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International Journal of Molecular... Jan 2022Changes in the female genital tract microbiome are consistently correlated to gynecological and obstetrical pathologies, and tract dysbiosis can impact reproductive... (Review)
Review
Changes in the female genital tract microbiome are consistently correlated to gynecological and obstetrical pathologies, and tract dysbiosis can impact reproductive outcomes during fertility treatment. Nonetheless, a consensus regarding the physiological microbiome core inside the uterine cavity has not been reached due to a myriad of study limitations, such as sample size and experimental design variations, and the influence of endometrial bacterial communities on human reproduction remains debated. Understanding the healthy endometrial microbiota and how changes in its composition affect fertility would potentially allow personalized treatment through microbiome management during assisted reproductive therapies, ultimately leading to improvement of clinical outcomes. Here, we review current knowledge regarding the uterine microbiota and how it relates to human conception.
Topics: Dysbiosis; Endometrium; Female; Fertilization; Humans; Microbiota; Pregnancy; Pregnancy Outcome; Virulence
PubMed: 35008911
DOI: 10.3390/ijms23010485 -
JBRA Assisted Reproduction Mar 2016Fertility - the ability to produce offspring - is considered a prerequisite for the development and perpetuation of species. Several factors may positively or negatively... (Review)
Review
Fertility - the ability to produce offspring - is considered a prerequisite for the development and perpetuation of species. Several factors may positively or negatively affect one's reproductive capabilities, such as regular exercises and maintaining a healthy bodyweight, versus aging, obesity, and stress. Follicular fluid (FF) is a liquid composed primarily of hormones, enzymes, anticoagulants, electrolytes, reactive oxygen species and antioxidants, which fills the follicular antrum and acts as an important mediator in the communication between cells in the antral follicle while bathing and carrying nutrients to the oocyte. Thus, human FF is a key element to the success of natural fertilization present in every stage of the conception process, from the communication between gametes to the development of fully viable embryos, and a vital component in the occurrence of spontaneous pregnancies. This literature review aimed to describe the possible effects of human follicular fluid on the natural fertilization process and to assess its role in follicular growth, oocyte quality, sperm capacitation, fertilization, and early embryonic development.
Topics: Female; Fertilization; Follicular Fluid; Humans; Male; Pregnancy; Sperm Capacitation
PubMed: 27203305
DOI: 10.5935/1518-0557.20160009 -
Current Topics in Developmental Biology 2019Gametogenesis, the process of forming mature germ cells, is an integral part of both an individual's and a species' health and well-being. This chapter focuses on... (Review)
Review
Gametogenesis, the process of forming mature germ cells, is an integral part of both an individual's and a species' health and well-being. This chapter focuses on critical male and female genetic and epigenetic processes underlying normal gamete formation through their differentiation to fertilization. Finally, we explore how knowledge gained from this field has contributed to progress in areas with great clinical promise, such as in vitro gametogenesis.
Topics: Animals; Cell Differentiation; Embryonic Stem Cells; Female; Fertilization; Gametogenesis; Gene Expression Regulation, Developmental; Germ Cells; Humans; Male
PubMed: 30797511
DOI: 10.1016/bs.ctdb.2018.12.006 -
Frontiers in Endocrinology 2022Fertilization failure during assisted reproductive technologies (ART) is often unpredictable, as this failure is encountered only after in vitro fertilization (IVF) and... (Review)
Review
Fertilization failure during assisted reproductive technologies (ART) is often unpredictable, as this failure is encountered only after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) have been performed. The etiology of fertilization failure remains elusive. More and more mutations of genes are found to be involved in human fertilization failure in infertile patients as high throughput sequencing techniques are becoming widely applied. In this review, the mutations of nine important genes expressed in sperm or oocytes, , and , were summarized and discussed. These abnormalities mainly have shown Mendelian patterns of inheritance, including dominant and recessive inheritance, although de novo mutations were present in some cases. The review revealed the crucial roles of each reported gene in the fertilization process and summarized all known mutations and their corresponding phenotypes. The review suggested the mutations might become promising targets for precision treatments in reproductive medicine. Moreover, our work will provide some helpful clues for genetic counseling, risk prediction, and optimizing clinical treatments for human infertility by supplying the useful and timely information on the genetic causes leading to fertilization failure.
Topics: Humans; Male; Fertilization; Fertilization in Vitro; Infertility; Mutation; Semen; Sperm Injections, Intracytoplasmic; Tubulin
PubMed: 36589837
DOI: 10.3389/fendo.2022.1086883 -
Fertility and Sterility Oct 2020
Topics: Cerclage, Cervical; Counseling; Female; Fertilization; Humans; Pregnancy; Robotics; Uterine Cervical Incompetence
PubMed: 33040984
DOI: 10.1016/j.fertnstert.2020.08.1401 -
Reproduction & Fertility Jan 2022Lipids are dynamic biological molecules that play key roles in metabolism, inflammation, cell signalling and structure. They are biologically significant in the... (Review)
Review
UNLABELLED
Lipids are dynamic biological molecules that play key roles in metabolism, inflammation, cell signalling and structure. They are biologically significant in the physiology of conception and reproduction. Many of the mechanisms surrounding equine conception and the early feto-maternal dialogue are yet to be understood at a biochemical level. Recently, lipidomic technologies have advanced considerably and analytical strategies have been enhanced and diversified. Consequently, in-depth lipidomic exploration now has the potential to reveal new lipid biomarkers and biochemical relationships that improve our understanding of the processes leading to efficient and successful reproduction. This review considers the role of lipids in conception and establishment of pregnancy, providing new insights into the enigmatic pathways governing early reproductive physiology of the mare.
LAY SUMMARY
This paper discusses the role that lipids play in the very early stages of pregnancy in the mare. Lipids are microscopic non-soluble molecules that are important components of living cells. The manuscript discusses how lipids influence the reproductive cycle of mares, including ovulation and the detailed biological process of becoming pregnant. It explains how lipids are identified in a laboratory setting with a newly developing technology known as 'lipodomics'. The technology may lead to a more detailed understanding of how mares become pregnant. The focus of the paper is on mare reproduction, but it also draws on similarities with reproduction in other mammals. Remarkably there are gaps in much of our knowledge about the finer details of pregnancy in the horse, and the paper summarises what we already know about lipids, highlighting areas for further research.
Topics: Animals; Female; Fertilization; Horses; Lipidomics; Lipids; Mammals; Pregnancy; Reproduction
PubMed: 35350651
DOI: 10.1530/RAF-21-0104 -
Cold Spring Harbor Perspectives in... Oct 2015Vertebrate reproduction requires a myriad of precisely orchestrated events-in particular, the maternal production of oocytes, the paternal production of sperm,... (Review)
Review
Vertebrate reproduction requires a myriad of precisely orchestrated events-in particular, the maternal production of oocytes, the paternal production of sperm, successful fertilization, and initiation of early embryonic cell divisions. These processes are governed by a host of signaling pathways. Protein kinase and phosphatase signaling pathways involving Mos, CDK1, RSK, and PP2A regulate meiosis during maturation of the oocyte. Steroid signals-specifically testosterone-regulate spermatogenesis, as does signaling by G-protein-coupled hormone receptors. Finally, calcium signaling is essential for both sperm motility and fertilization. Altogether, this signaling symphony ensures the production of viable offspring, offering a chance of genetic immortality.
Topics: Acrosome Reaction; Animals; Calcium Signaling; Cell Division; Cell Proliferation; Female; Fertilization; Humans; Male; Meiosis; Oocytes; Reproduction; Signal Transduction; Sperm Capacitation; Spermatogenesis; Spermatozoa; Stem Cells; Vertebrates; Zygote
PubMed: 26430215
DOI: 10.1101/cshperspect.a006064 -
The New England Journal of Medicine Dec 1995The timing of sexual intercourse in relation to ovulation strongly influences the chance of conception, although the actual number of fertile days in a woman's menstrual...
BACKGROUND
The timing of sexual intercourse in relation to ovulation strongly influences the chance of conception, although the actual number of fertile days in a woman's menstrual cycle is uncertain. The timing of intercourse may also be associated with the sex of the baby.
METHODS
We recruited 221 healthy women who were planning to become pregnant. At the same time the women stopped using birth-control methods, they began collecting daily urine specimens and keeping daily records of whether they had sexual intercourse. We measured estrogen and progesterone metabolites in urine to estimate the day of ovulation.
RESULTS
In a total of 625 menstrual cycles for which the dates of ovulation could be estimated, 192 pregnancies were initiated, as indicated by increases in the urinary concentration of human chorionic gonadotropin around the expected time of implantation. Two thirds (n = 129) ended in live births. Conception occurred only when intercourse took place during a six-day period that ended on the estimated day of ovulation. The probability of conception ranged from 0.10 when intercourse occurred five days before ovulation to 0.33 when it occurred on the day of ovulation itself. There was no evident relation between the age of sperm and the viability of the conceptus, although only 6 percent of the pregnancies could be firmly attributed to sperm that were three or more days old. Cycles producing male and female babies had similar patterns of intercourse in relation to ovulation.
CONCLUSIONS
Among healthy women trying to conceive, nearly all pregnancies can be attributed to intercourse during a six-day period ending on the day of ovulation. For practical purposes, the timing of sexual intercourse in relation to ovulation has no influence on the sex of the baby.
Topics: Adult; Age Factors; Chorionic Gonadotropin; Coitus; Female; Fertilization; Humans; Male; Ovulation; Pregnancy; Prospective Studies; Sex Preselection; Spermatozoa; Time Factors
PubMed: 7477165
DOI: 10.1056/NEJM199512073332301 -
Biological Reviews of the Cambridge... Apr 2020Mammalian sperm must spend a minimum period of time within a female reproductive tract to achieve the capacity to fertilize oocytes. This phenomenon, termed sperm... (Review)
Review
Mammalian sperm must spend a minimum period of time within a female reproductive tract to achieve the capacity to fertilize oocytes. This phenomenon, termed sperm 'capacitation', was discovered nearly seven decades ago and opened a window into the complexities of sperm-female interaction. Capacitation is most commonly used to refer to a specific combination of processes that are believed to be widespread in mammals and includes modifications to the sperm plasma membrane, elevation of intracellular cyclic AMP levels, induction of protein tyrosine phosphorylation, increased intracellular Ca levels, hyperactivation of motility, and, eventually, the acrosome reaction. Capacitation is only one example of post-ejaculatory modifications to sperm (PEMS) that are widespread throughout the animal kingdom. Although PEMS are less well studied in non-mammalian taxa, they likely represent the rule rather than the exception in species with internal fertilization. These PEMS are diverse in form and collectively represent the outcome of selection fashioning complex maturational trajectories of sperm that include multiple, sequential phenotypes that are specialized for stage-specific functionality within the female. In many cases, PEMS are critical for sperm to migrate successfully through the female reproductive tract, survive a protracted period of storage, reach the site of fertilization and/or achieve the capacity to fertilize eggs. We predict that PEMS will exhibit widespread phenotypic plasticity mediated by sperm-female interactions. The successful execution of PEMS thus has important implications for variation in fitness and the operation of post-copulatory sexual selection. Furthermore, it may provide a widespread mechanism of reproductive isolation and the maintenance of species boundaries. Despite their possible ubiquity and importance, the investigation of PEMS has been largely descriptive, lacking any phylogenetic consideration with regard to divergence, and there have been no theoretical or empirical investigations of their evolutionary significance. Here, we (i) clarify PEMS-related nomenclature; (ii) address the evolutionary origin, maintenance and divergence in PEMS in the context of the protracted life history of sperm and the complex, selective environment of the female reproductive tract; (iii) describe taxonomically widespread types of PEMS: sperm activation, chemotaxis and the dissociation of sperm conjugates; (iv) review the occurence of PEMS throughout the animal kingdom; (v) consider alternative hypotheses for the adaptive value of PEMS; (vi) speculate on the evolutionary implications of PEMS for genomic architecture, sexual selection, and reproductive isolation; and (vii) suggest fruitful directions for future functional and evolutionary analyses of PEMS.
Topics: Acrosome Reaction; Animals; Ejaculation; Male; Sperm Capacitation; Spermatozoa
PubMed: 31737992
DOI: 10.1111/brv.12569 -
BioMed Research International 2019For human infertility both male and female factors may be equally important. Searching for molecular biomarkers of male infertility, neglected for decades, and the... (Review)
Review
For human infertility both male and female factors may be equally important. Searching for molecular biomarkers of male infertility, neglected for decades, and the attempts to explain regulatory mechanisms of fertilization become thus extremely important. Apart from examination of the structure and function of male gametes, also the possible importance of seminal plasma components should be considered. In this article we discuss data that indicate for the substantial significance of active seminal plasma components for conception and achievement of healthy pregnancy. Seminal plasma impact on the storage and cryopreservation of human and animal sperm and regulatory role of glycodelin on human sperm capacitation as well as hypothesized course of female immune response to allogenic sperm and conceptus has been discussed. The possible involvement of carbohydrates in molecular mechanism of fetoembryonic defense has been also mentioned.
Topics: Animals; Cryopreservation; Fertilization; Humans; Infertility, Male; Male; Semen; Semen Preservation; Sperm Capacitation; Sperm Motility; Spermatozoa
PubMed: 31531356
DOI: 10.1155/2019/5397804