The majority of countries that support the use of donor insemination (DI) in artificial reproductive technology (ART) limit the number of children born from one donor. The setting of these donor limits, though intended to control for the risk of inadvertent half-sibling unions between the offspring of anonymous donors, actually have no evidence base. Controlling for the risk of inadvertent half-sibling unions may soon become unnecessary due to the increasing world-wide use of open-identity sperm donors and the revocation of donor anonymity in many countries. With the shift from anonymous to open-identity donation, the central issue is not the risk of genetic abnormality from inadvertent half-sibling consanguinity; it is the psycho-social impact of the multiple use of open-identity sperm donors. Despite this, the jurisdictions that allow or mandate the use of open-identity donors continue to observe existing limits that do not consider nor specifically control for the psycho-social impact of the multiple use of open-identity sperm donors. It is proposed that: (i) conservative interim donor limits be placed on the multiple use of open-identity donors, while research into the psycho-social impact of disclosure is undertaken to inform the establishment of evidence-based limits; and (ii) the existing limits in jurisdictions where anonymity is still commonly practiced or protected could be raised, if an updated mathematical model was used for calculating evidence-based anonymous donor limits.

Recommendation and review posted by G. Smith

BACKGROUND

The use of quarantined cryopreserved semen is mandatory in donor insemination programs. Whether sperm cells can survive and retain their ability to fertilize after long-term storage remains a controversial issue. The objective of this study was to determine the effect of the duration of cryostorage in liquid nitrogen on the sperm cells’ progressive motility concentration (PMC) in a large study group.

METHODS

A total of 2525 thawed sperm specimens, packed in straws and donated by 72 sperm bank donors for intrauterine insemination (IUI), were evaluated in an assisted reproduction institute. PMC was recorded after 0.5–14.4 years of cryostorage.

RESULTS

The mean (±SD) value of PMC of all study samples was 10.8 ± 3.3 x 10⁶/ml after freezing/thawing and before cryostorage (T0), and 12.3 ± 2.9 x 10⁶/ml after storage and before using the specimen for IUI (T1, P < 0.0001). Specimen storage for different lengths of time revealed that storage duration had no significant influence on the PMC of the specimens (r = –0.03, P = 0.08). The PMC of partially filled straws was lower than in full straws. Cryostorage duration made no difference in the PMC of raw and washed sperm specimens.

CONCLUSION

Prolonged storage of donated sperm in liquid nitrogen had no influence on the PMC of the specimens and therefore should not alter the fertilization potency of donated sperm. The high post-storage values of the PMC compared with the pre-storage PMC values was probably an artifact of the small volume of the pre-storage sample.

Recommendation and review posted by G. Smith

BACKGROUND

A key step in studying the biology of spermatogonia is to determine their global gene expression profile. However, disassociation of these cells from the testis may alter their profile to a considerable degree. To characterize the molecular phenotype of human spermatogonia, including spermatogonial stem cells (SSCs), within their cognate microenvironment, a rare subtype of human defective spermatogenesis was exploited in which spermatogonia were the only germ cell type.

METHODS

The global expression profile of these samples was assessed on the Affymetrix microarray platform and compared with tissues showing homogeneous Sertoli-cell-only appearance; selected genes were validated by quantitative real-time PCR and immunohistochemistry on disparate sample sets.

RESULTS

Highly significant differences in gene expression levels correlated with the appearance of spermatogonia, including 239 best candidates of human spermatogonially expressed genes. Specifically, fibroblast growth factor receptor 3 (FGFR3), desmoglein 2 (DSG2), E3 ubiquitin ligase c-CBL (casitas B-cell lymphoma), cancer/testis antigen NY-ESO-1 (CTAG1A/B), undifferentiated embryonic cell transcription factor 1 (UTF1) and synaptosomal-associated protein, 91 kDa homolog (SNAP91) were shown to represent specific biomarkers of human spermatogonia.

CONCLUSIONS

These biomarkers, specifically the surface markers FGFR3 and DSG2, may facilitate the isolation and enrichment of human stem and/or progenitor spermatogonia and thus lay a foundation for studies of long-term maintenance of human SSCs/progenitor cells, spermatogonial self-renewal, clonal expansion and differentiation.

Recommendation and review posted by G. Smith

BACKGROUND

Grafting of testicular tissue into immunodeficient mice has been used to differentiate the neonatal testes from different animal species up to the level of complete spermatogenesis; however, this approach has not been successful for human testicular tissue. The aim of this study was to evaluate the capacity for differentiation of infant human testicular tissue grafts.

METHODS AND RESULTS

Testicular tissue from a 3-month-old patient with testicular cancer was grafted into immunodeficient nude mice. At the time of grafting, A spermatogonia were the only germ cells present in the testicular tissue. B spermatogonia and first spermatocytes were observed at 7 months and 1 year after grafting, respectively. Positive immunostaining with antibodies against BOULE and CDC25A suggested that spermatocytes in the graft were not arrested but in meiosis. Furthermore, ultrastructural and immunohistochemical analyses showed that the onset of both Sertoli cell maturation and partial differentiation of Leydig cells preceded the appearance of spermatocytes. Differentiation of testicular cells was accelerated compared with in vivo development.

CONCLUSIONS

Spermatogenesis in the xenograft of infant human testicular tissues proceeded successfully from the stage of spermatogonial stem cells until pachytene spermatocyte formation. The differentiation of Sertoli cells and Leydig cells was reproduced in a manner similar to that in normal testicular development. Grafting of infant human testicular tissue may be a powerful tool to examine the early period of human spermatogenesis and may pave the way for fertility preservation among infant patients.

Recommendation and review posted by G. Smith

BACKGROUND

Obesity has been identified as a risk factor for spontaneous miscarriage although the mechanism is unclear. The purpose of this study is to better understand the effect of obesity on early pregnancy success by examining the cytogenetic results of miscarriages in women with normal and elevated body mass index (BMI).

METHODS

We conducted a retrospective case–control study in an academic infertility practice. Medical records of women ages <40 years with first trimester missed abortion (n = 204), who underwent dilatation and curettage between 1999 and 2008, were reviewed for demographics, BMI, diagnosis of polycystic ovary syndrome (PCOS) and karyotype analysis. ² and Student's t-test analysis were used for statistical analysis, with P < 0.05 considered significant.

RESULTS

A total of 204 miscarriages were included, from women with a mean age of 34.5 years. The overall rate of aneuploidy was 59%. Women with BMI ≥ 25 kg/m² had a significant increase in euploid miscarriages compared with women with lower BMI (P = 0.04), despite a similar mean age (34.4 years for both).

CONCLUSIONS

We found a significant increase in normal embryonic karyotypes in the miscarriages of overweight and obese women (BMI ≥ 25). These results suggest that the excess risk of miscarriages in the overweight and obese population is independent of embryonic aneuploidy. Further studies are needed to assess the impact of lifestyle modification, insulin resistance and PCOS on pregnancy outcomes in the overweight and obese population.

Recommendation and review posted by G. Smith

BACKGROUND

Routes of trophoblast invasion seem to be clear, whereas specific invasive pathways need further elucidation. Extravillous trophoblasts (EVTs) transform spiral arteries to guarantee appropriate blood flow to the placenta in the second trimester. Embryo nutrition during the first trimester is thought to be histiotrophic, whereas proof that EVTs also invade uterine glands is lacking. We developed novel three-dimensional confrontation co-culture models to elucidate invasion of EVTs into uterine glands.

METHODS

First trimester decidua parietalis and placental villous explants were directly confronted and co-cultured for 72 h, or confronted indirectly after 72 h pre-culture for re-epithelialization of decidua pieces. Cryosections were stained by immunohistochemistry or immunofluorescent/immunohistochemical double labelling and compared with first trimester placentation sites in situ.

RESULTS

EVTs deeply invaded decidual tissues in direct confrontation assays and were found between the decidual epithelial cells and epithelial basement membrane. EVTs were also detected in the decidual stroma in direct proximity to glands, sometimes even replacing glandular epithelial cells. Similar observations were made in sections from the first trimester decidua/placental bed. In the invaded parts of sections of decidua basalis, 55% ± 7% (mean ± SEM; n = 10, range 6–11 weeks) of glandular cross sections were associated with or infiltrated by EVTs.

CONCLUSIONS

Using novel confrontation co-culture assays, a potential new route of EVT invasion was detected. EVTs appear to break through the basement membrane of uterine glands to open their lumen towards the intervillous space. These data support the hypothesis of histiotrophic nutrition of the embryo prior to onset of maternal blood flow within the placenta.

Recommendation and review posted by G. Smith