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At least 19 recordsLinked to original sources
PubMed1997

Sperm-induced oocyte activation in the rhesus monkey: nuclear and cytoplasmic changes following intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) has increased the potential of the assisted reproductive technologies to propagate mammalian species and has provided an opportunity for research into cell cycle control and the mechanisms involved in sperm-induced oocyte activation. We have investigated the efficacy of ICSI in the rhesus monkey, the mechanism of fertilization following sperm injection and the cytoskeletal rearrangement that occurs upon oocyte activation. These studies were conducted on mature, and to a lesser extent, immature oocytes. Ejaculated spermatozoa, washed, capacitated and activated before immobilization, were injected into oocytes using conventional ICSI methodology. Sperm injection into mature oocytes induced oocyte activation (19/22; 86%) and pronuclear formation. In contrast, sham-injected oocytes did not activate readily (2/16; 13%). To localize oocyte activation factor(s), spermatozoa were separated mechanically into heads and tails which were then injected individually into mature oocytes. Activation occurred in 87% (20/23) of oocytes receiving heads. After tail injection, a single microtubule aster was nucleated and one pronucleus (PN) was seen in four of 21 oocytes. Intracytoplasmic injection of sperm extract (SE) resulted in oocyte activation at a significantly higher rate than occurred following sham injection (76 versus 13%). Sperm-induced oocyte activation was also evaluated in immature metaphase (MI) oocytes; activation occurred in 46% (12/26) of cases; however, only 8% of the activated oocytes exhibited 2 PN. Finally, beta-tubulin localization in untreated and taxol-treated oocytes was established as a marker for cytoplasmic changes associated with oocyte activation. These results are consistent with the hypothesis that spermatozoa contain an oocyte activating factor(s) which is primarily localized in the sperm head. Moreover, an activation response is limited to mature oocytes and is accompanied by cytoskeletal changes analogous to those seen following conventional fertilization.

Animals↗
PubMed1999

In vitro fertilization by intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is the latest, and by far the most efficient, variant of micromanipulation-assisted fertilization, whereby a single spermatozoon is selected, aspirated into a microinjection needle and injected to the oocyte cytoplasm. The development of this technique is mainly linked to application in human assisted reproduction for which it enables fertilization with defective spermatozoa that would not otherwise be able to penetrate an oocyte by their proper means. Because ICSI by-passes many steps of the natural fertilization process, it offers an extremely interesting model for the study of basic mechanisms underlying fertilization. This is particularly true for oocyte activation, whose mechanism needs to be revisited in light of the current ICSI research. The massive application of ICSI in human infertility treatment also represents a huge laboratory in which the impact of different genetic and epigenetic anomalies of the male gamete on fertilization and embryonic development can be studied.

Female↗
PubMed2001

Full term development of rabbit oocytes fertilized by intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) has been applied successfully in the treatment of male infertility in humans and in fertilization research in mice. However, the technique has had limited success in producing offspring in other species including the rabbit. The aim of this research was to test the in vitro and in vivo developmental of rabbit oocytes after ICSI. Sperm used for ICSI were collected from mature Dutch Belted buck and washed 2-3 times with PBS +0.1% polyvinyl alcohol (PVA) and then mixed with 10% polyvinyl pyrrolidone (PVP) prior to microinjection. Oocytes were collected from superovulated does 14-15 hr after hCG injection and were fertilized by microinjection of a single sperm into the ooplasm of each oocyte without additional activation treatment. After ICSI, the presumed zygotes were either cultured in KSOM +0.3% BSA for 4 days or transferred into oviducts of recipient does at the pronuclear or 2-cell stage. A high percentage of fertilization (78%, n = 114) and blastocyst development (39%) was obtained after ICSI. Control oocytes, receiving a sham injection, exhibited a lower activation rate (31%, n = 51) and were unable to develop to the blastocyst stage, suggesting that the blastocysts developed following ICSI were derived from successful fertilization rather than parthenogenetic development. A total of 113 embryos were transferred to six recipient does. Two recipients became pregnant and delivered seven live young. Our results demonstrated that rabbit oocytes can be successfully fertilized and activated by ICSI and can result in the birth of live offspring.

Animals↗
PubMed2000

Cellular and molecular events after in vitro fertilization and intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) has heralded an era of tremendous improvements in treating male infertility leading to the births of thousands of babies. However, recent concerns over possible long-term effects of ICSI on offspring has prompted the development of a preclinical, nonhuman primate model to assess the safety of ICSI. Fluorescent imaging of rhesus macaque IVF zygotes revealed that this species shares many similarities with humans in terms of cytoskeletal and chromatin dynamics during fertilization. However, rhesus monkey zygotes fertilized by ICSI resulted in abnormal nuclear remodeling leading to asynchronous chromatin decondensation in the apical region of the sperm head, delaying the onset of DNA synthesis. The persistence of the acrosome and perinuclear theca on the apex of sperm introduced into the oocyte by ICSI may constrict the DNA in this region. Despite these differences, normal rhesus monkey ICSI embryos have been produced and have lead to several births after transfer. The irregularities described in this paper raise concerns that the ICSI procedure may result in chromatin damage during DNA decondensation and further highlight the need for devising improved pre-clinical assessment prior to global acceptance of this, and other, novel methods of assisted reproduction.

Animals↗
PubMed2001

Genetic effects of intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) must be proved safe as well as efficacious. In this communication we first review available data following ICSI pregnancies concerning frequency of spontaneous abortion, malformations, and chromosomal abnormalities. In ICSI the spontaneous abortion rate is slightly increased, just as it is in in vitro fertilization (IVF) without ICSI. Among 6077 ICSI cycles begun in 1997 in the United States, there were 17.5% pregnancy losses. The same cohort showed a malformation rate of 1.7% in live-born infants. Malformations in live-born infants are not increased: 1.7% in the United States and 2.3% in Brussels. However, the Swedish IVF Registry encompassing 1139 ICSI infants found hypospadias to be increased (relative risk 2.9, 95% C.I. 1.4 to 5.4). Birth weight and prematurity rate in ICSI pregnancies seem similar to that following conventional IVF without ICSI. The category of genetic defects for which concerns have most often been raised is chromosomal abnormalities. A cohort of 1987 pregnancies in Brussels yielded a frequency of de novo autosomal rearrangements of 0.36% and a de novo sex chromosomal abnormalities of 0.83%. Both rates are higher than expected in the general population. Various explanations for these increased cytogenetic autosomal abnormalities are explored in this communication. In addition to arising from the procedure per se, a genetic or cytogenetic abnormality in offspring of an ICSI pregnancy could arise as result of offspring inheriting the mutant gene or chromosomal abnormality conferring paternal infertility: Y deletions (DAZ) in oligospermia males, cystic fibrosis in offspring of males with congenital bilateral absence vas deferens (CBAVD), and sex chromosomal abnormalities in offspring of Klinefelter syndrome (47,XXY) males.

Abortion, Spontaneous↗
PubMed2000

Clustering of male infertility in the families of couples treated with intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is an effective treatment modality for male factor infertility, but it could promote the transgenerational transmission of genetic defects causing gametogenic failure. Cytogenetic and molecular techniques permit the diagnosis of some infertility-causing genetic aberrations, but many more probably evade detection with currently available technology. The analysis of the recurrence pattern of infertility in infertile couples' families could define the importance of heritable factors in the pathogenesis of human infertility. We have subjected 621 consecutive infertile couples treated with ICSI in a single institution to a comprehensive genetic workup including documentation of the family history, karyotyping and various DNA tests. In all, 1302 fertile couples served as controls. Of the infertile couples 6.4% were shown to have a fertility problem with a definite genetic basis. Male, but not female fertility problems displayed a distinct pattern of familial aggregation. In addition, the infertile couples had fewer siblings than the fertile controls, a finding compatible with suboptimal fertility already among the infertile couples' parents. In summary, our data indicate that male factor infertility should be considered a potentially heritable condition. The recurrence risk for infertility in the offspring of couples treated with ICSI might be substantial.

Adult↗
PubMed2006

Effect of transgene concentration, flanking matrix attachment regions, and RecA-coating on the efficiency of mouse transgenesis mediated by intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) of DNA-loaded sperm cells has been shown to be a valuable tool for the production of transgenic animals, especially when DNA constructs with submegabase magnitude are used. In order to optimize and to understand the mechanism of the ICSI-mediated transgenesis, we have evaluated the impact of transgene DNA concentration, transgene flanking with nuclear matrix attachment regions (MARs), and the use of recombinase A (RecA)-coated DNA on the efficiency of mouse transgenesis production by ICSI. Presented data include assays with three DNA constructs; an enhanced green fluorescent protein (EGFP) plasmid of 5.4 kb, this plasmid flanked with two MAR elements (2.3 Kb of the human beta-interferon domain boundaries), and a yeast artificial chromosome (YAC) construct of approximately 510 kb (the largest transgenic construct introduced by ICSI that we have seen reported). ICSI-mediated transgenesis was done in the B6D2 mouse strain using different concentrations for each construct. Analysis of generated data indicated that ICSI allows the use of higher DNA concentrations than the ones used for pronuclear microinjection, however, when a certain threshold is exceeded, embryo/fetal viability decrease dramatically. In addition, independently of the transgene concentration tested, transgene flanking with MAR sequences did not have a significant impact on the efficiency of this transgenesis method. Finally, we observed that although the overall efficiency of ICSI-mediated transgenesis with fresh spermatozoa and RecA-complexed DNA was similar to the one obtained with the common ICSI-mediated transgenesis approach with frozen-thawed spermatozoa and RecA free DNA, this method was not as efficient in maintaining a low frequency of founder animal mosaicism, suggesting that different mechanisms of transgene integration might result from each procedure.

Animals↗
PubMed2005

Individual assessment of sperm morphology of single spermatozoa used for intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is an integral part of assisted reproduction. Although many papers have shown that global sperm count, sperm motility and sperm morphology of the ejaculate play no role in the fertilization rate after ICSI, embryologists who carry out ICSI, try to use the 'best looking' spermatozoa. The aim of the study was to investigate whether those spermatozoa with the best morphology really achieve the highest fertilization rate. In the present study, a total of 798 spermatozoa used for ICSI were documented by high-resolution photo. After ICSI the oocytes were cultured in single droplets and the formation of pronuclei was assessed 16 h later. The spermatozoa (all normal according to WHO criteria) were classified into four groups of different morphology. Group 1: normal head shape (approximately 5 microm diameter), group 2: like group 1, but with 15-20% smaller diameter, group 3: like group 1, but with 15-20% larger diameter, and group 4: like group 1, but with slight mid-piece cytoplasmic irregularities. Using the Pearson chi-square test, no significant difference in terms of fertilization was found among the different groups, showing that marginal sperm differences do not alter the fertilization process in ICSI.

Humans↗
PubMed2002

A comparative study of the effect of ovarian stimulation protocols with different gonadotropin preparations on the biological and clinical parameters of the outcome of intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is widely employed today in cases of severe male factor infertility. This technique requires denuding the oocytes from the surrounding granulosa cells prior to sperm injection. One can thus assess oocyte maturity more accurately and can study the effects of various ovarian stimulation protocols on egg maturation and the rest of the parameters of the outcome of ICSI. The aim of the present study was to compare the outcome of ovarian stimulation using human menopausal gonadotropin (hMG) with that achieved by using highly purified follicle stimulating hormone (pFSH). The biological and clinical parameters of the outcome of ICSI in 99 subfertile couples were studied. Group A consisted of 46 patients to whom hMG was administered and Group B consisted of 53 patients to whom pFSH was employed for ovarian stimulation. The fertilization rate was significantly higher in the pFSH group but all other factors were similar, including the percentage of mature oocytes and pregnancy rate. The latter does not seem to be affected by the gonadotropin preparation employed for ovarian stimulation. This is very helpful for the physician to know since a gonadotropin with a lower cost can be employed and, in addition, shortage of some preparations of gonadotropins occurs frequently.

Administration, Intranasal↗
PubMed2002

Intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) with ejaculated, epididymal or testicular spermatozoa was first successful in 1992 and has since become the widely accepted treatment for couples with severe male-factor infertility. The outcome of several thousands of ICSI cycles in terms of fertilization, embryo cleavage and implantation is similar to that for conventional in-vitro fertilization in couples with tubal or idiopathic infertility. To evaluate the important issue of safety of the new technique of ICSI, a prospective follow-up study of children born after ICSI was carried out. The aim was to compile data on karyotypes, congenital malformations, growth parameters and developmental milestones. Parents' agreement to genetic counseling was obtained, as well as prenatal diagnosis, followed by a physical examination of the children at 2 months, 1 and 2 years. Important outcome data to be examined comprise information on major and minor congenital malformations obtained prenatally or after birth, as well as on the further development of the children.

Adult↗
PubMed1994

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 Transfer↗
PubMed1997

Intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) can now alleviate infertility in couples who could not conceive by other means. Most patients with obstructive azoospermia and some patients with non-obstructive azoospermia can now be treated. The practice of five years of ICSI (1991-1995) is reviewed in terms of patients selection and counselling, controlled ovarian stimulation and oocyte handling, semen evaluation and preparation, ICSI procedure, oocyte damage and pronuclear status after ICSI, embryo development, embryo transfer, freezing of supernumerary embryos, obstetrical outcome, prenatal diagnosis and follow-up study of the children resulting from ICSI.

Embryo Transfer↗
PubMed2001

Fertilization rate and preimplantation development after intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is the treatment of choice in cases of male factor infertility. In the present review, all data from the literature regarding early fertlilization and preimplantation embryo development are analysed. ICSI seems to offer better fertilization rates than conventional IVF, even in the absence of a male factor and in prospective, randomized studies on sibling oocytes. Blastocyst formation is lower in ICSI than in IVF. This may be due to sublethal disturbances in oocyte architecture and function. Implantation and pregnancy rates, however, are similiar in ICSI and conventional IVF. Therefore, it can be concluded that ICSI offers a safe approach, as far as is known to date, for the treatment of male factor infertility. Embryo selection in cases of sublethal damage to oocytes seems to take place in the early preimplantation stages. Nor does the risk of monozygotic twinning, which was also proposed to be higher in ICSI compared with conventional IVF, seem to increase with this procedure.

Journal Article↗
PubMed1999

Evaluation of parental mitochondrial inheritance in neonates born after intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is now used when severe male-factor infertility has been documented. Since defective mitochondrial functions may result in male hypofertility, it is of prime importance to evaluate the risk of paternal transmission of an mtDNA defect to neonates. DNA samples from the blood of 21 infertile couples and their 27 neonates born after ICSI were studied. The highly polymorphic mtDNA D-loop region was analyzed by four PCR-based approaches. With denaturing gradient gel electrophoresis (DGGE), which allows 2% of a minor mtDNA species to be detected, the 27 newborns had a DGGE pattern identical to that of their mother but different from that of their father. Heteroplasmy documented in several parents and children supported an exclusive maternal inheritance of mtDNA. The parental origin of the children's mtDNA molecules also was studied by more-sensitive assays: restriction-endonuclease analysis (REA) of alpha[32P]-radiolabeled PCR products; paternal-specific PCR assay; and depletion of maternal mtDNA, followed by REA. We did not detect paternal mtDNA in nine neonates, with a sensitivity level of 0.01% in five children, 0.1% in two children, and 1% in two children. The estimated ratio of sperm-to-oocyte mtDNA molecules in humans is 0.1%-1.5%. Thus, we conclude that, in these families, the ICSI procedure performed with mature spermatozoa did not alter the uniparental pattern of inheritance of mtDNA.

Base Sequence↗
PubMed1996

Results of cytogenetic analysis in men with severe subfertility prior to intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is increasingly becoming the treatment of choice for severe male subfertility. Cytogenetic evaluation of men with andrological subfertility reveals an increased incidence of chromosomal abnormalities when compared with the normal population. We performed chromosomal analysis on the male partners of 32 couples referred for andrological subfertility. In two of these men, constitutional chromosomal translocations were diagnosed prior to ICSI [(45,XY,t(21;22)(p11;q11) and 46,XY,t(22;Y)(p11;q12)]. Since ICSI bypasses many potential barriers of fertilization, successful pregnancy can be achieved despite the presence of severely impaired spermatozoa in a population at high risk for chromosomal aberrations. It is well known that the presence of a chromosomal aberration plays a significant role in partial or complete spermatogenic arrest. ICSI does not seem to increase the risk of fetal chromosomal abnormalities when a spermatozoon from a chromosomally normal male is used. To exclude a higher risk for spontaneous abortion and fetal chromosomal abnormalities, we advocate cytogenetic screening of males with severe male subfertility who opt for ICSI.

Adult↗
PubMed1998

Indications for intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is the latest of several microfertilization techniques that have been utilized predominantly to overcome severe male subfertility, giving fertilization and term pregnancy rates similar to conventional in-vitro fertilization (IVF) (but for other indications). Even though available data on children born after ICSI are very encouraging, the procedure must still be considered as novel and the safety aspect to a great extent unexplored. In our opinion, therefore, ICSI should only be used for specific indications, and in this communication the non-existent, relative and absolute indications for performing ICSI are outlined and discussed. With an apparently normal sperm sample, ICSI should not be used in a first cycle even if only few oocytes are obtained. When there is reason to suspect poor fertilization, ICSI can be used in combination with conventional IVF in a split cycle. This includes cases of 'subnormal' sperm samples, high titres of antisperm antibodies, or following a single cycle of poor fertilization using conventional IVF. Absolute indications for ICSI include two previous fertilization failures with conventional IVF, use of epidiymal or testicular sperm samples, or when only acrosomeless or immotile spermatozoa are available. The fertilization of oocytes prior to preimplantation genetic diagnosis is another absolute indication. It is, however, important to keep in mind that for this novel technique, indications should not be rigid, but remain variable with respect to new findings.

Ciliary Motility Disorders↗
PubMedDate not supplied

[Oocyte maturation and intracytoplasmic sperm injection].

Intracytoplasmic sperm injection (ICSI), treatment of severe male infertility allows an accurate evaluation of oocyte maturity at recovery after corona-cell removal. In cycles comprising a GnRH analog desensitization and a stimulation by hMG or FSH, 12% of oocytes aspirated from follicles (> 14 mm), 34 hours post-hCG are still immature, in prophase or metaphase 1. They are able to achieve meiosis in vitro in 66% of the cases and will be fertilized (2 PN) by ICSI in 51% of the cases as the in vivo mature oocytes of the same cohort. Nevertheless, the quality of cytoplasmic maturation and consequently of embryonic viability remains to be assessed as there still are few pregnancies arising from in vitro matured oocytes. ICSI also represents the only way to obtain normal fertilization in some exceptional but observed anomalies of oocyte maturation, particularly when there is a lack of zona reaction leading to repetitive polyspermy in conventional IVF.

Adult↗
PubMed1996

[Micro-insemination with intracytoplasmic sperm injection].

Intracytoplasmic sperm injection (ICSI) is now established in the treatment of infertility. Fertilization is achieved by microinjection of a single spermatozoon into the ooplasma. Oligoasthenoteratozoospermia is the main indication, but ICSI is also used in cases of failed fertilization after standard IVF, retrograde ejaculation and male immunological infertility. In obstructive azoospermia ICSI is performed after aspiration of epididymal or testicular spermatozoa. In some anejaculatoric men spermatozon can be obtained following penile vibration or electro-stimulation, but they often have poor motility and ICSI may be used for fertilization. ICSI may also be used after thawing of semen cryopreserved prior to treatment of a malignant disease. Since 1991 the ICSI technique has been improved, and today the pregnancy rates are at least as good as after standard IVF. So far, studies of the foetuses and children born after ICSI show that the number of malformations and abnormal karyotypes is within the range of the normal population.

Female↗