No abstract

SUMMARYSperm DNA methylation abnormalities have been detected in oligozoospermic men. However, the association between sperm DNA methylation defects, sperm parameters and sperm DNA, and chromatin integrity remains poorly understood. This study was designed to clarify this issue. We recruited a cohort of 92 men (62 normozoospermic and 30 oligoasthenozoospermic) presenting for infertility evaluation during a 1-year period. Sperm global DNA methylation was evaluated by an ELISA-like method, DNA fragmentation was evaluated by flow cytometry-based terminal transferase dUTP nick end-labeling (TUNEL) assay (reported as DNA fragmentation index or DFI), and sperm denaturation was evaluated by aniline blue staining (reported as sperm denaturation index or SDI, a marker of chromatin compaction). We found a significant positive association between sperm global DNA methylation level and conventional sperm parameters (sperm concentration and motility), supported by the results of methylation analysis on H19-DMR. We also identified significant inverse relationships between sperm global DNA methylation, and, both DFI and SDI. However, sperm global DNA methylation level was not related to sperm vitality or morphology. Our findings suggest that global sperm DNA methylation levels are related to conventional sperm parameters, as well as, sperm chromatin and DNA integrity.

No abstract

Investigations of apparently balanced chromosomal rearrangements in patients with abnormal phenotype by molecular cytogenetics tools, especially by array CGH, revealed a proportion of unsuspected imbalances. It was estimated recently that 40% of apparently balanced de novo translocations with abnormal phenotype were associated with cryptic deletion. We explored 47 unrelated mental retardation patients carrying an apparently balanced chromosomal rearrangement with high-resolution oligonucleotides arrays. We included 33 de novo cases (21 translocations, 7 inversions and 5 complex chromosomal rearrangements (CCR)) and 14 inherited cases (7 translocations, 5 inversions and 2 CCR). Twenty of the 47 cases (42.6%) carried a cryptic deletion ranging from 60 kb to 15.37 Mb. It concerned 16/33 de novo rearrangements (8/21 translocations, 4/7 inversions and 4/5 CCR) and 4/14 inherited rearrangements (1/7 translocations, 2/5 inversions and 1/2 CCR). The proportion of imbalances was not statistically different between de novo and inherited cases. Our results support that about 40% apparently balanced chromosomal rearrangements with abnormal phenotype are in fact imbalanced and that these rearrangements should be systematically investigated by array CGH independently of their de novo or inherited character.

This study assessed sperm quality declining on relation to paternal age and its impact on in vitro fertilization (IVF) outcomes in order to estimate the APA (Advanced Paternal Age) cutoff. For this, 83 couples undergoing IVF treatment for male factor infertility were enrolled. The women age was ≤39 years, whereas the men were divided in two groups: APA (n = 41; age ≥ 40 years) and young (Y) (n = 42; age < 40 years). Conventional semen parameters (volume, concentration, motility, vitality, and morphology) were analyzed in the collected sperm samples. Furthermore, sperm genome decays (SGD) was assessed by TUNEL assay (DNA fragmentation), aniline blue staining (chromatin decondensation), and fluorescent in situ hybridization (aneuploidy). No significant difference was found concerning the conventional semen parameters between APA and Y groups. Conversely, SGD analysis showed increased DNA fragmentation; chromatin decondensation and sperm aneuploidy rates in the APA group (respectively, 41%, 43%, and 14% vs. 25%, 23%, and 4% in Y group). IVF outcomes also were affected by paternal age as indicated by the rates of cancelled embryo transfers, clinical pregnancy and miscarriage in the two groups APA and Y (29%, 17%, and 60% vs. 10%, 32%, and 42%). Finally, statistical analysis of the results suggests that the age of 40 should be considered as the APA cutoff during ART attempts.