HUMAN REPRODUCTION

Predictive value of testicular histology in secretory azoospermic subgroups and clinical outcome after microinjection of fresh and frozen-thawed sperm and spermatids
Souza M, Cremades N, Silva J, Oliveira C, Ferraz L, Da Silva JT, Viana P, Barros A
From the Department of Medical Genetics, Faculty of Medicine, University of Porto, Centre for Reproductive Genetics, Porto, and Laboratory of Cell Biology, Institute of Biomedical Sciences Abel Salazar, University of Porto, Portugal
Hum Reprod. 2002; 17:1800-10

• Background: A retrospective study was carried out on 159 treatment cycles in 148 secretory azoospermic patients to determine whether histopathological secretory azoospermic subgroups were predictive for gamete retrieval, and to evaluate outcome of microinjection using fresh or frozen-thawed testicular sperm and spermatids.
• Methods: Sperm and spermatids were recovered by open testicular biopsy and microinjected into oocytes. Fertilization and pregnancy rates were assessed.
• Results: In hypoplasia, 97.7% of the 44 patients had late spermatids/sperm recovered. In maturation-arrest (MA; 47 patients), 31.9% had complete MA, and 68.1% incomplete MA due to a focus of early (36.2%) or late (31.9%) spermiogenesis. Gamete retrieval was achieved in 53.3, 41.2 and 93.3% of the cases respectively. In Sertoli cell-only syndrome (SCOS; 57 patients), 61.4% were complete SCOS, whereas incomplete SCOS cases showed one focus of MA (5.3%), or of early (29.8%) and late (3.5%) spermiogenesis. Only 29.8% of the patients had a successful gamete retrieval, 2.9% in complete and 77.3% in incomplete SCOS cases. In total, there were 87 ICSI, 39 elongated spermatid injection (ELSI) and 33 round spermatid injection (ROSI) treatment cycles, with mean values of fertilization rate of 71.4, 53.6 and 17%, and clinical pregnancy rates of 31.7, 26.3 and 0% respectively.
• Conclusions: Histopathological subgroups were positively correlated with successful gamete retrieval. No major outcome differences were observed between testicular sperm and elongated spermatids, either fresh or frozen-thawed. However, injection of intact round-spermatids showed very low rates of fertilization and no pregnancies.
  
  
• Editorial Comment
  The chance of sperm retrieval is very different for men with obstructive and non-obstructive (secretory) azoospermia. Men with obstructive azoospermia have normal sperm production while those with non-obstructive azoospermia have testicular failure. However, direct evaluation of testis biopsy specimens demonstrates sperm in some men with non-obstructive azoospermia (NOA), which can be retrieved and used for intracytoplasmic sperm injection (ICSI). It means that NOA men may have marginal sperm production within the testis.
  The present study shows that the findings of a diagnostic biopsy are helpful in evaluating the success of sperm retrieval. In addition, the chance of finding sperm is more likely if at least one area of spermatogenic activity is identified, in spite of the testicular histology pattern. The authors also report their excellent results with ICSI using testicular fresh/frozen sperm, which is similar to fresh/frozen ejaculated sperm. Cryopreservation of testicular sperm is, therefore, an excellent option for NOA men, since these men have very limited sperm production, and repeated sperm extraction is not always successful.
  In the last years, several points have become evident regarding spermatid injection. First, the technique of spermatid injection is very inefficient for producing normal fertilization. Second, the efficiency of embryonic implantation is extremely poor. Third, the nomenclature used by different investigators is highly variable; for one group spermatid is often what another call a testicular sperm. Four, it is widely believed that the identification of spermatids using standard optics or phase contrast microscopy is highly unreliable. Many investigators now believe that round spermatids, if present in a testis in the absence of spermatozoa, are usually undergoing apoptosis and are not capable of normal fertilization after injection into the oocyte. Therefore, microinjection of round spermatid should not be used, although further research is needed.

Dr. Sandro C. Esteves
Androfert
Campinas, SP, Brazil