Unraveling the Balance between Genes, Microbes, Lifestyle and the Environment to Improve Healthy Reproduction

Evaluation of the impact of environmental pollutants on the sex ratio: a systematic review

In several industrialized countries, there has been a report of a decrease in the proportion of male births. The current study is designed to perform a systematic review and present a comprehensive summary of current epidemiological evidence of an association between exposure to the mentioned pollutants and sex ratio. The present systematic review was executed according to the PRISMA protocol. A comprehensive online search was performed in PubMed Medline, Scopus, Web of Science, Embase databases, Google Scholar, and the World Health Organization databases from 2000 to September 2023. After searching all databases, 20 articles were included in this systematic review. Regarding the studied pollutants found that exposure to increased PM10, PM2.5, and Nitrogen dioxide (NO2) levels was significantly associated with the sex ratio. Both maternal Benzophenone (BP)-2 and paternal BP-2 were significantly associated with an excess of female births. Finally, it must be said that the effect of some environmental pollutants on the sex ratio is undeniable. However, the sex ratio is the result of multiple factors that interact simultaneously during pregnancy. Additional research is required to examine the mechanisms responsible for the change in sex ratio.

Unveiling the Neurotransmitter Symphony: Dynamic Shifts in Neurotransmitter Levels during Menstruation

The menstrual cycle is an intricate biological process governed by hormonal changes that affect different facets of a woman's reproductive system. This review provides an overview of neurotransmitter alterations during different menstrual cycle phases and their effects on physiology and psychology. During the follicular phase, rising estrogen levels increase serotonin synthesis, enhancing mood, cognition, and pain tolerance. Estrogen may also influence dopamine levels, promoting motivation and reward sensitivity. GABA, involved in anxiety regulation, may be modulated by estrogen, inducing relaxation. Ovulation involves fluctuating dopamine and serotonin levels, potentially affecting motivation and positive mood. In the luteal phase, rising estrogen and progesterone may reduce serotonin availability, contributing to mood dysregulation, while enhanced GABAergic neurotransmission promotes sedation. Menstruation is characterized by declining estrogen and progesterone, potentially leading to mood disturbances, fluctuating GABAergic and dopaminergic neurotransmitter systems, relaxation, fatigue, motivation, and pleasure variations. Understanding neurotransmitter alterations during the menstrual cycle unveils the neurobiological mechanisms behind menstrual-related symptoms and disorders, facilitating targeted interventions. Pharmacological approaches targeting neurotransmitter systems, nutritional interventions, and lifestyle modifications show promise in managing menstrual symptoms. Future research should focus on further understanding neurotransmitter dynamics, personalized medicine, unexplored neurotransmitter roles, and integrating psychosocial factors. This knowledge will enhance well-being and quality of life for individuals experiencing menstrual-related challenges.

Autophagy and Female Fertility: Mechanisms, Clinical Implications, and Emerging Therapies

Autophagy, an evolutionarily conserved cellular mechanism essential for maintaining internal stability, plays a crucial function in female reproductive ability. In this review, we discuss the complex interplay between autophagy and several facets of female reproductive health, encompassing pregnancy, ovarian functions, gynecologic malignancies, endometriosis, and infertility. Existing research emphasizes the crucial significance of autophagy in embryo implantation, specifically in the endometrium, highlighting its necessity in ensuring proper fetal development. Although some knowledge has been gained, there is still a lack of research on the specific molecular impacts of autophagy on the quality of oocytes, the growth of follicles, and general reproductive health. Autophagy plays a role in the maturation, quality, and development of oocytes. It is also involved in reproductive aging, contributing to reductions in reproductive function that occur with age. This review explores the physiological functions of autophagy in the female reproductive system, its participation in reproductive toxicity, and its important connections with the endometrium and embryo. In addition, this study investigates the possibility of emerging treatment approaches that aim to modify autophagy, using both natural substances and synthetic molecules, to improve female fertility and reproductive outcomes. Additionally, this review intends to inspire future exploration into the intricate role of autophagy in female reproductive health by reviewing recent studies and pinpointing areas where current knowledge is lacking. Subsequent investigations should prioritize the conversion of these discoveries into practical uses in the medical field, which could potentially result in groundbreaking therapies for infertility and other difficulties related to reproduction. Therefore, gaining a comprehensive understanding of the many effects of autophagy on female fertility would not only further the field of reproductive biology but also open new possibilities for diagnostic and treatment methods.

Microbial Dysbiosis and Male Infertility: Understanding the Impact and Exploring Therapeutic Interventions

The human microbiota in the genital tract is pivotal for maintaining fertility, but its disruption can lead to male infertility. This study examines the relationship between microbial dysbiosis and male infertility, underscoring the promise of precision medicine in this field. Through a comprehensive review, this research indicates microbial signatures associated with male infertility, such as altered bacterial diversity, the dominance of pathogenic species, and imbalances in the genital microbiome. Key mechanisms linking microbial dysbiosis to infertility include inflammation, oxidative stress, and sperm structural deterioration. Emerging strategies like targeted antimicrobial therapies, probiotics, prebiotics, and fecal microbiota transplantation have shown potential in adjusting the genital microbiota to enhance male fertility. Notably, the application of precision medicine, which customizes treatments based on individual microbial profiles and specific causes of infertility, emerges as a promising approach to enhance treatment outcomes. Ultimately, microbial dysbiosis is intricately linked to male infertility, and embracing personalized treatment strategies rooted in precision medicine principles could be the way forward in addressing infertility associated with microbial factors.

Inference of drowning sites using bacterial composition and random forest algorithm

Diagnosing the drowning site is a major challenge in forensic practice, particularly when corpses are recovered from flowing rivers. Recently, forensic experts have focused on aquatic microorganisms, including bacteria, which can enter the bloodstream during drowning and may proliferate in corpses. The emergence of 16S ribosomal RNA gene (16S rDNA) amplicon sequencing has provided a new method for analyzing bacterial composition and has facilitated the development of forensic microbiology. We propose that 16S rDNA amplicon sequencing could be a useful tool for inferring drowning sites. Our study found significant differences in bacterial composition in different regions of the Guangzhou section of the Pearl River, which led to differences in bacteria of drowned rabbit lungs at different drowning sites. Using the genus level of bacteria in the lung tissue of drowned rabbits, we constructed a random forest model that accurately predicted the drowning site in a test set with 100% accuracy. Furthermore, we discovered that bacterial species endemic to the water were not always present in the corresponding drowned lung tissue. Our findings demonstrate the potential of a random forest model based on bacterial genus and composition in drowned lung tissues for inferring drowning sites.

Metagenomics Reveals Specific Microbial Features in Males with Semen Alterations

Infertility incidence is rising worldwide, with male infertility accounting for about 50% of cases. To date, several factors have been associated with male infertility; in particular, it has been suggested that semen microbiota may play a role. Here, we report the NGS-based analyses of 20 semen samples collected from men with (Case) and without (Control) semen alterations. Genomic DNA was extracted from each collected sample, and a specific PCR was carried out to amplify the V4-V6 regions of the 16S rRNA. Sequence reactions were carried out on the MiSeq and analyzed by specific bioinformatic tools. We found a reduced richness and evenness in the Case versus the Control group. Moreover, specific genera, the Mannheimia, the Escherichia_Shigella, and the Varibaculum, were significantly increased in the Case compared to the Control group. Finally, we highlighted a correlation between the microbial profile and semen hyperviscosity. Even if further studies are required on larger groups of subjects to confirm these findings and explore mechanistic hypotheses, our results confirm the correlation between semen features and seminal microbiota. These data, in turn, may open the way to the possible use of semen microbiota as an attractive target for developing novel strategies for infertility management.

Fibronectin Molecular Status in Plasma of Women with Endometriosis and Fertility Disorders

The diagnosis of endometriosis and fertility disorders is difficult; therefore, it is necessary to look for reliable biomarkers. Analysis of the molecular status of fibronectin as a key player in repair and wound healing processes, as well as in coagulation and fibrinolysis pathways, is justified. ELISA and SDS-agarose immunoblotting were applied to determine the fibronectin concentration and presence and occurrence of soluble FN-fibrin complexes in the blood plasma of women with endometriosis (n = 38), fertility disorders (n = 28) and the healthy group (n = 25). The concentration of fibronectin in the blood plasma of women with endometriosis (292.61 ± 96.17 mg/L) and fertility disorders (287.53 ± 122.68 mg/L) was significantly higher than in the normal group (226.55 ± 91.98 mg/L). The presence of FN-fibrin complexes of 750, 1000, 1300, 1600 and 1900 kDa in the plasma of women with endometriosis and fertility disorders was shown. The presence of FN-fibrin complexes with a molecular mass of more than 1300 kDa in women with endometriosis and infertility and the complete absence of these complexes in healthy women may indicate an increased and chronic activation of coagulation mechanisms in these patients. The presence of complexes of high molecular mass may be one of the biomarkers of fertility disorders in women.