Search Results (117)

The sea urchin Paracentrotus lividus is a good model in ecotoxicology, but adults living along the Italian coasts have a limited reproductive period. In this species, natural or human-driven pressures may lead to limited gamete availability for ecotoxicological surveys. This study investigates the quality of early developmental stages of wild and cultured sea urchins to be used in ecotoxicology, avoiding field collection of mature specimens. Adult sea urchins were cultured in the laboratory for 2 years. Every 45 days, fertilization and larval quality were checked and compared to those from adults sampled in the wild. Fertilization was never affected, differently from development, which was impaired in the larvae obtained from sea urchins reared for more than one year. Fertilization and embryotoxicity were performed using copper nitrate in wild and cultured sea urchins. Fertilization did not differ up to ten months, while similar embryotoxicity was only found up to 5 months. This study promotes rearing sea urchins in ‘ready-to-spawn’ conditions for ecotoxicology surveys by recommending 10- and 5-month rearing times to assess fertilization and embryo toxicity, respectively. Here, we provided a baseline in marine ecotoxicology to obtain gametes on demand, irrespective of reproductive period and other pressures that may impact gamete availability. Full article

Numerous infants have been conceived by in vitro fertilization (IVF) and other assisted reproductive technologies (ART). Increasing evidence indicates that these approaches induce minor alterations in molecules during the initial phases of embryogenesis. This narrative review examines the molecular pathophysiology of embryonic cardiogenesis in the context of assisted reproductive technology, emphasizing transcriptional and epigenetic regulation. Essential transcription factors for cardiac development, including NKX2-5, GATA4, TBX5, ISL1, MEF2C, and HAND1/2, play a crucial role in mesodermal specification, heart tube formation, and chamber morphogenesis. Animal models and human preimplantation embryos have demonstrated that ART-related procedures, including gamete micromanipulation, supraphysiological hormone exposure, and extended in vitro culture, can alter the expression or epigenetic programming of these genes. Subsequent to ART, researchers have identified anomalous patterns of DNA methylation, alterations in histones, and modifications in chromatin accessibility in cardiogenic loci. These alterations indicate that errors occurred during the initial reprogramming process, potentially resulting in structural congenital heart abnormalities (CHDs) or modifications in cardiac function later in life. Analysis of the placental epigenome in babies conceived using assisted reproductive technology reveals that imprinted and developmental genes critical for cardiac development remain dysfunctional. This review proposes a mechanistic theory about the potential subtle alterations in the cardiogenic gene network induced by ART, synthesizing findings from molecular embryology, transcriptomics, and epigenomics. Understanding these molecular issues is crucial not only for enhancing ART protocols but also for evaluating the cardiovascular risk of children conceived by ART postnatally and for early intervention. Full article

The capability to generate induced pluripotent stem cells (iPSCs) from adult somatic cells, enabling them to differentiate into any cell type, has been demonstrated in several studies. In humans and mice, iPSCs have been shown to differentiate into primordial germ cells (PGCs), spermatozoa, and oocytes. However, research on iPSCs in deer is novel. Despite the necessity for establishing germplasm banks from endangered cervid species, the collection and cryopreservation of gametes and embryos have proven complex for this group. Therefore, the focus of this study was to establish protocols for deriving stable iPSC lines from Blastocerus dichotomus (Marsh deer) using primary cells derived from antler, adipose tissue, or skin, with the ultimate goal of producing viable gametes in the future. To achieve this, two main reprogramming approaches were tested: (1) transfection using PiggyBac transposons (plasmid PB-TET-MKOS) delivered via electroporation and (2) lentiviral transduction using the STEMCCA system with either human (hOSKM) or murine (mOSKM) reprogramming factors. Both systems utilized murine embryonic fibroblasts (MEFs) as feeder cells. The PiggyBac system was further supplemented with a culture medium containing small molecules to aid reprogramming, including a GSK inhibitor, MEK inhibitor, ALK/TGF inhibitor, and thiazovivin. Initial colony formation was observed; however, these colonies failed to expand post-selection. Despite these challenges, important insights were gained that will inform and guide future studies toward the successful generation of iPSCs in deer. Full article

Male-factor infertility accounts for approxiamately half of all infertility cases globally, yet therapeutic options remain limited for individuals with no retrievable spermatozoa, such as those with non-obstructive azoospermia (NOA). In recent years, artificial gametogenesis has emerged as a promising avenue for fertility restoration, driven by advances in two complementary strategies: organotypic in vitro spermatogenesis (IVS), which aims to complete spermatogenesis ex vivo using native testicular tissue, and in vitro gametogenesis (IVG), which seeks to generate male gametes de novo from pluripotent or reprogrammed somatic stem cells. To evaluate the current landscape and future potential of these approaches, a narrative, semi-systematic literature search was conducted in PubMed and Scopus for the period January 2010 to February 2025. Additionally, landmark studies published prior to 2010 that contributed foundational knowledge in spermatogenesis and testicular tissue modeling were reviewed to provide historical context. This narrative review synthesizes multidisciplinary evidence from cell biology, tissue engineering, and translational medicine to benchmark IVS and IVG technologies against species-specific developmental milestones, ranging from rodent models to non-human primates and emerging human systems. Key challenges—such as the reconstitution of the blood–testis barrier, stage-specific endocrine signaling, and epigenetic reprogramming—are discussed alongside critical performance metrics of various platforms, including air–liquid interface slice cultures, three-dimensional organoids, microfluidic “testis-on-chip” devices, and stem cell-derived gametogenic protocols. Particular attention is given to clinical applicability in contexts such as NOA, oncofertility preservation in prepubertal patients, genetic syndromes, and reprocutive scenarios involving same-sex or unpartnered individuals. Safety, regulatory, and ethical considerations are critically appraised, and a translational framework is outlined that emphasizes biomimetic scaffold design, multi-omics-guided media optimization, and rigorous genomic and epigenomic quality control. While the generation of functionally mature sperm in vitro remains unachieved, converging progress in animal models and early human systems suggests that clinically revelant IVS and IVG applications are approaching feasibility, offering a paradigm shift in reproductive medicine. Full article

Environmental xenobiotics, including heavy metals, endocrine-disrupting chemicals (EDCs), pesticides, air pollutants, nano- and microplastics, mycotoxins, and phycotoxins, are widespread compounds that pose significant risks to human health. These substances, originating from industrial and agricultural activities, vehicle emissions, and household products, disrupt cellular homeostasis and contribute to a range of diseases, including cancer and neurodegenerative diseases, among others. Emerging evidence indicates that epigenetic alterations, such as abnormal deoxyribonucleic acid (DNA) methylation, aberrant histone modifications, and altered expression of non-coding ribonucleic acids (ncRNAs), may play a central role in mediating the toxic effects of environmental xenobiotics. Furthermore, exposure to these compounds during critical periods, such as embryogenesis and early postnatal stages, can induce long-lasting epigenetic alterations that increase susceptibility to diseases later in life. Moreover, modifications to the gamete epigenome can potentially lead to effects that persist across generations (transgenerational effects). Although these modifications represent significant health risks, many epigenetic alterations may be reversible through the removal of the xenobiotic trigger, offering potential for therapeutic intervention. This review explores the relationship between environmental xenobiotics and alterations in epigenetic signatures, focusing on how these changes impact human health, including their potential for transgenerational inheritance and their potential reversibility. Full article

Reproductive toxicity is of special concern among the harmful effects induced by environmental pollutants; consequently, further studies on such a topic are required. To avoid the use of mammalians, lower eukaryotes like Drosophila are viable alternatives. This study addresses the gap in understanding the link between reproductive adverse outcomes and the presence of pollutants in reproductive organs by using Drosophila. Silver nanoparticles (AgNPs) were selected for their ease of internalization, detection, and widespread environmental presence. Both male and female flies were exposed to AgNPs (28 ± 4 nm, 100 and 400 µg/mL) for one week. Internalization and bioaccumulation of AgNPs in organs were assessed using transmission electron microscopy, confocal microscopy, and inductively coupled plasma mass spectrometry. Substantial accumulation of AgNPs in the gastrointestinal tract, Malpighian tubules, hemolymph, reproductive organs (ovaries and testes), and gametes were observed. The highest AgNP content was observed in testes. Exposure to AgNPs reduced ovary size and fecundity, though fertility and gender ratios of the offspring were unaffected. Significant deregulation of reproductive-related genes was observed, particularly in males. These findings underscore the utility of Drosophila as a model for evaluating reproductive hazards posed by AgNP exposure. The ease of AgNP internalization in Drosophila reproductive targets could be extrapolated to mammalians, raising concerns about the potential impacts of nanoparticle exposure on reproduction toxicity in humans. Full article

In mammals, the pineal hormone melatonin is the most powerful pacemaker of the master circadian clock and is responsible for reproduction in seasonal breeders. It is also well known that melatonin and its metabolites play antioxidant roles in many tissues, including reproductive cells. Melatonin synthesis and secretion from the pineal gland occurs during scotophase (the dark phase during a day–night cycle), while its inhibition is observed during photophase (period of light during a day–night cycle). Short-day breeders, such as goats, are stimulated to breed in a manner dependent on high endogenous levels of melatonin. This hormone can be synthesized in various extra-pineal tissues, such as retina, gastrointestinal tract, ovaries, and testis, with its main function being as a local antioxidant, given that melatonin and its metabolites are potent scavengers of reactive oxygen and nitrogen species. Moreover, it has been reported that some functions of melatonin can be exerted through plasma membrane and intracellular receptors expressed in the male reproductive system, including germ cells, immature and mature spermatozoa. It has been shown that melatonin may enhance gamete cryosurvival mainly by its addition into the media and/or in exogenous melatonin treatments in several species. In the present review, the physiological effects of endogenous melatonin in mammals are described, with a deeper focus on caprine reproduction. Additionally, results from recent investigations on the roles of exogenous melatonin aimed at improving the reproductive efficiency of goat bucks are discussed. There are contradictory findings and a limited amount of research available in the field of goat sperm cryopreservation associated with the use of melatonin. Understanding and improving goat reproduction and production is essential for many marginalized human populations around the world who directly depend on goats to maintain and improve their lifestyle. Full article

In this review, we introduce the concept of cell competition, which occurs between heterogeneous neighboring cell populations. Cells with higher relative fitness become “winners” that outcompete cells of lower relative fitness (“losers”). We discuss the idea of super-competitors, mutant cells that expand at the expense of wild-type cells. Work on adult stem cells (ASCs) has revealed principles of neutral competition, wherein ASCs can be stochastically lost and replaced, and of biased competition, in which a winning ASC with a competitive advantage replaces its neighbors. Germline stem cells (GSCs) are ASCs that are uniquely endowed with the ability to produce gametes and, therefore, impact the next generation. Mechanisms of GSC competition have been elucidated by studies in Drosophila gonads, tunicates, and the mammalian testis. Competition between ASCs is thought to underlie various forms of cancer, including spermatocytic tumors in the human testis. Paternal age effect (PAE) disorders are caused by de novo mutations in human GSCs that increase their competitive ability and make them more likely to be inherited, leading to skeletal and craniofacial abnormalities in offspring. Given its widespread effects on human health, it is important to study GSC competition to elucidate how cells can become winners or losers. Full article

Phenols, parabens, and phthalates (PPPs) are suspected or known endocrine disruptors. They are used in consumer products that pregnant women and their progeny are exposed to daily through the placenta, which could affect offspring health. This review aims to compile data from cohort studies and in vitro and in vivo models to provide a summary regarding placental transfer, fetoplacental development, and the predisposition to adult diseases resulting from maternal exposure to PPPs during the gestational period. In humans, using the concentration of pollutants in maternal urine, and taking the offspring sex into account, positive or negative associations have been observed concerning placental or newborn weight, children’s BMI, blood pressure, gonadal function, or age at puberty. In animal models, without taking sex into account, alterations of placental structure and gene expression linked to hormones or DNA methylation were related to phenol exposure. At the postnatal stage, pollutants affect the bodyweight, the carbohydrate metabolism, the cardiovascular system, gonadal development, the age of puberty, sex/thyroid hormones, and gamete quality, but these effects depend on the age and sex. Future challenges will be to explore the effects of pollutants in mixtures using models and to identify the early signatures of in utero exposure capable of predicting the health trajectory of the offspring. Full article

Spermatogenesis produces male gametes from spermatogonial stem cells (SSC), beginning at puberty. Modern-day laboratory techniques allow for the long-term culture of SSC and in vitro spermatogenesis. The specific biochemical processes that occur during spermatogenesis remain poorly understood. One particular element of spermatogenesis that has yet to be characterized is the role of microRNAs (miRNA), short, non-transcribed RNAs that act as post-translational regulators of gene activity. In this study, we seek to describe the presence of miRNA in a two-dimensional (2D) SSC culture and a 3D human testis organoid (HTO) system. Testicular cells were isolated from the frozen tissue of three brain-dead subjects, propagated in cultures for four to five weeks, and used to form 3D HTOs. Following organoid formation, differentiation of testicular cells was induced. RNA was isolated from the whole testis tissue (WT) showing in vivo conditions, HTO Day Zero (2D SSC culture), Day 2 HTOs, and Day 23 differentiated HTOs, then analyzed for changes in miRNA expression using the Nanostring nCounter miRNA panel. One hundred ninety-five miRNAs met the criteria for expression in WT, 186 in 2D culture, 190 in Day 2 HTOs, and 187 in differentiated HTOs. One hundred thirty-three miRNAs were common across all conditions, and 41, 17, 6, and 11 miRNAs were unique for WT, 2D culture, Day 2 HTOs, and differentiated HTOs, respectively. Twenty-two miRNAs were similar between WT and differentiated HTOS. We evaluated the miRNA expression profiles of progressively complex stages of testicular cell culture, culminating in a 3D organoid model capable of meiotic differentiation, and compared these to WT. We identified a great variance between the native tissue and the culture system; however, some miRNAs are preserved. These data may provide avenues for deeper understanding of spermatogenesis and the ability to improve this process in the laboratory. Research on miRNA continues to be an essential avenue for understanding human spermatogenesis. Full article

With the improvement of medical devices for diagnosis and radiotherapy, concerns about the effects of low doses of ionizing radiation are also growing. There is no consensus among scientists on whether they might have beneficial effects on humans in certain cases or pose more risks, making the exposure unreasonable. While the damaging consequences of high-dose radiation have been known since the discovery of radioactivity, low-dose effects present a much bigger investigative challenge. They are highly specific and include radio-adaptive responses, bystander effects, and genomic instability. Current data regarding the consequences of exposure to low-dose radiation on the quality of male gametes and fertility potential are contradictory. The reports suggest two directions: indirect impact on male gametes—through spermatogenesis—or direct effects at low doses on already mature spermatozoa. Although mature gametes are used for observation in both models, they are fundamentally different, leading to varied results. Due to their unique physiological characteristics, in certain cases, exposure of spermatozoa to low-dose ionizing radiation could have positive effects. Despite the findings indicating no beneficial effects of low-dose exposure on male fertility, it is essential to research its impact on mature spermatozoa, as well. Full article

Reproductive failure in dogs is often due to unknown causes, and correct diagnosis and treatment are not always achieved. This condition is associated with various congenital and acquired etiologies that develop inflammatory processes, causing an increase in the number of leukocytes within the female reproductive tract (FRT). An encounter between polymorphonuclear neutrophils (PMNs) and infectious agents or inflammation in the FRT could trigger neutrophil extracellular traps (NETs), which are associated with significantly decreased motility and damage to sperm functional parameters in other species, including humans. This study describes the interaction between canine PMNs and spermatozoa and characterizes the release of NETs, in addition to evaluating the consequences of these structures on canine sperm function. To identify and visualize NETs, May–Grünwald Giemsa staining and immunofluorescence for neutrophil elastase (NE) were performed on canine semen samples and sperm/PMN co-cultures. Sperm viability was assessed using SYBR/PI and acrosome integrity was assessed using PNA-FITC/PI by flow cytometry. The results demonstrate NETs release in native semen samples and PMN/sperm co-cultures. In addition, NETs negatively affect canine sperm function parameters. This is the first report on the ability of NETs to efficiently entrap canine spermatozoa, and to provide additional data on the adverse effects of NETs on male gametes. Therefore, NETs formation should be considered in future studies of canine reproductive failure, as these extracellular fibers and NET-derived pro-inflammatory capacities will impede proper oocyte fertilization and embryo implantation. These data will serve as a basis to explain certain reproductive failures of dogs and provide new information about triggers and molecules involved in adverse effects of NETosis for domestic pet animals. Full article

In recent years, the awareness that pesticides can have other effects apart from generic toxicity is growing. In particular, several pieces of evidence highlight their influence on human fertility. In this study, we investigated, by a virtual screening approach, the binding between pesticides and proteins present in human gametes or associated with reproduction, in order to identify new interactions that could affect human fertility. To this aim, we prepared ligand (pesticides) and receptor (proteins) 3D structure datasets from online structural databases (such as PubChem and RCSB), and performed a virtual screening analysis using Autodock Vina. In the comparison of the predicted interactions, we found that famoxadone was predicted to bind Cellular Retinol Binding Protein-III in the retinol-binding site with a better minimum energy value of −10.4 Kcal/mol and an RMSD of 3.77 with respect to retinol (−7.1 Kcal/mol). In addition to a similar network of interactions, famoxadone binding is more stabilized by additional hydrophobic patches including L20, V29, A33, F57, L117, and L118 amino acid residues and hydrogen bonds with Y19 and K40. These results support a possible competitive effect of famoxadone on retinol binding with impacts on the ability of developing the cardiac tissue, in accordance with the literature data on zebrafish embryos. Moreover, famoxadone binds, with a minimum energy value between −8.3 and −8.0 Kcal/mol, to the IZUMO Sperm–Egg Fusion Protein, interacting with a network of polar and hydrophobic amino acid residues in the cavity between the 4HB and Ig-like domains. This binding is more stabilized by a predicted hydrogen bond with the N185 residue of the protein. A hindrance in this position can probably affect the conformational change for JUNO binding, avoiding the gamete membrane fusion to form the zygote. This work opens new interesting perspectives of study on the effects of pesticides on fertility, extending the knowledge to other typologies of interaction which can affect different steps of the reproductive process. Full article

There has been emerging research linking per- and poly-fluoroalkyl substances (PFAS) to gamete viability and fertility. PFAS, prevalent in the environment and water supplies, undergo slow degradation due to their C-F bond and a long half-life (2.3–8.5 years). In females, PFAS inhibit the hypothalamic–pituitary–gonadal (HPG) axis, reducing follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, leading to the inhibition of androgen and estradiol production. PFAS have been found to cause detrimental effects on egg quality through impairing folliculogenesis. In males, PFAS can impair sperm motility and morphology: two fundamental qualities of successful fertilization. PFAS exposure has been proven to inhibit testosterone production, sperm capacitation, and acrosomal reaction. After fertilization, the results of PFAS exposure to embryos have also been investigated, showing reduced development to the blastocyst stage. The aim of this review is to report the main findings in the literature on the impact of PFAS exposure to gamete competency and fertilization capability by highlighting key studies on both male and female fertility. We report that there is significant evidence demonstrating the negative impacts on fertility after PFAS exposure. At high doses, these environmentally abundant and widespread compounds can significantly affect human fertility. Full article

The generation of mature gametes and competent embryos in vitro from pluripotent stem cells has been successfully achieved in a few species, mainly in mice, with recent advances in humans and scarce preliminary reports in other domestic species. These biotechnologies are very attractive as they facilitate the understanding of developmental mechanisms and stages that are generally inaccessible during early embryogenesis, thus enabling advanced reproductive technologies and contributing to the generation of animals of high genetic merit in a short period. Studies on the production of in vitro embryos in pigs and cattle are currently used as study models for humans since they present more similar characteristics when compared to rodents in both the initial embryo development and adult life. This review discusses the most relevant biotechnologies used in veterinary medicine, focusing on the generation of germ-cell-like cells in vitro through the acquisition of totipotent status and the production of embryos in vitro from pluripotent stem cells, thus highlighting the main uses of pluripotent stem cells in livestock species and reproductive medicine. Full article