Female fertility loss and preservation: threats and opportunities.

BACKGROUND: Ovarian aging and cytotoxic treatments are the most common causes for fertility loss in women. With increasing numbers of young female survivors following cytotoxic cancer treatments, the issue of fertility preservation has assumed greater importance. METHODS: We review the literature on the causes of female fertility loss as well as the recent advances in fertility preservation options and strategies that might be of interest to oncologists. Currently, several methods and techniques exist for fertility preservation of female patients with cancer including embryo freezing, ovarian protection techniques, oocyte cryopreservation, ovarian tissue cryopreservation followed by autotransplantation, and recently in vitro culture of ovarian tissue, follicles, and oocytes. Each method or technique has advantages and disadvantages related to current success rate, required delay in cancer treatment, sperm requirement, and risk of reintroducing cancer cells. RESULTS: To date, embryo freezing is the only established method successfully and widely used for fertility preservation of female patients with cancer. The other methods are promising but still considered experimental. CONCLUSION: Patient awareness, physician knowledge, early counseling, costs management, international registry, interdisciplinary networks, and research development are necessary to improve the current care in the field of female fertility preservation.

Cytoskeletal characterization of a neuroectodermal cell line and embryonic mouse brain.

The cytoskeleton of a newly isolated mouse embryo brain-derived cell line and of dissected mesencephalon-rhombencephalon samples of the 10- to 11-day-old mouse embryo, constituted of a ventricular zone only, has been examined by immunocytochemistry, electrophoretic separation and Western blotting techniques. In accordance with their epithelial organization, the ventricular cells contain cytokeratins as main constituents of their cytoskeleton. Vimentin has been also revealed as early as day 10.5 of gestation. The complex cytokeratin polypeptide pattern puts this histological type of epithelia into the category of complex, rather than simple, epithelia and calls for explanations other than keratinization for the presence and functional role of the high-molecular weight, basic keratins. The cytoskeletal composition of the embryo brain-derived gliogenic cell line reflects the vimentin- and cytokeratin-positive character of the ventricular cells.

Protein synthesis in embryonic tissues during mouse postimplantation development.

Mouse embryos of the NMRI strain between the 7th and 9th day of gestation were isolated from the uterus and dissected into the various tissue derivatives in order to investigate newly synthesized proteins during morphogenesis. The day 7 embryo was fragmented into trophoblast and ectoplacental cone, distal and proximal endoderm, extraembryonic and embryonic ectoderm. The day 8 and day 9 embryos were divided into trophoblast and placental anlage, yolk sac, amnion, and allantois, as well as cranial, central, and caudal embryonic tissue. The intact embryos were incubated in Dulbecco's minimum essential medium in the presence of 35S-methionine for 4 h, then dissected into the various fragments, and further processed for two-dimensional gel electrophoresis. Protein synthesis of the isolated tissue derivatives was analyzed and compared for the three developmental stages. Concerning the proteins with isoelectric points in the range of 4.5 to 8.0 and molecular weight ratio (M(r)) values between 20,000 and 200,000, we found several significant quantitative and qualitative differences in the various tissue fragments. In addition, we observed further quantitative and qualitative differences in protein synthesis during the postimplantation period investigated. We propose that the differences reflect some of the cell lineage- and developmental stage-specific changes in gene expression during early mammalian differentiation.

Different protein patterns derived from follicular fluid of mature and immature human follicles.

The purpose of our study was to compare the protein patterns originating from fluids of mature and immature human follicles in order to gain further insight into their biochemical composition. A total of 10 patients were stimulated for in-vitro fertilization (IVF) using different stimulation protocols. Follicular fluids were aspirated transvaginally and analysed microscopically for the presence of oocytes. Follicular fluids were stored at -18 degrees C. Samples of 500 microliters were processed for two-dimensional gel electrophoresis. Up to 60 proteins in various groups could be detected. Seven protein spots were selected for chemical analysis by cutting them out of the gels and subjecting them to internal amino acid sequencing procedures. Our results can be summarized as follows: (i) major differences were not detected between the protein patterns from the various mature follicles of a particular patient, nor were significant differences observed in the proteins derived from follicular fluids collected from the seven patients with mature follicles; (ii) considerable differences were observed in the protein patterns derived from fluids of immature compared with mature follicles. Fluid from the three patients with immature follicles contained many fewer proteins, some of which were expressed at low levels. We conclude that the observed variations in protein composition of follicles of different developmental age reflect their physiological condition and serve as biomedical markers for follicular maturity.

Protein synthesis in murine organs during postimplantation development detected by two-dimensional gel electrophoresis.

Mouse embryos were isolated from the uterus on days 10 to 11 of gestation and incubated in Dulbecco's modified Eagle's medium (DMEM) with [35S]methionine for 4 h. Subsequently, their hearts and the brains were dissected. The brain was divided into three parts, containing the telencephalon, mesencephalon, and myelencephalon. These tissues were then processed for two-dimensional (2-D) gel electrophoresis. Protein synthesis of the isolated tissues was analyzed for organ-and cell lineage-specific patterns. We studied proteins with isoelectric points (pI) ranging from 4 to 10 and relative molecular weights (M(r)) varying from 10000 to 200000 and found several significant quantitative and qualitative differences between the tissues and the developmental stages analyzed. In particular, we were able to distinguish between protein spots that we now attribute putatively to the corresponding embryonic organs. These differences may reflect some of the organ- and cell lineage-specific changes in protein synthesis and gene expression during early mammalian differentiation.

Comparison of protein analysis between embryonic and extraembryonic tissues during the 11th day of gestation of the mouse.

At day 11 of gestation, embryos and their extraembryonic tissues were isolated from the uterus of Him OF1/SPF mice and incubated in Dulbecco's modified Eagle's medium (DMEM) containing L-[35S]methionine. After 4 h of incubation, the embryos were dissected to obtain the heart, liver, limb buds, and brain. The latter was fragmented into the telencephalon, mesencephalon, and myelencephalon. These organs and the extraembryonic tissues such as chorion, yolk sac, and placenta were processed for two-dimensional (2-D) gel electrophoresis. About 1000 proteins with relative molecular weights (M(r) varying from 10,000 to 200,000 and isoelectric points ranging from 4 to 10 could be detected on these gels. The protein patterns of the various organs and tissues were analyzed for organ- and cell lineage-specific protein spots. We detected subtle differences in the protein patterns of the three cerebral areas when compared to each other. In addition, we found protein spots characteristic for the entire brain. We also found several heart-specific protein spots. Distinct protein synthesis was also detected in liver and limb buds. Several groups of protein spots seem to be differentially regulated in these organs. Substantial differences between the patterns of embryonic and extraembryonic tissues were observed. In addition, several clusters of protein spots of well-defined molecular weight could be detected only in extraembryonic tissues. We propose that organ- and tissue-specific differences in protein synthesis are linked to some of the morphogenetic and functional processes during mammalian embryogenesis. Identification of particular proteins will serve as a basis to search for the corresponding genes.