Feed items

Oncofertility: ethical, legal, social, and medical perspectives. Preface.

Oncofertility: ethical, legal, social, and medical perspectives. Preface.

Cancer Treat Res. 2010;156:v-vii

Authors: Woodruff TK, Zoloth L, Campo-Engelstein L, Rodriguez S

PMID: 21213472 [PubMed - indexed for MEDLINE]

In vitro oocyte maturation and preantral follicle culture from the luteal-phase baboon ovary produce mature oocytes.

In vitro oocyte maturation and preantral follicle culture from the luteal-phase baboon ovary produce mature oocytes.

Biol Reprod. 2011 Apr;84(4):689-97

Authors: Xu M, Fazleabas AT, Shikanov A, Jackson E, Barrett SL, Hirshfeld-Cytron J, Kiesewetter SE, Shea LD, Woodruff TK

Abstract

Female cancer patients who seek fertility preservation but cannot undergo ovarian stimulation and embryo preservation may consider 1) retrieval of immature oocytes followed by in vitro maturation (IVM) or 2) ovarian tissue cryopreservation followed by transplantation or in vitro follicle culture. Conventional IVM is carried out during the follicular phase of menstrual cycle. There is limited evidence demonstrating that immature oocyte retrieved during the luteal phase can mature in vitro and be fertilized to produce viable embryos. While in vitro follicle culture is successful in rodents, its application in nonhuman primates has made limited progress. The objective of this study was to investigate the competence of immature luteal-phase oocytes from baboon and to determine the effect of follicle-stimulating hormone (FSH) on baboon preantral follicle culture and oocyte maturation in vitro. Oocytes from small antral follicle cumulus-oocyte complexes (COCs) with multiple cumulus layers (42%) were more likely to resume meiosis and progress to metaphase II (MII) than oocytes with a single layer of cumulus cells or less (23% vs. 3%, respectively). Twenty-four percent of mature oocytes were successfully fertilized by intracytoplasmic sperm injection, and 25% of these developed to morula-stage embryos. Preantral follicles were encapsulated in fibrin-alginate-matrigel matrices and cultured to small antral stage in an FSH-independent manner. FSH negatively impacted follicle health by disrupting the integrity of oocyte and cumulus cells contact. Follicles grown in the absence of FSH produced MII oocytes with normal spindle structure. In conclusion, baboon luteal-phase COCs and oocytes from cultured preantral follicles can be matured in vitro. Oocyte meiotic competence correlated positively with the number of cumulus cell layers. This study clarifies the parameters of the follicle culture system in nonhuman primates and provides foundational data for future clinical development as a fertility preservation option for women with cancer.

PMID: 21123815 [PubMed - indexed for MEDLINE]

Results from the survey for preservation of adolescent reproduction (SPARE) study: gender disparity in delivery of fertility preservation message to adolescents with cancer.

Results from the survey for preservation of adolescent reproduction (SPARE) study: gender disparity in delivery of fertility preservation message to adolescents with cancer.

J Assist Reprod Genet. 2011 Mar;28(3):269-77

Authors: Köhler TS, Kondapalli LA, Shah A, Chan S, Woodruff TK, Brannigan RE

Abstract

PURPOSE: Diminished reproductive capacity is a devastating consequence of life-sparing therapies for childhood malignancy. In 2006, the American Society of Clinical Oncology (ASCO) published fertility preservation recommendations (ASCOR) emphasizing the importance of early discussion and intervention for fertility preservation strategies. Using the Survey for Preservation of Adolescent REproduction (SPARE), we sought to determine fertility preservation attitudes and practice patterns post-ASCOR from pediatric oncology specialists nationwide.

MATERIALS AND METHODS: The SPARE survey consists of 22 questions assessing pediatric oncology specialists' attitudes and practice patterns toward fertility preservation. Broad perspectives on fertility preservation, including a willingness to discuss fertility, knowledge of current fertility preservation methods and awareness of ASCOR, were assessed.

RESULTS: The majority of respondents acknowledged that fertility threats are a major concern for them and agreed that all pubertal cancer patients should be offered a fertility consultation, but only 46% reported they refer male pubertal cancer patients to a fertility specialist prior to cancer treatment >50% of the time, and only 12% reported they refer female pubertal cancer patients to a fertility specialist prior to cancer treatment > 50% of the time. While 44% of respondents were familiar with the 2006 ASCOR, only 39% of those utilized them to guide decision-making in greater than half of their patients.

CONCLUSION: Our study demonstrates pediatric oncologists' motivation to preserve fertility in pediatric cancer patients; however, barriers to both gamete cryopreservation and referral to fertility specialists persist. Female pubertal patients are referred to fertility preservation specialists with much less frequency than are male pubertal patients, highlighting a disparity.

PMID: 21110080 [PubMed - indexed for MEDLINE]

Zinc requirement during meiosis I-meiosis II transition in mouse oocytes is independent of the MOS-MAPK pathway.

Zinc requirement during meiosis I-meiosis II transition in mouse oocytes is independent of the MOS-MAPK pathway.

Biol Reprod. 2011 Mar;84(3):526-36

Authors: Bernhardt ML, Kim AM, O'Halloran TV, Woodruff TK

Abstract

Zinc is essential for many biological processes, including proper functioning of gametes. We recently reported that zinc levels rise by over 50% during oocyte maturation and that attenuation of zinc availability during this period could be achieved using the membrane-permeable heavy metal chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN). This zinc insufficiency resulted in formation of large polar bodies, failure to establish metaphase II arrest, and impaired establishment of cortical polarity. As these phenotypes resemble those of MOS null oocytes, we examined the impact of zinc insufficiency on the MOS-MAPK pathway. Reduced levels of both MOS protein and phosphorylation of MAP2K1/2 are observed in zinc-insufficient oocytes; however, these differences appear only after completion of the first meiotic division. In addition, activation of the downstream effector of the MOS pathway, MAPK3/1, is not affected by zinc insufficiency, and reduced MOS levels are observed only with the presence of TPEN after the first polar body extrusion. These data are inconsistent with the hypothesis that reduced MOS mediates the observed phenotype. Finally, MOS overexpression does not rescue the phenotype of zinc-insufficient oocytes, confirming that the observed disruption of asymmetric division and spindle abnormalities cannot be attributed to impaired MOS signaling. Zinc-insufficient oocytes do not increase maturation promoting factor (MPF) activity following the first meiotic division, and increasing MPF activity through expression of nondegradable cyclin B1 partially rescues the ability of zinc-insufficient oocytes to enter metaphase II. Although we have shown that zinc has a novel role in the meiotic cell cycle, it is not mediated through the MOS-MAPK pathway.

PMID: 21076080 [PubMed - indexed for MEDLINE]

Research funding. Politics and parthenotes.

Research funding. Politics and parthenotes.

Science. 2010 Oct 22;330(6003):453

Authors: Tingen C, Rodriguez S, Campo-Engelstein L, Woodruff TK

PMID: 20966235 [PubMed - indexed for MEDLINE]

A new hypothesis regarding ovarian follicle development: ovarian rigidity as a regulator of selection and health.

A new hypothesis regarding ovarian follicle development: ovarian rigidity as a regulator of selection and health.

J Assist Reprod Genet. 2011 Jan;28(1):3-6

Authors: Woodruff TK, Shea LD

Abstract

The mammalian ovary consists of a large number of dormant immature follicles, each containing a single oocyte and located on the periphery of the ovary. With each reproductive cycle, a group of immature follicles is sequentially activated to resume growth, and pituitary gonadotropins and ovarian steroid and peptide hormones cooperate to ensure further growth and development. A single dominant follicle eventually emerges, ovulates, and then involutes to allow the selection of the next group of follicles. While hormones are known to control the later stages of folliculogenesis, little is known about the pathways that activate individual immature primordial follicles in the dormant follicle pool. We advance a new hypothesis: that follicle activation is dependent on the physical environment of the ovary in addition to well-established hormonal cues. This novel perspective on ovarian function may provide new avenues to study follicle dynamics and identify therapeutic targets for ovarian dysfunction.

PMID: 20872066 [PubMed - indexed for MEDLINE]