Sex chromosomal abnormalities and intracytoplasmic sperm injection

Developmental outcomes of children born through ICSI versus conventional IVF (cIVF) in couples with non-male factor infertility

STUDY QUESTION

In non-male factor infertile couples, are there any differences in the developmental outcomes between children born through ICSI and conventional IVF (cIVF)?

SUMMARY ANSWER

In this preliminary study, ICSI and cIVF seem to have a comparable effect on developmental outcomes after 12 months in children born to non-male factor infertile couples.

WHAT IS KNOWN ALREADY

ICSI, an invasive technique, has raised concerns about potential developmental abnormalities in children. Limited data are available regarding the developmental outcomes of ICSI-conceived infants born to non-male factor infertile couples.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study involved a follow-up of all children aged 12 months or older who were born from pregnancies resulting from either ICSI or cIVF as part of a previous randomized controlled trial (RCT) (NCT03428919).

PARTICIPANTS/MATERIALS, SETTING, METHODS

In the original RCT, 1064 women were randomly assigned to the ICSI or cIVF groups (532 women for each group). Follow-up was conducted with 155 couples (195 children) in the ICSI group and 141 couples (185 children) in the cIVF group. The Vietnamese version of the Ages & Stages Third Edition Questionnaires (ASQ-3) and the Development Red Flags questionnaires were completed by the participants. A total of 141 (90.1%) women (177 children) in the ICSI group and 113 (80.1%) women (145 children) in the cIVF group returned fully completed questionnaires. The primary outcomes were the developmental outcomes based on responses to the ASQ-3 and the Red Flags questionnaire.

MAIN RESULTS AND THE ROLE OF CHANCE

The mean age of children at follow-up was 19.5 ± 5.0 months in the ICSI group and 19.3 ± 5.5 months in the cIVF group. The mean height and weight of children in both groups were similar. The overall proportion of children with any abnormal ASQ-3 score did not differ significantly between the ICSI and cIVF groups (16.9% vs 13.1%, P = 0.34). The proportion of children with Red Flag signs was also comparable between the two groups (6.2% vs 9.2%, P = 0.36, ICSI vs cIVF, respectively).

LIMITATIONS, REASONS FOR CAUTION

Despite a reasonably high follow-up response rate, there is a potential risk of sampling bias, and overall, the number of children with developmental abnormalities was very small. The study relied solely on questionnaires as screening tools, rather than incorporating additional behavioral observations or physical developmental tests; this may have affected the statistical power and the significance of between-group comparisons.

WIDER IMPLICATIONS OF THE FINDINGS

The current findings contribute to the existing evidence and support the comparative safety of ICSI and cIVF regarding early childhood development. However, more extensive and prolonged follow-up data for these children are needed to draw definitive conclusions.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was received for this study, and no authors reported conflicting interests.

TRIAL REGISTRATION NUMBER

NCT04866524 (clinicaltrials.gov).

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.

First birth following assisted sperm fusion insemination using sperm bound to zona pellucida

PURPOSE

To report a live birth after transfer of a vitrified-warmed blastocyst produced by assisted sperm fusion insemination (ASFI).

METHODS

Oocyte retrieval and in vitro fertilization (IVF) were performed on a 37-year-old woman. Six hours after IVF, an oocyte exhibited a single polar body and so was defined as an unfertilized oocyte. A motile sperm was collected from the zona pellucida of the unfertilized oocyte by an injection needle. The motile sperm was pressed onto the membrane of the unfertilized oocyte.

RESULTS

Two oocytes were matured and subjected to IVF. One of the 2 oocytes exhibited only one polar body and was defined as an unfertilized oocyte at 6 h after IVF; this oocyte then was subjected to ASFI. Two pronuclei were observed on the next day and cultured to the blastocyst stage. This embryo achieved blastocyst status and was vitrified on day 5. The resulting vitrified-warmed blastocyst was transferred, resulting in pregnancy and subsequent delivery of a healthy boy.

CONCLUSION

This report describes the first case of a successful birth following transfer of a vitrified-warmed blastocyst produced by ASFI.

Improving ICSI: A review from the spermatozoon perspective

Intracytoplasmic sperm injection (ICSI) is the most frequently applied method for fertilization making the process of identifying the perfect spermatozoon fundamental. Herein we offer a critical and thorough presentation on the techniques reported regarding (i) handling and preparing semen samples, (ii) identifying and 'fishing' spermatozoa, and (iii) improving key factors, such as motility for a successful ICSI practice. These approaches are suggested to make the process easier and more effective especially in atypical and challenging circumstances. Furthermore, we present an epigrammatic opinion-where appropriate-based upon our collective experience. Techniques such as intracytoplasmic morphologically selected sperm injection, hyaluronic binding, polarized light microscopy, and annexin V agent identification for comparing sperm cells and their chromatin integrity are analyzed. Moreover, for the demanding cases of total sperm immotility the use of the hypoosmotic swelling test, methylxanthines, as well as the option of laser assisted immotile sperm selection are discussed. Finally, we refer to the employment of myoinositol as a way to bioreactively improve ICSI outcome for oligoasthenoteratozoospermic men. The diversity and the constant development of novel promising techniques to improve ICSI from the spermatozoon perspective, is certainly worth pursuing. The majority of the techniques discussed are still a long way from being established in routine practices of the standard IVF laboratory. In most cases an experienced embryologist could yield the same results. Although some of the techniques show great benefits, there is a need for large scale multicenter randomized control studies to be conducted in order to specify their importance before suggesting horizontal application. Taking into consideration the a priori invasive nature of ICSI, when clinical application becomes a possibility we need to proceed with caution and ensure that in the pursuit for innovation we are not sacrificing safety and the balance of the physiological and biological pathways of the spermatozoon's dynamic.

ABBREVIATIONS

ICSI: intracytoplasmic sperm injection; IVF: in vitro fertilization; PGD: reimplantation genetic diagnosis; IVM: in vitro maturation; HCV/HIV: hepatitis C virus/human immunodeficiency virus; IMSI: intracytoplasmic morphologically selected sperm injection; DGC: density gradient centrifugations; S-U: swim-up; ART: assisted reproduction technology; IUI: intrauterine insemination; PVP: polyvinylpyrrolidone; HA: hyaluronic acid; MSOME: motile sperm organelle morphology examination; ZP: zona pellucida; MACS: magnetic activation cell sorting; HOST: hypo-osmotic swelling test; TESE: testicular sperm extraction; MMP: mitochondrial membrane potential; OAT: oligoasthenoteratozoospermic.

An intracytoplasmic injection of deionized bovine serum albumin immediately after somatic cell nuclear transfer enhances full-term development of cloned mouse embryos

In mouse somatic cell nuclear transfer (SCNT), polyvinylpyrrolidone (PVP) is typically included in the nuclear donor injection medium. However, the cytotoxicity of PVP, which is injected into the cytoplasm of oocytes, has recently become a cause of concern. In the present study, we determined whether bovine serum albumin deionized with an ion-exchange resin treatment (d-BSA) was applicable to the nuclear donor injection medium in SCNT as an alternative to PVP. The results obtained showed that d-BSA introduced into the cytoplasm of an enucleated oocyte together with a donor nucleus significantly enhanced the rate of in vitro development of cloned embryos to the blastocyst stage compared with that of a conventional nuclear injection with PVP in SCNT. We also defined the enhancing effects of d-BSA on the blastocyst formation rate when d-BSA was injected into the cytoplasm of oocytes reconstructed using the fusion method with a hemagglutinating virus of Japan envelope before oocyte activation. Furthermore, immunofluorescence experiments revealed that the injected d-BSA increased the acetylation levels of histone H3 lysine 9 and histone H4 lysine 12 in cloned pronuclear (PN) and 2-cell embryos. The injection of d-BSA before oocyte activation also increased the production of cloned mouse offspring. These results suggested that intracytoplasmic injection of d-BSA into SCNT oocytes before oocyte activation was beneficial for enhancing the in vitro and in vivo development of mouse cloned embryos through epigenetic modifications to nuclear reprogramming.

Effect of polyvinylpyrrolidone on sperm function and early embryonic development following intracytoplasmic sperm injection in human assisted reproduction

The objective here was to review the effects of polyvinylpyrrolidone (PVP) upon sperm function and embryonic development in humans. PVP has been used successfully in intracytoplasmic sperm injection (ICSI) to facilitate the handling and immobilization of sperm for both domestic animals and humans. In our previous reports, PVP solution exists locally in embryos injected during the early developmental period, and also exerts influence over the developmental capacity of such embryos. In other reports, PVP causes significant damage to sperm membranes that can be detected by transmission electron microscopy, and has been associated with chromosomal abnormalities in pregnancy derived from ICSI embryos. In some Japanese clinics, PVP-free media has been used for sperm immobilization in order to optimise safety. Consequently, it is strongly suggested that the success rate of fertilization and clinical pregnancy could be improved by using PVP-free solution for human ICSI. In conclusion, our interpretation of the available data is to perform ICSI without PVP or select a lower concentration of PVP solution in order to reduce safety for pregnancy and children born via ICSI.

Cervical screening in England: the past, present, and future

Cervical screening in England commenced in a disorganized fashion in 1964. The flaws of this approach became apparent in the mid-1980s and led to the inception of the National Health Service Cervical Screening Programme (NHSCSP). The main features of this program are its population-based registry, accessibility to all women within the screening age range, its systematic process of call and recall, national coordination, and quality assurance. Its success is in part based on its ability to evolve as evidence necessitates, and throughout the period of 2000-2010, it embarked upon a series of developments involving liquid-based cytology, which also provided the means to conduct reflex high-risk human papillomavirus (HR-HPV) testing and the potential to automate the screening process. As a result of evidence acquired since 2000, the NHSCSP is currently based on a system of primary cytology with HPV triage for low-grade abnormalities combined with cytology plus a HR-HPV "test of cure" for women who have received treatment for cervical intraepithelial neoplasia. Future challenges for the program will involve finding solutions to increasing screening uptake among women <30 years of age-a problem that may be exacerbated when vaccinated women reach the screening age, while making plans to accommodate HPV primary screening.

A physiological replacement for polyvinylpyrrolidone (PVP) in assisted reproductive technology

The technique of intracytoplasmic sperm injection (ICSI) requires mechanical immobilization of the sperm that are to be injected; damage thus caused to the sperm membrane is considered to be necessary to activate the sperm for fertilization. Mechanical immobilization and the injection procedure are facilitated by introducing the sperm into a viscous medium that will hinder motility: a solution of polyvinylpyrrolidone (PVP) has been used successfully for this purpose. PVP is an artificial polymer, which has been regarded as chemically inert, although adverse effects have been reported as a result of its use both in vivo and in vitro. Therefore, the use of hyaluronate, the natural component of the extracellular matrix of the cumulus-oocyte complex, was investigated as a replacement for PVP during ICSI. A solution of hyaluronate was found to be as effective as PVP in facilitating the injection procedure, its effect on sperm motility was readily reversible, and its use did not affect the outcome of the treatment cycles in terms of fertilization, pregnancy and live birth rates. Every attempt should be made to eliminate artificial factors in assisted reproductive procedures. Hyaluronate, a natural and readily degradable glycosaminoglycan can be used as a substitute for the artificial PVP polymer without jeopardising the outcome of the treatment cycle.

Effect of PVP on sperm capacitation status and embryonic development in cattle

The objective of this study was to investigate the effects of polyvinylpyrrolidone (PVP) on sperm capacitation status and embryonic development in cattle (Bos taurus). Acrosome-reacted sperm (chlortetracycline stain) and the fertilization rate after intracytoplasmic sperm injection (ICSI) were enhanced (P<0.05) when sperm were cultured in a medium containing 10% PVP. However, injection of bovine in vitro-produced (IVP) embryos with medium containing 10% PVP suppressed development of these embryos to the 2-cell, morula, and blastocyst stages and cell number at the blastocyst stage (P<0.01) but did not affect chromosomal integrity (P>0.05). Embryo developmental capacity differed (P<0.01) among PVP from three suppliers, but there were no significant differences among three solvent media. The PVP remained localized in 40.9% of PVP-injected IVP embryos. In conclusion, PVP affected the acrosome reaction and enhanced the fertilization rate after ICSI. However, PVP remained detectable in IVP embryos and suppressed their developmental capacity.

Production of a transgenic piglet by a sperm injection technique in which no chemical or physical treatments were used for oocytes or sperm

As a method of producing transgenic animals, spermatozoa have been used to fertilize mammalian oocytes through natural copulation, artificial insemination (AI), and in vitro fertilization (IVF). Our objective was to produce live piglets expressing the enhanced green fluorescent protein (eGFP) by the modified ICSI procedure based on Yong et al. (2003) (Hum. Reprod. 18:2390) where this procedure resulted in an improvement in development in vitro as compared to conventional ICSI and IVF. After injecting frozen-thawed sperm, recovered from the descendant of a transgenic boar derived by oocyte transduction, into in vitro matured oocytes the injected oocytes were surgically transferred into the oviduct of six surrogate gilts. Two gilts (33%) became pregnant. One gave birth to a healthy male piglet. Expression of the eGFP was easily observed in the nose and hooves by direct epifluorescent examination in the newborn piglet. These results show the production of the first viable transgenic piglet by in vitro maturation and our new sperm injection method.

International collaborative study of intracytoplasmic sperm injection-conceived, in vitro fertilization-conceived, and naturally conceived 5-year-old child outcomes: cognitive and motor assessments

OBJECTIVE

To date, very few studies have been conducted on the neurodevelopmental well-being of children conceived through intracytoplasmic sperm injection (ICSI). The limitations of these studies often include a lack of comparison with a demographically matched, naturally conceived (NC) group and the investigation of only very young children, with relatively small samples sizes. One study showed that there were no differences in IQ scores among ICSI-conceived, in vitro fertilization (IVF)-conceived, and NC children at 5 years of age. Unfortunately, psychomotor development was not assessed in that study. Because findings regarding these children's cognitive and motor development are inconclusive, the aim of this study was to shed more light on the cognitive and motor development of 5-year-old ICSI-conceived children.

METHODS

A total of 511 ICSI-conceived children were compared with 424 IVF-conceived children and 488 NC controls. Children were recruited in 5 European countries, ie, Belgium, Denmark, Greece, Sweden, and the United Kingdom. Participation rates ranged from 45% to 96% in the ICSI and IVF groups and from 34% to 78% in the NC group. Cognitive and motor development was assessed with the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R) and McCarthy Scales of Children's Abilities (MSCA) Motor Scale, respectively. The WPPSI-R consists of 2 major scales, ie, Verbal and Performance, each including 6 subtests. The 6 Performance Scale subtests are object assembly, geometric design, block design, mazes, picture completion, and animal pegs. The 6 Verbal Scale subtests are information, comprehension, arithmetic, vocabulary, similarities, and sentences. Scores on the Performance and Verbal Scale subtests are summed to yield the performance IQ (PIQ) and verbal IQ (VIQ), respectively. Scores on both the Performance Scale and the Verbal Scale yield the full-scale IQ (FSIQ). IQ scales have a mean score of 100 and a SD of 15. Each subtest has a mean score of 10 and a SD of 3. The MSCA consists of 6 scales, ie, Verbal, Perceptual-Performance, Quantitative, General Cognitive, Memory, and Motor Scale. In this study, only the Motor Scale was administered. This scale assesses the child's coordination during performance of a variety of gross- and fine-motor tasks. Leg coordination, arm coordination, and imitative action tests provide measures of gross-motor ability. Draw-a-design and draw-a-child assess fine-motor coordination, as revealed by the levels of hand coordination and finger dexterity. The mean score for this test is 50, with a SD of .

RESULTS

No differences were identified among ICSI, IVF, and NC children with respect to VIQ, PIQ, or FSIQ scores of the WPPSI-R. Furthermore, there were no differences between groups regarding the discrepancy between VIQ and PIQ scores. These results were not influenced by gender, country, or maternal educational level. However, in the subgroup of firstborn children with mothers who gave birth at an older age (33-45 years), NC children obtained significantly better VIQ and FSIQ scores than did children conceived through assisted reproductive technologies. These differences in VIQ and FSIQ scores between ICSI/IVF and NC children were relative, because NC children scored <1 IQ point higher than ICSI/IVF children. Therefore, these scores show no clinical relevance. For Verbal Scale subtests, variables such as age of the mother at the time of the birth, educational level of the mother, and gender and nationality of the child interacted with mode of conception, resulting in clinically irrelevant differences between scores for the ICSI/IVF and NC groups on the arithmetic, vocabulary, and comprehension subtests. For Performance Scale subtests, these same demographic factors interacted with mode of conception for the block design, object assembly, and animal pegs subtests, again resulting in clinically irrelevant differences among groups. In the 3 groups (ICSI, IVF, and NC), we observed equal numbers of children scoring below 1 SD from the mean on the WPPSI-R and the MSCA.

CONCLUSIONS

This study includes a substantial number of children from several European countries. Apart from a few interaction effects between mode of conception and demographic variables, no differences were found when ICSI, IVF, and NC scores on the WPPSI-R and MSCA Motor Scale were compared. Nevertheless, the aforementioned interaction effects could indicate that demographic variables such as maternal age at the time of the birth and maternal educational level play different roles in the cognitive development of IVF and ICSI children, compared with NC children. Additional research is needed to explore and verify this finding. Previous studies revealed that ICSI children, in comparison with NC children, more frequently obtained scores below 1 SD from the mean on 3 subtests of the Performance Scale (object assembly, block design, and mazes) or showed a trend of 5.2% of ICSI children, compared with 2.5% of IVF children and 0.9% of NC children, obtaining a score below 1 SD from the mean, but those findings were not confirmed in this study. Here no differences were found among the 3 groups in the numbers of children scoring below 1 SD from the mean on the VIQ, PIQ, and FSIQ tests and the Verbal and Performance Scale subtests. Motor development results were somewhat more conclusive. There were no differences between the scores of ICSI, IVF, and NC children on the MCSA Motor Scale. No interaction effects were found between mode of conception and demographic variables, indicating that these results are not influenced by gender, nationality, maternal educational level, or maternal age at the time of the birth. Furthermore, equal proportions of children in all 3 groups scored below 1 SD from the mean. The results of this study are reassuring for parents who conceived through ICSI (or IVF). The findings indicate that the motor and cognitive development of their offspring is very similar to that of NC children. However, demographic factors such as maternal educational level and maternal age at the time of the birth might play different roles in the cognitive development of ICSI and IVF children, compared with NC children.

Sperm movement in the ooplasm, dithiothreitol pretreatment and sperm freezing are not required for the development of porcine embryos derived from injection of head membrane-damaged sperm

The present study investigated the correlation of sperm movement in the ooplasm, pretreatment of sperm with dithiothreitol (DTT) and sperm freezing with the development of porcine embryos derived from modified intracytoplasmic sperm injection (ICSI). In vitro, matured gilt oocytes without centrifugation were injected with head membrane-damaged spermatozoa aspirated tail-first. In Exp. 1, frozen-thawed sperm were categorized into three groups: impaired, immotile or motile. Oocytes injected with motile sperm (43.6%) showed a higher (P < 0.05) fertilization rate compared to oocytes injected with impaired or immotile sperm (34.5 or 37.2%). The survival rate was significantly higher (P < 0.05) in oocytes injected with impaired sperm (92.9%) than in oocytes injected with immotile or motile sperm (84.8 or 86.7%). No differences were observed in the rates of cleavage or blastocyst formation, and in total cell number of blastocysts among three groups of oocytes. In Exp. 2, motile frozen-thawed sperm were pretreated with DTT before injection and non-treated sperm served as controls. Higher rates (P < 0.05) of fertilization, male pronucleus (MPN) and decondensed sperm head (DSH) formation were observed in oocytes injected with control sperm (41.1, 50.0 and 91.1%, respectively) than in oocytes injected with DTT-treated sperm (22.1, 30.2 and 72.1%, respectively). No differences in embryo development and total cell number of blastocysts were observed between two groups of oocytes. In Exp. 3, motile frozen-thawed or fresh sperm without DTT pretreatment were injected into oocytes. The rates of fertilization and MPN formation were significantly higher (P < 0.05) in oocytes injected with fresh sperm (59.8 and 73.5%) than in oocytes injected with frozen-thawed sperm (36.7 and 59.2%). No differences in embryo development and total cell number of blastocysts were observed between two groups of oocytes. In conclusion, the present study clearly demonstrated that sperm movement in the ooplasm, use of DTT and fresh spermatozoa did not significantly affect on embryo development in porcine modified ICSI.

Genetic counselling issues and male infertility

In the past few years, the major genetic causes of male infertility have been elucidated and many of these can now be treated using intracytoplasmic sperm injection (ICSI). This has raised a number of wider issues in the families of people with this type of infertility. Coupled with the essential need for individual (or family) confidentiality, this type of treatment demands a very careful and sensitive counselling approach. The main requirement is for fertility and genetic teams to collaborate to provide a person-oriented approach to the application of two very complex and intimidating technologies. An apparent difference between established fertility approaches and those of genetic teams relates to individual informed choice. The fertility team must address 'the welfare of the child' as is encapsulated in the Human Fertilisation and Embryology Authority (HFEA) Act of 1990. Since the welfare of the child is a subjective matter, decisions are often made by reproductive medicine ethics committees in conjunction with fertility teams. This aspect requires further development to include the ethos of genetic counselling, which is based more on individual informed choice for couples who have been provided with accurate information about the impact of a condition on a possible future child. The different ethical emphasis is not as great as it might initially appear. Ethics committees are now placing much more emphasis on a couple's autonomy in individual situations and, correspondingly, genetic centres are providing much more information about the possible effects of a couple's decision on the welfare of future children.

Performing ICSI using an injection pipette with the smallest possible inner diameter and a long taper increases normal fertilization rate, decreases incidence of degeneration and tripronuclear zygotes, and enhances embryo development

PURPOSE

To compare the efficacy of two types of injection pipette used for ICSI, one with a larger (5-7 microns) inner diameter and a shorter taper with that inner diameter, and another with the smallest (3-5 microns) possible inner diameter and a longer taper with that inner diameter.

METHODS

Retrieved oocytes at metaphase II stage were injected using one of two types of injection pipette, in 33 and 94 cycles, respectively, in a total of 127 cycles in 108 patients.

RESULTS

In comparison to the injection pipette with a larger (5-7 microns) inner diameter and a shorter taper with that inner diameter, the injection pipette with the smallest (3-5 microns) possible inner diameter and a longer taper with that inner diameter increased normal fertilization rate ((70 +/- 3.6)% vs. (86 +/- 2.2)%; P = .001; mean +/- SEM); decreased the incidence of degeneration ((14 +/- 2.4)% vs. (5 +/- 1.4)%; P = .001) and tripronuclear zygotes ((1.0 +/- 0.35)% vs. (0.1 +/- 0.21)%; P = .03); increased Day-2 diploid embryos ((69 +/- 3.7)% vs. (85 +/- 2.2)%; P = .001) and good-quality Day-2 diploid embryos ((67 +/- 4.0)% vs. (79 +/- 2.4)%; P = .03), all per injected oocyte; and increased the number of blastomeres per good-quality Day-2 diploid embryo ((3.0 +/- 0.21 vs. 3.8 +/- 0.12; P = .0003).

CONCLUSIONS

Performing ICSI using an injection pipette with the smallest (3-5 microns) possible inner diameter and a longer taper with that inner diameter maximizes normal fertilization rate, minimizes the incidence of postinjection degeneration and tripronuclear zygotes, and enhances embryo development.