Testicular tissue extraction (TESE) to obtain spermatozoa for use with intracytoplasmic sperm injection (ICSI) has recently been employed in patients with non-obstructive azoospermia. Standard protocol is to retrieve a new sample of testis tissue on the day of oocyte recovery. Unfortunately, approximately 30% of men will possess no spermatozoa in their tissue, making ICSI an impossibility. We investigated whether testicular tissue that was intentionally obtained well before any planned ICSI cycle and cryopreserved could then serve as an efficacious sperm source in a subsequent ICSI cycle. This study reports on 10 men with non-obstructive azoospermia who did have spermatozoa found within their testis tissue at the time of TESE and who chose to use their frozen samples as the source of spermatozoa for a later cycle of ICSI. In 19 cycles the overall fertilization rate was 48%. Embryo transfer occurred in 89% of cycles. Two couples have achieved pregnancy (one ongoing, one delivered). All patients except one had multiple vials of frozen tissue remaining following their first cycle. This approach is offered as an alternative to repeated testicular tissue sampling, as the availability of spermatozoa is assured prior to the initiation of ovulation induction. This tissue can be harvested at the same time as diagnostic biopsy, thereby minimizing the number of surgical procedures.
Through the screening of embryos for abnormality in chromosome number or structure and selecting only normal embryos for transfer, PGS was envisioned and applied as a therapeutic tool for improving implantation and live birth rates from in-vitro fertilization and providing a means of attenuating pregnancy loss in recurrent pregnancy loss patients. An array of reports on the effects of PGS on embryo implantation and live birth rates has been made since its introduction, showing, variously, increases, decreases or no changes in these parameters. Various factors may influence the efficacy of PGS, including the patient population to which it is applied, technical aspects such as embryo biopsy, the genetic analysis and embryo culture environment, the current limitation of the genetic analysis (a subset of, rather than all, the 24 chromosomes) and the mosaicism of the embryo and blastocyst. Collectively, these contribute to the challenge of optimizing PGS and understanding how the screening result reflects the ultimate genetic constitution of the conceptus. Emerging cytogenetic and molecular technologies such as comparative genomic hybridization and microarray analysis may provide a broader appraisal of the embryo for a more comprehensive evaluation of developmental potential and prognosis for live birth.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.