María-José Escribá

Twins born after transplantation of ovarian cortical tissue and oocyte vitrification

OBJECTIVE To present a combination of ovarian tissue and oocyte cryopreservation as an effective strategy for achieving pregnancy in a breast cancer patient. DESIGN Case report. SETTING Tertiary care university-affiliated hospital, tissue bank, and infertility clinic. PATIENT(S) A 36-year-old patient diagnosed with atypical medullar breast cancer and negative for estrogen, P, and HER2 receptors underwent ovarian tissue cryopreservation before receiving chemotherapy and radiotherapy. INTERVENTION(S) Laparoscopic ovarian cortex extraction, ovarian tissue cryopreservation, ovarian tissue thawing and transplantation, controlled ovarian stimulation (COS), oocyte retrieval, vitrification and IVF, and embryo culture and replacement. MAIN OUTCOME MEASURE(S) Resumption of spontaneous ovarian function after transplantation, response to COS, oocyte vitrification, IVF, pregnancy, and delivery. RESULT(S) Menses occurred 63 days after transplantation. Sixteen mature oocytes were obtained in four COS procedures. All vitrified oocytes survived warming, and 77.7% were fertilized. Two day 3 embryos were replaced, and two healthy boys were born at 34 weeks. CONCLUSION(S) Ovarian tissue cryopreservation and grafting preserves fertility. Simultaneous oocyte vitrification increases the success of assisted reproductive technology in poor-prognosis patients and avoids the consequences of the short lifespan of the transplanted tissue.

Morphologic indicators predict the stage of chromatin condensation of human germinal vesicle oocytes recovered from stimulated cycles

OBJECTIVE To assess germinal vesicles (GV) recovered from stimulated cycles by means of morphometric and morphologic examination (using contrast-phase and image analysis) and chromatin configuration (using fluorescent DNA imaging), and to evaluate the relevance of morphometric and morphologic parameters as forecasters of chromatin status. DESIGN Experimental study. SETTING University-affiliated infertility clinic. PATIENT(S) One hundred and thirty-one GV oocytes donated to patients for intracytoplasmic sperm injection. INTERVENTION(S) We evaluated 131 GVs by means of morphology and morphometry with the use of contrast phase microscopy. They were subsequently fixed, DNA stained, and assessed by fluorescent microscopy. Compiled data were retrospectively grouped according to three models. MAIN OUTCOME MEASURE(S) Model A: ova were grouped according to chromatin condensation (noncondensed vs. condensed). Model B: ova were grouped according to chromatin distribution in relation to the nucleolus-like body (NLB) (not surrounding vs. surrounding and/or absent) but regardless of the condensation stage. Model C: GV oocytes were grouped according to the combination of both of the previously mentioned parameters (chromatin condensation and distribution in relation to the NLB). RESULT(S) According to the GV classification of model A, nucleoplasm, nucleus position, nuclear envelope continuity, and oocyte size were shown to be relevant and were included in a mathematical model for predicting chromatin condensation stage. CONCLUSION(S) Noninvasive analysis of GV oocytes using contrast-phase microscopy maintains oocytes in a viable state and allows the chromatin condensation status to be predicted.

The dynamics of in vitro maturation of germinal vesicle oocytes

OBJECTIVE To evaluate the dynamics of the nuclear maturation (NM) of in vitro-matured (IVM) oocytes and to determine the most favorable duration of meiosis II (MII) arrest in relation to the normal activation response. DESIGN Experimental. SETTING University-affiliated infertility clinic. PATIENT(S) Donated immature germinal vesicle oocytes (GV). INTERVENTION(S) The GV underwent spontaneous IVM and the dynamics of NM studied by real-time monitoring. The IVM oocytes were parthenogenetically activated at different MII arrest points and their response assessed. MAIN OUTCOME MEASURE(S) Moment of GV breakdown; extrusion of the first polar body; duration of MI and MII arrest; activation rate (AR) and type. RESULT(S) Two GV populations-early (E-IVM, 18.4 ± 2.7 hours) and late (L-IVM, 26.3 ± 3.8 hours) maturing-were defined according to the time required for extrusion of the first polar body. Significantly more E-IVM than L-IVM exhibited a normal activation response (61.3% vs. 34.6%), but AR were similar (average, 88.6%) in both groups. Duration of the GV stage differed between the two groups, but MI arrest (14.0 ± 0.3 hours) was constant. The E-IVM arrested at MII for at least 4.3 hours displayed significantly lower AR and similar normal activation rates (61.3%) to E-IVM arrested for a shorter time (83.9% vs. 100%). The L-IVM displayed a similar AR (80.8%), but lower normal activation rates than E-IVM (34.6%), regardless of when activation took place. CONCLUSION(S) The success of IVM depends on the NM timing rather than on the length of MII arrest.

Vitrification of isolated human blastomeres

This article describes a new methodology for preserving and banking isolated human blastomeres, whose originality is based on packing the blastomere into an emptied zona pellucida before vitrification. After warming, 75.7% of blastomeres survived and developed at a rate comparable to that in noncryopreserved blastomeres (62.5% cleavage, 26.6% compaction, and 20.3% cavitation).