Improving ICSI: A review from the spermatozoon perspective (original) (raw)
Related papers
2020
Since the introduction of intracytoplasmic sperm injection (ICSI), the importance of sperm morphology assessment has been given attention in the assisted reproduction field. It is important to select a good-quality motile spermatozoon for giving a better embryo quality in assisted reproduction technique (ART). In ICSI, sperm morphology evaluation is limited due to its low magnification. However, by using intracytoplasmic morphologically selected sperm injection (IMSI), the selection is done at high magnification of ×6600 using motile sperm organelle morphology examination (MSOME). Therefore, it becomes possible to select a good quality spermatozoon with an intact nucleus that may enhance the pregnancy outcomes. Although all patients can benefit from IMSI, it is important to standardize which techniques (IMSI or ICSI) could be used or which group of patients benefit from IMSI to maximize the efficiency of this advanced technology.
Focus on intracytoplasmic morphologically selected sperm injection (IMSI): a mini-review
Asian Journal of Andrology, 2013
Intracytoplasmic sperm injection (ICSI) is the recommended treatment in many cases of male-factor infertility. Several studies have demonstrated a positive correlation between optimal sperm morphology and positive ICSI outcomes. In fact, spermatozoa with severe abnormalities of the head are well documented to be associated with low fertilisation, implantation and pregnancy rates. However, a spermatozoon which is classified as 'normal' by microscopic observation at low magnification could contain ultrastructural defects that impair both the fertilisation process and embryonic development. The intracytoplasmic morphologically selected sperm injection (IMSI) procedure changed the perception of how a spermatozoon suitable for injection should appear. Sperm selection is carried out at 36000 magnification, allowing improved assessment of the sperm nucleus. Currently, standardized clinical indications for IMSI are lacking and the candidates are selected on the grounds of their medical history or of a careful analysis of the sperm suspension. Further prospective randomized studies are needed to confirm the advantages of IMSI in specific groups of patients. In addition to providing a brief overview of the IMSI procedure, this study aims to review the literature, which explains the theoretical basis and the clinical outcomes of this technique. Several reports show that IMSI is associated with improved implantation and clinical pregnancy rates as well as lower abortion rates when compared to ICSI. Although a possible correlation between the sperm's abnormal nucleus shape, increased DNA fragmentation and negative laboratory and clinical outcomes has been long investigated, the results are conflicting.
Using high magnification to select sperm: a large prospective cohort study comparing ICSI and IMSI
Clinical Obstetrics, Gynecology and Reproductive Medicine, 2020
Purpose: To compare two methods for the observation and selection of spermatozoa before microinjection. Methods: We analyzed 9012 treatment cycles-3339 cycles of intracytoplasmic sperm injection (ICSI) (37.1%) and 5673 cycles of intracytoplasmic injection of morphologically selected spermatozoa (IMSI) (62.9%)-for fertilization, pregnancy, live birth, and miscarriage rates. The primary endpoints were clinical pregnancy rate and live birth. Secondary endpoints were fertilization, blastulation, and miscarriage rates. Results: In the ICSI group, 530 cycles (15.9%) ended with no embryos appropriate for transfer or freezing, versus 426 cycles (7.5%) in the IMSI group (P < 0.01). After correction for age, body mass index, anti-Müllerian hormone level, and number of previous treatments, IMSI cycles were more likely to end in a pregnancy (odds ratio [OR] 1.17, P = 0.009). When the cohort was adjusted according to total motile sperm count, IMSI performed particularly well in cases with severe oligozoospermia: 70% more pregnancies (OR 1.68, 95% confidence interval [CI] 1.19-2.35) and twice as many live births (OR 2.05, 95% CI 1.36-3.08) compared with ICSI. The miscarriage rate was also significantly lower using IMSI (13.5%) than with ICSI (23.2%) (P = 0.03). Conclusion: We recommend that IMSI be considered immediately in cases of severe male factor infertility, and as a second-line approach in cases of ICSI failure.
Spermatozoa - Facts and Perspectives, 2018
Routine sperm parameters are used to evaluate fertility potential of the male partner. Since the introduction of intracytoplasmic sperm injection (ICSI), it seems that the importance of routine parameters of sperm morphology has decreased in the field of assisted reproduction. ICSI has facilitated to achieve fertilization, embryo development, and pregnancies, from the treatment of males with poor-quality spermatozoa. Morphology is the only criteria for sperm aspiration during ICSI. Routine criteria are based on the raw ejaculatestained sperm cells. Thus, it is important to score and aspirate a good-quality motile spermatozoon, which will contribute to the quality of the developing embryo after ICSI, in real time of the procedure. In ICSI, assessment of sperm morphology is limited due to the low magnification (200 × 400×) and concomitant low resolution. By using intracytoplasmic morphologically selected sperm injection (IMSI), it was demonstrated that a spermatozoon with normal morphology, and more precisely normal nucleus, might affect the incidence of pregnancy. Although the usage of IMSI is currently wider, it is necessary to standardize which sperm to aspirate, due to criteria based on accumulating data. Correlation to DNA integrity, embryo development in vitro, female age, male age, or the routine use of IMSI for all cases are raised in order to maximize the efficiency of IMSI technology.
Reproductive BioMedicine Online, 2009
Marco Nadalini obtained his Biology degree in 2002 at the University of Bologna, Italy. Since then he has been working in the field of assisted reproduction and in 2006 he became a permanent staff member of Tecnobios Procreazione, Centre for Reproductive Health in Bologna. Current research interests include cytogenetic and male infertility, especially regarding molecular biology of the male germ cell and structure of sperm chromatin.
International journal of fertility & sterility, 2014
The intra-cytoplasmic sperm injection (ICSI) technique selects sperm according to morphology and motility. However, these parameters cannot predict the chromatin integrity of sperm. Considering the detrimental effects of DNA-damaged sperm on reproductive outcomes, novel sperm selection procedures have been proposed to circumvent the possibility of inseminating DNA-damaged sperm. It has been shown that different potential hypo-osmotic swelling test (HOST) patterns possess the potential to differentiate between sperm that have intact or damaged chromatin. Therefore, for the first time, this preliminary study evaluates the role of HOST as a sperm selection procedure in a clinical setting. In this preliminary prospective clinical trial study, we divided infertile couples diagnosed with male infertility into two groups. In the treatment group (n=39), half of the oocytes were inseminated by sperm selected following density gradient centrifugation (DGC group). The remaining oocytes from th...
Intracytoplasmic sperm injection (ICSI) in 2006: Evidence and Evolution
Human Reproduction Update, 2007
The introduction of intracytoplasmic sperm injection (ICSI) in 1992 has dramatically changed the management of severe male infertility. In severe male infertility, live birth rates with ICSI are superior to those with other nondonor treatments. In non-male infertility, however, pregnancy rates are not better with ICSI than with in vitro fertilization (IVF). With obstructive or non-obstructive azoospermia, reasonable pregnancy rates are now possible with ICSI after recovery of sperm from the testes followed by ICSI. Genetic counselling is indicated for severe male infertility, whether or not ICSI is considered. ICSI is indicated in preimplantation genetic diagnosis (PGD) to avoid contamination by extraneous DNA in the case of PCR-based testing and to increase the number of embryos available for testing. In turn, PGD may be indicated in pregnancies that are at high risk of aneuploidy because of genetic factors associated with azoospermia. As with IVF, not all couples succeed, but 2% of couples with failed ICSI cycles will conceive without treatment. ICSI outcome studies indicate that there is a significant increase in prematurity, low birthweight, and perinatal mortality associated with single and multiple births, similar to the outcomes of conventional IVF. However, as evidenced in long-term follow-up studies, the higher rates of urogenital abnormalities and increased use of healthcare may be associated with paternal characteristics.
When to do intracytoplasmic sperm injection: a prospective comparison
Archives of Gynecology and Obstetrics, 2019
Purpose The purpose of the study was to assess the fertilization rate and embryo development in sibling human oocytes after split insemination in patients with and without isolated teratozoospermia. Methods A prospective cohort study at a university affiliated reproduction center was performed. Hundred and three patients during the time periods 01-2013 to 12-2015 had split insemination ordered for their first IVF cycle. The primary outcome measured was fertilization rate. Secondary outcomes were the number and quality of embryos. Results Mature oocytes at the time of collection were assigned as follows: 558 to IVF and 556 to ICSI. An additional 48 immature oocytes matured while awaiting spontaneous fertilization with IVF for a total of 606 in that group. The study group of normal strict sperm morphology ≤ 4 included 61 patients, and the control group included 42 patients with normal strict sperm morphology > 4. ICSI was statistically favored over IVF only in cases with normal strict sperm morphology ≤ 4%. There was a higher fertilization rate in ICSI compared to IVF (74.4% vs. 38%, p < 0.0001), a higher number of day 2 (4 ± 3.4 vs. 2.4 ± 2.7, p < 0.0001), day 3 (4 ± 3.4 vs. 2.2 ± 2.7, p < 0.0001) and day 5 embryos (2.2 ± 2.6 vs. 1.2 ± 2, p = 0.001), and they were of better quality; however, it did not reach significance (p = 0.062). A similar advantage for ICSI was seen in a subgroup of unexplained infertility with normal strict sperm morphology > 4%. Conclusions In conclusion, in couples with normal strict sperm morphology ≤ 4%, there is an advantage of ICSI over IVF in terms of fertilization rate, quantity and quality of cleavage stage embryos and blastocysts. Based on the results, ICSI seems reasonable as a first-line treatment in patients with normal strict sperm morphology ≤ 4%, as well as in patients with unexplained infertility.