Ex vivo human testes as a practical model to simulate ultrasound-guided testicular cell transplantation for human fertility restoration

Abstract Objective To develop an ex vivo model to practice ultrasound-guided injection of cellular material into human seminiferous tubules to simulate testicular cell transplantation (TCT). Design Simulated TCT injections were performed in human testes removed during orchiectomy. The rete testis was the targeted site of injection. Successful retrograde infiltration of injected material into the lumen of the seminiferous tubules was detected using ultrasound and confirmed with histology. Setting Single academic surgical center. Patients Adult patients undergoing orchiectomy for non-oncologic indications. Interventions Testes were injected with sonographic contrast (Optison™), methylene blue, and fluorescent labeled cells. Main outcome measures A characteristic streaming pattern of sonographic contrast in the testis was used to define sonographic success, and the presence of methylene blue and fluorescent labeled cells within the seminiferous tubules confirmed histologic success. Results We performed simulated TCT injections in 30 testes obtained from 16 patients undergoing orchiectomy. We were able to achieve sonographic success in 57% of injections and confirmed that sonographic success correlates with histologic success. Conclusions TCT injections can be practiced using human testes. As there appears to be a learning curve associated with this procedure, developing this infrastructure to practice these skills is critical prior to implementation in patients.