Based on current findings, the presence of oxidative stress has a significant impact on the quality of gametes and embryos when performing assisted reproductive techniques (ART). Unfortunately, in vitro manipulation of these cells exposes them to a higher level of reactive oxygen species (ROS). The primary goal of this review is to provide a comprehensive overview of the development of oxidative stress in female and male reproductive systems, as well as in the case of the pre-implantation embryo and its environment. This review also focuses on the origins of ROS and the mechanisms of oxidative stress-induced damage during ART procedures. A well-known but underestimated hazard, light exposure-related photo-oxidation, is particularly concerning. The effect of oxidative stress on ART outcomes, as well as the various strategies for preventing it, are also discussed. We emphasize the role and significance of antioxidants and light protection including forms, functions, and mechanisms in the development of gametes and embryos in vivo and in vitro.

The global prevalence of insulin resistance (IR) is increasing continuously, influencing metabolic parameters and fertility. The metabolic changes due to IR can alter the molecular composition of plasma and other body fluids. Follicular fluid (FF) is derived mainly from plasma, and it is a critical microenvironment for the developing oocytes. It contains various metabolites and amino acids, and the quality of the oocytes is linked at least partially to amino acid metabolism. Our goal was to quantitatively determine the amino acid (AA) profile of FF in IVF patients and to compare IR and non-insulin resistance (NIR) groups to investigate the AA changes in their FF. Using UHPLC-based methods, we quantified the main 20 amino acids from human FF samples in the IR and NIR groups. Several amino acids (aspartate, glycine, glutamate, and cysteine) differed significantly (p < 0.05 or less) between the two groups. The most significant alterations between the IR and NIR groups were related to the glutathione metabolic pathway involving glycine, serine, and threonine. Since insulin resistance alters the amino acid composition of the FF, the oocytes may undergo metabolism-induced changes resulting in poor oocyte quality and less fertility in the insulin resistance groups.

Infertility affects millions worldwide, posing a significant global health challenge. The proteomic analysis of follicular fluid provides a comprehensive view of the complex molecular landscape within ovarian follicles, offering valuable information on the factors influencing oocyte development and on the overall reproductive health. The follicular fluid is derived from the plasma and contains various proteins that can have different roles in oocyte health and infertility, and this fluid is a critical microenvironment for the developing oocytes as well. Using the high-performance liquid chromatography-mass spectrometry method, we investigated the protein composition of the follicular fluid, and after classification, we carried out relative quantification of the identified proteins in the pregnant (P) and non-pregnant (NP) groups. Based on the protein–protein interaction analysis, albumin and apolipoprotein A1 (ApoA1) were found to be hub proteins, and the quantitative comparison of the P and NP groups resulted in a significantly lower concentration of ApoA1 and high-density lipoprotein cholesterol in the P group. As both molecules are involved in the cholesterol transport, we also investigated their role in the development of oocytes and in the prediction of fertility.

Background/Objectives: Endometriosis (EM) is a chronic gynecological condition associated with infertility, oxidative stress, and altered metabolic regulation. Follicular fluid (FF) reflects the microenvironment of the developing oocyte, and changes in its amino acid composition may affect reproductive outcomes. This study aimed to characterize alterations in the amino acid composition of the FF in EM and to identify potential reproductive outcomes. Methods: Targeted metabolomic analysis of 20 amino acids was performed on FF samples from 56 women undergoing in vitro fertilization (17 with endometriosis, 39 controls). Amino acid concentrations were quantified and compared between groups, adjusting for age and body mass index. Pathway, biomarker, and multivariate analyses were conducted to explore metabolic alterations and potential diagnostic markers. Results: Asparagine, histidine, and glycine concentrations were significantly higher in the EM group after adjustment for age and BMI. Pathway analysis indicated perturbations in glycine/serine metabolism, glutathione metabolism, and porphyrin metabolism, consistent with oxidative stress and mitochondrial dysfunction. Multivariate modeling demonstrated partial separation between groups, while biomarker analysis identified asparagine (AUC = 0.76), along with glycine and histidine, as potential discriminators. Additional enrichment of bile acid and methylation-related pathways suggested broader systemic metabolic changes in EM. Conclusions: EM is associated with distinct amino acid alterations in the FF, particularly elevated asparagine, histidine, and glycine, reflecting oxidative and mitochondrial imbalance in the follicular environment. These metabolites emerged as candidate biomarkers requiring validation for EM-related oocyte quality changes and may help individualize in vitro fertilization approaches.

This study aimed to evaluate the interrelationship between telomere length, telomerase activity and oxidative DNA damage in patients undergoing in vitro fertilization (IVF). This single-center, observational clinical study comprised 102 unselected, consecutive patients with various infertility diagnoses. Granulosa cells (GCs) and follicular fluid (FF) were analyzed simultaneously for telomere functions and for the marker of oxidative DNA damage, 8-hydroxy-2-deoxyguanosine (8-OHdG). An Absolute Human Telomere Lengths Quantification qPCR Assay kit and Telomerase Activity Quantification qPCR Assay kit (Nucleotestbio, Budapest, Hungary), as well as an 8-OHdG ELISA kit (Abbexa Ltd., Cambridge, United Kingdom) were used for analyses. Similar telomere lengths were found in GCs and FF, however telomerase activity was markedly depressed, while 8-OHdG levels were markedly elevated in FF compared with those in GCs (p < 0.01). Telomere lengths were independent of telomerase activity both in GCs and FF. However, GC 8-OHdG was inversely related to telomerase activity in GCs and FF (p < 0.05). Importantly, 8-OHdG levels both in GCs and FF had significant negative impact on the number of the retrieved and MII oocytes (p < 0.01), whereas FF 8-OHdG was negatively related further to the number of fertilized oocytes and blastocysts (p < 0.01). In conclusion, we could not confirm the direct association of telomere function and reproductive potential. However, oxidative DNA damage, as mainly reflected by 8-OHdG, adversely affected early markers of IVF outcome and clinical pregnancies.

The global prevalence of insulin resistance (IR) is increasing continuously, influencing metabolic parameters and fertility as well. The metabolic changes due to IR can alter the molecular composition of plasma and other body fluids. Follicular fluid (FF) is derived mainly from plasma, and it is a critical microenvironment for the developing oocytes. It contains various metabolites and amino acids, and the quality of the oocytes is linked at least partially to amino acid metabolism. Our goal was to determine quantitatively the amino acid (AA) profile of FF in IVF patients and to compare IR and non-insulin resistance (NIR) groups to investigate the AA changes in their FF. By UHPLC-based method we quantified the main 20 amino acids from human FF samples in the IR and NIR groups. Several amino acids (aspartate, glycine, glutamate, and cysteine) differed significantly (p<0.05 or less) between the two groups. The most significant alterations between the IR and NIR groups were related to the glutathione metabolic pathway involving glycine, serine, and threonine. Since insulin resistance alters the amino acid composition of the FF, the oocytes may undergo metabolism-induced changes resulting in poor oocyte quality and less fertility in the insulin resistance groups.