-2016) or after (2020-2022) revision of the legislation, allowing extended culture for 12 zygotes. Live birth rates (LBR) and cumulative LBR (cLBR) were compared in fresh and frozen embryo transfer strategies in both periods. Adjusted multivariable mixed model analyses were performed to determine OR and incidence rate ratios (IRR).

Results: Before revision of the legislation, LBR was higher for fresh embryo transfers compared with frozen embryo transfers (27.2% versus 22.7%; P = 0.006). After revision of the legislation, LBR was lower for fresh embryo transfers (29.3% versus 36.3%; P < 0.001), and cLBR was higher for the freeze-all embryo transfer strategy (59.0% versus 39.8%; P < 0.001). However, in a multivariable analysis, no difference in the odds of live birth was found between fresh and frozen embryo transfers (OR = 1.08, 95% CI 0.95-1.22), and the freeze-all embryo transfer strategy was not found to be more effective than the fresh embryo transfer strategy (IRR = 1.12, 95% CI 0.98-1.27). In a subgroup analysis, fresh blastocyst embryo transfers showed higher LBR than cleavage stage embryo transfers (OR = 2.01, 95% CI 1.62-2.49).

Conclusion: The change in national legislation provided the unique opportunity to evaluate the legal impact on reproductive outcomes. Besides a reduction in the number of multiple births, LBR in frozen embryo transfers improved, resulting in comparable success of fresh and frozen embryo transfer strategies. In addition to technological improvement, the legal framework influences the evolution of clinical practice, thereby contributing to enhanced reproductive outcomes.

The importance of oxidative stress in the aetiology of male infertility has occasioned numerous clinical trials designed to assess the potential of antioxidants for treating this condition. These trials have not returned definitive results, probably because they have never selected participants on the basis of oxidative stress. Clearly, if a moderate to severe state of oxidative stress does not exist in semen, antioxidants can hardly be expected to improve fertility. To resolve this issue, robust, user-friendly point-of-care assays need to be developed that will enable clinicians to quickly diagnose and monitor oxidative stress in patients' semen. Traditional assays of total antioxidant capacity do not fulfil this role, because they are time consuming, expensive and laboratory based. The introduction of an alternative electrochemical system (MiOXSYS®) was designed to address this problem. This assay records the static oxido-reductive potential of semen and then creates an index by dividing this measurement by the sperm concentration. The creation of such an index is flawed and undermines many of the data generated to date. This commentary explains the nature of this problem and emphasizes the continuing unmet need for effective diagnostic procedures capable of detecting seminal oxidative stress in the patient population.

Research question: Does a short co-incubation of gametes in conventional IVF affect post-insemination outcomes and embryo morphokinetics?

Design: Sibling oocyte randomized pilot study conducted between December 2020 and March 2023. Eligible couples (n = 55) were women aged 18-43 years with BMI 35 km/m² or lower and male normal semen parameters. Cumulus oocyte complexes (COC) (six to 12) were randomized in a 1:1:2 proportion in long (16-18 h) or short (2 h) co-incubation IVF exposure and ICSI, respectively. All oocytes inseminated via IVF were monitored by time-lapse. Blastocysts graded BL3CC or higher underwent trophectoderm biopsy on days 5, 6 or 7, and were analysed by next-generation sequencing.

Results: A total of 954 COC were distributed to long co-incubation (n = 235 [24.6%]), short co-incubation (n = 235 [24.6%]) and ICSI (n = 484 [50.7%]). In total, 202 were MII after long co-incubation, 209 after short co-incubation and 394 at ICSI. Regression analyses showed that short co-incubation groups (OR 0.72, 95% CI 0.46 to 1.11, P = 0.139) and ICSI (OR 1.43, 95% CI 0.95 to 2.15, P = 0.090) did not significantly affect normal fertilization rates (2PN) compared with long co-incubation. Usable blastocysts per MII, per 2PN, and euploid blastocysts per MII, per 2PN and per tested blastocysts were similar among the groups. The rate of embryo arrest (hazard ratio [HR] 0.79, 95% CI 0.57 to 1.11, P = 0.183) and timings to reach morphokinetic milestones among embryos reaching blastulation were similar between IVF groups (P > 0.05 for all).

Conclusion: A short 2-h co-incubation of gametes in IVF yields comparable fertilization, blastocyst and euploidy rates without adverse embryo morphokinetic events, compared with standard overnight co-incubation.