Intracytoplasmic injection of round and elongated spermatids from azoospermic patients: results and review

Abstract

Microinjection is established as the method of choice in the treatment of severe male factor infertility as well as in azoospermic patients. Recent studies have shown that fertilization and cleavage can be achieved by injection of ejaculated as well as testicular elongated spermatids into oocytes. Here we report on the two first pregnancies worldwide resulting from elongated spermatid injection from frozen-thawed testicular tissue. Four patients with complete Sertoli cell-only syndrome (SCOS) and two with spermatogenetic maturation arrest were included in our microinjection programme. Tissues from open testicular biopsies were cryopreserved until the time of follicle puncture. A total of 67 oocytes were harvested. In the two patients with maturation arrest, cryopreserved elongated spermatids were successfully injected, while in two of the other four SCOS patients only cryopreserved round spermatids were available to be injected into the oocytes. Out of 18 injected oocytes, 10 were fertilized in the first group, while nine out of 49 injected oocytes showed fertilization and cleavage in the second group. Two clinical pregnancies were achieved with elongated spermatids from frozen-thawed testicular tissue, while no pregnancy was established in the case of round spermatids. This study confirms that fertilization, cleavage and pregnancy can be successfully achieved in cases with spermatogenetic maturation arrest by injecting cryopreserved elongated spermatids into oocytes. The literature on pregnancies following spermatid injection, as well as the problems using this technique and possible risks, are discussed.

The Effect on Intracytoplasmic Sperm Injection Outcome of Genotype, Male Germ Cell Stage and Freeze-Thawing in Mice

“…However, no nuclear or subcellular events involved in this transition were so far identified. Further information should be important for more efficient and safer ELSI/ROSI in humans as well as in mice because there is also an apparent gap between the efficiencies of ELSI and ROSI in IVF clinics [43].…”

DNA Methylation Analysis in Immature Testicular Sperm Cells at Different Developmental Stages

“…Additional factors might play a role. Especially round spermatid injections into the oocyte (ROSI) result in low fertilisation rates and high developmental arrest [20][21][22][23]. The possibility of imprinting defects cannot be excluded.…”

Is intracytoplasmic sperm injection safe? Current status and future concerns

“…The most recent attempts to use immature sperm (elongating and round spermatids) for ICSI raises the possibility of introducing new, unknown risks to the ICSI procedure. Reports have shown that fertilization and cleavage of embryos may be achieved with both elongated and round spermatids, potentially offering paternity to men with failure of complete sperm maturation [50,51]. Fertilization rates approaching those seen with fully mature sperm (50% to 71%) were reported in small series using elongated spermatid injection (ELSI), and several pregnancies and live births were reported [50].…”

“…Reports have shown that fertilization and cleavage of embryos may be achieved with both elongated and round spermatids, potentially offering paternity to men with failure of complete sperm maturation [50,51]. Fertilization rates approaching those seen with fully mature sperm (50% to 71%) were reported in small series using elongated spermatid injection (ELSI), and several pregnancies and live births were reported [50]. However, fertilization rates with round spermatid injection (ROSI) remain very low (20% to 25%) [52].…”