Factors associated with the collection of isolated immature oocytes during ovarian tissue cryopreservation.

PURPOSE: To identify patient characteristics associated with successful isolated immature oocyte retrieval (IsO) during ovarian tissue cryopreservation (OTC) and to determine whether they are predictive of the collection of larger numbers of oocytes. METHODS: We retrospectively analyzed all patients undergoing OTC with IsO for fertility preservation over three years of activity at a university hospital. Univariate and multivariate analyses were used to identify the patients with the highest and lowest chances of oocyte recovery, and those with the largest numbers of oocytes. We also analyzed the correlation of IsO with the number of ovarian fragments collected and histological parameters. RESULTS: We analyzed 257 consecutive patients undergoing these procedures, at a median age of 17.1 years [0.3-38.3 years]. Isolated oocytes were obtained from 47.1% of patients, and IsO was more likely in patients with ovulatory cycles (63.0% vs. 38.6%; P≤ .001), without chemotherapy before OTC (61.4% vs. 33.1; P< .001) and with non-malignant diseases other than Turner syndrome (77.5%). Oocyte collection failure rates were highest in patients with Turner syndrome (OR 25.0, 95% CI 3.99-157.0; P< .001) or undergoing chemotherapy with alkylating agents before OTC (OR 37.6, 95% CI 8.36-168.8; P< .001). Prepubescent status (P= .043) and large numbers of ovarian fragments (P< .001) were associated with the retrieval of larger numbers of oocytes. Oocyte recovery was correlated with the presence of follicles in the medulla, but not with follicular density. CONCLUSION: The chances of IsO differ between patients. Identifying patients with the highest chances of success facilitates appropriate resource allocation.

Ovarian tissue cryopreservation for fertility preservation in 418 girls and adolescents up to 15 years of age facing highly gonadotoxic treatment. Twenty years of experience at a single center.

INTRODUCTION: The preservation of fertility is an integral part of care of children requiring gonadotoxic treatments for cancer or non-malignant diseases. In France, the cryopreservation of ovarian tissue has been considered and has been offered as a clinical treatment since its inception. The aim of this study is to review 20 years of activity in fertility preservation by ovarian tissue cryopreservation (OTC) for children and the feasibility of oocyte isolation and cryopreservation from the ovarian tissue at a single center. MATERIAL AND METHODS: Retrospective study including patients aged 15 years or younger who underwent OTC, combined for some with oocyte cryopreservation of isolated oocytes, before a highly gonadotoxic treatment for malignant or non-malignant disease was initiated. We describe the evolution of activities in our program for fertility preservation and patient characteristics at the time of OTC and follow up. RESULTS: From April 1998 to December 2018, 418 girls and adolescents younger than 15 years of age underwent OTC, representing 40.5% of all females who have had ovarian tissue cryopreserved at our center. In all, 313 patients had malignant diseases and 105 had benign conditions. Between November 2009 and July 2013, oocytes were isolated and also cryopreserved in 50 cases. The mean age of patients was 6.9 years (range 0.3-15). The most frequent diagnoses in this cohort included neuroblastoma, acute leukemia and hemoglobinopathies; neuroblastoma being the most common diagnosis in very young patients. During follow up, three patients requested the use of their cryopreserved ovarian tissue. All had undergone ovarian tissue transplantation, one for puberty induction and the two others for restoring fertility. So far, no pregnancies have been achieved. Eighty-four patients who had OTC died. CONCLUSIONS: Ovarian tissue cryopreservation is the only available technique for preserving fertility of girls. To our knowledge this is the largest series of girls and adolescents younger than 15 years so far reported on procedures of OTC before highly gonadotoxic treatment in a single center.

Different Levels of DNA Methylation Detected in Human Sperms after Morphological Selection Using High Magnification Microscopy.

Objective. To analyze DNA methylation levels between two groups of spermatozoa taken from the same sample, following morphological selection by high magnification (HM) at 6100x microscopy. A prospective study was conducted and studied 876 spermatozoa from 10 randomly selected men. Sperm morphology was characterized at HM according to criteria previously established. High-scoring Score 6 and low-scoring Score 0 sperm were selected. Sperm DNA methylation level was assessed using an immunoassay method targeting 5-methylcytosine residues by fluorescence microscopy with imaging analysis system to detect DNA methylation in single spermatozoon. Results. In total, 448 S6 spermatozoa and 428 S0 spermatozoa were analyzed. A strong relationship was found between sperm DNA methylation levels and sperm morphology observed at HM. Sperm DNA methylation level in the S6 group was significantly lower compared with that in the S0 group (p < 10(-6)), OR = 2.4; and p < 0.001, as determined using the Wilcoxon test. Conclusion. Differences in DNA methylation levels are associated with sperm morphology variations as observed at HM, which allows spermatozoa with abnormal levels to be discarded and ultimately decrease birth defects, malformations, and epigenetic diseases that may be transmitted from sperm to offspring in ICSI.