A demographic projection of the contribution of assisted reproductive technologies to world population growth.

Enormous unmet needs for infertility treatment exist because access to assisted reproductive technologies is demographically skewed. Since the first IVF baby in 1978, the number of people conceived by reproductive technology has grown much faster than expected, reaching several million today and rapidly approaching 0.1% of the total world population.

Jean Marian Purdy remembered - the hidden life of an IVF pioneer.

Jean Purdy is almost forgotten as one of the British trio that introduced clinical IVF to the world. An unlikely pioneer, she qualified as a nurse but through indefatigable effort and unstinting loyalty to a programme that faced vitriolic opposition she became the clinical embryologist for the first IVF baby. In 1980, she helped to launch fertility services as the 'Technical Director' of Bourn Hall Clinic, near Cambridge.

General principles of cryopreservation.

Cryopreservation quickly became a cornerstone technology in assisted reproduction because the banking of gametes, embryos, and gonadal tissues has increased the effectiveness of assisted reproductive technology cycles for infertility treatment as well as fertility preservation for patients at risk of premature sterilization. Cryopreservation protocols, both slow/equilibrium cooling and vitrification methods, have evolved empirically and still depend heavily on operator skill, but further automation promises to improve reproducibility and uniformity of results.

Oocyte development and loss.

Soon after implantation, cell lineages bifurcate into future somatic and germ cells. Canonical expression of germ cell-specific genes continues during and after their migration to the gonadal ridge, where, after further cell cycles, they enter meiosis, form syncytial clusters, and arrest at diplotene for folliculogenesis. The balance between cell survival and death leaves an ovarian follicular reserve as a legacy.

Memoir of fertility preservation.

Fertility preservation has been practiced for at least 50 years using semen banking, pelvic surgery, and radiation shields, but in the past 20 years it has emerged as a rapidly growing subspecialty of reproductive medicine. A dramatic rise in survivorship of young cancer patients and the widespread postponement of family building to the later years of the female reproductive lifespan have been major driving forces. Throughout the history of fertility preservation, low temperature banking has played a pivotal role, first for gametes and later for embryos and immature germ cells, while ovarian transplantation recently began to contribute and spermatogonial stem cell transfer holds future promise for men and prepubertal boys.

Programmes and prospects for ovotechnology.

Oocytes hold enormous significance in biology, pathology and ageing, but they are exceedingly rare cells in adults. According to a theory almost universally held until recently, expansion of the germline is halted perinatally when oogonial stem cells differentiate to form to primordial follicles. Thus, there is a finite follicle store which becomes exhausted around the time of menopause because the great majority is lost by atresia instead of undergoing ovulation.

Eggs come in from the cold.

Eggs can be 'forever'. A longstanding goal in assisted reproductive technology (ART) has been realized at last, namely, cryopreservation of oocytes by vitrification technology. This breakthrough heralds benefits for infertility treatment, fertility preservation, and even postponement of reproduction but, as so often with ARTs, new waves of technology draw ethical and societal concerns in their wake.

Imatinib mesylate at therapeutic doses has no impact on folliculogenesis or spermatogenesis in a leukaemic mouse model.

Imatinib should be avoided in women planning to become pregnant or during pregnancy, due to a higher risk of congenital malformations. However, it is not known whether imatinib affects future potential for fertility. Here we analysed ovaries and testes from adult mice receiving imatinib, focusing on testicular and ovarian functions.

Cryopreservation: a cold look at technology for fertility preservation.

Objective: To outline the history of cryopreservation technology and its contributions to reproductive medicine, including fertility preservation.

Design: A search of the relevant literature using Medline and other online tools.

Setting: Research and laboratory protocol development.

Regulation of mouse oocyte microtubule and organelle dynamics by PADI6 and the cytoplasmic lattices.

Organelle positioning and movement in oocytes is largely mediated by microtubules (MTs) and their associated motor proteins. While yet to be studied in germ cells, cargo trafficking in somatic cells is also facilitated by specific recognition of acetylated MTs by motor proteins. We have previously shown that oocyte-restricted PADI6 is essential for formation of a novel oocyte-restricted fibrous structure, the cytoplasmic lattices (CPLs).

Egg sharing for assisted conception: a window on oocyte quality.

The steep decline in both natural fertility and success after assisted reproduction treatment with increasing maternal age is universally recognized. Large variations in the developmental competence of oocytes collected are seen during assisted cycles,and a link between the biological competence of oocytes retrieved and age has been confirmed. Patients who require donated oocytes can benefit from egg sharing programmes, in which a proportion of oocytes collected from selected patients aged 35 years undergoing conventional assisted reproduction treatment are shared with a matched recipient.

In situ identification of follicles in ovarian cortex as a tool for quantifying follicle density, viability and developmental potential in strategies to preserve female fertility.

Background: Ovarian tissue cryopreservation, in combination with autotransplantation or long-term culture, has been proposed as a means of fertility preservation. However follicle density within ovarian cortex has a profound impact on the success of in vivo and in vitro systems designed to support follicle growth and restore fertility. The objective of this study was to investigate the dye neutral red (NR) as a tool to quantify follicle density in situ, without compromising follicle viability and developmental potential.

The Src homology 2 domain-containing adapter protein B (SHB) regulates mouse oocyte maturation.

SHB (Src homology 2 domain-containing adapter protein B) is involved in receptor tyrosine kinase signaling. Mice deficient in the Shb gene have been found to exhibit a transmission ratio distortion with respect to inheritance of the Shb null allele among offspring and this phenomenon was linked to female gamete production. Consequently, we postulated that Shb plays a role for oocyte biology and thus decided to investigate oocyte formation, meiotic maturation, and early embryo development in relation to absence of the Shb gene.

Portrait of an oocyte: our obscure origin.

Oocytes play a pivotal role in the cycle of human life. As we discuss here, after emerging from germline stem cells in the fetus, they grow in a follicular niche in which development is harmonized for timely ovulation and hormone secretion after puberty. Most human oocytes have poor developmental competence and are peculiarly vulnerable to chromosomal malsegregation, especially as women pass the optimal years of fertility and may begin to turn to assisted reproductive technologies (ARTs) and egg donation.

Robert T. Morris, M.D.--appreciation of an enlightened surgeon and pioneer of ovarian transplantation.

Objective: To show that ovarian transplantation is a promising strategy for preserving fertility in young women and children who have cryopreserved tissue before undergoing potentially sterilizing treatment for cancer and other conditions.

Conclusion: Credit for the first transplants is because of a forgotten pioneer, Robert Morris of New York, who was an innovative surgeon as well as a model clinical investigator over a century ago.

Duration of fertility after fresh and frozen ovary transplantation.

Objective: To evaluate the function of human ovarian transplants.

Design: Follow a series of fresh ovarian transplants for up to 5 years, and compare fresh and frozen ovarian tissue transplantation.

Setting: Tertiary referral community hospital.

Ovarian function 6 years after cryopreservation and transplantation of whole sheep ovaries.

Whole ovary cryopreservation and transplantation has been proposed as a method for preserving long-term ovarian function. This work reports ovarian function 6years post transplantation of frozen-thawed whole sheep ovaries. Three 9-month-old Assaf sheep underwent unilateral oophorectomy to provide organs for the experiments.

Character, distribution and biological implications of ice crystallization in cryopreserved rabbit ovarian tissue revealed by cryo-scanning electron microscopy.

Background: Ovarian tissue banking is an emerging strategy for fertility preservation which has led to several viable pregnancies after transplantation. However, the standard method of slow cooling was never rigorously optimized for human tissue nor has the extent and location of ice crystals in tissue been investigated. To address this, we used cryo-scanning electron microscopy (cryo-SEM) to study ice formation in cryopreserved ovarian tissue.