BACKGROUND Human spermatozoa appear to be guided by chemotaxis to the oocyte in the female genital tract. While one of the sources of sperm chemoattractants is the cumulus cells that surround the oocyte, the identity of the chemoattractant secreted from them is unknown. Progesterone, recognized to be secreted from cumulus cells, was demonstrated, at the pM concentration range, to be a chemoattr...

Cumulus oocyte complex (COC) expansion is induced through hyaluronic acid production and accumulation of proteins of the inter-alpha-trypsin inhibitor family in the gonadotropin-stimulated cumulus cells. Link protein, a glycoprotein found in cartilage, interacts specifically with hyaluronic acid and stabilizes the binding of proteoglycan monomers to hyaluronic acid to form aggregates. The aim o...

OBJECTIVES During ovulation, it has been shown that LH stimulus induces the expression of numerous genes via PKA, p38 MAPK, PI3K and ERK1/2 in cumulus cells and granulosa cells. Our recent study showed that EGF-like factor and its protease (TACE/ADAM17) are required for the activation of EGF receptor (EGFR), cumulus expansion and oocyte maturation of porcine cumulus-oocyte complexes (COCs). In ...

Immature oocytes benefit from nutrient modification of the follicular environment by the surrounding cumulus mass. However, the oxygen concentration that the oocyte may be exposed to could be lower than the antral follicular concentration due to the metabolism of surrounding cumulus cells. Using metabolic data previously determined, we have developed a mathematical model of O(2) diffusion acros...

Previous our studies have shown that CD44, the principal receptor for hyaluronan, is present on cumulus cells during oocyte maturation. Although hyaluronan-CD44 interaction has been implicated in cumulus expansion and/or oocyte maturation, the full significance of CD44 remains unknown. The objective of the present study was to further investigate the role of CD44 in cumulus expansion and oocyte...

OBJECTIVE In this study, we aimed to evaluate the influence of autologous cumulus oocyte complex (COC) coculture on embryonic development and quality, and investigate the implantation and pregnancy rates after cumulus-aided embryo transfer in the ICSI-ET cycles. MATERIAL AND METHODS Ninety five consecutive infertile women undergoing their first cycle of IVF teratment were included in the stud...

background: in vitro maturation (ivm) of oocytes is a promising technique to reduce the costs and avert the side-effects of gonadotropin stimulation for in vitro fertilization (ivf). the pregnancy rates from oocytes matured in vitro are much lower than those of in vivo stimulation cycles, indicating that optimization of ivm remains a challenge. objective: in this study, we investigated the effe...

Understanding the mechanisms regulating oocyte developmental competence is essential to enhance the clinical efficiency of assisted reproduction. FSH orchestrates the acquisition of oocyte competence, both in vivo and in vitro. Multiple pathways are implicated in FSH signalling; however, their precise coordination remains unresolved. A robust system to investigate FSH signalling is oocyte in vi...

BACKGROUND Approximately 20% of oocytes are classified as immature and discarded following intracytoplasmic sperm injection (ICSI) procedures. These oocytes are obtained from gonadotropin-stimulated patients, and are routinely removed from the cumulus cells which normally would mature the oocytes. Given the ready access to these human oocytes, they represent a potential resource for both clinic...

Fatty acid oxidation is an important energy source for the oocyte; however, little is known about how this metabolic pathway is regulated in cumulus-oocyte complexes. Analysis of genes involved in fatty acid oxidation showed that many are regulated by the luteinizing hormone surge during in vivo maturation, including acyl-CoA synthetases, carnitine transporters, acyl-CoA dehydrogenases and acet...