Immature germ cell conception—in vitro germ cell manipulation

Advances in Fertility Options of Azoospermic Men

“…Accordingly, many investigators are interested in spermatid in vitro culture and an attempt to find the appropriate medium that could successfully mature round spermatids up to the elongated stage in vitro or even to mature spermatozoa at a reasonable rate (Cremades et al, 1999). Also, the research on in vitro culturing of round spermatids should study the optimum temperature for maturation, the reason why spermatogenesis in vitro seems accelerated, and whether the whole spermatogenic population can be used instead of isolated cells (Tesarik et al, 2000;Amarin et al, 2002). In our TESE culture experiments, a few round spermatids displayed a slight shape changes after 24 to 48 hour culture, but we can not determine whether this culture may promote round spermatids to become elongated spermatids because we did not track individual spermatid growth.…”

Andrology Lab Corner*: Using the Male Gamete for Assisted Reproduction: Past, Present, and Future

“…The first birth after fertilization with elongated spermatids was reported in 1995 (Fishel et al, 1995). The ability of elongated spermatids to act as male gametes after injection into human oocytes (elongated spermatid injection [ELSI]) was further confirmed by different groups (Araki et al, 1997; Vanderzwalmen et al, 1997; Bernabeu et al, 1998; Kahraman et al, 1998; Sofikitis et al, 1998; Al‐Hasani et al, 1999; Sousa et al, 1999; Tesarik et al, 2000). However, most of these reports did not mention the exact phase of spermiogenesis of the elongated spermatids that were used.…”

“…The original enthusiasm inspired by reports of births (Tesarik et al, 1995; Vanderzwalmen et al, 1997; Barak et al, 1998; Gianaroli et al, 1999) and ongoing pregnancies (Antinori et al, 1997a,b) after fertilization with round spermatids was subsequently tempered by the low success rates obtained in a larger series of round spermatid injection (ROSI) attempts (Al‐Hasani et al, 1999; Tesarik et al, 2000). On the basis of a meta‐analysis of data reported by different groups (255 treatment attempts), the overall fertilization, pregnancy, and confirmed birth rate after ROSI were 30.5%, 5.1%, and 2.0%, respectively (Tesarik et al, 2000). The results of ROSI were deceiving, especially as to the low birth rate, which resulted not only from the low implantation potential of embryos developing from oocytes fertilized with round spermatids but also from the unusually high rate of early wastage of spermatid‐derived pregnancies (Amer et al, 1997).…”

“…Several early studies described the occurrence of spermatogenic events during in vitro culture of pieces of animal and human testicular tissue (reviewed in Tesarik et al, 2000). However, these attempts acquired potential clinical importance only in the last decade, when micro‐manipulation methods capable of delivering poorly motile sperm and sperm precursor cells to the interior of the oocyte became available.…”

“…A high incidence of DNA fragmentation in round spermatids from men with complete maturation arrest at the round spermatid stage (Tesarik et al, 1998a; Jurisicova et al, 1999) is suspected to be at the origin of the high prevalence of assisted reproduction failure when round spermatids are used for fertilization (Tesarik et al, 2000). However, a high incidence of DNA fragmentation is also often found in mature spermatozoa from some patients with complete spermatogenesis (Gandini et al, 2000; Muratori et al, 2000).…”