Transplantation of Normal Boar Testicular Cells Resulted in Complete Focal Spermatogenesis in a Boar Affected by the Immotile Short‐tail Sperm Defect

Abstract

Transplantation of testicular cells, also known as spermatogonial stem cell transplantation, is a relatively new approach in the field of male infertility. We used this technique to determine whether donor-derived sperm production in unrelated porcine recipients is possible following ultrasound-guided transfer of testicular cells. This study was undertaken because we had a strain of Finnish Yorkshire boars with a hereditary recessive gene defect rendering all spermatozoa immotile and anatomically abnormal in homozygous boars. Thus, monitoring of the focal success of colonization of donor spermatogonia with subsequent production of progressively motile spermatozoa was extremely sensitive. Testicular cells from young normal crossbred boars were transplanted into the testes of two boars affected with the immotile short-tail sperm (ISTS) defect. Prior to the transplantations, busulfan was used to suppress recipients' endogenous spermatogenesis. The ejaculates were collected and analysed for the presence of motile spermatozoa. In one of the two recipient boars transplanted with testicular cells from normal donors, motile spermatozoa appeared in the ejaculates 12 weeks after the transplantation. Spermatozoa manually selected under a microscope from a frozen aliquot of ejaculate collected 27 weeks after transplantation were genotyped. In two of the 20 vials the donor-derived genotype was visible. The genotyping results substantiated the success - as indicated by the appearance of motile spermatozoa after the spermatogonial transfer. Thus, donor-derived sperm production in unrelated recipients is possible. In addition, the production after transplantation of progressively motile spermatozoa with normal tail lengths shows that the ISTS defect in Finnish Yorkshire boars apparently results from defective transcription of an essential gene for sperm motility in germline cells. To conclude, the transplantation of donor testicular cells can, at least in boars with the ISTS defect, result in complete focal spermatogenesis.

Eliminating malignant contamination from therapeutic human spermatogonial stem cells

“…Brinster and colleagues provided the initial demonstration that testicular cells from a fertile mouse could be transplanted into the seminiferous tubules of an infertile recipient, in which they produced complete spermatogenesis and sometimes restored fertility (12)(13)(14). Regeneration of spermatogenesis following SSC transplantation has now been established in several animal models, including rodents, goats, sheep, pigs, dogs, and monkeys (13)(14)(15)(16)(17)(18)(19)(20)(21)(22).…”

Separating spermatogonia from cancer cells in contaminated prepubertal primate testis cell suspensions

“…SSC transplantation has proven effective for regenerating spermatogenesis and fertility in small and large animal models (Brinster and Avarbock, 1994;Ogawa et al, 2000;Shinohara et al, 2001;Nagano et al, 2001;Brinster et al, 2003;Honaramooz et al, 2003;Orwig and Schlatt, 2005;Mikkola et al, 2006;Kim et al, 2008). Clinical translation of this technique is imminent and may provide hope for future fertility in cases where there are no other options to preserve and/or restore fertility, such as prepubertal cancer patients.…”

“…Although prepubertal boys are not making sperm, their testes contain SSCs that are poised to initiate spermatogenesis at puberty (Ehmcke et al, 2006;Culty, 2009;Wu et al, 2009). In animal models (rodents, pigs, goats and dogs), transplantation of SSCs into the testes of infertile males can lead to restoration of spermatogenesis (Brinster and Avarbock, 1994;Ogawa et al, 2000;Shinohara et al, 2001;Nagano et al, 2001;Brinster et al, 2003;Honaramooz et al, 2003;Orwig and Schlatt, 2005;Mikkola et al, 2006;Kim et al, 2008). Stem cells from all ages, newborn to adult, are competent to produce complete spermatogenesis following transplantation into recipient testes (Shinohara et al, 2001;Ryu et al, 2003).…”

Spermatogonial Stem Cells and Animal Transgenesis

“…Although most studies have been performed in rodents, germ cell transplantation has also been applied to non-rodent species as pigs, goats, cattle, monkeys and recently fish and chickens (Honaramooz et al, 2002a(Honaramooz et al, ,b, 2003Schlatt et al, 2002;Izadyar et al, 2003b;Takeuchi et al, 2003;Yoshizaki et al, 2005;Lee et al, 2006;Mikkola et al, 2006;Okutsu et al 2006;Trefil et al 2006), as reviewed by Dobrinski, (2008). The first hurdle found when germ cell transplantation was applied to livestock species was the differences in testicular anatomy and physiology.…”