Sperm flow cytometric parameters are associated with ICSI outcome

Molecular Drivers of Developmental Arrest in the Human Preimplantation Embryo: A Systematic Review and Critical Analysis Leading to Mapping Future Research

Developmental arrest of the preimplantation embryo is a multifactorial condition, characterized by lack of cellular division for at least 24 hours, hindering the in vitro fertilization cycle outcome. This systematic review aims to present the molecular drivers of developmental arrest, focusing on embryonic and parental factors. A systematic search in PubMed/Medline, Embase and Cochrane-Central-Database was performed in January 2021. A total of 76 studies were included. The identified embryonic factors associated with arrest included gene variations, mitochondrial DNA copy number, methylation patterns, chromosomal abnormalities, metabolic profile and morphological features. Parental factors included, gene variation, protein expression levels and infertility etiology. A valuable conclusion emerging through critical analysis indicated that genetic origins of developmental arrest analyzed from the perspective of parental infertility etiology and the embryo itself, share common ground. This is a unique and long-overdue contribution to literature that for the first time presents an all-inclusive methodological report on the molecular drivers leading to preimplantation embryos’ arrested development. The variety and heterogeneity of developmental arrest drivers, along with their inevitable intertwining relationships does not allow for prioritization on the factors playing a more definitive role in arrested development. This systematic review provides the basis for further research in the field.

Assessing the impact of semen quality on embryo development in an egg donation model

Objective

To investigate if any of the World Health Organization semen parameters and/or male age are associated with embryo development.

Design

Retrospective chart review between January 2008 and May 2015.

Setting

Academic fertility practice.

Patients

Anonymous egg donors aged ≤30 years.

Interventions

Chart review.

Main Outcome Measures

Sperm parameters were evaluated on a continuum and were dichotomized to determine if low values (strict morphology < 4%, concentration < 15 × 10⁶, low motility < 40%) or older age (>50 years) are associated with embryo morphology. Repeated linear regression measures to determine the associations and multivariate testing to determine independent effects for each predictor were performed.

Results

Three hundred eighty-four donors with 574 egg donation cycles were identified, and 205 subjects with 275 cycles were included in the final analysis. The mean donor age was 25.31 ± 2.81 years, with a mean antral follicle count of 28.09 ± 10.5. The mean male age was 43.25 ± 6.65 years. The mean World Health Organization semen parameters at fertilization were 55.8 × 10⁶ ± 44.3 × 10⁶/mL concentration, 44.8% ± 20.2% motility, and 6.9% ± 5.3% strict morphology. Neither male age nor sperm morphology was associated with embryo morphology. A low total motile count was significantly associated with a higher cell number in day-3 embryos and a 1.56-times higher chance of poor day-3 cell symmetry. There was no statistically significant difference in blastocyst formation, clinical pregnancy, or live-birth rates.

Conclusions

Although statistically significant, the effect of the low total motile count on day-3 cell number and cell symmetry are likely clinically insignificant. Male age, race, or poor sperm morphology were not associated with a poor cycle outcome or impaired embryo development. The use of intracytoplasmic sperm injection likely alleviates the negative effect of diminished semen quality on treatment outcome.

Effect of Spermatic Nuclear Quality on Live Birth Rates in Intracytoplasmic Sperm Injection

Background:

Our study defines the clinical role of sperm DNA damage in the assisted reproductive technology procedure.

Aim:

To investigate if the compaction of chromatin explored added to the analysis of the sperm DNA fragmentation allows obtaining a new indicator for sperm genome quality linked to live birth rate (LBR).

Design:

This was a prospective study, undergoing 101 cycles in the intracytoplasmic sperm injection (ICSI) program.

Materials and Methods:

The sperm DNA fragmentation index (DFI) has been measured with sperm chromatin dispersion examination. The sperm decondensation index (SDI) of chromatin has been measured with aniline blue procedure; with these indexes, a new parameter has been created: DFI × SDI.

Statistical Analysis:

Pearson's correlation coefficient, Student's t-test, and Chi-square test were used. The quantitative variables were described as mean ± standard deviation. Multivariate logistic regressions were performed with live birth as outcome.

Results:

The sperm concentration, motility, and normal morphology were lower when the DFI was high (P = 0.001). The fertilization rates and the number of obtained embryos were not statistically significant different according to the DFI groups. The SDI does not appear to be linked either with the spermatic parameters or with the ICSI parameters. A low DFI seems to be a beneficial factor to obtain a live birth in ICSI procedure (P = 0.064). In case of high DFI, a high SDI allows to obtain a higher LBR than a low SDI.

Conclusion:

The DFI is a good prognostic for a delivery rate in ICSI procedure, and the SDI could be added to DFI to create a new parameter of sperm nuclear quality. This new parameter seems to be linked to LBR.

A systematic review and meta-analysis to determine the effect of sperm DNA damage on in vitro fertilization and intracytoplasmic sperm injection outcome

Sperm DNA damage is prevalent among infertile men and is known to influence natural reproduction. However, the impact of sperm DNA damage on assisted reproduction outcomes remains controversial. Here, we conducted a meta-analysis of studies on sperm DNA damage (assessed by SCSA, TUNEL, SCD, or Comet assay) and clinical pregnancy after IVF and/or ICSI treatment from MEDLINE, EMBASE, and PUBMED database searches for this analysis. We identified 41 articles (with a total of 56 studies) including 16 IVF studies, 24 ICSI studies, and 16 mixed (IVF + ICSI) studies. These studies measured DNA damage (by one of four assays: 23 SCSA, 18 TUNEL, 8 SCD, and 7 Comet) and included a total of 8068 treatment cycles (3734 IVF, 2282 ICSI, and 2052 mixed IVF + ICSI). The combined OR of 1.68 (95% CI: 1.49–1.89; P < 0.0001) indicates that sperm DNA damage affects clinical pregnancy following IVF and/or ICSI treatment. In addition, the combined OR estimates of IVF (16 estimates, OR = 1.65; 95% CI: 1.34–2.04; P < 0.0001), ICSI (24 estimates, OR = 1.31; 95% CI: 1.08–1.59; P = 0.0068), and mixed IVF + ICSI studies (16 estimates, OR = 2.37; 95% CI: 1.89–2.97; P < 0.0001) were also statistically significant. There is sufficient evidence in the existing literature suggesting that sperm DNA damage has a negative effect on clinical pregnancy following IVF and/or ICSI treatment.