Abnormal Sperm Parameters in Humans Are Indicative of an Abortive Apoptotic Mechanism Linked to the Fas-Mediated Pathway

Expression of the Fas-ligand gene in ejaculated sperm from adolescents with and without varicocele

“…FasL is produced as a type II membrane protein and is a member of the tumor necrosis factor family of proteins [34,[45][46][47]. Upon binding to FasL, Fas induces apoptotic activation of intracellular caspases, effector proteins, which in turn activate the cascade of events leading to cell death [27,41,44].…”

“…In any case, Sakkas et al described the presence of Fas on ejaculated sperm, suggesting that abortive apoptosis may indeed be a major stakeholder in male infertility [27]. Other authors have suggested that the expression of Fas in ejaculated sperm may serve as a biomarker for apoptosis [49,50].…”

“…Other authors have suggested that the expression of Fas in ejaculated sperm may serve as a biomarker for apoptosis [49,50]. In addition, several studies have associated the presence of DNA strand breaks with some form of apoptosis [27].…”

“…Sakkas et al negatively correlated the presence of Fas in the ejaculate with sperm concentration [11,27]. In addition, the authors suggested that the Fas system is important in eliminating defective spermatozoa, but can show irregularities in sperm quality [27]. Also, Perticarari et al explained that the presence of Fas on ejaculated sperm is due to abortive apoptosis [60].…”

“…Thus, apoptosis is a normal and necessary occurrence during spermatogenesis, in order to select germ cells and regulate the number of germ cells [21][22][23][24][25][26]. In some cases, apoptosis may initiate but abort, in a process known as abortive apoptosis, leading to the ejaculation of mature sperm with apoptotic traits, such as fragmented DNA and membrane-bound Fas [27,28].…”