Methylation changes in mature sperm deoxyribonucleic acid from oligozoospermic men: assessment of genetic variants and assisted reproductive technology outcome.

Objective: To characterize a potential genetic cause for methylation errors described in oligozoospermia.

Design: Analysis of PEG1/MEST-DMR and H19-DMR methylation level in sperm, in parallel with the study of several genes on the Y chromosome, DNMT3A, and DNMT3L. Clinical outcome was also looked at regarding PEG1/MEST-DMR and H19-DMR methylation level in sperm.

Sperm transcriptome profiling in oligozoospermia.

Purpose: Investigate in what extent sperm transcriptome of infertile men is different from that of fertile individuals.

Methods: Semen samples were collected for determination of sperm parameters as well as for RNA isolation. Gene expression profile was investigated in spermatozoa of 8 infertile and 3 fertile men by microarray analysis using the Affymetrix Chip HG-U133 Plus 2.

Polymorphisms in MTHFR and MTRR genes associated with blood plasma homocysteine concentration and sperm counts.

Objective: To investigate the relationship between MTHFR and MTRR genetic variants with respect to both blood plasma homocysteine concentration and sperm counts.

Design: Polymerase chain reaction followed by specific enzymatic digestion to determine the genotype of the individuals and blood plasma homocysteine quantification by high-performance liquid chromatography.

Setting: Research laboratory.

Malonaldehyde formation and DNA fragmentation: two independent sperm decays linked to reactive oxygen species.

Malondialdehyde (MDA), a product involved in membrane lipid peroxidation, was dosed in the sperm of 163 patients who had consulted the clinic regarding hypofertility. We attempted to determine if there was correlation between MDA content, sperm World Health Organization parameters and DNA fragmentation that results mainly from reactive oxygen species assaults. We found that no correlation could be established; however MDA and sperm decondensation were shown to be significantly linked.

Paternal age and sperm DNA decay: discrepancy between chromomycin and aniline blue staining.

The effect of paternal age on sperm DNA fragmentation and decondensation was determined in a retrospective study involving 1769 patients. TdT (terminal deoxynucleotidyl transferase)-mediated dUDP nick-end labelling (TUNEL) assay was used to assess fragmentation, and DNA decondensation was measured with either chromomycin or aniline blue staining. The impact of atypical forms was also analysed.

Imprinting: RNA expression for homocysteine recycling in the human oocyte.

Objective: To investigate whether homocysteine, a well known inhibitor of methylation, which is produced after imprinting and other methylation processes, can be recycled to methionine in the oocyte, at least until the stage of maternal to zygotic transition (i.e., four- to eight-cell stage); before this stage, most of the biochemical processes are carried out with the use of maternal stores of protein and mRNA.

Effect of maternal and paternal age on pregnancy and miscarriage rates after intrauterine insemination.

More than 17,000 intrauterine insemination (lUI) cycles were analysed retrospectively with respect to outcome according to differing aetiologies of infertility. The quantity and motility of spermatozoa in the final preparation used for insemination had a positive effect on the outcome, as classically observed in the past. It was found that advanced maternal age had a negative effect on the pregnancy rate and was associated with increased miscarriage rate.

Correlation between DNA damage and sperm parameters: a prospective study of 1,633 patients.

Objective: To investigate DNA fragmentation by using terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling in relation to World Health Organization parameters and computer-aided sperm analysis (CASA) in sperm to determine the possibility of obtaining a correlation among CASA parameters, sperm morphology, and DNA fragmentation.

Design: Sperm analysis according to World Health Organization parameters, terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) for sperm DNA fragmentation, and CASA for sperm movement. Prospective study.

Adequate ovarian follicular status does not prevent the decrease in pregnancy rates associated with high sperm DNA fragmentation.

Objective: Potential reparation of sperm DNA fragmentation in the oocyte may disturb any relationship between DNA-damaged sperm and the implantation ability of resulting embryos. To rule out this factor, we analyzed the consequences of sperm DNA fragmentation on IVF-ET outcome in women with healthy ovarian function.

Design: Prospective study.

Antioxidants to reduce sperm DNA fragmentation: an unexpected adverse effect.

Reactive oxygen species (ROS) have a negative impact on sperm DNA, leading to the formation of oxidative products such as 8-oxo-7,8-dihydroxyguanosine. This compound causes fragmentation and, thus, has a mutagenic effect. Patient treatment with oral antioxidant vitamins is, therefore, standard practice for male infertility, in an attempt to decrease formation of ROS and improve fertility.

High-magnification ICSI overcomes paternal effect resistant to conventional ICSI.

Previous studies have shown that repeated intracytoplasmic sperm injection (ICSI) failures can be caused by a paternal effect. Other studies have suggested that ICSI results are compromised if morphologically abnormal spermatozoa are injected into oocytes. This study was undertaken to evaluate the usefulness of a high-magnification optical system to select spermatozoa to be used for ICSI (high-magnification ICSI) in couples with repeated conventional ICSI failures.

Serum antimüllerian hormone/müllerian-inhibiting substance appears to be a more discriminatory marker of assisted reproductive technology outcome than follicle-stimulating hormone, inhibin B, or estradiol.

Objective: To test the hypothesis that the concentration of early follicular phase serum antimullerian hormone (AMH) or mullerian-inhibiting substance (MIS) is a useful marker of ovarian response and assisted reproductive technology (ART) outcome.

Design: Retrospective analysis of day 3 serum samples drawn before treatment.

Setting: Private ART program.

Multiparameter analysis of human oocytes at metaphase II stage after IVF failure in non-male infertility.

Background: Using fluorescence imaging, an a posteriori multiparametric analysis was performed of human oocytes which failed to give pronucleated zygotes after IVF in cases of very low rates of fertilization or complete fertilization failure.

Methods: The analysis included: (i) the state of the maternal and paternal chromatin; (ii) quality of the metaphase II oocytes; and (iii) cortical granule (CG) distribution.

Results: Most oocytes were arrested in metaphase II, but they were abnormal in 50% of cases.

Chromatin configuration and transcriptional control in human and mouse oocytes.

In vitro maturation of human oocytes at the germinal vesicle (GV) stage could offer an alternative in several cases of female infertility. It however rests on a better knowledge of the quality of human oocyte. Using fluorescence imaging of DNA and of the transcription sites, combined with electron microscopy, we show that human oocytes follow size-dependent changes in chromatin configuration, transcription sites distribution and nuclear ultrastructure that follow those observed in mouse GV oocytes.