The two-step process of ovarian follicular growth and maturation in mammals can be compared to a fruit ripening where quality depends on the second step

2021 ◽  
Author(s):  
Marc-André Sirard
Keyword(s):  
Follicular Development ◽  
Ovarian Response ◽  
Oocyte Quality ◽  
Second Step ◽  
Stimulation Protocol ◽  
Dynamic Nature ◽  
Apple Ripening ◽  
Ovarian Follicular Growth ◽  
Biphasic Process ◽  
Human Ivf

Abstract In human IVF, the main uncertainty factor impacting on success is oocyte quality, which largely depends on the follicular status at the time of collection. Decades of debate ensued to find the perfect stimulation protocol demonstrated the complexity of the ovarian response to exogenous gonadotropins and the dynamic nature of late folliculogenesis. Although several follicular markers, proteins, RNA from granulosa cells or microRNA and follicular fluid metabolites have been associated with outcome, the possibility to influence them during stimulation remains elusive. The heterogeneity of the follicle’s maturity following control ovarian stimulation is also an important factor to explain average poor oocyte quality still observed today. In this review, the analogy between the apple ripening on the tree and follicular development is presented to focus the attention on a biphasic process: growth and differentiation. The molecular analysis of the progressive follicular differentiation indicates 2 competing phenomena: growth and differentiation where a delicate balance must operate from one to the other to ensure proper maturity at ovulation. As long as FSH stimulates growth, follicles remain green, and it is only when FSH is replaced by LH that the ripening process begins, and “apples” become red. Both fruits, follicles and apples, depend on a perfect timing of events to generate offspring.

scholarly journals A flexible short protocol in women with poor ovarian response over 40 years old

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xinyue Zhang ◽  
Ting Feng ◽  
Jihong Yang ◽  
Yingying Hao ◽  
Suying Li ◽  
...  
Keyword(s):  
Embryo Implantation ◽  
Ovarian Response ◽  
Oocyte Quality ◽  
Poor Ovarian Response ◽  
Stimulation Protocol ◽  
Start Time ◽  
Ovulation Stimulation ◽  
Mild Stimulation ◽  
Successful Clinical Outcome ◽  
Over 40 Years

Abstract Background Ovarian responsiveness to controlled ovarian stimulation is essential for a successful clinical outcome in assisted reproductive technology (ART) cycles. We aimed to find a suitable new ovulation stimulation protocol for poor ovarian response (POR) patients over 40 years old. Methods A retrospective analysis of 488 ART cycles was evaluated from January 2015 to June 2019. Comparisons were made between the flexible short protocol (FSP), routine short protocol and mild stimulation protocol. Results Compared with the routine short protocol, the FSP delayed the gonadotropin start time and reduced the total gonadotropin dose per stimulation cycle. At the same time, compared with the mild stimulation protocol, the FSP improved oocyte quality and embryo quality and improved embryo implantation potential after transfer. Furthermore, the use of the FSP reduced the probability of premature ovulation, as it inhibited the premature luteinizing hormone (LH) surge to a certain extent. Conclusions The FSP yielded better outcomes than other protocols for patients with POR over 40 years old in our study. However, further prospective studies are needed to provide more substantial evidence and to determine whether the FSP can be successful for both patients over 40 years group and younger POR patients.

Effect of ovarian stimulation protocol and ovarian response on oocyte quality

2008 ◽  
Vol 90 ◽  
pp. S325
Author(s):  
R.d.C.S. Figueira ◽  
D.P.A.F. Braga ◽  
L.S. Francisco ◽  
C. Madaschi ◽  
A. Iaconelli ◽  
...  
Keyword(s):  
Ovarian Stimulation ◽  
Ovarian Response ◽  
Oocyte Quality ◽  
Stimulation Protocol

Evaluation of Follicular Development and Oocyte Quality in Pre-pubertal Cats

2010 ◽  
Vol 45 (6) ◽  
pp. e405-e411 ◽  
Author(s):  
K Uchikura ◽  
M Nagano ◽  
M Hishinuma
Keyword(s):  
Follicular Development ◽  
Oocyte Quality

scholarly journals Large-Scale Metadata Analysis of Ovary Based Multi-Omics Datasets for Understanding the Genes Regulating Litter Size

2020 ◽  
Author(s):  
Ayyappa Kumar Sista Kameshwar ◽  
Julang Li
Keyword(s):  
Gene Expression ◽  
Differentially Expressed Genes ◽  
Litter Size ◽  
Large Scale ◽  
Expression Patterns ◽  
Genetic Selection ◽  
Follicular Development ◽  
Oocyte Quality ◽  
Differentially Expressed ◽  
Metadata Analysis

Abstract Background : Litter size is a very important production index in the livestock industry, which is controlled by various complex physiological processes. To understand and reveal the common gene expression patterns involved in controlling prolificacy, we have performed a large-scale metadata analysis of five genome-wide transcriptome datasets of pig and sheep ovary samples obtained from high and low litter groups, respectively. We analyzed separately each transcriptome dataset using GeneSpring v14.8 software by implementing standard, generic analysis pipelines and further compared the list of most significant and differentially expressed genes obtained from each dataset to identify genes that are found to be common and significant across all the studies. Results : We have observed a total of 62 differentially expressed genes common among more than two gene expression datasets. The KEGG pathway analysis of most significant genes has shown that they are involved in metabolism, the biosynthesis of lipids, cholesterol and steroid hormones, immune system, cell growth and death, cancer-related pathways and signal transduction pathways. Of these 62 genes, we further narrowed the list to the 25 most significant genes by focusing on the ones with fold change >1.5 and p<0.05. These genes are CYP11A1, HSD17B2, STAR, SCARB1, IGSF8, MSMB, SERPINA1 , FAM46C, HEXA, PTTG1, TIMP1, FAM167B, CCNG1, FAXDC2, HMGCS1, L2HGDH, Lipin1, MME, MSMO1, PARM1, PTGFR, SLC22A4, SLC35F5, CCNA2, CENPU, CEP55, RASSF2, and SLC16A3 . Conclusions : Interestingly, comparing the list of genes with the list of genes obtained from our literature search analysis, we found only three genes in common. These genes are HEXA, PTTG1, and TIMP1. Our finding points to the potential of a few genes that may be important for ovarian follicular development and oocyte quality. Future studies revealing the function of these genes will further our understanding of how litter size is controlled in the ovary while also providing insight on genetic selection of high litter gilts.

scholarly journals Role of Melatonin as a Survival Factor for In vitro Development of Sheep Preantral Follicles

2021 ◽  
Author(s):  
C. Chetan Kumar ◽  
B. Rambabu Naik ◽  
A.V.N. Siva Kumar ◽  
A. Ravi ◽  
L.S.S. Varaprasad Reddy ◽  
...  
Keyword(s):  
Growth Factors ◽  
Ovarian Function ◽  
Follicular Development ◽  
Oocyte Quality ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Optimum Level ◽  
Preantral Follicles ◽  
Positive Effects

Background: Melatonin, a powerful free radical scavenger and broad-spectrum antioxidant may directly affect ovarian function by regulating folliculogenesis, maintenance of follicular integrity, oocyte quality and maturation capacity. Therefore, we aimed to study effects of melatonin and its interaction with growth factors in sheep preantral follicles. Methods: The influence of different concentrations of Melatonin (5-500 pM) on in vitro culture of preantral follicles (PFs’) isolated from sheep ovaries was studied. Experiments I and II were conducted to standardize the optimum concentration of Melatonin that supports better development of preantral follicles. Experiment III was conducted with the optimum level of Melatonin derived in the Experiments I and II to evaluate the effect of melatonin at 100pM in combination with various growth factors. Result: Overall follicular development was found to be the best in the PFs’ cultured in medium supplemented with 100pM of Melatonin. Melatonin supplementation showed positive effects on the preantral follicular development in combination with different growth factors.

Factors affecting folliculogenesis in ruminants

1999 ◽  
Vol 68 (2) ◽  
pp. 257-284 ◽  
Author(s):  
R. Webb ◽  
R. G. Gosden ◽  
E. E. Telfer ◽  
R. M. Moor
Keyword(s):  
New Technologies ◽  
Ovarian Function ◽  
Major Gene ◽  
Follicular Development ◽  
Oocyte Quality ◽  
Ovulation Rate ◽  
Follicular Growth ◽  
Stages Of Development ◽  
Hormone Production ◽  
Factors Affecting

AbstractThis review addresses the reasons for the lack of progress in the control of superovulation and highlights the importance of understanding the mechanisms underlying follicular development. The present inability to provide large numbers of viable embryos from selected females still restricts genetic improvement, whilst variability in ovarian response to hormones limit the present capacity for increasing reproductive efficiency.Females are born with a large store of eggs which rapidly declines as puberty approaches. If these oocytes are normal then there is scope for increasing the reproductive potential of selected females. Oocytes must reach a certain size before they can complete all stages of development and the final changes that occur late in follicular development. It is likely that oocytes that do not produce specific factors at precise stages of development will not be viable. Hence, it is important to characterize oocyte secreted factors since there are potential indicators of oocyte quality.The mechanisms that determine ovulation rate have still not been fully elucidated. Indeed follicular atresia, the process whereby follicles regress, is still not known. A better understanding of these processes should prove pivotal for the synchronization of follicular growth, for more precise oestrous synchronization and improved superovulatory response.Nutrition can influence a whole range of reproductive parameters however, the pathways through which nutrition acts have not been fully elucidated. Metabolic hormones, particularly insulin and IGFs, appear to interact with gonadotrophins at the level of the gonads. Certainly gonadotropins provide the primary drive for the growth of follicles in the later stages of development and both insulin and IGF-1, possibly IGF-2, synergize with gonadotrophins to stimulate cell proliferation and hormone production. More research is required to determine the effects of other growth factors and their interaction with gonadotropins.There is evidence, particularly from studies with rodents, that steroids can also modulate follicular growth and development, although information is very limited for ruminants. There may be a rôle for oestrogens in synchronizing follicular waves, to aid in oestrous synchronization regimes and for removing the dominant follicle to achieve improved superovulatory responses. However more information is required to determine whether these are feasible approaches.Heritability for litter size is higher in sheep than in cattle. Exogenous gonadotropins are a commercially ineffective means of inducing twinning in sheep and cattle. Although there are differences in circulating gonadotropin concentrations, the mechanism(s) responsible for the high ovulation appear to reside essentially within the ovaries. The locus of the Booroola gene, a major gene for ovulation rate, has been established but not specifically identified. However sheep possessing major genes do provide extremely valuable models for investigating the mechanisms controlling ovulation rate, including a direct contrast to mono-ovulatory species such as cattle.In conclusion, the relationship between oocyte quality, in both healthy follicles and those follicles destined for atresia, must be resolved before the future potential for increasing embryo yield can be predicted. In addition, a greater understanding of the factors affecting folliculogenesis in ruminants should ensure that the full benefits ensuing from the precise control of ovarian function are achieved. The improved use of artificial insemination and embryo transfer that would ensue from a greater understanding of the processes of folliculo genesis, coupled with the new technologies of genome and linkage mapping, should ensure a more rapid rate of genetic gain.

Role of progesterone concentrations during early follicular development in beef cattle: I. Characteristics of LH secretion and oocyte quality

2018 ◽  
Vol 196 ◽  
pp. 59-68 ◽  
Author(s):  
F.M. Abreu ◽  
M.A. Coutinho da Silva ◽  
L.H. Cruppe ◽  
M.L. Mussard ◽  
G.A. Bridges ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Follicular Development ◽  
Oocyte Quality ◽  
Lh Secretion

scholarly journals Anti-müllerian Hormone for the Prediction of Ovarian Response in Progestin-Primed Ovarian Stimulation Protocol for IVF

2019 ◽  
Vol 10 ◽  
Author(s):  
Jialyu Huang ◽  
Jiaying Lin ◽  
Hongyuan Gao ◽  
Yun Wang ◽  
Xiuxian Zhu ◽  
...  
Keyword(s):  
Ovarian Stimulation ◽  
Ovarian Response ◽  
Stimulation Protocol

High ovarian response does not affect oocyte quality: a model based on sharing donated oocytes

2007 ◽  
Vol 88 ◽  
pp. S285-S286
Author(s):  
D. Glujovsky ◽  
M. Carro ◽  
J.F. Jimenez Lara ◽  
G. Maggiotto ◽  
G.E. Fiszbajn ◽  
...  
Keyword(s):  
Ovarian Response ◽  
Oocyte Quality ◽  
Model Based

Regulation of folliculogenesis and the determination of ovulation rate in ruminants

2011 ◽  
Vol 23 (3) ◽  
pp. 444 ◽  
Author(s):  
R. J. Scaramuzzi ◽  
D. T. Baird ◽  
B. K. Campbell ◽  
M.-A. Driancourt ◽  
J. Dupont ◽  
...  
Keyword(s):  
Follicular Development ◽  
Oocyte Quality ◽  
Ovulation Rate ◽  
Fetal Life ◽  
Cellular Events ◽  
Sequence Of Events ◽  
Reproductive Cycles ◽  
Ovulatory Follicles ◽  
Original Concept

The paper presents an update of our 1993 model of ovarian follicular development in ruminants, based on knowledge gained from the past 15 years of research. The model addresses the sequence of events from follicular formation in fetal life, through the successive waves of follicular growth and atresia, culminating with the emergence of ovulatory follicles during reproductive cycles. The original concept of five developmental classes of follicles, defined primarily by their responses to gonadotrophins, is retained: primordial, committed, gonadotrophin-responsive, gonadotrophin-dependent and ovulatory follicles. The updated model has more extensive integration of the morphological, molecular and cellular events during folliculogenesis with systemic events in the whole animal. It also incorporates knowledge on factors that influence oocyte quality and the critical roles of the oocyte in regulating follicular development and ovulation rate. The original hypothetical mechanisms determining ovulation rate are retained but with some refinements; the enhanced viability of gonadotrophin-dependent follicles and increases in the number of gonadotrophin-responsive follicles by increases in the throughput of follicles to this stage of growth. Finally, we reexamine how these two mechanisms, which are thought not to be mutually exclusive, appear to account for most of the known genetic and environmental effects on ovulation rate.

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