What importance do donors and recipients attribute to the nuclear DNA-related genetic heritage of oocyte donation?

STUDY QUESTION: How do oocyte donors and recipients perceive the genetic link related to the transfer of nuclear DNA between donors and offspring? SUMMARY ANSWER: Whether they are donors or recipients, individuals attach great importance to the transmission of their genetic heritage, since 94.5% would opt for the pronuclear transfer method to preserve this genetic link in the context of oocyte donation. WHAT IS KNOWN ALREADY: Since 1983, the use of oocyte donation has increased worldwide. Performed in France since the late 1980s and initially offered to women with premature ovarian insufficiency, its indications have progressively expanded and now it is proposed in many indications to prevent the transmission of genetically inherited diseases. This has resulted in an increase in the waiting time for access to oocyte donation due to the difficulty in recruiting oocyte donors in French ART centres. Several articles have discussed how to fairly distribute donor oocytes to couples, but few have interviewed women in the general population to record their feelings about oocyte donation, as either the donor or recipient and the importance given to the genetic link between the oocyte donors and the children born. Mitochondrial replacement therapy (MRT) is a technique originally developed for women at risk of transmitting a mitochondrial DNA mutation. Recently, MRT has been considered for embryo arrest and oocyte rejuvenation as it could help females to reproduce with their own genetic material through the transfer of their oocyte nucleus into a healthy donor oocyte cytoplasm. STUDY DESIGN, SIZE, DURATION: We conducted an opinion survey from January 2021 to December 2021, during which 1956 women completed the questionnaire. Thirteen participants were excluded from the analysis due to incomplete responses to all the questions. Consequently, 1943 women were included in the study. PARTICIPANTS/MATERIALS, SETTING, METHODS: We specifically developed a questionnaire for this study, which was created and distributed using the Drag'n Survey® software. The questionnaire consisted of 21 items presented alongside a video created with whiteboard animation software. The aim was to analyse whether certain factors, such as age, education level, marital status, number of children, use of ART for pregnancy, video viewing, and knowledge about oocyte donation, were associated with feelings towards oocyte donation, by using a univariate conditional logistic regression model. This statistical method was also used to assess whether women would be more inclined to consider oocyte donation with the pronuclear transfer technique rather than the whole oocyte donation. All parameters found to be statistically significant in the univariate analysis were subsequently tested in a multivariate model using logistic regression. MAIN RESULTS AND THE ROLE OF CHANCE: Most women were concerned about the biological genetic contribution of the donated oocyte (94.8%). The most common reason for a women's reluctance to donate their oocytes was their unwillingness to pass on their genetic material (33.3%). Nearly 70% of women who were initially hesitant to donate their oocytes indicated that they would reconsider their decision if the oocyte donation was conducted using donated cytoplasm and the pronuclear transfer technique. Concomitantly, >75% of the respondents mentioned that it would be easier to receive a cytoplasm donation. The largest proportion of the population surveyed (94.5%) expressed their support for its legalization. LIMITATIONS, REASONS FOR CAUTION: In this study, a substantial portion of the responses came from individuals with medical or paramedical backgrounds, potentially introducing a recruitment bias among potential donors. The rate of missing responses to the question regarding the desire to become an oocyte donor was 13.6%, while the question about becoming an oocyte cytoplasm donor had a missing response rate of 23%. These missing responses may introduce a bias in the interpretation of the data. WIDER IMPLICATIONS OF THE FINDINGS: This study was the first to demonstrate that, for the French population studied, the combination of oocyte cytoplasm donation with pronuclear transfer could offer a promising approach to enhance the acceptance of oocyte donation for both the donor and the recipient. STUDY FUNDING/COMPETING INTEREST(S): No external funding was used for this study. The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

What is the threshold of mature oocytes to obtain at least one healthy transferable cleavage-stage embryo after preimplantation genetic testing for fragile X syndrome?

STUDY QUESTION: What are the chances of obtaining a healthy transferable cleavage-stage embryo according to the number of mature oocytes in fragile X mental retardation 1 (FMR1)-mutated or premutated females undergoing preimplantation genetic testing (PGT)? SUMMARY ANSWER: In our population, a cycle with seven or more mature oocytes has an 83% chance of obtaining one or more healthy embryos. WHAT IS KNOWN ALREADY: PGT may be an option to achieve a pregnancy with a healthy baby for FMR1 mutation carriers. In addition, FMR1 premutation is associated with a higher risk of diminished ovarian reserve and premature ovarian failure. The number of metaphase II (MII) oocytes needed to allow the transfer of a healthy embryo following PGT has never been investigated. STUDY DESIGN, SIZE, DURATION: The study is a monocentric retrospective observational study carried out from January 2006 to January 2020 that is associated with a case-control study and that analyzes 38 FMR1 mutation female carriers who are candidates for PGT; 16 carried the FMR1 premutation and 22 had the full FMR1 mutation. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 95 controlled ovarian stimulation (COS) cycles for PGT for fragile X syndrome were analyzed, 49 in premutated patients and 46 in fully mutated women. Only patients aged ≤38 years with anti-Müllerian hormone (AMH) >1 ng/ml and antral follicle count (AFC) >10 follicles were eligible for the PGT procedure. Each COS cycle of the FMR1-PGT group was matched with the COS cycles of partners of males carrying any type of translocation (ratio 1:3). Conditional logistic regression was performed to compare the COS outcomes. We then estimated the number of mature oocytes needed to obtain at least one healthy embryo after PGT using receiver operating characteristic curve analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, in the FMR1-PGT group, the median number of retrieved and mature oocytes per cycle was 11 (interquartile range 7-15) and 9 (6-12), respectively. The COS outcomes of FMR1 premutation or full mutation female carriers were not altered compared with the matched COS cycles in partners of males carrying a balanced translocation in their karyotype. Among the 6 (4-10) Day 3 embryos obtained in the FMR1-PGT group, a median number of 3 (1-6) embryos were morphologically eligible for biopsy, leading to 1 (1-3) healthy embryo. A cutoff value of seven MII oocytes yielded a sensitivity of 82% and a specificity of 61% of having at least one healthy embryo, whereas a cutoff value of 10 MII oocytes led to a specificity of 85% and improved positive predictive value. LIMITATIONS, REASONS FOR CAUTION: This study is retrospective, analyzing a limited number of cycles. Moreover, the patients who were included in a fresh PGT cycle were selected on ovarian reserve parameters and show high values in ovarian reserve tests. This information could influence our conclusion. WIDER IMPLICATIONS OF THE FINDINGS: The results relate only to the target population of this study, with a correct ovarian reserve of AMH >1 and AFC >10. However, the information provided herein extends knowledge about the current state of COS for FMR1 mutation carriers in order to provide patients with proper counseling regarding the optimal number of oocytes needed to have a chance of transferring an unaffected embryo following PGT. STUDY FUNDING/COMPETING INTEREST(S): None. TRIAL REGISTRATION NUMBER: N/A.

Detection of Loa loa Microfilariae in Follicular Fluid During Assisted Reproductive Technology: Case Report and Review of the Literature.

We report on a case of loiasis revealed during an assisted reproductive technology (ART) cycle. Loa loa could limit implantation outcome. We propose to focus on an ART strategy with frozen embryos to treat the patient before any transfer.

Similar in vitro maturation rates of oocytes retrieved during the follicular or luteal phase offer flexible options for urgent fertility preservation in breast cancer patients.

STUDY QUESTION: Are in vitro maturation (IVM) rates of cumulus-oocyte complexes (COCs), retrieved from breast cancer patients seeking urgent fertility preservation (FP) before neoadjuvant chemotherapy, different between those recovered in the follicular or in the luteal phase of the cycle? SUMMARY ANSWER: The present investigation reveals no major difference in the number of COCs recovered or their IVM rates whatever the phase of the cycle at which egg retrieval is performed, suggesting that IVM is a promising tool for breast cancer patients seeking urgent oocyte cryopreservation. WHAT IS KNOWN ALREADY: FP now represents a standard of care for young cancer patients having to undergo gonadotoxic treatment. Mature oocyte cryopreservation after IVM of COCs has been proposed for urgent FP, especially in women, who have no time to undergo ovarian stimulation, or when it is contraindicated. STUDY DESIGN, SIZE, DURATION: From January 2011 to December 2014, we prospectively studied 248 breast cancer patients awaiting neoadjuvant chemotherapy, aged 18-40 years, candidates for oocyte vitrification following IVM, either at the follicular or the luteal phase of the cycle. PARTICIPANTS/MATERIALS, SETTING, METHODS: Serum anti-Müllerian hormone and progesterone levels and antral follicle count (AFC) were measured prior to oocyte retrieval. Patients were sorted into two groups according to the phase of the cycle during which eggs were harvested (Follicular phase group, n = 127 and Luteal phase group, n = 121). Number of COCs recovered, maturation rates after 48 h of culture and total number of oocytes cryopreserved were assessed. Moreover, the oocyte retrieval rate (ORR) was calculated by the number of COCs recovered ×100/AFC. MAIN RESULTS AND THE ROLE OF CHANCE: In the Follicular and the Luteal phase groups, women were comparable in terms of age, BMI and markers of follicular ovarian status. There was no significant difference in the number of COCs recovered (mean ± SEM), 9.3 ± 0.7 versus 11.1 ± 0.8, and ORR (median (range)) 43.1 (1-100) versus 47.8 (7.7-100)%. Moreover, maturation rates after 48 h of culture (median (range)) were comparable in the follicular and luteal phase groups, 66.7 (20-100) versus 64.5 (0-100)%. Finally, the total number of oocytes cryopreserved (mean ± SEM) was similar in both groups (6.2 ± 0.4 versus 6.8 ± 0.5). LIMITATIONS, REASONS FOR CAUTION: Despite the intact meiotic competence of immature oocytes recovered during the follicular or the luteal phase, there is a dramatic lack of data regarding the outcome of IVM oocytes cryopreserved in cancer patients. WIDER IMPLICATIONS OF THE FINDINGS: IVM of oocytes may be an interesting method of FP in urgent situations. Improving the culture conditions will be needed to increase the maturation rates and the overall potential of in vitro matured oocytes. STUDY FUNDING/COMPETING INTERESTS: None. TRIAL REGISTRATION NUMBER: N/A.

[Embryo vitrification: French clinical practice analysis for BLEFCO]. / Vitrification embryonnaire : état des pratiques en France par les BLEFCO.

Frozen thawed embryo transfer is currently an important part of present-day assisted reproductive technology (ART) aiming at increasing the clinical pregnancy rate per oocyte retrieval. Although slow freezing method has been the reference during 2 decades, the recent years witnessed an expansion of ultrarapid cryopreservation method named vitrification. Recently in France, vitrification has been authorized for cryopreserving human embryos. Therefore BLEFCO consortium decides to perform a descriptive study through questionnaires to evaluate the state of vitrification in the French clinical practice. Questionnaires were addressed to the 105 French centres of reproductive biology and 60 were fully completed. Data analysis revealed that embryo survival rate as well as, clinical pregnancy rate were increased after vitrification technology when compared to slow freezing procedure. Overall, these preliminary data suggest that vitrification may improve ART outcomes through an increasing of the cumulative pregnancy rate per oocyte retrieval.

Metformin exposure affects human and mouse fetal testicular cells.

BACKGROUND: Metformin is a drug used in the treatment of diabetes and of some disorders related to insulin resistance, such as polycystic ovary syndrome. Gestational diabetes can cause complications for both mother and child, and some studies have shown a beneficial effect of metformin during pregnancy without an increase in perinatal complications. However, the effects on the gonads have not been properly studied. Here we investigated the effect of metformin administered during pregnancy on the development and function of the fetal testis. METHODS: A dual approach in vitro and in vivo using human and mouse models was chosen. Cultures of human and murine organotypic testes were made and in vivo embryonic testes were analysed after oral administration of metformin to pregnant mice. RESULTS: In human and mouse organotypic cultures in vitro, metformin decreased testosterone secretion and mRNA expression of the main factors involved in steroid production. In vitro, the lowest observed effect concentration (LOEC) on testosterone secretion was 50 µM in human, whereas it was 500 µM in mouse testis. Lactate secretion was increased in both human and mouse organotypic cultures with the same LOEC at 500 µM as observed in other cell culture models after metformin stimulation. In vivo administration of metformin to pregnant mice reduced the testicular size of the fetal and neonatal testes exposed to metformin during intrauterine life. Although the number of germ cells was not affected by the metformin treatment, the number of Sertoli cells, the nurse cells of germ cells, was slightly yet significantly reduced in both periods (fetal period: P = 0.007; neonatal period: P = 0.03). The Leydig cell population, which produces androgens, and the testosterone content were diminished only in the fetal period at 16 days post-coitum. CONCLUSIONS: This study showed a potentially harmful effect of metformin treatment on the development of the fetal testis and should encourage future human epidemiological studies.

Antral follicle responsiveness to follicle-stimulating hormone administration assessed by the Follicular Output RaTe (FORT) may predict in vitro fertilization-embryo transfer outcome.

BACKGROUND: Looking for a qualitative marker of ovarian function, we aimed to verify whether responsiveness of antral follicles to FSH administration, as reflected by the Follicular Output RaTe (FORT), is related to their reproductive competence. METHODS: We studied 322 IVF-ET candidates aged 25-43 years who underwent controlled ovarian hyperstimulation with similar initial FSH doses. Antral follicle (3-8 mm) count (AFC) and pre-ovulatory follicle (16-22 mm) count (PFC) were performed, respectively, at the achievement of pituitary suppression (before FSH treatment) and on the day of hCG administration. The FORT was calculated by PFC × 100/AFC. FORT groups were set according to tercile values: low (<42%; n= 102), average (42-58%; n= 123) and high (>58%; n= 97). RESULTS: The average FORT was 50.6% (range, 16.7-100.0%). Clinical pregnancy rates per oocyte retrieval increased progressively from the low to the high FORT groups (33.3, 51.2 and 55.7%, respectively, P< 0.003) and such a relationship assessed by logistic regression was independent of the confounding covariates, women's ages, AFC and PFC. CONCLUSIONS: The observed relationship between IVF-ET outcome and the percentage of antral follicles that effectively respond to FSH administration reaching pre-ovulatory maturation suggests that FORT may be a qualitative reflector of ovarian follicular competence. Further studies with broader inclusion criteria and more personalized protocols are needed to validate these results.

[Cancellation of IVF-ET cycles: poor prognosis, poor responder, or variability of the response to controlled ovarian hyperstimulation? An analysis of 142 cancellations]. / Annulations en fécondation in vitro : mauvais pronostic, mauvaises répondeuses, ou variabilité de la réponse à la stimulation ? Analyse de 142 annulations.

INTRODUCTION: This retrospective study aimed at analyzing IVF-ET management and outcome after cancellation of a first cycle for poor response. PATIENTS AND METHOD: One hundred and forty-two infertile patients were included in this observational study. After an overall analysis on the outcome of the second IVF-ET attempt, a sub-analysis was performed according to the presence or the absence of poor prognostic criteria defined as mentioned: patient age superior to 38 years old, antral follicle count (3-9 mm in diameter) inferior to 10 on cycle day 3 and day 3 serum AMH and FSH levels less than 1 ng/mL and more than 10 IU/mL, respectively. Main outcome measures were the cancellation rates, pregnancy and live birth rates. RESULTS: When a controlled ovarian stimulation was performed, patients with poor prognosis had higher cancellation rates (37.8% vs. 13.3%, P<0.004) and lower pregnancy and live birth rates (22.2% vs. 35.0%, P<0.05 and 11.1% vs. 26.1%, P<0.05, respectively) as compared to good prognosis women. CONCLUSION: The relatively high cancellation rate in patients with poor prognosis raises the question of the use of IVF modified natural cycle in this group.

[Preimplantation diagnosis with HLA typing: birth of the first double hope child in France]. / Diagnostic préimplantatoire avec typage HLA : naissance du premier enfant du double espoir en France.

Preimplantation genetic diagnosis (PGD) is authorized in France since 1999. After 10 years, technical results are encouraging. With the development of new technologies, our team is able to diagnosis the large majority of chromosome translocations and 75 monogenic diseases. However, PGD remains limited because of the growing augmentation of demands causing an increasing delay for the first procedure of more than 18 months. Since 2006, 19 couples asked for a PGD with HLA typing. In January 2011, 11 couples have already been included in our PGD program. The birth of the first child after PGD with HLA typing offers new perspectives of treatment for these couples.

[Serum AMH level is not a predictive value for IVF in modified natural cycle: analysis of 342 cycles]. / L'AMH sérique n'a pas de valeur prédictive en fécondation in vitro en cycle naturel modifié : analyse de 342 cycles.

The objective is to compare the IVF procedures in modified natural cycle outcomes according to serum anti-Mullerian hormone (AMH) levels. We included in this retrospective study 342 patients undergoing their first IVF in modified natural cycle. Patients were regrouped in three groups according to their serum AMH level: group 1 was defined by patients with AMH level<0.97 ng/mL (<25th percentile), group 2, patients with AMH level between 0.97 ng/mL and 2.60 ng/mL (25-75th percentile), and group 3, patients with AMH level between 2.61 ng/mL and 6.99 ng/mL (>75th percentile). The main outcomes were cancellation rate, embryo transfer rate and clinical pregnancy rate, ongoing pregnancy rate and implantation rate. No difference has been observed on cancellation rate, embryo transfer rate, clinical pregnancy rate and implantation rate. The ongoing pregnancy rate per IVF cycle was respectively: 12.8±3.6% for AMH inferior to 0.97 ng/mL versus 12.5±2.5% for AMH between 0.97 to 2.60 ng/mL and 13.4±4.2% for AMH between 2.61 ng/mL and 6.99 ng/mL. In conclusion, IVF in modified natural cycles procedures should be considered as an option for patients with an altered ovarian reserve defined by a serum AMH inferior to 1 ng/mL. Serum AMH level seems a quantitative marker of the ovary but not a quality factor. Serum AMH level does not seem to be a prognostic factor for ongoing pregnancy rated in IVF modified cycles.

[In vitro maturation of oocytes: an option for fertility preservation in women]. / Préservation de la fertilité féminine: place de la maturation ovocytaire in vitro.

Although female cancer incidence may be on rise, antineoplastic regimens have become more successful. As a result, an increasing number of women with cancer survive to endure the long-term consequences of chemotherapy. One of the most important long-term consequences of cancers treatments in young female is premature ovarian failure and infertility. Because of the increasing survival rates, many of these young women are seeking methods to preserve their fertility. Currently, embryo/oocytes cryoporeservation obtained after ovarian stimulation appears to provide the best fertility preservation option. However, patients may not have sufficient time to undergo ovarian stimulation prior to chemotherapy and/or the hormones used in ovarian stimulation are contra-indicated for estrogen-dependant tumors. In vitro maturation of oocytes (IVM) has been suggested to avoid ovarian stimulation and time requirement in patients with cancer, and can be combined with ovarian tissue cryobanking. In this review, we will discuss the position of IVM in the strategy of fertility preservation in young women.

[Impact of elective single embryo transfer criteria on the twin pregnancy rate in a French population]. / L'impact des critères du élective single embryo transfer sur le taux de grossesses gémellaires dans la population française.

To reduce the twin pregnancy rate and their morbidity, several recommendations have been proposed to practice the "elective single embryo transfer" in a selected population. We decided to apply the criteria that were proposed in five articles from the literature to our population to evaluate the percentage of our population concerned and the impact on our twin pregnancy rate. The result is that these criteria only concern 2,4 to 10,8% of our population with a minor reduction of our twin pregnancy rate with a potential lake of chance concerning the pregnancy rate. We should study others possibilities than the population's criteria to reduce the number of embryo transferred.

[Non-obstructive azoospermia: option of the testicular sperm extraction performed on the day of oocyte retrieval]. / Azoospermie non obstructive: intérêt du prélèvement testiculaire synchrone du recueil ovocytaire.

OBJECTIVE: Analyzing the results and validating the procedure of testicular sperm extraction (TESE) performed on the day of oocyte retrieval in non obstructive azoospermia (NOA) patients. PATIENTS AND METHODS: Sixty TESE were performed on the day of oocyte retrieval (dOR), in 52 NOA men. Patients were sorted into three groups according to the results of the surgical procedure: 1: sperm recovery with possible sperm freezing (n=20); 2: sperm recovery without freezing (n=27); 3: "negative" biopsy (n=13). ICSI outcomes in the two groups with sperm recovery were compared to those of ICSI performed with frozen-thawed sperm obtained from TESE performed (n=13). RESULTS: The rate of positive sperm retrieval was 78%. While the overall clinical pregnancy rate was 50%, no difference in the fertilization, implantation and clinical pregnancy rates was found in the two groups with positive sperm retrieval as compared to frozen-thawed sperm group. Twelve pregnancies were obtained in patients without further sperm cryopreservation. CONCLUSION: After TESE in NOA men, cryopreserved sperm produced comparable results with freshly obtained sperm. However, TESE performed on dOR can offer the opportunity, in patients with rare sperm that might not survive freeze-thaw, to have a possible fresh embryo transfer. Couples should be counselled regarding the possibility of oocyte retrieval without sperm for ICSI.

[Secrets of proportions in follicular liquid]. / Les secrets des dosages dans le liquide folliculaire.

Only 5% of oocytes lead to life birth after IVF. Currently, it is difficult to evaluate oocyte quality on the sole basis of morphology criteria. Embryo morphology is considered as a good marker of potential implantation of embryo after ET, however it is not enough. Therefore, we need to develop non invasive assessment of oocyte quality. Research performed on follicular fluid may represent a new tool of increasing interest. The presence of G-CSF in follicular fluid could predict ongoing pregnancy. Cytokines, IL-7 and IL-17 could be also a predictor of success.

Meiosis initiation in the human ovary requires intrinsic retinoic acid synthesis.

BACKGROUND: The initiation of meiosis is crucial to fertility. While extensive studies in rodents have enhanced our understanding of this process, studies in human fetal ovary are lacking. METHODS: We used RT-PCR and immunohistochemistry to investigate expression of meiotic factors in human fetal ovaries from 6 to 15 weeks post fertilization (wpf) and developed an organ culture model to study the initiation of human meiosis. RESULTS: We observed the first meiotic cells at 11 wpf, when STRA8, SPO11 and DMC1 are first expressed. In culture, meiosis initiation is observed in 10 and 11 wpf ovaries and meiosis is maintained by addition of fetal calf serum. Meiosis is stimulated, compared with control, by retinoic acid (RA) (P < 0.05). No major change occurred in mRNA for CYP26B1, the RA-degrading enzyme proposed to control the timing of meiosis in mice. We did, however, observe increased mRNA levels for ALDH1A1 in human ovary when meiosis began, and evidence for a requirement to synthesize RA and thus sustain meiosis. Indeed, ALDH inhibition by citral prevented the appearance of meiotic cells. Finally, 8 wpf ovaries (and earlier stages) were unable to initiate meiosis whatever the length of culture, even in the presence of RA and serum. However, when human germ cells from 8 wpf ovaries were placed in a mouse ovarian environment, some did initiate meiosis. CONCLUSIONS: Our data indicate that meiosis initiation in the human ovary relies partially on RA, but that the progression and regulation of this process appears to differ in many aspects from that described in mice.

Oocyte in-vitro maturation: BCL2 mRNA content in cumulus cells reflects oocyte competency.

BCL2-associated X protein (BAX) and B-cell leukaemia/lymphoma gene-2 (BCL2), which are, respectively, pro- and anti-apoptotic proteins of the BCL2 gene family, participate in the mitochondria-dependent apoptosis pathway. A correlation between low incidence of apoptosis in cumulus cells and oocyte maturation has previously been suggested in ovarian stimulation. However, little is known in unprimed ovaries. These authors have investigated whether BAX and BCL2 expression in cumulus cells affects the competency of in-vitro matured oocytes. We have studied 100 cumulus-oocyte-complexes (COC) recovered from unprimed ovaries of 13 women diagnosed with polycystic ovary syndrome (PCOS) and undergoing in-vitro maturation (IVM) with their informed consent. COC were matured for 24 h in a specific maturation medium and the cumulus was stripped from the oocyte. BAX and BCL2 mRNA content was measured in each COC using real-time polymerase chain reaction. We found that BCL2 mRNA expression was significantly higher in cumulus cells associated with mature oocytes than those associated with immature oocytes while BAX mRNA concentrations did not vary in cumulus cells. Regarding fertilization, higher BCL2 mRNA content was found in cumulus cells enclosing fertilized oocytes (0.140 versus 0.075; P = 0.03). These results suggest that BCL2 expression is strongly associated with the ability of oocytes to complete nuclear maturation and to be fertilized.

Characterization of human PGD blastocysts with unbalanced chromosomal translocations and human embryonic stem cell line derivation?

Novel embryonic stem cell lines derived from embryos carrying structural chromosomal abnormalities obtained after preimplantation genetic diagnosis (PGD) are of interest to study in terms of the influence of abnormalities on further development. A total of 22 unbalanced blastocysts obtained after PGD were analysed for structural chromosomal defects. Morphological description and chromosomal status of these blastocysts was established and they were used to derive human embryonic stem cell (ESC) lines. An outgrowth of cells was observed for six blastocysts (6/22; 27%). For two blastocysts, the exact morphology was unknown since they were at early stage, and for four blastocysts, the inner cell mass was clearly visible. Fifteen blastocysts carried an unbalanced chromosomal defect linked to a reciprocal translocation, resulting in a positive outgrowth of cells for five blastocysts. One human ESC line was obtained from a blastocyst carrying a partial chromosome-21 monosomy and a partial chromosome-1 trisomy. Six blastocysts carried an unbalanced chromosomal defect linked to a Robertsonian translocation, and one showed a positive outgrowth of cells. One blastocyst carried an unbalanced chromosomal defect linked to an insertion and no outgrowth was observed. The efficiency of deriving human ESC lines with constitutional chromosomal disorders was low and probably depends on the initial morphological aspect of the blastocysts and/or the type of the chromosomal disorders.