Oxidative stress and fertility: incorrect assumptions and ineffective solutions?

One of the most important concerns in assisted reproduction (ART), and in particular ICSI, is the quality of sperm DNA. Oxidative stress is one of the major causes of damage to DNA and attempting to reduce generation of DNA damage related to reactive oxygen species (ROS) through consumption of antioxidants is often tempting. However, current antioxidant treatments, given irrespectively of clinically quantified deficiencies, are poorly efficient, potentially detrimental and over-exposure is risky. Here we discuss new treatments in relation to present day concepts on oxidative stress. This discussion includes stimulation of endogenous anti-ROS defense i.e. glutathione synthesis and recycling of homocysteine, the epicentre of multiple ROS-linked pathologies.

New insights into human pre-implantation metabolism in vivo and in vitro.

The metabolism of pre-implantation embryos is far from being understood. In human embryos, the two major obstacles are the scarcity of material, for obvious ethical reasons, and complete absence of a relevant in vivo control model. Over-extrapolation from animal species to human systems adds to the complexity of the problem. Removal of some metabolites from media has been proposed, such as glucose and essential amino acids, on the basis of their pseudo "toxicity". In contrast, addition of some compounds such as growth factors has been proposed in order to decrease apoptosis, which is a natural physiologic process. These suggestions reflect the absence of global knowledge, and in consequence mask reality. Some aspects of metabolism have been ignored, such as lipid metabolism. Others are seriously underestimated, such as oxidative stress and its relationship to imprinting/methylation, of paramount importance for genetic regulation and chromosomal stability. It has become increasingly obvious that more studies are essential, especially in view of the major extension of ART activities worldwide.

A 16-year bicentric retrospective analysis of ovarian tissue cryopreservation in pediatric units: indications, results, and outcome.

Background: Cancer treatments of the last decades improve the survival rate of children and adolescents. However, chemo- and radiotherapy result in gonadal damage, leading to acute ovarian failure and sterility. The preservation of fertility is now an integral part of care of children requiring gonadotoxic treatments. Ovarian tissue cryopreservation (OTC) is an effective fertility preservation option that allows long-term storage of primordial follicles, subsequent transplantation, and restoration of endocrine function and fertility. The efficacy of this technique is well-demonstrated in adults but the data are scarce for pediatric patients. Currently, OTC represents the only possibility of preserving the potential fertility in prepubertal girls. Procedure: This is a retrospective study of OTC practice of two French centers from January 2004 to May 2020. A total of 72 patients from pediatric units underwent cryopreservation of ovarian tissue before gonadotoxic therapy for malignant or non-malignant diseases. The ovarian cortex was cut into fragments and the number of follicles per square millimeter was evaluated histologically. The long-term follow-up includes survival rate and hormonal and fertility status. Results: The mean age of patients at OTC was 9.3 years [0.2-17] and 29.2% were postpubertal; 51 had malignant diseases and 21 had non-malignant diseases. The most frequent diagnoses included acute leukemia, hemoglobinopathies, and neuroblastoma. Indication for OTC was stem cell transplantation for 81.9% (n = 59) of the patients. A third of each ovary was collected for 62.5% (n = 45) of the patients, a whole ovary for 33.3% (n = 24) of the patients, and a third of one ovary for 4.2% (n = 3) of the patients. An average of 17 fragments [5-35] per patient was cryoconserved. A correlation was found between the age of the patients and the number of fragments (p < 0.001). More fragments were obtained from partial bilateral harvesting than from whole ovary harvesting (p < 0.05). Histological analysis of ovarian tissue showed a median of 6.0 primordial follicles/mm2 [0.0-106.5] and no malignant cells were identified. A negative correlation was found between age and follicular density (p < 0.001). Median post-harvest follow-up was 92 months [1-188]. A total of 15 girls had died, 11 were still under treatment for their pathology, and 46 were in complete remission. Of all patients, 29 (40.2%) were subjected to a hormonal status evaluation and 26 were diagnosed with premature ovarian insufficiency (POI) (p < 0.001). One patient had undergone thawed ovarian tissue transplantation. Conclusion: OTC should be proposed to all girls with high risk of developing POI following gonadotoxic therapies in order to give them the possibility of fertility and endocrine restoration.

Carnitine content in the follicular fluid and expression of the enzymes involved in beta oxidation in oocytes and cumulus cells.

PURPOSE: The purpose of this study is to study lipid metabolism in oocytes and embryos that is a neglected parameter in human IVF. METHODS: We have tested the total carnitine content (TC) in the follicular fluid of 278 patients (217 non pregnant, 61 pregnant) undergoing IVF. RESULTS: The follicular fluid TC is neither correlated with the circulating estradiol content in serum nor with the outcome the IVF attempt. Carnitine, through the carnitine shuttle, is a major partner in lipid beta oxidation, metabolic pathway involved in the acquisition of oocyte competence. The expression of carnitine synthesis enzymes and lipid beta oxidation was studied in cumulus cells collected at the time of ovum retrieval and in oocyte. Surprisingly the expression for carnitine synthesis is not detectable in oocytes whereas the enzymes involved in lipid beta oxidation are rather strongly expressed. CONCLUSIONS: The addition of carnitine in oocyte maturation and embryo culture media should not be overlooked.

Luteal phase stimulation, the future of fertility preservation? Retrospective cohort study of luteal phase versus follicular phase stimulation.

RESEARCH QUESTION: Is luteal phase stimulation capable of improving fertility preservation? MATERIALS AND METHODS: We performed a retrospective cohort study of consecutive ovarian stimulations, during July 2012 and September 2018 at Strasbourg University Teaching Hospital in France. Enrollment criteria were patients aged below 40 who had been referred to our center following a diagnosis of cancer or requiring gonadotoxic treatment. All patients enrolled had regular menstrual cycles and normal ovulation. Non-enrollment criteria were an expected low ovarian response (defined by an anti-Müllerian hormone (AMH) level <0.75µg/L and/or an antral follicle count inferior (AFC) inferior than 5), polycystic ovarian syndrome, amenorrhea, prior history of infertility or gonadotoxic treatment. The primary endpoint is the number of mature oocytes (metaphase II) obtained. Secondary outcomes were oocyte yields obtained, stimulation duration, initial gonadotropin dose and total gonadotropin dose. RESULTS: A total of 100 patients were included: 20 in luteal phase and 80 in follicular phase. A larger number of mature oocytes was obtained in luteal phase versus follicular phase (13.1+/8.0 versus 9.2+/-5.8 with p=0.01). A greater amount of total (mature and immature) oocytes was obtained in luteal phase versus follicular phase with a significant difference (16.8+/-9.3 versus 11.8+/-7.3 with p=0.01). No difference was found for the initial and total doses of gonadotropin. CONCLUSIONS: Luteal phase stimulation has the advantage of a better flexibility with positives results as to the number of oocytes obtained in fertility preservation.

Luteal phase progesterone supplementation following induced natural cycle frozen embryo transfer: A retrospective cohort study.

INTRODUCTION: The objective of this study was to assess the impact on the clinical pregnancy rate of luteal phase progesterone treatment in patients being prepared for natural cycle frozen embryo transfer (FET) with induced ovulation. MATERIAL AND METHODS: This retrospective cohort study collect all the FET protocols over a 6-month period at Strasbourg University Hospital fertility unit between December 2016 and May 2017. In total 293 consecutive patients with regular menstrual cycles were prepared for natural cycle FET during this period. All patients had an embryo cryopreservation secondary to in vitro fertilisation (IVF) or by intracytoplasmic sperm injection (ICSI). There were 2 protocols during this period and patients either received or did not received progesterone. Ovulation was routinely triggered in all patients by injection of choriogonadotrophin alfa. Patients in the treated group received vaginal natural micronized progesterone treatment of 400mg daily, starting on the day of ovulation. The principal assessment criterion was the occurrence of pregnancy. RESULTS: In total, 231 patients were analysed: 108 in the group not receiving progesterone and 123 in the group receiving progesterone. Patient characteristics were comparable between groups. A higher clinical pregnancy rate (39% vs. 24.1%, p=0.02; 95CI [1.10; 3.74]) was recorded in the treated group. CONCLUSIONS: Our results suggest that luteal phase support with vaginal progesterone statistically increases the clinical pregnancy rate following hCG-triggered natural cycle FET and that it should be used more widely.