Biomarkers of Ovarian Reserve

The primary function of the female ovary is the production of a mature and viable oocyte capable of fertilization and subsequent embryo development and implantation. At birth, the ovary contains a finite number of oocytes available for folliculogenesis. This finite number of available oocytes is termed “the ovarian reserve”. The determination of ovarian reserve is important in the assessment and treatment of infertility. As the ovary ages, the ovarian reserve will decline. Infertility affects approximately 15%–20% of reproductive aged couples. The most commonly used biomarker assay to assess ovarian reserve is the measurement of follicle stimulating hormone (FSH) on day 3 of the menstrual cycle. However, anti-müllerian hormone and inhibin-B are other biomarkers of ovarian reserve that are gaining in popularity since they provide direct determination of ovarian status, whereas day 3 FSH is an indirect measurement. This review examines the physical tools and the hormone biomarkers used to evaluate ovarian reserve

Molecular and Cellular Mechanisms Underlying Preimplantation Embryo Development

Preimplantation embryo development refers to the maturation of a fertilized ovum to a blastocyst. This process is highly regulated and required for proper implantation of the blastocyst into the endometrium. During this phase, several tasks must be accomplished. The differentiated zygotic genome must undergo reprogramming back to totipotency in order to generate all of the different types of tissue making up a human. Next, certain cells begin to differentiate to prepare for implantation which occurs at approximately day 7 post-fertilization. This progression is a result of a careful interplay between maternally persistent RNA transcripts and activation of the zygotic genome. After the embryonic genome activation, blastomere differentiation begins to occur. Cellular polarity has been shown to be the signal transduction that initiates this differentiation. Understanding the molecular and cellular mechanisms regulating preimplantation embryo development is of fundamental importance for reproductive science and has numerous applications in fields such as assisted reproductive technology and stem cell therapy

Clinical Utilities of Anti-Müllerian Hormone

The anti-Müllerian hormone (AMH) plays an essential role in sex determination in early embryonic development. Through a series of sequential steps that follows inheriting an XY chromosome, Sertoli cell differentiation upregulates the expression of AMH-suppressing Müllerian duct development and maintains the AMH at a high level until puberty. In females, the AMH is produced by granulosa cells of follicles beginning in the second half of fetal life and continues through adulthood, with a steady decline through the reproductive years and severe decline at menopause, until levels eventually become undetectable. The AMH is essential for the regulation of follicular maturation via the recruitment of primordial follicles throughout folliculogenesis. AMH serum concentration in women strongly correlates with ovarian reserve quantity and reflects ovulation potential. Because the AMH is expressed almost exclusively by growing follicles before FSH-dependent selection, it commonly serves as a marker for ovarian function in various clinical situations, including in the diagnosis and pathogenesis of polycystic ovarian syndrome, artificial reproductive technology, and predictions of menopause or premature ovarian failure

Influences of in Vitro Oocyte Aging on Microfertilization in the Mouse With Reference to Zona Hardening

Our purpose was to investigate the influence of in vitro oocyte aging on fertilization and subsequent embryonic development following subzonal sperm injection with reference to spontaneous zona hardening in the mouse

Enhanced Embryo Development of Rabbit Oocytes Fertilized in Vitro With Platelet Activating Factor (PAF)-Treated Spermatozoa

The purpose of this study was to determine the effects of PAF treatment of rabbit spermatozoa on in vitro fertilization and subsequent blastocyst formation. Rabbit spermatozoa were exposed to PAF (10-7 M ), lyso-PAF (10-7 M ), or HIS (385 mOsm/kg) for 15 min prior to insemination of ovulated oocytes. Fertilized oocytes were cultured to the hatched blastocyst stage

Treatment of Sperm With High-Ionic Strength Medium Increases Microsurgical Fertilization Rates of Rabbit Oocytes Fertilized by Subzonal Placement of Sperm

This study was conducted to investigate the requirement for sperm processing in microsurgical subzonal placement of sperm in rabbit oocytes. Fertilization rates with standard in vitro fertilization and microsurgical subzonal sperm placement were found to be similar (56 and 55%) when sperm treated with high-ionic strength Brackett\u27s defined inedium to initiate capacitation were used. Statistically significant reductions in fertilization rates for both standard in vitro fertilization and subzonal placement were noted when twice-washed spermatozoa were used. Initiation of capacitation of spermatozoa results in higher fertilization results even when the zona pellucida is bypassed during fertilization

Survival and Cell Acquisition Rates After Preimplantation Embryo Biopsy: Use of Two Mechanical Techniques and Two Mouse Strains

Two strains of mouse embryos at the four- and eight-cell stages had biopsy specimens obtained by means of two different mechanical techniques: aspiration and displacement. Embryos and biopsy specimen cells were evaluated for survival and development. Blastomere acquisition rates were significantly higher with the displacement biopsy technique; however, no difference in survival or developmental rates was found in blastomere biopsy specimens removed from either four-cell or eight-cell embryos. A maximum of one blastomere can be removed from a four-cell embryo, whereas three blastomeres can be taken at biopsy from an eight-cell mouse embryo without significantly affecting embryo development, although mouse strain differences were noted. Intact, viable, biopsied blastomeres will develop in vitro when cocultured with morphologically intact embryos. Births of live offspring after embryo biopsy are reported