The role of ultrasonographically guided puncture of the human rete testis in the therapeutic management of nonobstructive azoospermia

Updates in Sertoli Cell-Mediated Signaling During Spermatogenesis and Advances in Restoring Sertoli Cell Function

Since their initial description by Enrico Sertoli in 1865, Sertoli cells have continued to enchant testis biologists. Testis size and germ cell carrying capacity are intimately tied to Sertoli cell number and function. One critical Sertoli cell function is signaling from Sertoli cells to germ cells as part of regulation of the spermatogenic cycle. Sertoli cell signals can be endocrine or paracrine in nature. Here we review recent advances in understanding the interplay of Sertoli cell endocrine and paracrine signals that regulate germ cell state. Although these findings have long-term implications for treating male infertility, recent breakthroughs in Sertoli cell transplantation have more immediate implications. We summarize the surge of advances in Sertoli cell ablation and transplantation, both of which are wedded to a growing understanding of the unique Sertoli cell niche in the transitional zone of the testis.

Testicular cell transplantation into the human testes

OBJECTIVE

To translate spermatogonial stem cell (SSC) transplantation towards a clinical application.

DESIGN

Mouse green fluorescent protein (GFP)-positive testicular cells were labeled with (99m)technetium and microbubbles. These labeled cells were injected into the rete testis of isolated human testes under ultrasound guidance. Three different conditions were tested: 1) 800 μL of a 20 million cells/mL suspension; 2) 800 μL of a 10 million cells/mL suspension; and 3) 1,400 μL of a 10 million cells/mL suspension. After injection, the human cadaver testes were analyzed with the use of single-photon-emission computerized tomography (SPECT) imaging and histology.

SETTING

Laboratory research environment.

PATIENT(S)

Cadaver testes, obtained from autopsies at the pathology department.

INTERVENTION(S)

Ultrasound-guided injection of mouse GFP-positive testicular cells.

MAIN OUTCOME MEASURE(S)

Presence of radioactive-labeled cells in the human cadaver testes and GFP-positive cells in the seminiferous tubules.

RESULT(S)

In all of the experimental groups, GFP-positive cells were observed in the seminiferous tubules, near and far from the rete testis, but also in the interstitium. On SPECT, significant difference was seen between the group injected with 800 μL of a 20 million cells/mL suspension (1,654.6 ± 907.6 mm³) and the group injected with 1,400 μL of a 10 million cells/mL suspension (3,614.9 ± 723.1 mm³). No significant difference was reached in the group injected with 800 μL of a 10 million cells/mL suspension.

CONCLUSION(S)

Injecting cells in the human cadaver testis is feasible, but further optimization is required.

Efforts to create an artificial testis: culture systems of male germ cells under biochemical conditions resembling the seminiferous tubular biochemical environment

Induction of meiotic and post-meiotic alterations of male germ cells in vitro has been the target of several research efforts since 1960. However, to date, the establishment of an ideal culture system in which spermatogonial stem cells can be maintained and directed to proliferate and undergo meiosis and complete spermiogenesis does not exist. This is attributed to the difficulties concerning the isolation and purification of defined subpopulations of germ cells and the establishment of male germ cell lines. In addition, there is no adequate knowledge regarding the optimal biochemical conditions that promote the survival and differentiation of germ cells in long-term cultures. This review focuses on the methodologies that have been proved sufficient to achieve differentiation of cultured male germ cells. Furthermore, the factors regulating spermatogenesis and the technical prerequisites to achieve differentiation of cultured male germ cells are described. Finally, the role of in vitro cultures of immature diploid germ cells in the therapeutic management of men negative for haploid cells in their testes and the subsequent potential genetic and epigenetic risks are discussed.

Percutaneous aspiration biopsy using an intravenous catheter for testicular sperm retrieval in patients with obstructive azoospermia

Testicular needle aspiration has been proposed as a simple alternative to open biopsy for the diagnosis and treatment of azoospermia. This study describes a new modification of needle aspiration biopsy using an ordinary intravenous catheter to retrieve testicular spermatozoa from patients with obstructive azoospermia, and compares it to the classical fine-needle aspiration (FNA) method. The study included 86 consecutive patients with obstructive azoospermia. Thirty-one patients underwent FNA using butterfly needles (G21 or G23) and a 20 ml syringe. For the remaining 55 patients, an i.v. catheter (G14 or G16) was used instead of the butterfly needle. When testicular tissue was seen in the aspirate, the catheter was clamped and removed from the testis. If, after a maximum of three punctures, insufficient spermatozoa were retrieved, an open biopsy was carried out. Successful sperm retrieval was achieved in 54 out of 55 patients (98.1%) using an i.v. catheter, compared with 16 out of 31 patients (51.6%) using FNA (P < 0.05). Enough aspirated tissue was obtained for cryopreservation of spermatozoa in all 54 patients using the i.v. catheter, compared with 6/16 (37.5%) of the patients undergoing classical FNA. No significant complications were reported. In conclusion, the use of an i.v. catheter for testicular aspiration biopsy significantly improved sperm retrieval compared with FNA in obstructive azoospermia, and allowed for cryopreservation of excess tissue. The procedure is simple and inexpensive, however regular follow up and testing of possible adverse consequences of this method is indicated to establish its safety.