The aim of this prospective randomized study was to assess the advantages of a new modified intracytoplasmic sperm injection (ICSI) technique called intracytoplasmic morphologically selected sperm injection (IMSI) over the conventional ICSI procedure in the treatment of patients with severe oligoasthenoteratozoospermia. The new procedure consisted of IMSI based on a preliminary motile sperm organellar morphology examination under x6600 high magnification. A total of 446 couples with at least two previous diagnoses of severe oligoasthenoteratozoospermia, 3 years of primary infertility, the woman aged 35 years or younger, and an undetected female factor were randomized to IVF micro-insemination treatments: ICSI (n = 219; group 1) and IMSI (n = 227; group 2). A comparison between the two different techniques was made in terms of pregnancy, miscarriage and implantation rates. The data showed that IMSI resulted in a higher clinical pregnancy rate (39.2% versus 26.5%; P = 0.004) than ICSI when applied to severe male infertility cases. Despite their initial poor reproductive prognosis, patients with two or more previous failed attempts benefited the most from IMSI in terms of pregnancy (29.8% versus 12.9%; P = 0.017) and miscarriage rates (17.4% versus 37.5%). At present, 35 healthy babies have been born following the introduction of this promising technique in daily IVF practice.

Vitrification, an ultra-rapid cooling technique, offers a new perspective in attempts to develop an optimal cryopreservation procedure for human oocytes and embryos. To further evaluate this method for human oocytes, 796 mature oocytes (metaphase II) were collected from 120 volunteers. Since Italian legislation allows the fertilization of a maximum of only three oocytes per woman, there were 463 supernumerary oocytes; instead of being discarded, they were vitrified. When, in subsequent cycles, these oocytes were utilized, 328 out of 330 (99.4%) oocytes survived the warming procedure. The fertilization rate, pregnancy rate and implantation rate per embryo were 92.9, 32.5 and 13.2% respectively. Thus, as already reported in the literature, the vitrification procedure seems to be highly effective, safe (since healthy babies have been born) and easy to apply. In situations where embryo cryopreservation is not permitted (as in Italy), there is now good indication for routine application of the method, once further standardization is achieved.

In vitro maturation of vitrified immature germinal vesicle (GV) oocytes is a promising fertility preservation option. We analyzed the ultrastructure of human GV oocytes after Cryotop vitrification (GVv) and compared it with fresh GV (GVc), fresh mature metaphase II (MIIc) and Cryotop-vitrified mature (MIIv) oocytes. By phase contrast microscopy and light microscopy, the oolemmal and cytoplasmic organization of fresh and vitrified oocytes did not show significant changes. GVv oocytes showed significant ultrastructural alterations of the microvilli in 40% of the samples; small vacuoles and occasional large/isolated vacuoles were abnormally present in the ooplasm periphery of 50% of samples. The ultrastructure of nuclei and mitochondria-vesicle (MV) complexes, as well as the distribution and characteristics of cortical granules (CGs), were comparable with those of GVc oocytes. MIIv oocytes showed an abnormal ultrastructure of microvilli in 30% of the samples and isolated large vacuoles in 70% of the samples. MV complexes were normal, but mitochondria-smooth endoplasmic reticulum aggregates appeared to be of reduced size. CGs were normally located under the oolemma but presented abnormalities in distribution and matrix electron density. In conclusion, Cryotop vitrification preserved main oocyte characteristics in the GV and MII stages, even if peculiar ultrastructural alterations appeared in both stages. This study also showed that the GV stage appears more suitable for vitrification than the MII stage, as indicated by the good ultrastructural preservation of important structures that are present only in immature oocytes, like the nucleus and migrating CGs.

Between July 1995 and May 1996, 36 patients with non-obstructive azoospermia of secretory origin underwent intracytoplasmic injection of spermatids. A previous histological biopsy was performed on all patients: 15 had spermatogenic arrest, a further 13 had Sertoli cell-only syndrome, and the remaining eight had post-cryptorchidism tubal atrophy. The ejaculate was duly examined and a complete absence of spermatozoa and spermatids was confirmed, with only bacteria and debris being found. Testicular sperm extraction (TESE) was then performed. In 19 out of 36 cases round spermatids only were found, while elongated spermatids were found in the remaining 17. Both round and elongated spermatids were isolated and used for injection. A total of 135 oocytes at metaphase II were recovered from 19 partners and injected with round spermatids, while 123 mature oocytes from 17 partners were injected with elongated spermatids. The number of oocytes fertilized, as judged by the presence of two pronuclei, was 75 (55.5%) and 71 (57.7%) respectively. By 34 h after injection, the number of embryos which had cleaved to the 2-cell stage was 56 (74.6%) with round spermatids and 55 (77.4%) with elongated spermatids. All cleaved embryos were transferred into the uterus of the partners. Clinical pregnancies were established in two cases of round spermatid cycles (10.5%) (both are still ongoing), and three cases of elongated spermatid cycles (17.6%) (two are still ongoing; one was lost after 8 weeks of gestation). Chromosomal analysis showed that all fetuses had a normal karyotype (three male and one female) with no chromosomal abnormalities.

The effect of cryopreservation on the integrity and fertilizing capacity of round spermatids was studied in two azoospermic patients. In December 1995 the patients, both with maturation arrest of spermatogenesis, were submitted to testicular sperm extraction (TESE) after an extensive examination of their ejaculate. Only round spermatids were found after testicular biopsy. Some of the spermatids were isolated and used for a first injection, while the remainder of the preparation was cryopreserved for successive cycles. Because of the failure of the first attempt, 3 months later, the same two patients were submitted to a second one. The frozen preparation was thawed and examined to evaluate the integrity and the viability of surviving round spermatids. More than 70% of the thawed spermatids were viable for injection. Fifteen oocytes at metaphase II, retrieved from the patients' wives, were microinjected with thawed round spermatids. Eighteen hours after the injection, seven out of 15 oocytes showed normal fertilization, with the presence of two pronuclei. The zygotes were cultured to observe embryonic development. After 48 h, six cleaving embryos had developed to at least the two-cell stage, while one had arrested at the pronuclear stage. At 72 h, the cleaving embryos showed further development to the four- to six-cell stage. They were then transferred into the uterus. After 3 weeks a clinical pregnancy was established in one patient [beta-human chorionic gonadotrophin (beta HCG) concentration was 2100 UI]. At 16 weeks of gestation, chromosomic analysis was performed, which confirmed the presence of a fetus with normal karyotype. The pregnancy is ongoing.