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Human Reproduction Update Jun 2020Neurotrophins of the nerve growth factor family are soluble polypeptides that are best known for their role in nerve growth, survival and differentiation in the central...
BACKGROUND
Neurotrophins of the nerve growth factor family are soluble polypeptides that are best known for their role in nerve growth, survival and differentiation in the central nervous system. A growing body of literature shows that neurotrophins and their receptors are also expressed throughout the reproductive tract.
OBJECTIVE AND RATIONALE
Neurotrophins are key regulatory proteins in reproductive physiology during development and throughout adult life. Of the neurotrophins, the literature describing the expression and function of brain-derived neurotrophic factor (BDNF) and its high-affinity receptor, neurotrophin receptor kinase-2 (NTRK2), has been expanding rapidly. We therefore conducted a systematic inductive qualitative review of the literature to better define the role of the BDNF in the reproductive tract. We postulate that BDNF and NTRK2 are central regulatory proteins throughout the reproductive system.
SEARCH METHODS
An electronic search of Medline (PubMed) and Web of Science for articles relating to BDNF and the reproductive system was carried out between January 2018 and February 2019.
OUTCOMES
In the ovary, BDNF expression and levels have been linked with follicle organisation during ovarian development, follicle recruitment and growth and oocyte maturation. In the endometrium, BDNF is involved in cell proliferation and neurogenesis. In contrast, literature describing the role of BDNF in other reproductive tissues is sparse and BDNF-NTRK2 signalling in the male reproductive tract has been largely overlooked. Whilst estradiol appears to be the primary regulator of BDNF expression, we also identified reports describing binding sites for glucocorticoid and myocyte enhancer factor-2, a calcium-response element through activation of an N-methyl-D-aspartate (NMDA) receptor, and aryl hydrocarbon receptor nuclear transporter protein-4 (ARNT) response elements in promoter regions of the BDNF gene. Expression is also regulated by multiple microRNAs and post-translational processing of precursor proteins and intracellular shuttling. BDNF-NTRK2 signalling is modulated through tissue specific receptor expression of either the full-length or truncated NTRK2 receptor; however, the functional importance remains to be elucidated. Dysregulation of BDNF expression and circulating concentrations have been implicated in several reproductive disorders including premature ovarian failure, endometriosis, pre-eclampsia, intra-uterine growth restriction (IUGR) and several reproductive cancers.
WIDER IMPLICATIONS
We conclude that BDNF and its receptors are key regulatory proteins central to gonadal development, ovarian regulation and uterine physiology, as well as embryo and placenta development. Furthermore, dysregulation of BDNF-NTRK2 in reproductive diseases suggests their potential role as candidate clinical markers of disease and potential therapeutic targets.
Topics: Animals; Brain-Derived Neurotrophic Factor; Endometrium; Female; Gene Expression; Genitalia; Humans; Mammals; Oogenesis; Pregnancy; Receptor, trkB; Signal Transduction
PubMed: 32378708
DOI: 10.1093/humupd/dmaa008 -
Cryobiology Aug 2018Combination of in vitro maturation (IVM) and cryopreservation offers new opportunities for women with contraindication in ovarian stimulation, and females who desire to... (Meta-Analysis)
Meta-Analysis
Combination of in vitro maturation (IVM) and cryopreservation offers new opportunities for women with contraindication in ovarian stimulation, and females who desire to postpone the childbearing due to different problems. There are still controversies regarding IVM procedure and its impact on oocytes fertilization capability. This systematic review and meta-analysis were conducted to evaluate the impact of vitrification on human oocyte maturation rate during IVM procedure. In this review, we searched Medline, Embase, Scopus and ISI web of science to identify English-language studies. The last search was implemented on 3 February 2018. The original articles which assessed maturation rate after vitrification of MI or GV oocytes were included. Animal trials and the studies that performed cryopreservation using slow-freeze method were excluded. Bias and quality assessments were performed. 2476 articles were screened primarily. After duplication removing and the application of inclusion and exclusion criteria, 14 studies included for the analysis. All studies compared maturation rate between the oocytes that were vitrified at the GV or MI stage before maturation and oocytes which were matured in vitro without vitrification. Meta-analysis showed that oocyte vitrification at GV stage had a significant negative impact on maturation rate (RR = 0.76, 95% CI: 0.66-0.88); I = 85.2%; P = 0.000). Finally, based on our results, oocyte vitrification decreases the maturation rate by 24%.
Topics: Cryopreservation; Female; Freezing; Humans; In Vitro Oocyte Maturation Techniques; Oocytes; Oogenesis; Vitrification
PubMed: 29842869
DOI: 10.1016/j.cryobiol.2018.05.003 -
Toxicology and Applied Pharmacology Dec 2014A finite number of oocytes are established within the mammalian ovary prior to birth to form a precious ovarian reserve. Damage to this limited pool of gametes by... (Review)
Review
A finite number of oocytes are established within the mammalian ovary prior to birth to form a precious ovarian reserve. Damage to this limited pool of gametes by environmental factors such as cigarette smoke and its constituents therefore represents a significant risk to a woman's reproductive capacity. Although evidence from human studies to date implicates a detrimental effect of cigarette smoking on female fertility, these retrospective studies are limited and present conflicting results. In an effort to more clearly understand the effect of cigarette smoke, and its chemical constituents, on female fertility, a variety of in vivo and in vitro animal models have been developed. This article represents a systematic review of the literature regarding four of experimental model types: 1) direct exposure of ovarian cells and follicles to smoking constituents' in vitro, 2) direct exposure of whole ovarian tissue with smoking constituents in vitro, 3) whole body exposure of animals to smoking constituents and 4) whole body exposure of animals to cigarette smoke. We summarise key findings and highlight the strengths and weaknesses of each model system, and link these to the molecular mechanisms identified in smoke-induced fertility changes.
Topics: Animals; Cell Culture Techniques; Disease Models, Animal; Female; Humans; In Vitro Techniques; Infertility, Female; Oogenesis; Ovary; Smoke; Smoking; Tissue Culture Techniques
PubMed: 25448442
DOI: 10.1016/j.taap.2014.10.010 -
Archives of Gynecology and Obstetrics Jul 2018To summarize available evidence from randomized-controlled trials which have evaluated triggering of final oocyte maturation with concomitant GnRH agonists and hCG in... (Meta-Analysis)
Meta-Analysis
PURPOSE
To summarize available evidence from randomized-controlled trials which have evaluated triggering of final oocyte maturation with concomitant GnRH agonists and hCG in patients undergoing IVF, and to analyze whether dual triggering is as efficacious as hCG triggering in terms of oocyte and pregnancy outcomes.
METHODS
A comprehensive literature search was performed to identify randomized-controlled trials comparing IVF outcomes between women receiving combined administration of hCG with GnRH agonists and those receiving hCG alone for triggering of final oocyte maturation.
RESULTS
Four studies including 527 patients eligible for inclusion in meta-analysis were identified. No significant difference in the number of mature oocytes or fertilized oocytes retrieved was found between groups. Clinical pregnancy rate with dual triggering was significantly higher as compared with hCG-alone triggering (pooled OR = 0.48, 95% CI 0.31-0.77, P = 0.002), but there was no significant difference in the ongoing pregnancy rate between groups.
CONCLUSION
Results of meta-analysis indicate comparable or significantly improved outcomes with the use of GnRH agonists plus hCG as compared with hCG alone for triggering of final oocyte maturation.
Topics: Chorionic Gonadotropin; Female; Fertilization in Vitro; Gonadotropin-Releasing Hormone; Hormone Antagonists; Humans; Oocytes; Oogenesis; Ovulation Induction; Pregnancy; Pregnancy Rate; Randomized Controlled Trials as Topic; Sperm Injections, Intracytoplasmic
PubMed: 29600322
DOI: 10.1007/s00404-018-4751-3