Preimplantation genetic diagnosis (PGD) of first polar bodies (1PBs) has been used in carriers of balanced chromosomal reorganizations and also for aneuploidy screening. Although an acceptable number of normal or balanced embryos is usually obtained using PGD in translocation carriers, the pregnancy rate is disappointingly low. To determine whether aneuploidy of chromosomes not involved in the chromosome rearrangements could be the cause of the low pregnancy rates achieved, the present authors analysed the segregation products of three translocation carriers, t(8;13)(q24.1;q22) and two Robertsonian (Rob)(13;14), using 1PBs, and afterwards another eight chromosomes in the same 1PBs, for a total of 10 chromosomes in each 1PB, that is chromosomes 1, 8, 13, 14, 15, 16, 17, 18, 21, 22 and X. In the reciprocal translocation, chromosomes with different chromatids due to meiotic recombination were found. Only one out of nine 1PBs was normal for the reorganization products but no aneuploidies were found after PGD in this case. In the two balanced Rob(13;14), six out of 12 and four out of 11 1PBs were normal or balanced for the reorganization but only one oocyte was euploid for all the chromosomes analysed in each case; a single embryo transfer was made in both but no pregnancy was achieved. The incidence of aneuploidy for the chromosomes not involved in the Robertsonian translocations was extremely high (91.7% and 81.8%). Extra chromosomes were present in most of the aneuploid oocytes (81.8% and 90%). The reason for this increase could be the tendency to non-disjunction related to advanced maternal age combined with an interchromosomal effect resulting in the presence of synaptic errors in other chromosome pairs.
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A Pujol, M Durban, J Benet, I Boiso, JM Calafell, J Egozcue, and J Navarro
Teresa K Woodruff
In 2007, I was asked by the University of Calgary to participate in a symposium called ‘Pushing the Boundaries – Advances that Will Change the World in 20 Years’. My topic was oncofertility, a word I had just coined to describe the intersection of two disciplines – oncology and fertility – and I was thrilled to share my passion for this new field and help young women with cancer protect their future reproductive health. Fertility preservation in the cancer setting lacked a concerted effort to bridge the disciplines in an organized manner. In early 2015, I was delighted to deliver a presentation for the Society for Reproduction and Fertility titled ‘Sex in Three Cities’, where I gave an update on the oncofertility movement, a remarkable cross-disciplinary, global collaboration created to address the fertility preservation needs of young cancer patients. During my tour of the UK, I was impressed by the interest among the society and its members to engage colleagues outside the discipline as well as the public in a dialogue about cutting-edge reproductive science. In this invited review, I will describe the work of the Oncofertility Consortium to provide fertility preservation options in the cancer setting and accelerate the acceptance of this critical topic on a global scale. I hope that one day this word and field it created will change the world for women who had been left out of the equation for far too long.
JE Smitz and RG Cortvrindt
In recent years several follicle culture systems have been pioneered in different mammalian species for studying ovarian folliculogenesis and culturing immature oocytes. Applications of these in vitro techniques include fertility preservation for humans, conservation of rare animals and development of oocyte banks for research purposes. Immature female gametes in the ovarian cortex can be cryopreserved for later use if culture techniques are available afterwards to promote growth and maturation. This review focuses on biochemical and biophysical factors related to oocyte culture in mice, the only animal in which live offspring have been produced after folliculogenesis in vitro. The advantage of using mice for these studies is that, in parallel to development of follicle culture systems, essential knowledge on folliculogenesis can be obtained from knockout mouse models. Recent experiments in mice stressed the principal role of the oocyte in follicle development and the strict timing of the biological processes underlying oogenesis in vitro. In large domestic animals and humans, study of oocyte culture is confounded by the constitutively prolonged nature of ovarian follicle development. In humans, only some aspects of follicle development have been studied because of the limited availability of suitable material for experimentation, technical difficulties related to manipulation of very small structures and lack of knowledge on physiological regulation of the early stages of follicle growth. Only a few reports describe ovarian follicular growth in vitro. In this review, relevant information on hormonal and growth factor regulation of the earliest stages of follicle growth in mammals is reviewed. Techniques are becoming available for the precise isolation of distinct classes of follicle and powerful molecular biology techniques can be used in studies of ovarian tissue culture.
Margarida Avo Santos, Ewart W Kuijk, and Nick S Macklon
The use of assisted reproductive technologies (ART) has been increasing over the past three decades, and, in developed countries, ART account for 1–3% of annual births. In an attempt to compensate for inefficiencies in IVF procedures, patients undergo ovarian stimulation using high doses of exogenous gonadotrophins to allow retrieval of multiple oocytes in a single cycle. Although ovarian stimulation has an important role in ART, it may also have detrimental effects on oogenesis, embryo quality, endometrial receptivity and perinatal outcomes. In this review, we consider the evidence for these effects and address possible underlying mechanisms. We conclude that such mechanisms are still poorly understood, and further knowledge is needed in order to increase the safety of ovarian stimulation and to reduce potential effects on embryo development and implantation, which will ultimately be translated into increased pregnancy rates and healthy offspring.
G D Palermo, C L O’Neill, S Chow, S Cheung, A Parrella, N Pereira, and Z Rosenwaks
Among infertile couples, 25% involve both male and female factors, while male factor alone accounts for another 25% due to oligo-, astheno-, teratozoospermia, a combination of the three, or even a complete absence of sperm cells in the ejaculate and can lead to a poor prognosis even with the help of assisted reproductive technology (ART). Intracytoplasmic sperm injection (ICSI) has been with us now for a quarter of a century and in spite of the controversy generated since its inception, it remains in the forefront of the techniques utilized in ART. The development of ICSI in 1992 has drastically decreased the impact of male factor, resulting in millions of pregnancies worldwide for couples who, without ICSI, would have had little chance of having their own biological child. This review focuses on the state of the art of ICSI regarding utility of bioassays that evaluate male factor infertility beyond the standard semen analysis and describes the current application and advances in regard to ICSI, particularly the genetic and epigenetic characteristics of spermatozoa and their impact on reproductive outcome.
J. Carroll, D. G. Whittingham, M. J. Wood, E. Telfer, and R. G. Gosden
Summary. Isolated primary mouse follicles can be frozen successfully and thawed in the presence of 1·5 m-DMSO. Similar proportions of freshly collected and frozen–thawed primary follicles undergo folliculogenesis in the absence of other ovarian tissue. Some of the mature oocytes recovered from these follicles were fertilized in vitro and, after transfer to pseudopregnant recipients at the 2-cell stage, developed into live young. Cryopreservation and extra-ovarian development of immature follicles provide a unique opportunity to store large numbers of female gametes.
Keywords: cryopreservation; mouse; oocyte; primary follicle; in-vitro folliculogenesis; oocyte maturation; in-vitro fertilization; embryo transfer
Joshua Sommovilla, Warren B Bilker, Ted Abel, and Richard M Schultz
The oldest assisted reproductive technologies (ART)-conceived child is only 27 years old. Thus, the effects of ART on longevity are unknown, and it will be many years before this can be assessed in humans. We recently reported that culturing preimplantation mouse embryos under suboptimal conditions results in differences in how the offspring perform in behavioral assays that reflect anxiety (elevated zero maze) and spatial memory (Morris hidden water maze; ). Here we monitored the mice generated in our previous study and found no difference in their longevity.
Fang Yang, Ye-Chun Ruan, Yun-jie Yang, Kai Wang, Shan-shan Liang, Yi-bin Han, Xiao-Ming Teng, and Jian-Zhi Yang
Women with polycystic ovary syndrome (PCOS) undergoing IVF–embryo transfer based-assisted reproductive technology (ART) treatment show variable ovarian responses to exogenous FSH administration. For better understanding and control of PCOS ovarian responses in ART, the present study was carried out to compare the follicular hormones and the expression of granulosa cell genes between PCOS and non-PCOS women during ART treatment as well as their IVF outcomes. Overall, 138 PCOS and 78 non-PCOS women were recruited for the present study. Follicular fluid collected from PCOS women showed high levels of testosterone. The expression of aromatase was found significantly reduced in luteinized granulosa cells from PCOS women. In cultured luteinized granulosa cells isolated from non-PCOS women, their exposure to testosterone at a level that was observed in PCOS follicles could decrease both mRNA and protein levels of aromatase in vitro. The inhibitory effect of testosterone was abolished by androgen receptor antagonist, flutamide. These results suggest that the hyperandrogenic follicular environment may be a key hazardous factor leading to the down-regulation of aromatase in PCOS.
Lorna G Moore
High altitude offers a natural laboratory for studying the effects of chronic hypoxia on reproductive health. Counter to early accounts, fertility (the number of livebirths) appears little affected although stillbirths are more common. Birth weights are lower due to fetal growth restriction, not shortened gestation. Multigenerational (Andean or Tibetan) compared with newcomer residents appear relatively protected from pregnancy loss as well as altitude-associated fetal growth restriction, perhaps due in part to preservation of the normal rise in uterine artery blood flow. Myometrial artery vasodilator response, a key determinant of uterine blood flow, is blunted in healthy Colorado high-altitude residents, similar to what occurs in intrauterine growth restriction or preeclampsia at low altitude. The high-altitude vessels are also more sensitive to the vasodilatory actions of AMP kinase (AMPK) activation. The gene region containing PRKAA1 (coding for AMPK’s alpha-1 catalytic subunit) has been acted upon by natural selection in Andeans and is related to preservation of normal blood flow and fetal growth at high altitude, suggesting one mechanism by which high-altitude adaptation may have been achieved. Preeclampsia is more common at high altitudes but unknown is whether multigenerational residents are protected relative to newcomers. Postnatal loss is diminished in Tibetans vs Han with equal access to health care, perhaps due in part to better maintained arterial O2 saturation during infancy. Finally, pregnancy and intrauterine development not only affect immediate survival but also susceptibility to the later-in-life cardiovascular disease, chronic mountain sickness.
DELPHINE M. V. PARROTT
Normal offspring were obtained from mice with orthotopic ovarian grafts of tissue that had been frozen and stored at —79° C. Tissue so treated showed a remarkable capacity for reorganization and function, but the number of oocytes surviving was small and the reproductive life of the females bearing the grafts was curtailed in each of the four strains of mice used.
The most successful method of preservation involved soaking the tissue for 30 to 40 min in a medium consisting of 12% glycerol in horse serum before slow cooling to — 79° C. Oocyte destruction was increased when the concentration of glycerol was reduced to 8%, when the tissue was soaked for 1 to 2 hr in 15% glycerol in horse serum, and when the tissue was stored at —79° C for longer than 24 hr. Soaking in glycerol solutions at room temperature for 1½ hr without subsequent freezing also eliminated many oocytes. No viable grafts were obtained after `twostage' rapid cooling.
Preservation of the fertility of mice with grafts of ovarian tissue has proved to be more difficult than maintenance of cyclic cornification of the vagina. The problems involved are discussed.