Serum supplementation and Co-Culture of embryos belong to the past. Defined nonprotein or recombinant protein supplements are becoming a viable alternative during gamete and embryo manipulation procedures

system only requires the use of one type of medium throughout the entire culture process (18). The latter has been proposed as possibly being beneficial since it allows embryos to regulate their own microenvironment, while simultaneously it facilitates workload by removing an extra step in the culture process

The various steps of the conventional ICSI, from oocyte denudation to sperm immobilization to sperm injection into the egg, seem well established considering the 1000s of highly trained ICSI technicians/embryologists in the world performing the procedure

This is, however, only partially true. As a matter of fact, there are still potential weaknesses in established ICSI protocols and what is common in performing micromanipulation procedures is the lack of attention to details other than the mechanical aspects.

However, a successful fertilization is not guaranteed unless preventative mechanism(s) inhibiting fertilization by more than one sperm,

a condition known as polyspermy, is established immediately following gamete fusion since polyploidy is fatal to an embryo.

while mammalian polyspermic fertilization is considered abnormal, which leads to developmental failure of the zygote and spontaneous abortion in humans.

The focus of the present study is the effect of cumulus cells on the oocyte aging process, as these cells play important roles in oocyte maturation and subsequent embryonic development.

cumulus cell‐oocyte complex (COC) reported that prolonged culture of oocytes with intact cumulus cells induces apoptotic changes,19, 20, 21 suggesting that oocyte denudation should be performed as soon as possible after oocyte retrieval.

Although some researchers have investigated the optimal timing of cumulus cell removal in ICSI procedures,8, 10, 11, 12, 31 there is yet no consensus.

PLCζ is a cytosolic sperm protein introduced into the oocyte following fertilisation, and induces oocyte activation via the release of intracellular calcium ions (Ca2+) from endoplasmic reticulum stores

The Ca2+ released, distinguished either as a series of oscillations (in mammals) or as a single transient (in non-mammals), regulates a sequence of molecular events that are collectively referred to as ‘oocyte activation’.

These events include the release of meiotic arrest, cortical granule exocytosis, maternal mRNA recruitment, pronuclear formation, polyspermy prevention, and the ultimate initiation of embryo development

The biological processes to which ADAMs have been linked functionally include sperm–egg interactions, cell fate determination in the nervous system, cell migration, axon guidance, muscle development and diverse aspects of immunity. In humans, ADAM-17 (otherwise known as tumour necrosis factor-α converting enzyme, TACE) orchestrates immune and inflammatory responses via activation of pro-TNF-α, but is also essential during development for activation of membrane-associated ligands of the epidermal growth factor receptor (EGFR)

It is a well-known fact that the molecular complex arylsulfatase A (ARSA), hyaluronidase sperm adhesion molecule 1 (SPAM1), and heat shock protein 2 (HSPA2) plays a significant role in sperm–zona pellucida (ZP) binding

One remarkable insight is the importance of membrane cholesterol efflux in initiating transmembrane signaling events that confer fertilization competence.

Mammalian spermatozoa leaving the testis attains functional maturity (progressive motility and the ability to fertilize a metaphase-II arrested egg)

only during its residence in the female reproductive tract