Category Archives: Human Reproduction

BACKGROUND

Since prepubertal boys cannot benefit from sperm banking, a potential alternative strategy for fertility preservation involves immature testicular tissue (ITT) banking aimed at preservation of spermatogonial stem cells. Survival of spermatogonia has been demonstrated after ITT freezing, which is considered ethically acceptable. We report the results of a pilot program set up for fertility preservation in prepubertal boys.

METHODS

All boys undergoing ITT cryobanking from May 2005 were identified from our clinical register. Data were collected from medical files.

RESULTS

Testicular tissue was retrieved from 52 prepubertal patients under 12 years of age and 10 peripubertal patients aged between 12 and 16 years, in whom no spermatozoa were identified in testicular biopsies. Malignant disease accounted for 80.6% of cases; the remaining patients suffered from benign disorders requiring gonadotoxic treatments. Mean ages, Tanner stages and occurrence rates of urogenital pathology were 6.43 ± 3.32 and 14 ± 1.23 years, I and I–IV, and 13.5 and 20% for pre- and peripubertal patients, respectively. Mean volumes of removed tissue were 20.1 ± 8.6 and 42.4 ± 15.6 mm³ for pre- and peripubertal patients, respectively. No complications occurred during or after tissue retrieval and 93.5% of referred patients accepted ITT storage. The presence of spermatogonia, and thus the potential for later tissue use, was established in all of these patients.

CONCLUSIONS

The majority of cryopreserved samples showed reproductive potential. Storage was accepted by most parents. All parents and children considered this fertility preservation strategy a positive approach.

OBJECTIVE

Cryopreservation of supernumerary embryos resulting from IVF treatment offers extra chances to conceive. The objective of this study is to describe patients’ decisions to continue or discontinue storage of their embryos after a minimum storage period of 2 years.

METHODS

Female patients who had embryos stored at the Infertility Centre of the Ghent University Hospital (Belgium) were sent a mail questionnaire to be completed anonymously.

RESULTS

The questionnaire had a response rate of 79% (326/412). After an embryo storage period of at least 2 years, 40% of the couples who were still together wished to continue storage of their embryos. Half of these had no concrete plans for a transfer and wanted to postpone the decision or keep all options open. For those who decided to discontinue storage (60%), the main reason was the completion of their families. Despite the fact that the patients’ child wish was the main factor in their storage decision, two groups of patients with distinct profiles made decisions that were inconsistent with their child wish: those who wanted to continue storage while not wanting a(nother) child (7% of those with no child wish), and those who wanted a(nother) child but decided to discontinue storage (25% of those with a child wish). Overall, these patients more often expressed emotional difficulties regarding this decision.

CONCLUSIONS

This study demonstrates the importance of gaining more insight into patients’ embryo storage decisions (along with their embryo disposition decisions) and into the emotional factors playing a role in patients’ decision-making.

BACKGROUND

Two decades after the introduction of Swedish legislation that allows children born as a result of gamete donation access to identifying information about the donor, a nationwide multicentre study on the psychosocial consequences of this legislation for recipients and donors of gametes was initiated in 2005. The aim of the present study was to investigate recipient couples’ attitudes and behaviour regarding disclosure to offspring and others, attitudes towards genetic parenthood and perceptions of information regarding parenthood after donation.

METHODS

The present study is part of the prospective longitudinal ‘Swedish study on gamete donation', including all fertility clinics performing donation treatment in Sweden. A consecutive cohort of 152 heterosexual recipient couples of donated oocytes (72% response) and 127 heterosexual recipient couples of donated sperm (81% response) accepted participation in the study. In connection with the donation treatment, male and female participants individually completed two questionnaires with study-specific instruments concerning disclosure, genetic parenthood and informational aspects.

RESULTS

About 90% of participants (in couples receiving anonymous donated gametes) supported disclosure and openness to the offspring concerning his/her genetic origin. Only 6% of all participants had not told other people about their donation treatment. Between 26 and 40% of participants wanted additional information/support about parenthood following donation treatment.

CONCLUSIONS

Two decades after the Swedish legislation of identifiable gamete donors, recipient couples of anonymously donated sperm and oocytes are relatively open about their treatment and support disclosure to offspring. Recipient couples may benefit from more information and support regarding parenthood after gamete donation. Further studies are required to follow-up on the future parents’ actual disclosure behaviour directed to offspring.

BACKGROUND

The first week of human embryonic development comprises a series of events that change highly specialized germ cells into undifferentiated human embryonic stem cells (hESCs) that display an extraordinarily broad developmental potential. The understanding of these events is crucial to the improvement of the success rate of in vitro fertilization. With the emergence of new technologies such as Omics, the gene expression profiling of human oocytes, embryos and hESCs has been performed and generated a flood of data related to the molecular signature of early embryo development.

METHODS

In order to understand the complex genetic network that controls the first week of embryo development, we performed a systematic review and study of this issue. We performed a literature search using PubMed and EMBASE to identify all relevant studies published as original articles in English up to March 2010 (n = 165). We also analyzed the transcriptome of human oocytes, embryos and hESCs.

RESULTS

Distinct sets of genes were revealed by comparing the expression profiles of oocytes, embryos on Day 3 and hESCs, which are associated with totipotency, pluripotency and reprogramming properties, respectively. Known components of two signaling pathways (WNT and transforming growth factor-β) were linked to oocyte maturation and early embryonic development.

CONCLUSIONS

Omics analysis provides tools for understanding the molecular mechanisms and signaling pathways controlling early embryonic development. Furthermore, we discuss the clinical relevance of using a non-invasive molecular approach to embryo selection for the single-embryo transfer program.

BACKGROUND

Pluripotent stem cells have been derived from a variety of sources such as from the inner cell mass of preimplantation embryos, from primordial germ cells, from teratocarcinomas and from male germ cells. The recent development of induced pluripotent stem cells demonstrates that somatic cells can be reprogrammed to a pluripotent state in vitro.

METHODS

This review summarizes our current understanding of the origins of mouse and human pluripotent cells. We pay specific attention to transcriptional and epigenetic regulation in pluripotent cells and germ cells. Furthermore, we discuss developmental aspects in the germline that seem to be of importance for the transition of germ cells towards pluripotency. This review is based on literature from the Pubmed database, using Boolean search statements with relevant keywords on the subject.

RESULTS

There are distinct molecular mechanisms involved in the generation and maintenance of the various pluripotent cell types. Furthermore, there are important similarities and differences between the different categories of pluripotent cells in terms of phenotype and epigenetic modifications. Pluripotent cell lines from various origins differ in growth characteristics, developmental potential, transcriptional activity and epigenetic regulation. Upon derivation, pluripotent stem cells generally acquire new properties, but they often also retain a ‘footprint’ of their tissue of origin.

CONCLUSIONS

In order to further our knowledge of the mechanisms underlying self-renewal and pluripotency, a thorough comparison between different pluripotent stem cell types is required. This will progress the use of stem cells in basic biology, drug discovery and future clinical applications.

BACKGROUND

Implantation is a complex initial step in the establishment of a successful pregnancy. Although embryo quality is an important determinant of implantation, temporally coordinated differentiation of endometrial cells to attain uterine receptivity and a synchronized dialog between maternal and embryonic tissues are crucial. The exact mechanism of implantation failure is still poorly understood.

METHODS

This review summarizes the current knowledge about the proposed mechanisms of implantation failure in gynecological diseases, the evaluation of endometrial receptivity and the treatment methods to improve implantation.

RESULTS

The absence or suppression of molecules essential for endometrial receptivity results in decreased implantation rates in animal models and gynecological diseases, including endometriosis, hydrosalpinx, leiomyoma and polycystic ovarian syndrome. The mechanisms are diverse and include abnormal cytokine and hormonal signaling as well as epigenetic alterations.

CONCLUSIONS

Optimizing endometrial receptivity in fertility treatment will improve success rates. Evaluation of implantation markers may help to predict pregnancy outcome and detect occult implantation deficiency. Treating the underlying gynecological disease with medical or surgical interventions is the optimal current therapy. Manipulating the expression of key endometrial genes with gene or stem cell-based therapies may some day be used to further improve implantation rates.