Pregnancy after transfer of sperm under zona

Evolution of intracytoplasmic sperm injection: From initial challenges to wider applications

Background

In vitro fertilization (IVF) has revolutionized infertility treatment. Nevertheless, male infertility requires more effective solutions. In 1992, the first-ever case of human birth via intracytoplasmic sperm injection (ICSI) was reported. ICSI involves microscopically injecting a sperm into an ovum. Successful ICSI has become a reliable therapy for couples facing infertility, a significant milestone. However, it has also introduced various challenges. This study also delves into ethical dilemmas arising from widespread ICSI use.

Methods

This review traces the history of ICSI, presenting pioneering attempts, first successful attempts, and critical reports on account of the initial skepticism toward the technology. The review also focuses on chronological progress until ICSI was recognized as effective and became widely applied.

Main findings

The review reveals that ICSI, although transformative, presents challenges. Successes include addressing male infertility and aiding fertilization. However, concerns arise regarding optimal sperm and embryo selection, genetic mutations, and long-term health implications. Ethical considerations surrounding ICSI's broad applications also surface.

Conclusions

Despite its success and effectiveness, ICSI is still evolving as a therapeutic method. By comprehensively evaluating the historical progress and the current status of ICSI and exploring its future prospects, this study highlights the importance of ICSI in infertility treatment.

Effectivity of conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) when male factor is absent: a perspective point of view

An objective and individualized approach of in vitro fertilization techniques tends to decrease costs and improve the experience of infertile couples during treatment. The use of available technologies to diagnose and treat infertility based on scientific evidence seems to be the best practice, which is the guideline that motivates this review on the available techniques for laboratory oocyte insemination. Conventional IVF, the pioneering technique, was initially used in the treatment of tubal obstruction infertility, successfully expanding the treatment of infertile couples presenting with several other factors. However, it was less effective in cases of severe male factor infertility. Intracytoplasmic sperm injection, which was developed in 1992, proved to be the method of choice for treating couples with severe male factor infertility. Since then, it has been increasingly used regardless of the infertility factor. This review discusses the effectiveness of conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) when the male factor is absent in all aspects, as technical and clinical outcomes, associated risks, adjustments for using with other technologies and costs. Finally we discuss the advantages and disadvantages of each one, with all aspects reviewed.

The pioneering of intracytoplasmic sperm injection: historical perspectives

Intracytoplasmic sperm injection (ICSI) has often been heralded as a ground-breaking technique that has transformed the treatment of couples with infertility. By injecting a single spermatozoon into the cytoplasm of the oocyte, ICSI bypasses the zona pellucida and increases the chances of fertilization and subsequent embryo development, independent of semen parameters. Ever since the first live births using ICSI were reported in 1992, ICSI has become the mainstay of treating male factor infertility as well as overcoming fertilization failure associated with conventional in vitro insemination. Today, ICSI is utilized in nearly 66% of all assisted reproductive treatments worldwide and has resulted in the birth of millions of babies. The primary goal of this review is to provide historical perspectives about the pioneering of ICSI. We begin by highlighting the scientific work of early investigators who elucidated the mechanisms central to mammalian fertilization. Furthermore, we briefly discuss how these findings contributed to the development of IVF for the treatment of infertility. We then emphasize the shortcomings of IVF in treating severe forms of male factor infertility and enumerate the micromanipulation techniques that were developed to circumvent these shortcomings. Finally, we indicate how the inadequacies of these micromanipulation techniques lead to the inception, application and popularity of ICSI.

The effect of various assisted hatching techniques on the mouse early embryo development

Objective

In search of an ideal method of assisted hatching (AH), we compared the effects of conventional micropipette-AH and laser-AH on the blastocyst formation rate (BFR) and blastocyst cell numbers.

Methods

Four- to five-week-old ICR female mice were paired with male mice after superovulation using Pregnant mare's serum gonadotropin (PMSG) and hCG. The two-cell embryos were flushed from the oviducts of female mice. The retrieved two-cell embryos underwent one of five AH procedures: single mechanical assisted hatching (sMAH); cross mechanical assisted hatching (cMAH); single laser assisted hatching (sLAH); quarter laser assisted hatching (qLAH); and quarter laser zona thinning assisted hatching (qLZT-AH). After 72 hours incubation, double immunofluorescence staining was performed.

Results

Following a 72 hours incubation, a higher hatching BFR was observed in the control, sMAH, cMAH, and sLAH groups, compared to those in the qLAH and qLZT-AH groups (p<0.05). The hatched BFR was significantly higher in the qLAH and qLZT-AH groups than in the others (p<0.05 for each group). The inner cell mass (ICM) was higher in the control and sMAH group (p<0.05). The trophectoderm cell number was higher in the cMAH and qLAH groups (p<0.05).

Conclusion

Our results showed that the hatched BFR was higher in groups exposed the the qLAH and qLZT-AH methods compared to groups exposed to other AH methods. In the qLAH group, although the total cell number was significantly higher than in controls, the ICM ratio was significantly lower in than controls.

Assisted reproductive technologies and monozygous twins: implications for future study and clinical practice

That the zona pellucida (ZP) plays a prominent role in the physiology of some human twinning is an attractive, albeit incompletely proven, medical hypothesis. Indeed, an association has been proposed between manipulation of the ZP and/or native ZP microarchitecture and monozygotic (MZ) twins. Ovulation induction also has been theoretically linked to in vivo ZP alterations facilitating MZ twin development. In vitro fertilization (IVF) relies on necessary (and, in some cases extended) embryo culture techniques potentially creating subtle ZP changes and subsequent MZ twinning. With growing experience in the assisted reproductive technologies and particularly IVF, some preliminary reports have noted an increased frequency of MZ twins after procedures that artificially breach the ZP (i.e., intracytoplasmic sperm injection [ICSI], or ‘assisted hatching’). Such ZP manipulations ostensibly enhance oocyte fertilization or facilitate blastocyst hatching, thus improving pregnancy rates for couples undergoing fertility treatment. Evidence exists both to challenge and support the connection between these phenomena and MZ twins. This report outlines the fundamental embryological processes believed responsible for these conflicting observations; the current literature on the subject of human ZP micro-manipulation and MZ twins is also discussed. Twin Research (2000) 3, 217–223.

Infertility in Australia circa 1980: an historical population perspective on the uptake of fertility treatment by Australian women born in 1946-51

OBJECTIVE

To estimate the prevalence of lifetime infertility in Australian women born in 1946-51 and examine their uptake of treatment.

METHODS

Participants in the Australian Longitudinal Study on Women's Health born in 1946-51 (n=13,715) completed up to four mailed surveys from 1996 to 2004. The odds of infertility were estimated using logistic regression with adjustment for socio-demographic and reproductive factors.

RESULTS

Among participants, 92.1% had been pregnant. For women who had been pregnant (n=12738): 56.5% had at least one birth but no pregnancy loss (miscarriage and/or termination); 39.9% experienced both birth and loss; and 3.6% had a loss only. The lifetime prevalence of infertility was 11.0%. Among women who reported infertility (n=1511), 41.7% used treatment. Women had higher odds of infertility when they had reproductive histories of losses only (OR range 9.0-43.5) or had never been pregnant (OR=15.7, 95%CI 11.8-20.8); and higher odds for treatment: losses only (OR range 2.5-9.8); or never pregnant (1.96, 1.28-3.00). Women who delayed their first birth until aged 30+ years had higher odds of treatment (OR range 3.2-4.3).

CONCLUSIONS

About one in ten women experienced infertility and almost half used some form of treatment, especially those attempting pregnancy after 1980. Older first time mothers had an increased uptake of treatment as assisted reproductive technologies (ART) developed.

IMPLICATIONS

This study provided evidence of the early uptake of treatment prior to 1979 when the national register of invasive ART was developed and later uptake prior to 1998 when data on non-invasive ART were first collected.

In vitro fertilization rate of horse oocytes with partially removed zonae

Frozen-thawed ejaculated stallion spermatozoa were preincubated for 3 h in BO medium containing 5 mM caffeine and then treated with 0.1 micro M calcium ionophore A23187 for 60 sec. Aliquots of the sperm suspension (final concentration 1-2 x 10(7)/ml) were added to the oocytes which had been matured in vitro for 32 h. In Experiment 1, there were 3 groups of oocytes; cumulus intact, denuded zona-intact, and zona-free. Cumulus cells were removed with 0.5% hyaluronidase and the zona pellucida with 0.1% protease. The oocytes were fixed 20 h after insemination with acetic acid:ethanol (1:3) and stained with 1% orcein. The sperm penetration rate of zona-free oocytes was 83%, whereas the sperm penetration rate was very low (1 to 3%) in the cumulus-enclosed or zona-intact oocytes. In Experiment 2, denuded zona-intact oocytes were placed in PBS supplemented with 10% fetal bovine serum 1 h before the end of in vitro maturation. The zona pellucida was micromanipulated with a metal microblade under x 100 magnification within 20 min of treatment with 0.3 M sucrose. For partial zona dissection, a slit in the zona pellucida was made. For partial zona removal, oocytes were transferred to protein-free PBS to fix the oocytes on the bottom of the Petri-dish and to remove a piece of the zona pellucida. Micromanipulated oocytes were subjected to in vitro fertilization as described above. Zona-intact and zona-free oocytes treated with sucrose solution for 20 min were used as controls. The penetration rates were 4 (2/57), 12 (7/58), 52 (31/60), and 86% (44/51) for zona-intact, partially zona dissected, partially zona removed, and zona-free oocytes, respectively. Proportions of oocytes with monospermic penetration were 100 (2/2), 57 (4/7), 58 (18/31), and 34% (15/44), respectively. In Experiment 3, sperm penetration and male pronucleus formation in the partially zona removed oocytes were examined at 2.5 to 20.0 h of insemination. Sperm penetration started 2.5 h post-insemination (22%, 11/49), and increased to 38% (21/55) at 5 h, to 46% (23/50) at 10 h, and to 56% (27/48) at 20 h. The transformation of sperm heads into male pronuclei was first observed 10 h post insemination. These results indicate that assisted fertilization techniques may be a useful tool for achieving fertilization and embryo production in vitro in horses.

Micromanipulation

Micromanipulation technology entered the forum of human conceptionin vitroin the late 1980s. It was erroneously perceived as a new technology – a purely mechanical approach to bypass failures of conceptionin vitro, the aetiology of which were unknown. In fact, it is the modification of technology developed since the beginning of this century, and its logical utilization for conceptionin vitro, preconception (polar body) biopsy and preimplantation (blastomere and trophectoderm) biopsy in the realm of human infertility and genetic disorders.

Intracytoplasmic sperm injection — ICSI

For more than a decade in vitro fertilization (IVF) has been successful in the treatment of couples with long-standing infertility due to various aetiologies such as tubal disease, male-factor infertility, unexplained infertility and endometriosis. The usual fertilization rate in IVF for nonmale infertility cases is 60–70% of the inseminated cumulus-oocyte complexes and in andrological infertility it is only 20–30%. The lower the number of normally fertilized oocytes, the less chance there is of available embryos, so that patients may have no embryos to transfer. It has been the experience of all centres for reproductive medicine, including our own, that a certain number of couples with male-factor infertility cannot be helped by standard IVF treatment. After insemination with progressively motile spermatozoa the number of two-pronuclear oocytes was either zero or less than 5%. Furthermore, a sizeable number of couples cannot be accepted for IVF if the number of progressively motile spermatozoa in the ejaculate is below a certain threshold number such as 500 000. In the past five years, assisted fertilization procedures have been developed to circumvent the barriers that prevent sperm access to the ooplasma, namely the zona pellucida and the ooplasmic membrane. Pregnancies and births have been reported after partial zona dissection (PZD) and subzonal insemination (SUZI). The success rate of PZD and SUZI has remained moderate: the normal fertilization rate (two-pronuclear oocytes) has never exceeded 20–25% of the micromanipulated oocytes; only two-thirds of the patients have had embryo transfers of, usually, a low number of embryos, resulting in a reduced pregnancy and take-home baby rate.

Diagnostic significance of sperm-zona pellucida interaction

Spermatozoa binding to the zona pellucida is an early, critical event leading to fertilization and early pre-embryo development. Fertilization involves a complex and orderly sequence of events that is completed at syngamy, which is defined as the union of the two sets of haploid chromosomes to form a new diploid fertilized ovum (zygote). In order to be able to fertilize an oocyte, spermatozoa need to undergo a process called ‘capacitation’, which is usually defined as a series of changes that renders the sperm cells capable of undergoing the acrosome reaction. This process that naturally occurs within the female genital tract is possible under in vitro conditions. However, capacitation is not the only process spermatozoa must undergo to fertilize the oocytes successfully. To fertilize an oocyte, spermatozoa must also be at least highly motile, as well as being capable of undergoing the acrosome reaction timely, penetrating through the oocyte investments and fusing with the oocyte plasma membrane properly.

Engineering Approaches to Biomanipulation

This article presents a review on the existing techniques for manipulating biological cells. Because biomanipulation involves a wide range of disciplines, from biology to engineering, we concentrate on some of the key methodologies that would result in an efficient biomanipulation system. Some of the key methodologies discussed in this article for cell manipulation relate to the use of magnetics, microelectromechanical systems (MEMS)-based approaches, optics, electric field, and mechanical techniques. Recent advances in engineering have allowed researchers worldwide to address the problems arising from conventional manipulation techniques. This paper assimilates significance and limitations of biomanipulation techniques described in the literature.

The early days of IVF outside the UK

In this article the history of IVF in geographical regions outside the UK are traced by pioneers of that time. Following the birth of Louise Brown in 1978, live births after IVF occurred in Australia in 1980, in the USA in 1981 and in Sweden and France in 1982. Following the first IVF birth in Australia, the Government of Victoria established a review of IVF research and practice which led to the proclamation of the Infertility (Medical Procedures) Act 1984, the first legislation to regulate IVF and its associated human embryo research. Despite such restriction, IVF doctors and scientists from Victoria, especially those under the leadership of Carl Wood, Alan Trounson and Ian Johnston continued to initiate new treatments for infertility and new methods for delivering this treatment. In the USA IVF research began on animals as early as the 1930s, when Pincus and Enzmann at Harvard were involved in attempts at IVF in the rabbit. In the 1940s, John Rock attempted human IVF with 138 human oocytes without success. In 1965, Bob Edwards was with Georgeanna and Howard Jones at Johns Hopkins where attempts were made to fertilize oocytes in vitro. Clinical IVF began in earnest in the USA in 1980 with the first birth in 1981 achieved by the use of HMG--a first successful use with IVF. In France, two groups Frydman and Testart (Clamart) and Cohen, Mandelbaum and Plachot (Sevres) focused their research in particular directions. In 1981, the Clamart group developed a plasma assay for the initial rise in LH. The Sevres group developed a transport technique. Plachot produced a long series of cytogenetic analyses of oocytes and human embryos. Mandelbaum described the microstructures of the human oocyte. The start of IVF in France benefited from the help of animal researchers from the Institut National de la Recherche Agronomique. The first babies were born in Clamart in February 1982 and in Sèvres in June 1982. Important contributions to the development of IVF from the Nordic countries include techniques for ovarian stimulation, sonographic techniques for monitoring and vaginal oocyte retrieval and also unique possibilities for monitoring IVF safety. These developments, in combination with relatively permissive laws for the practice of reproductive medicine and relatively generous reimbursement policies, as well as a general public confidence in IVF, have led to an exceptionally high availability of IVF, within international comparison.

Intracytoplasmic sperm injection of bovine oocytes with stallion spermatozoa

Five experiments were designed to study the fertilizability and development of bovine oocytes fertilized by intracytoplasmic sperm injection (ICSI) with stallion spermatozoa. Experiment 1 determined the time required for pronuclear formation after ICSI. Equine sperm head decondensation began 3 h after ICSI; 42% were decondensed 6 h after ICSI. Male pronuclei (MPN) began to form 12 h after ICSI. Female pronuclei (FPN), however, formed as early as 6 h after ICSI. In Experiment 2, ionomycin, ionomycin plus 6-dimethylaminopurine (DMAP), and thimerosal were used to activate ICSI ova. None of the ICSI ova cleaved after treatment with thimerosal. Ionomycin activation after 24 and 30 h of oocyte maturation resulted in 29 and 48% cleavage rates, respectively. Ionomycin combined with DMAP resulted in 49, 6 and 3% cleavage, morula and blastocyst rates, respectively, when oocytes were activated after 24 h maturation. In Experiment 3, rates of cleavage (45-60%) and development to morulae (4-13%) and blastocysts (1-5%) stages following ICSI were not different (P>0.05) among three stallions. Treatment of stallion spermatozoa with ionomycin did not affect cleavage or development of ova fertilized by ICSI. The chromosomal constitution of blastocysts derived from ICSI was bovine, not bovine and equine hybrids. In Experiment 4, to make male and FPN form synchronously, colchicine and DMAP were used for 4 h to inhibit oocytes at metaphase during activation; 63% of oocytes were still at metaphase 8h after ICSI when treated with colchicine, and 50% of sperm nuclei were decondensed. About 18 h after ICSI, 21 and 50% male and FPN had formed, respectively, but cleavage rates were low, and only 1% developed to morulae. In Experiment 5, to test if capacitated equine sperm could fuse with the bovine oolemma, capacitated spermatozoa were injected subzonally (SUZI). Of the 182 SUZI oocytes, 49 (27%) contained extruded second polar bodies. After activation of oocytes with second polar bodies, 44, 22 and 15% developed to 2-, 4- and 8-cell stages, respectively, but development stopped at the 8-cell stage. None of the unactivated oocytes cleaved. In conclusion, equine spermatozoa can decondense and form MPN in bovine oocytes after ICSI, but subsequent embryonic development is parthenogenetic with only bovine chromosomes being found.

Fertilization, embryonic development and pregnancy losses with intracytoplasmic sperm injection for surgically-retrieved spermatozoa

Prior to the development of intracytoplasmic sperm injection (ICSI), azoospermic and severely oligozoospermic men had little to no chance of having a biological child. In this study, ICSI outcome in 454 transfers with ejaculated spermatozoa and 59 transfers with surgically retrieved spermatozoa were evaluated. Normal fertilization rate using ejaculated spermatozoa was 75% of 5995 oocytes, and 73% of 751 oocytes for surgically retrieved spermatozoa; with ongoing pregnancy rates of 53% (242/454) and 61% (36/59) respectively. Surgically retrieved spermatozoa significantly (P < 0.05) impacted 1PN oocytes (6.1%, 46/751), severely fragmented embryos (8.8%, 46/550) and incidence of pregnancy loss (11%, 4/36). When using ejaculated spermatozoa, incidence of 1PN oocytes, severely fragmented embryos and pregnancy loss was 2.9% (177/5995), 4.5% (200/4365), 2.4% (6/242) respectively.

Laser assisted immobilization of spermatozoa prior to intracytoplasmic sperm injection in humans

BACKGROUND

The conventional method of immobilization of spermatozoa prior to intracytoplasmic sperm injection (ICSI) is mechanical breakage of the tail by pressing it against the bottom of the injection dish.

METHODS

This prospective self-controlled study was set up to evaluate the potential of a non-contact 1.48 microm wavelength diode laser in terms of immobilization. In addition, the fertilization rate and further development potential of such zygotes were investigated. The patients included in our study (n = 60) had oestradiol concentrations >2000 pg/ml, and thus a relatively high number of MII oocytes could be expected. Approximately half the oocytes were injected with laser treated spermatozoa (n = 262, study group) and the other half with mechanically immobilized spermatozoa (n = 252, control group).

RESULTS

No significant differences between the two groups in terms of fertilization rate, early cleavage or blastocyst formation were observed. However, time required for identification, aspiration and injection of a potential spermatozoa was significantly shorter in the laser immobilized sperm group (P < 0.001).

CONCLUSIONS

The application of a non-contact diode laser for sperm immobilization prior to ICSI is a potentially useful alternative to the conventional mechanical approach.

A historical perspective of the clinical evolution of the assisted reproductive technologies

The practice of assisted reproduction technology today is the result of the dedicated patient care, observation, research, and experimentation undertaken by previous generations of physicians. The building blocks of progress have been assembled over past decades, by scientists whose primary objective has been to push forward the frontiers of knowledge, in order to offer more effective methods of infertility treatment. And fortunately that process continues today. Amongst the many scientific developments that have led to the modern practice in assisted reproductive technology, a small number stand out as having had a unique importance. This historical review redraws the path through which in vitro fertilization went from an experimental to an accepted infertility treatment.

Pregnancies, growth and development of children conceived by subzonal injection of spermatozoa

Subzonal injection of spermatozoa (SUZI) was one of the first micromanipulation techniques efficient in treating male factor infertility and unexplained in-vitro fertilization failures. The aim of this retrospective study was to evaluate the in-vitro development of embryos conceived by SUZI, the obstetric outcome, the rate of congenital malformations and subsequent follow-up in children. Fifty-five pregnancies were obtained between 1991 and 1994 (54 after fresh embryos were transferred and one after cryopreserved embryos were transferred). Among the 50 clinical pregnancies, there were seven miscarriages (14%) and two ectopic pregnancies (4%). Among the 41 resulting evolutive pregnancies, the discovery of one anencephaly led to a medical abortion. Forty deliveries including six twin pregnancies occurred, leading to the births of 45 live neonates and one stillbirth. The gender distribution of the offspring included 17 males and 29 females (ratio 0.59:1). Birth weight, length and head circumference were within the expected ranges. Two children presented a malformation: the first one had one thumb with congenital shelf and the second a polymalformative neurological syndrome. Growth curves were normal for all these children except one (weight above the 2 SD curve). Medical follow-up detected no pathological features in these children apart from a physical disability in one girl. In this small series a 4.2% rate of malformation was observed, particularly affecting the neural tube, in SUZI offspring. However, no firm conclusions can be drawn since the study was carried out on a small cohort. SUZI is no longer performed but these observations suggest that it is necessary to collect extensive data about children conceived by microfertilization.

Assessment of the dominant abnormal form is useful for predicting the outcome of intracytoplasmic sperm injection in the case of severe teratozoospermia

PURPOSE

Our purpose was to investigate the relation between the dominant sperm anomaly and sperm morphology and the outcome of intracytoplasmic sperm injection (ICSI).

METHODS

Two hundred ninety-five patients who underwent a total of 181 cycles of in vitro fertilization (n = 168) and/or 217 cycles of ICSI (n = 177) between July 1995 and May 1997 at Keio University Hospital were investigated.

RESULTS

The rates of fertilization and pregnancy were 63.3 and 27.8%, respectively, in ICSI cycles with < or = 4% normal forms. When the percentage of strictly normal morphology was < or = 4, the fertilization rate was lower in the case of severely tapered head (13.0%; n = 4) than in the cases of other deformities in ICSI. The acrosomal defect made no difference in the fertilization rate with ICSI.

CONCLUSIONS

The predominant abnormal form affects the ICSI outcome in the case of < or = 4% normal forms.

Approaches for obtaining sperm in patients with male factor infertility

OBJECTIVE

To describe methods of sperm retrieval for intracytoplasmic sperm injection (ICSI) in patients with male factor infertility and to review the clinical results using sperm from the different sources.

DESIGN

The literature on sperm-obtaining methods and ICSI was reviewed. Studies related to this topic were identified through MEDLINE.

RESULTS(S)

This review describes the evolution of sperm retrieval methods. Sperm can be obtained by microepididymal sperm aspiration (MESA), percutaneous sperm aspiration (PESA), and testicular sperm extraction (TESE), from patients with congenital absence of the vas deferens or acquired vas obstruction. When ICSI is performed with ejaculated, epididymal, or testicular sperm, good fertilization and pregnancy rates are achieved without significant differences among the various sperm sources. The original percutaneous sperm aspiration method has been modified slightly and yields successful results.

CONCLUSION(S)

Viable pregnancies can be achieved with ICSI by using not only ejaculated sperm, but also epididymal and testicular sperm. Microepididymal sperm aspiration, percutaneous sperm aspiration, modified percutaneous sperm aspiration, and testicular sperm extraction can be considered standard procedures to treat male factor infertility.

Effects of cancer on spermatozoa quality after cryopreservation: a 12-year experience

OBJECTIVE

To determine whether type of cancer and response to treatment was related to prefreeze or post-thaw semen quality and to predict post-thaw sperm motility from prefreeze motility.

DESIGN

Retrospective study.

SETTING

Tertiary care institution.

PATIENT(S)

One hundred six cancer patients cryopreserving their semen specimens.

INTERVENTION(S)

Computer-assisted semen analysis was performed before and after cryopreservation on each patient specimen.

MAIN OUTCOME MEASURE(S)

The relationship of sperm motility and motion characteristics to type of cancer and patient's response to treatment.

RESULT(S)

Prefreeze and post-thaw semen quality did not differ between patients presenting with testicular cancer and Hodgkin's disease. Patients with leukemia or advanced soft tissue cancer had a higher prefreeze and post-thaw motility and higher total and motile sperm count than testicular and Hodgkin's disease patients. A prefreeze sperm motility of > or = 15% could predict a post-thaw motility of > 10%.

CONCLUSION(S)

Prefreeze or post-thaw semen quality in cancer patients is not affected (except the prefreeze motile sperm count within the testicular cancer patients) by the type of disease. Prefreeze motility can predict post-thaw motility. Cryopreservation of semen should be offered to cancer patients irrespective of the type of disease.

The relationship between acridine orange fluorescence of sperm nuclei and the fertilizing ability of human sperm

OBJECTIVE

To determine whether the outcome of IVF can be predicted by acridine orange (AO) nuclear fluorescence of sperm.

DESIGN

Based on the fact that AO nuclear fluorescence color after acid treatment reflects maturity (green fluorescence) or immaturity (yellow to red fluorescence) of spermatozoa, the relationships between sperm maturity and the outcome of IVF, subzonal insemination, or intracytoplasmic sperm injection (ICSI) were investigated.

SETTING

The IVF program at the Obstetrics and Gynecology Hospital, Fukushima Medical College.

PATIENTS

Sixty-eight patients undergoing 68 IVF treatment cycles.

MAIN OUTCOME MEASURES

Acridine orange fluorescence of sperm nuclei and successful oocyte fertilization.

RESULTS

conventional semen parameters (sperm concentration and percentages of motile or morphologically normal spermatozoa in semen) did not correlate with the incidence of spermatozoa with green AO fluorescent (mature) nuclei. When > or = 50% of spermatozoa in semen samples exhibited green AO nuclear fluorescence, IVF was always successful. When green AO nuclear fluorescence was < 50%, only 39% of IVF treatment cycles (13/33) were successful. Only green AO fluorescent spermatozoa were able to bind efficiently human zona pellucida. When the incidence of green AO fluorescent spermatozoa was < 50%, no pregnancy resulted even though an average of 26% of the oocytes could be fertilized by ICSI.

CONCLUSIONS

The spermatozoa which fertilized oocytes in vivo and in IVF were limited to those whose nuclei exhibited green AO fluorescence. Intracytoplasmic sperm injection may be the method of choice when the incidence of green AO nuclear fluorescence is low regardless of the results of semen analysis.

A model for the incorporation of intracytoplasmic sperm injection into a private practice in vitro fertilization program

OBJECTIVE

To describe a method for the training of personnel and the implementation of intracytoplasmic sperm injection (ICSI) into an IVF program. The results of the first 75 cycles are reviewed.

DESIGN

Retrospective review of the first 75 consecutive ICSI procedures.

SETTING

Private, community-based IVF program.

MAIN OUTCOME MEASURES

The fertilization rate, damage rate, ongoing pregnancy rate (PR), and implantation rate were measured.

RESULTS

Nine percent of the injected oocytes were damaged. The fertilization rate was 60%, and the cleavage rate was 98%. Fifty-nine percent of the cycles resulted in an ongoing pregnancy, and the implantation rate per embryo was 26%.

CONCLUSIONS

A high initial PR can be obtained with ICSI using a systematic training regimen.

Effect of cryopreservation on semen quality in patients with testicular cancer

OBJECTIVES

Current techniques in cryopreservation of human semen substantially decrease sperm quality. In addition, the pregnancy rate using cryopreserved sperm obtained from testicular cancer patients is lower than when sperm from normal fertile men is used. However, it is still unclear whether cryopreserved sperm from these patients is inherently defective or if the sperm loses its motility after thawing. This study was undertaken to assess the effect of cryopreservation on the quality and motion characteristics of semen from patients with testicular cancer before definitive therapy compared with semen from normal volunteers.

METHODS

We compared the sperm quality before and after cryopreservation in samples from 34 patients with testicular cancer and 30 normal volunteers who were referred for sperm banking over a 7-year period. The effects of cancer stage and histologic type on various semen parameters were also examined. A computer-assisted semen analysis was performed before and after cryopreservation on each specimen. The nitrogen vapor technique using Test yolk buffer with glycerol as a cryoprotective agent was used for cryopreservation. The motile sperm count and motion characteristics (motility, velocity, linearity, amplitude of the lateral head movement, motility index) were analyzed before and after cryopreservation and compared between the groups.

RESULTS

Semen quality did not significantly differ among patients with Stage I, II, or III cancer. However, semen quality tended to be poorer at higher cancer stages. In general, semen quality was better among patients with pure seminomas than with pure embryonal tumors; quality was worst among patients with mixed germ cell tumors. However, 71.4% of patients with mixed tumors presented with Stage III disease, whereas all patients with seminomas presented with Stage I disease. Significant differences were also seen in prefreeze motility (median, 42% [interquartile range, 24 to 51] versus 60.5% [range, 49 to 73]; P = 0.0004) and motile sperm count (6.7 x 10(6)/mL [range, 3.4 to 14.4] versus 50.0 [range, 24.6 to 72.0]; P = 0.0001) in patients compared with controls, respectively. The motile sperm count and percent motility significantly decreased in both patients and controls after cryopreservation (P = 0.0001). However, the percentage decline in motile sperm count and motion characteristics after cryopreservation did not differ significantly between patients and controls (P > 0.01).

CONCLUSIONS

We conclude that the effect of cryopreservation on sperm quality in patients with testicular cancer is identical to its effect on sperm from normal fertile men. Differences in values after preservation are explained by poor semen characteristics before freezing; semen quality declines with more extensive disease. Stage I patients also had poorer quality than control subjects. Thus, we recommend that routine sperm banking be encouraged among all patients with testicular cancer before the initiation of specific medical treatment. We also recommend that future efforts be focused on improving the technique of sperm banking.

Micromanipulative and conventional insemination strategies for assisted reproductive technology

Micromanipulative techniques, such as subzonal insemination and direct intracytoplasmic sperm injection, are used when standard in vitro fertilization techniques have failed. These new approaches are currently under investigation in a variety of centers across the country. The projected results and the strengths and weaknesses of these techniques are reviewed.

Five decades of progress in management of the infertile couple

OBJECTIVE

To review milestones in the care of the infertile couple over the past five decades.

DATA RESOURCES

All issues of Fertility and Sterility were reviewed beginning with the first issue published in 1950 through volume 61, number 1 (January 1994). Other significant articles from the literature were reviewed as identified by directed Medline searches.

RESULTS

This historical review gives the reader a sense of the evolution of modern reproductive technology--how the past has shaped the present--through the development of modern surgical techniques, methods of ovulation induction, laparoscopy, ultrasound, endocrine assays, in vitro fertilization, cryopreservation of sperm and preembryos, and microscopic procedures on gametes and preembryos.

CONCLUSIONS

The remarkable capabilities of modern reproductive technologies are only possible because of the culmination of decades of innovative research.

Pronuclear formation and cleavage of mammalian eggs after microsurgical injection of freeze-dried sperm nuclei

A study was conducted to evaluate the ability of mammalian oocytes to develop to the pronuclear stage and beyond if injected with freeze-dried sperm nuclei. The rate of development of hamster eggs to the pronuclear stage after microinjection of freeze-dried hamster sperm nuclei was 90%. The pronuclear formation rate of hamster eggs injected with freeze-dried human sperm nuclei was 85%. On the other hand, the rates for eggs injected with untreated sperm nuclei were 84% and 89% respectively. The survival rate of rabbit eggs microinjected with freeze-dried rabbit sperm nuclei was 64%, the fertilisation rate 56% and the cleavage rate 38%. The survival, fertilisation and cleavage rates of eggs injected with non-freeze-dried sperm nuclei were 78%, 45% and 34%, respectively. There was no difference between eggs injected with freeze-dried sperm nuclei and those injected with sperm nuclei that had not been freeze-dried. Of the viable rabbit eggs injected with freeze-dried rabbit sperm nuclei, 6% developed to the 6- to 8-cell stage 62 h after injection.

Intracytoplasmic single sperm injection: preclinical training and first clinical results

OBJECTIVE

Our purpose was to reduce oocyte damage before clinical application of intracytoplasmic single sperm injection by training on aged unfertilized oocytes.

DESIGN

Intracytoplasmic single sperm injection (ICSI) was accomplished by micromanipulation of sperm and oocytes.

PATIENTS

Thirty-four patients consented to donate unfertilized aged oocytes to train for ICSI. Forty-four patients suffering from severe male infertility were treated with ICSI.

INTERVENTION

Oocytes were inseminated by intracytoplasmic single sperm injection.

MAIN OUTCOME MEASURES

Oocyte damage and fertilization and pregnancy rates were the outcome measures.

RESULTS

One hundred fifty-one aged unfertilized oocytes were gathered for training of which 121 were injected with a single sperm and 30 without a spermatozoon as a control group for activation. Oocyte damage, initially as high as 40%, was reduced to 15% after 60 oocytes. Normal fertilization (2PN) occurred in 18%, and polyploidy in 4.4%. The cleavage rate was 69%; none of these embryos were transferred. In the control group, seven oocytes were damaged, seven (30%) showed one pronucleus, and one showed two pronuclei. No cleavage was observed in the control group. In the clinical trial, 44 patients (61 cycles) were clinically treated with the same ICSI procedure, including 575 of 721 collected oocytes. Damage was 13%, activation was 11%, normal fertilization was 30%, and 5 (1%) polypoid zygotes were observed. The fertilization rate ranged from 5 to 100%, with a mean of 39.5 +/- 4% (SE). Nine patients had no fertilization (15%). Ninety-six percent of the zygotes cleaved and 47% were at the four-cell stage 45 hr after injection. One hundred twelve embryos were replaced in 48 transfers (2.3 embryos/ET). One live birth, one miscarriage, and eight ongoing pregnancies were obtained (22%/ET).

CONCLUSION

Preclinical practice on aged unfertilized oocytes seems useful before starting clinical ICSI, as the high initial oocyte damage can be reduced and subsequent clinical treatment successfully applied.

Clinical study of azoospermia

This study evaluated how many patients with azoospermia might have fertility potential using assisted conception techniques. A total of 102 male patients with azoospermia were included in the study. Thirteen patients had sex chromosomal abnormalities. Testicular biopsy performed in the other 89 patients showed incomplete spermatogenesis in 47 of them whereas 42 had complete spermatogenesis. In the latter 42 patients, distal vasography demonstrated bilateral obstruction of the excurrent ducts in 14 patients whereas no distal obstruction of the ducts was found in 28. The 89 patients were divided into three groups according to the findings of testicular biopsy and distal vasography. In the 14 patients with both complete spermatogenesis and distal obstruction of the excurrent ducts, surgical procedures are applicable. The pathogenesis of the 28 patients with complete spermatogenesis but without distal obstruction of the ducts should be clarified for further treatment.

Microassisted fertilization in assisted conception: indications and patient impact

Microassisted fertilization is fast becoming established as a routine clinical technique offering the chance of pregnancy to couples where none existed previously. The exceptional results of SUZI and, more particularly, ICSI now raise the prospect of pregnancy with any sperm in the ejaculate and are bringing to treatment focus some azoospermic men and men without an antegrade ejaculate. The advance in clinical results from SUZI and ICSI over earlier zona drilling and zona breaching techniques appear to be importantly related to the better implantation potential of the embryos. The implications for the way conventional IVF is performed still need to be digested but may be very important and may change our attitude to ovarian stimulation and insemination regimens.

Intracytoplasmic sperm injection

Intracytoplasmic sperm injection (ICSI) is a promising assisted fertilization technique that may benefit women who have not become pregnant by in-vitro fertilization. ICSI and subzonal insemination (SUZI) were used to treat couples who failed fertilization after standard IVF or who could not be accepted for IVF because too few motile spermatozoa were present in the ejaculate. This paper describes the outcome of 750 consecutive cycles of SUZI and ICSI. Different aspects of these novel assisted fertilization procedures are described: patient management, ovarian stimulation, semen evaluation and treatment, oocyte collection and preparation, SUZI and ICSI techniques, assessment of fertilization and embryo cleavage, outcome of embryo transfers and the evolution of the pregnancies.

Embryo viability associated with microassisted fertilization

Embryo morphology and cleavage rates represent useful, but not absolute, measures of embryo viability. Oocyte and embryo chromosomal abnormalities affect embryo viability and are reflected to some degree in the morphology of oocytes and embryos. Microassisted fertilization techniques have been successfully used to treat severe male-factor infertility. Zona drilling using acidified Tyrode's solution is detrimental to oocyte and embryo viability and should not be used. Partial zona dissection (PZD) produces viable embryos that have developmental competence no different from that of routine IVF embryos, but the oocytes should be shrunken in hypertonic sucrose prior to PZD to avoid distortion and mechanical damage. The size of the cut in the zona pellucida is also critical and should be kept to a minimum to avoid loss of blastomeres during transfer. It appears from data on embryo quality, pregnancy rates and implantation rates that SUZI embryos have viability comparable to that of routine IVF embryos. Astonishingly, the passage of an injection needle directly into the ooplasm during ICSI has no effect on fertilization or developmental competence, as demonstrated by the excellent clinical pregnancy rates.

Subzonal insemination and zona breaching techniques for assisting conception in vitro

The following comments can be made with regard to zona breaching procedures (PZD) and SUZI. First and foremost, it is important to establish that fertilization cannot occur with microdrop IVF or conventional IVF before proceeding with microassisted fertilization technology. PZD increases the rate of polyspermy, and this is significantly higher than when utilizing SUZI. SUZI increases the incidence of implantation in cases exhibiting severe teratozoospermia. SUZI increases the fertilization rate per patient and per oocyte in cases where IVF has previously failed on more than one occasion. SUZI increases the incidence of fertilization when very few motile sperm are available, and there is an increase in the incidence of cytoplasmic fragmentation with SUZI, which might be alleviated by improving methods of penetrating the zona pellucida, for example by using the Sonic Sword or utilizing a thinner, sharper injection needle alone or in addition to increasing the perivitelline space by dehydrating the oocyte (Yang et al, 1988). Morphology is an important parameter in predicting the outcome of IVF and therefore in guiding patients on the relevance of microinjection technology.

Subzonal insemination (SUZI) or in vitro fertilization (IVF) in microdroplets for the treatment of male-factor infertility

PURPOSE

The results of subzonal insemination (SUZI) and in vitro fertilization with microdroplet insemination used in couples with male-factor infertility are presented.

RESULTS

The total fertilization rate was 17.4% for SUZI (n = 89) and 49.3% for microdroplet IVF (n = 100). The fertilization rate for standard IVF (n = 510), not including any male-factor infertility and performed during the same period, was 73.2%. The "take-home baby rate" per started cycle and per embryo transfer (ET), respectively, was 10 and 17.6% for SUZI and 20 and 24.7% for microdrop IVF. For standard IVF these figures were 27 and 31.7%.

CONCLUSION

It was concluded that microdroplet IVF can be used with good results in cases of moderate male-factor infertility. The normal (2PN) fertilization rate with the SUZI technique was only 15.1%. However, despite the low fertilization rate, SUZI should be considered when dealing with severe male-factor infertility.

Subzonal insertion of multiple sperm is a treatment for male factor infertility

OBJECTIVE

To determine whether subzonal insemination of multiple sperm is an effective treatment for male factor infertility.

DESIGN

Subzonal insemination by micromanipulation of sperm and oocytes for male factor patients.

PATIENTS

Two hundred eight patients were selected on previous fertilization history and/or semen parameters. They could be assigned to one of three groups: group A had previous IVF failure, group B had a low fertilization rate with previous IVF, and group C had insufficient sperm for IVF.

INTERVENTIONS

Oocytes were inseminated by subzonal insertion of multiple sperm.

MAIN OUTCOME MEASURES

Fertilization and pregnancy rates.

RESULTS

There have been 208 patients treated through 332 treatment cycles. Of 2,789 oocytes inseminated, 784 oocytes were fertilized (28%) and 516 of these (66%) were monospermic. This represents normal fertilization in 207 cycles (62% of total patient cycles). These 207 cycles produced an average of 2.6 +/- 1.8 embryos. The resultant 487 embryos were either transferred or cryopreserved for future transfer. A total of 42 pregnancies (21% per ET) resulted from 200 ET procedures with 397 embryos. Miscarriages or elective terminations have occurred (11/42 pregnancies, 26% to date) and 21 deliveries have resulted in 26 babies. There are nine ongoing pregnancies. Three of the pregnancies have been from cryopreserved embryos. Group B patients had the highest fertilization rate (23%) but the lowest pregnancy rate (7%). No other significant relationships between patient group and outcome were found.

CONCLUSIONS

Subzonal insemination of multiple sperm is an effective treatment for some forms of male factor infertility.

Subzonal sperm insemination and total or extreme asthenozoospermia: an effective technique for an uncommon cause of male infertility

OBJECTIVE

To assess the value of subzonal insemination (SUZI) in cases of total or extreme asthenozoospermia.

DESIGN

The results of IVF after SUZI were assessed in six cycles (four couples) with documented asthenozoospermia.

SETTING

Institut de Médecine de la Reproduction, Marseille, France.

PATIENTS

Four couples underwent six retrieval cycles. In all cases asthenozoospermia was total (100% of immotile spermatozoa) or extreme (5% nonprogressive motility). Oligozoospermia and teratozoospermia were ruled out in all cases. In two cases electron microscopy revealed the absence of the central singlet in the flagellum axonemal complex and in one case a major dysplasia of the fibrous sheath in the flagellum principal piece.

RESULTS

The overall fertilization rate was 45%. The diploid embryo rate was 33%. Embryo quality was satisfactory. In five of six cycles, three embryos were transferred. Two triplet pregnancies were obtained corresponding to an implantation rate per transferred embryo of 40%.

CONCLUSION

Total or extreme asthenozoospermia seems to be a good indication for SUZI.

Association between human in vitro fertilization rate and pregnancy outcome: a possible involvement of spermatozoal quality in subsequent embryonic viability

A conventional view of mammalian fertilization is that the active component of the process: the spermatozoon, by virtue of its progressive motility and acrosomal enzymes, penetrates an otherwise passive oocyte. This concept has placed bias on spermatozoal normality as largely determining the outcome of fertilization; once this has been achieved then the contribution of the spermatozoon is often forgotten, and attention switches to the maternally derived "blue-print" for early embryonic development. Paternal genomic contribution is known to start at the eight-cell stage in the human, but this is usually after the time when early cleavage stage (2 to 8-cell stage) embryos are replaced in human assisted reproductive technologies (ART) procedures such as in vitro fertilization and embryo transfer (IVF-ET). Hence, fundamental abnormal contributions to embryogenesis derived from the fertilizing spermatozoon have often been ignored. Human IVF-ET has permitted far greater powers of analysis of the fertilization event, and fertilization success appears to be determined in such a system by three main factors: spermatozoal quality, oocyte quality, and quality of in vitro culture conditions (the gamete environment). If the second two factors are more carefully controlled than the first, as is the usual emphasis in routine human IVF practice, then any large variation in fertilization rates that are also significantly related to embryonic viability and ultimately pregnancy outcome, may be thought to be more directly associated with original quality of the fertilizing spermatozoon. An analysis of results of 758 IVF cases provides preliminary evidence to show that there is a close association between human in vitro fertilization rate and subsequent embryo viability following replacement. In accepting this hypothesis as a possibility, we should drastically change our attitude from one of the spermatozoon as a robust, simple initiator of embryonic development, and embrace the idea of the vulnerability of such germ cells both during and after their production, and how detrimental influences on this might profoundly affect embryogenesis after successful fertilization.

Clinical outcomes of pregnancies achieved by microinsemination by sperm transfer

Micromanipulative techniques such as microinsemination by sperm transfer are evolving as treatment for couples suffering from some forms of male factor infertility where previously donor insemination was the only option. Being a relatively new technology, the numbers of microinsemination by sperm transfer pregnancies that have progressed to term are still small. However, at this time, it would seem that outcome in terms of antenatal complications, gestation length, and birth weight is no different from that seen with conventional IVF. Continuing review of the rate of congenital malformation in microinsemination by sperm transfer progeny seems warranted.

Treatment of male infertility and idiopathic failure to fertilize in vitro with under zona insemination and direct egg injection

OBJECTIVE

Failure to fertilize eggs in vitro may be countered by micromanipulation of gametes to place selected spermatozoa underneath the zona pellucida of the egg or directly into the egg, thereby improving chances of fertilization and production of viable embryos. Analysis of our clinical data for assisted fertilization was undertaken to assess those factors of relevance in this therapy, and a description of our procedures are given.

STUDY DESIGN

Retrospective analysis of 85 cycles (73 couples) of in vitro fertilization and embryo transfer performed at a private infertility clinic, in which micromanipulation for assisted fertilization was used to overcome either severe male factor infertility or idiopathic failure to fertilize, was performed.

RESULTS

In 60 cycles where only embryos from under zona insemination were available for uterine transfer, 15 singleton and two twin pregnancies occurred (28.3% viable pregnancy rate per transfer, 14.1% embryonic implantation). In 14 of these cycles embryos arose only after repeated under zona insemination adding more spermatozoa; this accounted for four of the singleton and one of the twin pregnancies (38.5% pregnancy rate, 22.2% embryonic implantation). No embryos arose from partial zona dissection performed in five cycles on sibling eggs. However, in 16 cycles conventional insemination yielded fertilization in six cycles, and mixed transfer of these embryos and sibling embryos from under zona insemination gave rise to one pregnancy from four transfers (pregnancy rate 25%, embryonic implantation 7.1%). Likewise, in nine cycles donor spermatozoa yielded fertilization in eight cycles, and mixed transfer with sibling embryos fertilized by under zona insemination with partner's spermatozoa gave rise to two pregnancies from five transfers (pregnancy rate 40%, embryonic implantation 15.8%). Fertilization and pregnancy rates did not differ whether couples suffered either from male factor infertility or from previous idiopathic fertilization failure. Direct egg injection of a single spermatozoon into 105 eggs gave an 88.6% egg survival and 32.3% fertilization. Mixed transfers with sibling embryos from conventional and under zona insemination yielded one triplet, one twin, and three singleton pregnancies.

CONCLUSIONS

Overall, a 24.7% (21/85) viable pregnancy rate per cycle initiated occurred when only embryos from assisted fertilization were available. This strongly indicates that assisted fertilization made a real contribution in cases where either insufficient spermatozoa were available for conventional insemination or in cases where previous fertilization failure had arisen. The wide range of seminal parameters were found to be unhelpful in defining chances of success with assisted fertilization.