Endocrine disrupting chemicals and male fertility: from physiological to molecular effects.

The deleterious effects of chemical or non-chemical endocrine disruptors (EDs) on male fertility potential is well documented but still not fully elucidated. For example, the detection of industrial chemicals' metabolites in seminal plasma and follicular fluid can affect efficiency of the gametogenesis, the maturation and competency of gametes and has guided scientists to hypothesize that endocrine disrupting chemicals (EDCs) may disrupt hormonal homoeostasis by leading to a wide range of hormonal control impairments. The effects of EDCs exposure on reproductive health are highly dependent on factors including the type of EDCs, the duration of exposure, individual susceptibility, and the presence of other co-factors. Research and scientists continue to study these complex interactions. The aim of this review is to summarize the literature to better understand the potential reproductive health risks of EDCs in France.

Effect of Micronutrients and L-Carnitine as Antioxidant on Sperm Parameters, Genome Integrity, and ICSI Outcomes: Randomized, Double-Blind, and Placebo-Controlled Clinical Trial.

The evaluation of sperm DNA integrity is recommended in the sixth edition of the 2021 World Health Organization guidelines. Oxidative stress has been identified as a crucial factor leading to genome decay, lipid peroxidation, and nucleoprotein oxidation. This double-blind, placebo-controlled clinical trial aimed to assess the effect of oral antioxidant treatment (Fertilis), which contains L-carnitine and some micronutrients, in the improvement of conventional sperm parameters, sperm DNA integrity and in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes. A total of 263 participants were enrolled and randomly divided into two groups: 131 participants received the antioxidant treatment, while 132 participants received a placebo. The male partners in both groups underwent the antioxidant treatment or the placebo for a duration of three months. For each participant, we performed a hormonal test, an infectious test, a spermogram, a TUNEL assay for sperm DNA fragmentation, a toluidine blue staining for sperm DNA decondensation, and an IVF/ICSI procedure. Sperm characteristics analysis (volume, count, motility, and vitality), sperm DNA fragmentation, and sperm DNA decondensation were assessed and compared to the results preceding the antioxidant treatment. The study outcome revealed a significant decrease in the DNA fragmentation index and a significant increase in sperm motility after 3 months of treatment (p = 0.01 and p = 0.02, respectively). Additionally, a significant improvement in clinical pregnancy rate (p = 0.01) and life birth rate (p = 0.031) was observed. No significant changes were observed in conventional sperm parameters (volume, count, and vitality) or sperm DNA decondensation (SDI). Antioxidant therapy has a beneficial impact on achieving pregnancy, whether through spontaneous conception or assisted reproductive procedures (ART).

Paternal Age Matters: Association with Sperm Criteria's- Spermatozoa DNA Integrity and Methylation Profile.

Advanced age has been reported to negatively affect sperm parameters and spermatozoa DNA integrity. A decline in sperm criteria was also associated with altered epigenetic marks such as DNA methylation with a potential downstream impact on in vitro fertilization success and clinical outcomes. The aim of the present retrospective study was to clarify the association between advanced paternal age (APA) and sperm parameters, DNA integrity and DNA methylation profile. A total of 671 patients consulting for infertility underwent sperm analysis, sperm DNA integrity assessment and methylation level measurement. The principal finding was that individuals over 40 years of age exhibit a significant increase in DNA fragmentation levels compared to the younger group (15% versus 9%, respectively, p = 0.04). However, there was no significant difference in DNA decondensation and sperm parameters in association with APA. In addition, a drop in the global methylation level was also found in men over 40 years (6% in the young group versus 2% in the old group, p = 0.03). As a conclusion, men over 40 years are at higher risk of elevated sperm DNA fragmentation and lower methylation level. Based on these observations, it is recommended that the assessment of sperm DNA fragmentation should be taken into consideration particularly after the age of 40. Our findings support the idea that paternal age is a crucial factor that should not be neglected during fertility evaluation and treatment since it is associated with epigenetics changes in sperm. Although the underlying mechanism remains to be clarified, we believe that environmental and professional exposure factors are likely involved in the process.