The technology of reprogramming differentiated cells into a pluripotent state, which can be used to derive virtually any cell type in vitro, has ignited the field of regenerative medicine. An equally revolutionary, but yet to be harnessed phenomenon, is the reset of age that occurs en route to pluripotency. This rejuvenation is clearly evident during reproduction, resulting in a young offspring from aged parental cells. Artificial reprogramming techniques built off this process, such as somatic cell nuclear transfer (SCNT) and induced pluripotent stem cell (iPSC) reprogramming techniques, are showing growing evidence for rejuvenation at the cellular level. These findings all points to an intimate relationship between reprogramming to pluripotency and the reset of age, and iPSC technology, especially, offers the possibility of a man‐made intervention in the aging process. Though in vitro cell reprogramming has been studied arguably for the last three decades, this application of specifically developing a protocol to rejuvenate cells, tissues, even whole organs has only just begun to be explored. There are still many challenges to realization but this technology has already famously shown that cell differentiation is more than a one‐way street, and, maybe, so is aging.
Part of the book: Pluripotent Stem Cells
As infertility rates across nations become a growing concern, the interest in the development of treatments, such as in vitro gametogenesis (IVG), increases. This is especially the case for male infertility. For instance, the average sperm count continues to decline across nations, while more adult and pediatric patients survive cancer only to be left with little to no options for fertility restorative therapies. Understanding the male reproductive system and the process of spermatogenesis, however, has proven to be a difficult task. Progress occurs slowly and inconsistencies remain in the literature while reports attempt to better understand spermatogonial stem cells (SSCs) in conjunction with spermatogenesis. Interestingly, stem cell behavior, the decision to self-renewal or commit to differentiation, has shown to be closely linked to the stem cell’s microenvironment (i.e. niche). Perhaps the missing pieces required to better understanding spermatogenesis are found in the re-defined perspective of SSC niche dynamics.
Part of the book: New Insights into Theriogenology