ResearchPad - ovulation https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Corticosterone and testosterone treatment influence expression of gene pathways linked to meiotic segregation in preovulatory follicles of the domestic hen]]> https://www.researchpad.co/article/elastic_article_14547 Decades of work indicate that female birds can control their offspring sex ratios in response to environmental and social cues. In laying hens, hormones administered immediately prior to sex chromosome segregation can exert sex ratio skews, indicating that these hormones may act directly on the germinal disc to influence which sex chromosome is retained in the oocyte and which is discarded into an unfertilizable polar body. We aimed to uncover the gene pathways involved in this process by testing whether treatments with testosterone or corticosterone that were previously shown to influence sex ratios elicit changes in the expression of genes and/or gene pathways involved in the process of meiotic segregation. We injected laying hens with testosterone, corticosterone, or control oil 5h prior to ovulation and collected germinal discs from the F1 preovulatory follicle in each hen 1.5h after injection. We used RNA-sequencing (RNA-seq) followed by DESeq2 and gene set enrichment analyses to identify genes and gene pathways that were differentially expressed between germinal discs of control and hormone-treated hens. Corticosterone treatment triggered downregulation of 13 individual genes, as well as enrichment of gene sets related to meiotic spindle organization and chromosome segregation, and additional gene sets that function in ion transport. Testosterone treatment triggered upregulation of one gene, and enrichment of one gene set that functions in nuclear chromosome segregation. This work indicates that corticosterone can be a potent regulator of meiotic processes and provides potential gene targets on which corticosterone and/or testosterone may act to influence offspring sex ratios in birds.

]]>
<![CDATA[Periovulatory follicular fluid levels of estradiol trigger inflammatory and DNA damage responses in oviduct epithelial cells]]> https://www.researchpad.co/article/5989db4fab0ee8fa60bdbbe9

Objective

Ovarian steroid hormones (mainly E2 and P4) regulate oviduct physiology. Serum-E2 acts on the oviduct epithelium from the basolateral cell compartment. Upon ovulation, the apical compartment of the oviduct epithelium is temporarily exposed to follicular fluid, which contains much higher levels of E2 than serum. The aim of this study was to evaluate the effects of human periovulatory follicular fluid levels of E2 on oviduct epithelial cells using two porcine in vitro models.

Methods

A cell line derived from the porcine oviductal epithelium (CCLV-RIE270) was characterized (lineage markers, proliferation characteristics and transformation status). Primary porcine oviduct epithelial cells (POEC) were cultured in air-liquid interface and differentiation was assessed histologically. Both cultures were exposed to E2 (10 ng/ml and 200 ng/ml). Proliferation of CCLV-RIE270 and POEC was determined by real-time impedance monitoring and immunohistochemical detection of Ki67. Furthermore, marker gene expression for DNA damage response (DDR) and inflammation was quantified.

Results

CCLV-RIE270 was not transformed and exhibited properties of secretory oviduct epithelial cells. Periovulatory follicular fluid levels of E2 (200 ng/ml) upregulated the expression of inflammatory genes in CCLV-RIE270 but not in POEC (except for IL8). Expression of DDR genes was elevated in both models. A significant increase in cell proliferation could not be detected in response to E2.

Conclusions

CCLV-RIE270 and POEC are complementary models to evaluate the consequences of oviduct exposure to follicular fluid components. Single administration of periovulatory follicular fluid E2 levels trigger inflammatory and DNA damage responses, but not proliferation in oviduct epithelial cells.

]]>
<![CDATA[Etiological Subgroups of Small-for-Gestational-Age: Differential Neurodevelopmental Outcomes]]> https://www.researchpad.co/article/5989da51ab0ee8fa60b8dfd3

Objectives

It remains unclear why substantial variations in neurodevelopmental outcomes exist within small-for-gestational-age (SGA) children. We prospectively compared 5-y neurodevelopmental outcomes across SGA etiological subgroups.

Methods

Children born SGA (N = 1050) from U.S. Early Childhood Longitudinal Study-Birth Cohort (2001–2007) was divided into etiological subgroups by each of 7 well-established prenatal risk factors. We fit linear regression models to compare 5-y reading, math, gross motor and fine motor scores across SGA subgroups, adjusting for socio-demographic confounders.

Results

Compared to singleton SGA subgroup, multiple-birth SGA subgroup had lower mean reading (adjusted mean difference, -4.08 [95% confidence interval, -6.10, -2.06]) and math (-2.22 [-3.61, -0.84]) scores. These disadvantages in reading and math existed only among multiple-birth SGA subgroup without ovulation stimulation (reading, -4.50 [-6.64, -2.36]; math, -2.91 [-4.37, -1.44]), but not among those with ovulation stimulation (reading, -2.33 [-6.24, 1.57]; math 0.63 [-1.86, 3.12]). Compared to singleton SGA subgroup without maternal smoking and inadequate gestational weight gain, singleton SGA subgroup with co-occurrence of maternal smoking and inadequate gestational weight gain (GWG) had lower mean reading (-4.81 [-8.50, -1.12]) and math (-2.95 [-5.51, -0.38]) scores. These differences were not mediated by Apgar score.

Conclusions

Multiple-birth SGA subgroups (vs. singleton SGA) or singleton SGA subgroup with co-occurrence of smoking and inadequate GWG (vs. singleton SGA subgroup without maternal smoking and inadequate gestational weight gain) have poorer cognitive development up to 5 y.

]]>
<![CDATA[Top quality blastocyst formation rates in relation to progesterone levels on the day of oocyte maturation in GnRH antagonist IVF/ICSI cycles]]> https://www.researchpad.co/article/5989db5cab0ee8fa60bdfe0e

Cycles with progesterone elevation during controlled ovarian stimulation (COS) for IVF/ICSI are commonly managed with a “freeze-all” strategy, due to a well-recognized detrimental effect of high progesterone levels on endometrial receptivity. However, also a detrimental effect of elevated progesterone on day-3 embryo quality has recently been found with regards to top quality embryo formation rate. Because blastocyst culture and cryopreservation are largely adopted, we deemed relevant to determine whether this detrimental effect is also seen on blastocyst quality on day 5–6. This issue was investigated through a large two-center retrospective study including 986 GnRH antagonist IVF/ICSI cycles and using top quality blastocyst formation rate as the main outcome. Results showed that on multivariate analysis sperm motility (p<0.01) and progesterone levels at ovulation triggering (p = 0.01) were the only two variables that significantly predicted top quality blastocyst formation rate after adjusting for relevant factors including female age, BMI, basal AMH and total dose of FSH used for COS. More specifically, progesterone levels at induction showed an inverse relation with top quality blastocyst formation (correlation coefficient B = -1.08, 95% CI -1.9 to -0.02) and ROC curve analysis identified P level >1.49 ng/ml as the best cut-off for identification of patients at risk for the absence of top quality blastocysts (AUC 0.55, p<0.01). Our study is the first to investigate the top quality blastocyst formation rate in relation to progesterone levels in IVF/ICSI cycles, showing that increasing progesterone is associated with lower rates of top quality blastocyst. Hence, the advantages of prolonging COS to maximize the number of collected oocytes might eventually be hindered by a decrease in top quality blastocysts available for transfer, if increasing progesterone levels are observed. This observation extends the results of two recent studies focused on day-3 embryos and deserves further research.

]]>
<![CDATA[kmlShape: An Efficient Method to Cluster Longitudinal Data (Time-Series) According to Their Shapes]]> https://www.researchpad.co/article/5989da90ab0ee8fa60b9fd68

Background

Longitudinal data are data in which each variable is measured repeatedly over time. One possibility for the analysis of such data is to cluster them. The majority of clustering methods group together individual that have close trajectories at given time points. These methods group trajectories that are locally close but not necessarily those that have similar shapes. However, in several circumstances, the progress of a phenomenon may be more important than the moment at which it occurs. One would thus like to achieve a partitioning where each group gathers individuals whose trajectories have similar shapes whatever the time lag between them.

Method

In this article, we present a longitudinal data partitioning algorithm based on the shapes of the trajectories rather than on classical distances. Because this algorithm is time consuming, we propose as well two data simplification procedures that make it applicable to high dimensional datasets.

Results

In an application to Alzheimer disease, this algorithm revealed a “rapid decline” patient group that was not found by the classical methods. In another application to the feminine menstrual cycle, the algorithm showed, contrarily to the current literature, that the luteinizing hormone presents two peaks in an important proportion of women (22%).

]]>
<![CDATA[Age-related effects of body mass on fertility and litter size in roe deer]]> https://www.researchpad.co/article/5989db52ab0ee8fa60bdc809

We analysed effects of females’ body mass and age on reproductive capacity of European roe deer (Capreolus capreolus) in a large sample set of 1312 females (305 yearlings and 1007 adults), hunted throughout Slovenia, central Europe, in the period 2013–2015. Body mass positively affected probability of ovulation and potential litter size (number of corpora lutea), although its effect was more pronounced in yearlings than in adults. Between age groups, we found clear differences in responses of both reproductive parameters to body mass which influences primarily reproductive performance of younger, and in particular, lighter individuals: at the same body mass yearlings would at average have smaller litters than adults, and at lower body mass also young to middle-aged adults would have smaller litters than old ones. In addition, while yearlings have to reach a critical threshold body mass to attain reproductive maturity, adult females are fertile (produce ova) even at low body mass. However, at higher body mass also younger individuals shift their efforts into the reproduction, and after reaching an age-specific threshold the body mass does not have any further effects on the reproductive output of roe deer females. Increased reproductive capacity at more advanced age, combined with declining body mass suggests that old does allocate more of their resources in reproduction than in body condition.

]]>
<![CDATA[The Tyrosine Kinase Inhibitor Sunitinib Affects Ovulation but Not Ovarian Reserve in Mouse: A Preclinical Study]]> https://www.researchpad.co/article/5989d9f4ab0ee8fa60b6fac7

The aim of the study was to evaluate ovarian toxicity of tyrosine kinase inhibitor (TKI) sunitinib, since only scarce data are available on gonadal function after this treatment. Six-week-old female mice received orally, once daily, vehicle or sunitinib (50 mg/kg/d) during 5 weeks. Fertility parameters were analyzed from ovulation to litter assessment. Sunitinib exposure significantly reduced (i) corpora lutea number per ovary (1.1 ± 0.38 in sunitinib group versus 4 ± 0.79 in control group, p<0.01) and (ii) serum Anti Müllerian hormone (AMH) levels in sunitinib treated mice (12.01 ± 1.16) compared to control mice (14.33 ± 0.87 ng/ml, p< 0.05). However, primordial and growing follicles numbers per ovary were not different in both groups. After treatment withdrawal, female mice in both groups were able to obtain litters. These data could be helpful to counsel clinicians and patients, when fertility preservation methods are discussed, before TKI treatment in girls and young women.

]]>
<![CDATA[Dog cloning with in vivo matured oocytes obtained using electric chemiluminescence immunoassay-predicted ovulation method]]> https://www.researchpad.co/article/5989db50ab0ee8fa60bdbed4

Radioactive immunoassay (RIA) is a traditional serum hormone assay method, but the application of the method in reproductive studies is limited by the associated radioactivity. The aim of present study was to evaluate the reliability of RIA and to compare its canine serum progesterone concentration determination accuracy to that of the electric chemiluminescence immunoassay (ECLI). In vivo matured oocytes were utilized for canine somatic cell nuclear transfer (SCNT), and serum progesterone levels were assessed to accurately determine ovulation and oocyte maturation. Canine serum progesterone concentrations during both proestrus and estrus were analyzed by RIA and ECLI to determine the ovulation day. Although both methods detected similar progesterone levels before ovulation, the mean progesterone concentration determined using ECLI was significantly higher than of RIA three days before ovulation. Following ovulation, oocytes were collected by surgery, and a lower percentage of mature oocytes were observed using ECLI (39%) as compared to RIA (67%) if 4-8ng/ml of progesterone were used for determination of ovulation. A high percentage of mature oocytes was observed using ECLI when 6–15 ng/mL of progesterone was used for ovulation determination. To determine whether ECLI could be used for canine cloning, six canines were selected as oocyte donors, and two puppies were obtained after SCNT and embryo transfer. In conclusion, compared to the traditional RIA method, the ECLI method is a safe and reliable method for canine cloning.

]]>
<![CDATA[Follicular size predicts success in artificial insemination with frozen-thawed sperm in donkeys]]> https://www.researchpad.co/article/5989db5cab0ee8fa60bdfe5b

In asses, semen collection, cryopreservation, and artificial insemination (AI) with frozen-thawed semen have been scarcely described and success rate, particularly following AI, is reportedly low. In the absence of reliable protocols, assisted reproductive technologies cannot support the conservation efforts aimed at endangered wild ass species and domestic donkey breeds. Two experiments were conducted in this study. In experiment 1 we evaluated freezing Abyssinian donkey (N = 5, 4 ejaculates each) spermatozoa using three freezing extenders (Berliner Cryomedium + glycerol, BC+G; BotuCrio, BOTU; INRAFreeze, INRA) and two cryopreservation techniques (liquid nitrogen vapour, LNV; directional freezing, DF). Post-thaw evaluation indicated that BOTU and INRA were similar and both superior to BC+G (P ≤ 0.004 for all motility tests), and that DF was superior to LNV (P < 0.002 for all evaluation parameters). In experiment 2, relying on these results, we used Abyssinian donkey sperm frozen in BOTU and INRA by DF for AI (N = 20). Prior to AI, thawed samples were diluted in corresponding centrifugation media or autologous seminal fluids at 1:1 ratio. No difference was found between BOTU and INRA or between the addition of seminal fluids or media, all resulting in ~50% pregnancy, and no differences were noted between males (N = 4). The size of pre-ovulatory follicle was a significant (P = 0.001) predictor for AI success with 9/10 pregnancies occurring when follicular size ranged between 33.1–37.4 mm, no pregnancy when it was smaller, and only one when larger. A number of ass species face the risk of extinction. Knowledge gained in this study on the Abyssinian donkey can be customised and transferred to its closely related endangered species and breeds.

]]>
<![CDATA[Nitric Oxide Synthase (NOS) Inhibition during Porcine In Vitro Maturation Modifies Oocyte Protein S-Nitrosylation and In Vitro Fertilization]]> https://www.researchpad.co/article/5989db10ab0ee8fa60bcc157

Nitric oxide (NO) is a molecule involved in many reproductive processes. Its importance during oocyte in vitro maturation (IVM) has been demonstrated in various species although sometimes with contradictory results. The objective of this study was to determine the effect of NO during IVM of cumulus oocyte complexes and its subsequent impact on gamete interaction in porcine species. For this purpose, IVM media were supplemented with three NOS inhibitors: NG-nitro-L-arginine methyl ester (L-NAME), NG-monomethyl-L-arginine (L-NMMA) and aminoguanidine (AG). A NO donor, S-nitrosoglutathione (GSNO), was also used. The effects on the cumulus cell expansion, meiotic resumption, zona pellucida digestion time (ZPdt) and, finally, on in vitro fertilization (IVF) parameters were evaluated. The oocyte S-nitrosoproteins were also studied by in situ nitrosylation. The results showed that after 42 h of IVM, AG, L-NAME and L-NMMA had an inhibitory effect on cumulus cell expansion. Meiotic resumption was suppressed only when AG was added, with 78.7% of the oocytes arrested at the germinal vesicle state (P<0.05). Supplementation of the IVM medium with NOS inhibitors or NO donor did not enhance the efficiency of IVF, but revealed the importance of NO in maturation and subsequent fertilization. Furthermore, protein S-nitrosylation is reported for the first time as a pathway through which NO exerts its effect on porcine IVM; therefore, it would be important to determine which proteins are nitrosylated in the oocyte and their functions, in order to throw light on the mechanism of action of NO in oocyte maturation and subsequent fertilization.

]]>
<![CDATA[Preovulatory Aging In Vivo and In Vitro Affects Maturation Rates, Abundance of Selected Proteins, Histone Methylation Pattern and Spindle Integrity in Murine Oocytes]]> https://www.researchpad.co/article/5989daf1ab0ee8fa60bc12d6

Delayed ovulation and delayed fertilization can lead to reduced developmental competence of the oocyte. In contrast to the consequences of postovulatory aging of the oocyte, hardly anything is known about the molecular processes occurring during oocyte maturation if ovulation is delayed (preovulatory aging). We investigated several aspects of oocyte maturation in two models of preovulatory aging: an in vitro follicle culture and an in vivo mouse model in which ovulation was postponed using the GnRH antagonist cetrorelix. Both models showed significantly reduced oocyte maturation rates after aging. Furthermore, in vitro preovulatory aging deregulated the protein abundance of the maternal effect genes Smarca4 and Nlrp5, decreased the levels of histone H3K9 trimethylation and caused major deterioration of chromosome alignment and spindle conformation. Protein abundance of YBX2, an important regulator of mRNA stability, storage and recruitment in the oocyte, was not affected by in vitro aging. In contrast, in vivo preovulatory aging led to reduction in Ybx2 transcript and YBX2 protein abundance. Taken together, preovulatory aging seems to affect various processes in the oocyte, which could explain the low maturation rates and the previously described failures in fertilization and embryonic development.

]]>
<![CDATA[Should All Women with Polycystic Ovary Syndrome Be Screened for Metabolic Parameters?: A Hospital-Based Observational Study]]> https://www.researchpad.co/article/5989dad4ab0ee8fa60bb77b8

This hospital-based observational study aims to estimate differences in metabolic abnormalities between different polycystic ovary syndrome (PCOS) phenotypes and their distribution characteristics. The prevalence of metabolic abnormalities among different PCOS phenotypes, including diabetes mellitus (DM), metabolic syndrome (MS), pre-diabetes mellitus (pre-DM), insulin resistance (IR) and dyslipidemia were compared. A total of 2436 women who were ≥18 years old and who were hospitalized in Sun Yat-Sen University affiliated hospital from 1998 to 2015 in GuangZhou, China, were included in this study. PCOS phenotypes were recorded according to the 2003 Rotterdam criteria, including the polycystic ovary morphology (PCO), hyperandrogenism (HA) and ovulation dysfunction (OD) phenotype (PCO+HA+OD); the ovulation phenotype (PCO+HA); the non-PCO phenotype (HA+OD); and the non-HA phenotype (PCO+OD). Notably, 56% of the patients had the classic phenotype (PCO+HA+OD). Importantly, there was no significant difference in the prevalence of metabolic abnormalities or the distribution characteristics of the metabolic abnormalities among these four PCOS phenotypes. Our study supports the notion that metabolic abnormalities and the distribution characteristics of metabolic abnormalities should not be used to distinguish among the various clinical PCOS phenotypes.

]]>
<![CDATA[A Computational Model of the Rainbow Trout Hypothalamus-Pituitary-Ovary-Liver Axis]]> https://www.researchpad.co/article/5989da31ab0ee8fa60b84709

Reproduction in fishes and other vertebrates represents the timely coordination of many endocrine factors that culminate in the production of mature, viable gametes. In recent years there has been rapid growth in understanding fish reproductive biology, which has been motivated in part by recognition of the potential effects that climate change, habitat destruction and contaminant exposure can have on natural and cultured fish populations. New approaches to understanding the impacts of these stressors are being developed that require a systems biology approach with more biologically accurate and detailed mathematical models. We have developed a multi-scale mathematical model of the female rainbow trout hypothalamus-pituitary-ovary-liver axis to use as a tool to help understand the functioning of the system and for extrapolation of laboratory findings of stressor impacts on specific components of the axis. The model describes the essential endocrine components of the female rainbow trout reproductive axis. The model also describes the stage specific growth of maturing oocytes within the ovary and permits the presence of sub-populations of oocytes at different stages of development. Model formulation and parametrization was largely based on previously published in vivo and in vitro data in rainbow trout and new data on the synthesis of gonadotropins in the pituitary. Model predictions were validated against several previously published data sets for annual changes in gonadotropins and estradiol in rainbow trout. Estimates of select model parameters can be obtained from in vitro assays using either quantitative (direct estimation of rate constants) or qualitative (relative change from control values) approaches. This is an important aspect of mathematical models as in vitro, cell-based assays are expected to provide the bulk of experimental data for future risk assessments and will require quantitative physiological models to extrapolate across biological scales.

]]>
<![CDATA[The Local Effects of Ovarian Diathermy in an Ovine Model of Polycystic Ovary Syndrome]]> https://www.researchpad.co/article/5989dabfab0ee8fa60baff60

In order to develop a medical alternative to surgical ovarian diathermy (OD) in polycystic ovary syndrome (PCOS) more mechanistic information is required about OD. We therefore studied the cellular, molecular and vascular effects of diathermy on the ovary using an established ovine model of PCOS. Pregnant sheep were treated twice weekly with testosterone propionate (100 mg) from day 30–100 gestation. Their female offspring (n = 12) were studied during their second breeding season when the PCOS-like phenotype, with anovulation, is fully manifest. In one group (n = 4) one ovary underwent diathermy and it was collected and compared to the contralateral ovary after 24 hours. In another group a treatment PCOS cohort underwent diathermy (n = 4) and the ovaries were collected and compared to the control PCOS cohort (n = 4) after 5 weeks. Ovarian vascular indices were measured using contrast-enhanced ultrasound and colour Doppler before, immediately after, 24 hours and five weeks after diathermy. Antral follicles were assessed by immunohistochemistry and ovarian stromal gene expression by quantitative RT-PCR 24 hours and 5 weeks after diathermy. Diathermy increased follicular atresia (P<0.05) and reduced antral follicle numbers after 5 weeks (P<0.05). There was an increase in stromal CCL2 expression 24 hours after diathermy (P<0.01) but no alteration in inflammatory indices at 5 weeks. Immediately after diathermy there was increased microbubble transit time in the ovarian microvasculature (P = 0.05) but this was not seen at 24 hours. However 24 hours after diathermy there was a reduction in the stromal Doppler blood flow signal (P<0.05) and an increased ovarian resistance index (P<0.05) both of which persisted at 5 weeks (P<0.01; P<0.05). In the ovine model of PCOS, OD causes a sustained reduction in ovarian stromal blood flow with an increased ovarian artery resistance index associated with atresia of antral follicles.

]]>