Luteinizing Hormone Facilitates Antral Follicular Maturation and Survival via Thecal Paracrine Signaling in Cattle

Impact of Luteinizing Hormone on IVF/ICSI Assisted Reproduction on the Initiation Day of Gonadotropin-releasing Hormone Antagonist Protocol

OBJECTIVE

The aim of the study was to explore the optimal timing of gonadotropin initiation and the reasonable interval of luteinizing hormone (LH) level in the gonadotropin-releasing hormone antagonist (GnRH-A) protocol.

METHODS

A retrospective cohort study was conducted to analyze the LH level in patients with different ovarian response treated in GnRH-A protocol in 1361 IVF/ICSI cycles. Ovarian response (including AMH, AFC) in these patients were divided into the poor ovarian response group (an antral follicle count (AFC) ≤ 6, n = 394), the normal ovarian response group (an AFC > 6 and < 15, n = 570), and the high ovarian response group (an AFC ≥ 15, n = 397), according to the AFC. The patients were sub-grouped according to LH levels on the protocol initiation day, and the clinical outcomes (including dose of Gn initiation, Gn administration days, GnRH-ant administration days, P levels on the HCG day, E2 levels on the HCG day, LH levels on the HCG day, number of embryos transferred, total fertilization rate, embryo implantation rate (%), proportion of 2PN, proportion of good-quality embryos, endometrial thickness on the hCG injection day (mm), moderate to severe OHSS, AFC on the initiation day, proportion of type A endometrium on the hCG injection day, clinical pregnancy rate, biochemical pregnancy rate, early abortion rate, ectopic pregnancy rate) were compared.

RESULTS

On the GnRH-A protocol initiation day, among all patients with different ovarian responses, the body mass index (BMI) in those with an LH ≥ 5 IU/L was lower. The difference of pregnancy outcome between the LH < 5 IU/L group and the LH ≥ 5 IU/L group were not statistically significant among the different ovarian response groups, but the LH < 5 IU/L group had a higher proportion of good-quality embryos (80.3 ± 24.9 vs. 74.8 ± 26.9, P =0.035) than the LH≥5IU/Lgroup in those with poor ovarian response. The total fertilization rate (82.2 ± 18.1 vs 85.4 ± 15.1, P =0.021) and proportion of two pronuclei (2PN) (69.0 ± 20.9 vs 72.7 ± 19.9, P =0.035) were higher in the LH ≥ 5 IU/L group than the LH<5 IU/L group for those with normal ovarian response. The embryo implantation rate (41.4 ± 41.3 vs 52.6 ± 43.4, P =0.012) was higher in the LH ≥ 5 IU/L group than in the LH<5 IU/L group in those with high ovarian response. The results of the multivariate logistic analysis showed that the age of the female partner, number of embryos transferred, proportion of good-quality embryos, endometrial thickness on the hCG injection day, and moderate-to-severe ovarian hyperstimulation syndrome (OHSS) were independent factors correlated with the outcome of live births (P < 0.05).

CONCLUSION

The LH levels on the gonadotropins (Gn) initiation day in GnRH-A protocol will not affect pregnancy outcomes.

Effects and action mechanism of gonadotropins on ovarian follicular cells: A novel role of Sphingosine-1-Phosphate (S1P). A review

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) control antral follicular growth by regulating several processes, such as the synthesis of hormones and signaling molecules, proliferation, survival, apoptosis, luteinization, and ovulation. To exert these effects, gonadotropins bind to their respective Gs protein-coupled receptors, activating the protein kinase A (PKA) pathway or recruiting Gq proteins to activate protein kinase C (PKC) signaling. Although the action mechanism of FSH and LH is clear, recently, it has been shown that both gonadotropins promote the synthesis of sphingosine-1-phosphate (S1P) in granulosa and theca cells through the activation of sphingosine kinase 1. Moreover, the inhibition of SPHKs reduces S1P synthesis, cell viability, and the proliferation of follicular cells in response to gonadotropins, and the addition of S1P to the culture medium increases the proliferation of granulosa and theca cells without apparent effects on sexual steroid synthesis. Therefore, we consider that S1P is a crucial signaling molecule that complements the canonical gonadotropin pathway to promote the proliferation and viability of granulosa and theca cells.

A Subovulatory Dose of Human Chorionic Gonadotropin (hCG) May Sustain Terminal Follicle Development and Reproductive Efficiency during Anestrus in Sheep

The study tested the hypothesis that a single administration of hCG supports the LH-dependent phase of terminal follicular development in synchronized sheep during anestrus, using eCG as a functional reference. Using a clinical approach, four experiments were designed to achieve the following: (1) Identify the inhibitory influence of anestrus on reproduction efficiency; (2) Assess the potential of hCG to keep functional blood concentrations after a single dose; (3) Characterize the effect of different doses of hCG on reproductive functional markers; (4) To compare the ability of hCG to that of eCG to support follicular development and fertility based on the same markers. The results showed that anestrus seems to affect follicular and luteal function under LH dependency as FSH-dependent markers are not compromised; hCG maintains higher blood concentrations than controls for at least 48 h; hCG improves follicular development and ovulatory rates compared to controls and at standards comparable to a breeding season; and ewes treated with hCG exhibit similar performance to those treated with eCG. Our results conclude that hCG can be used to support follicular function during anestrus in sheep, aiming to perfect its regulation in assisted reproduction.

Unveiling the Role of IGF-I in Fertility: Effect of Long-Acting Bovine Somatotropin (bST) on Terminal Follicular Development and Fertility during an Annual Reproductive Cycle in Sheep

The study aimed to assess the effect of long-acting bST treatment, in a dose that only increases IGF-I plasma concentrations, on ovarian and fertility markers of estrous synchronized ewes that were fed to keep their bodyweight. Three experiments were designed to evaluate this effect: in Experiment 1, 18 ewes were distributed in groups (bST 0, 30, 50 mg) to measure plasma IGF-I and insulin for 15 days; in Experiment 2, 92 ewes (5 replicates) in two groups (0 and 30 mg bST) were synchronized using a 6-day progesterone protocol during the breeding season to assess the effect of bST on follicular and luteal performances, estrous and ovulation, and fertility after mating. In Experiment 3, 50 ewes (3 replicates) were used to repeat the study before but during anestrus. Results indicate that 50 mg bST increased IGF-I and insulin plasma concentrations, but 30 mg bST only increased IGF-I concentrations; and that only during the breeding season did 30 mg bST increase the number of lambs born and the reproductive success of ovulatory-sized follicles compared to controls. This occurred without it affecting any other reproductive marker. In conclusion, 30 mg bST treatment may improve oocyte competence for fertility during the breeding season.

Effect of follicle-stimulating hormone and luteinizing hormone on apoptosis, autophagy, and the release and reception of some steroid hormones in yak granulosa cells through miR-23a/ASK1 axis

Follicle-stimulating hormone (FSH), luteinizing hormone (LH), miR-23a, apoptosis signal-regulating kinase 1(ASK1)/c-Jun N-terminal kinase (JNK), autophagy and apoptosis play crucial roles in follicular development. However, their role in yak granulosa cells (GCs) remains unknown. Therefore, we examined the effect of miR-23a, ASK1, FSH, and LH on apoptosis, autophagy, and the release and reception of some steroid hormones in these cells. Our results showed that miR-23a overexpression significantly increased the abundance of Beclin1, the LC3II/I ratio, and the number of Ad-mRFP-GFP-LC3-labeled autophagosomes, and decreased p62 abundance. Additionally, Bax abundance and the number of terminal deoxynucleotidyl transferase deoxynucleotide triphosphate nick end labeling-positive cells were reduced, while Bcl2 expression was increased. Overexpression of miR-23a also significantly increased the abundance of estradiol receptor α (ER-α) and β (ER-β) and the concentrations of estradiol (E2), progesterone (P4) in yak GCs. Here, treating yak GCs with miR-23a decreased ASK1 expression, which regulates ASK1/JNK-mediated apoptosis, autophagy, E2 and P4 levels, and ER-α/β abundance. In contrast, treatment of yak GCs with FSH (10 μg/mL) and LH (100 μg/mL) increased miR-23a abundance, regulating the subsequent effect on ASK1/JNK-mediated apoptosis, autophagy, ER-α/β abundance, and E2 and P4 concentrations. In conclusion, miR-23a enhances autophagy in yak GCs, attenuates apoptosis, and increases ER-α/β abundance and E2 and P4 concentrations by downregulating ASK1. Additionally, FSH and LH can regulate these effects of miR-23a by altering its expression. These results provide important insights that can inform the development of strategies to reduce abnormal follicular atresia and improve the reproductive rate of yaks.

Ovarian response determines the luteinizing hormone suppression threshold for patients following the gonadotrophin releasing hormone antagonist protocol: A retrospective cohort study

Background

Ovarian reactivity to gonadotrophin stimulation varies, and individual adjustments to the timing and dose of gonadotrophin-releasing hormone (GnRH) antagonist administration are necessary to prevent excessive increases and decreases in luteinizing hormone (LH) levels in patients with different ovarian response following the GnRH antagonist (GnRH-A) protocol. The present study aims to investigate optimal LH suppression thresholds for patients with normal ovarian response (NOR), high ovarian response (HOR), and poor ovarian response (POR) following the GnRH-A protocol respectively.

Methods

A total of 865 in vitro fertilization (IVF) cycles using a flexible or fixed GnRH-A protocol were included. Patients were categorized into the HOR, NOR, or POR group according to their anti-Müllerian hormone (AMH) levels. Then, patients in each group were stratified into one of four subgroups according to the quartile (Q1-Q4) of the basal LH level to LH on triggering day ratio (bLH/hLH). The primary outcomes were the clinical pregnancy and live birth rates, and the secondary outcomes were the number of oocytes retrieved, MII oocytes, two pronucleus (2PN) embryos, and good-quality embryos.

Results

There were 526 patients with NOR, 180 with HOR, and 159 with POR. Basal LH level, LH on triggering day and bLH/hLH were identified as independent predictors of clinical pregnancy rate and live birth rate by logistics regression analysis. Compared to those with NOR, patients with POR had the lowest embryo implantation rate (22.6% vs. 32.8%, P < 0.05), clinical pregnancy rate (32.3% vs. 47.3%, P < 0.05) and live birth rate (22.6 vs. 37.8%, P < 0.05) of fresh embryo transfer (ET). The embryo implantation, clinical pregnancy and live birth rates of frozen embryo transfer (FET) were not significantly different among the three groups. In the subgroup analysis, patients with HOR had the highest embryo implantation rate (51.6%, P < 0.05), clinical pregnancy rate (68.4%, P < 0.05) and live birth rate (52.6%, P < 0.05) of ET in Q3, with a bLH/hLH ratio of 2.40-3.69. In the NOR group, the embryo implantation rate (41.9%, P < 0.05), clinical pregnancy rate (61.5%, P < 0.05) and live birth rate (50.8%, P < 0.05) of ET and live birth rate (53.1%, P < 0.05) of FET were highest in Q2, with a bLH/hLH ratio of 1.29-2.05. Patients with POR had the highest clinical pregnancy rate (57.1%, P < 0.05) and live birth rate (42.9%, P < 0.05) of ET in Q2, with a bLH/hLH ratio of 0.86-1.35.

Conclusions

In the present study, the bLH/hLH ratio represented the LH suppression threshold. The subgroup analysis of HOR, NOR and POR showed that, the LH suppression threshold varies according to ovarian response. We recommend LH suppression thresholds of 2.40-3.69 for HOR, 1.29-2.05 for NOR, and 0.86-1.35 for POR to obtain the highest clinical pregnancy rate and live birth rate. This study provides comprehensive and precise references for clinicians to monitor LH levels individually during controlled ovarian stimulation (COS) according to the patient's ovarian response following the GnRH-A protocol.

Effect of one or two fixed glutamate doses on follicular development, ovarian-intraovarian blood flow, ovulatory rate, and corpus luteum quality in goats with a low body condition score

This study aimed to investigate the effect of a short glutamate supply on the ovarian response in goats with low body condition scores. Twenty-one goats had their estrus and follicular waves synchronized using three injections of prostaglandin analog at seven-day intervals. Goats were allocated to groups receiving 10 mg/kg LW (iv) of glutamate administered in a single dose (group LBCG1, n = 7) or in two doses five days apart (group LBCG2, n = 7). The control group (LBC; n = 7) received saline solution. Glutamate treatment did not affect glucose, cholesterol, or glutathione peroxidase levels, body weight, or adipose deposits. During the experimental period, the LBCG2 group showed a higher (P < 0.05) number of follicles (> 3 mm) and an increase in follicle diameter (P < 0.05). Glutamate supply improved (P < 0.05) the intraovarian Doppler blood area size in the LBCG groups, and the second dose in LBCG2 also induced a higher (P < 0.05) systolic and diastolic peak of the ovary artery. After ovulation induction, LBCG2 exhibited a high (P < 0.05) volume of the corpus luteum and vascularized area. We concluded that the supply of two doses of glutamate five days apart was efficient in ovarian stimulation in goats with a low body condition.

New insights into the role of LH in early ovarian follicular growth: a possible tool to optimize follicular recruitment

Evidence shows that LH participates in enhancing transition from the early stage to the antral stage of folliculogenesis. It has been demonstrated that functional LH receptors are expressed, albeit at a very low level and even in smaller follicles, during the phase that was traditionally considered to be gonadotrophin independent, suggesting a role for LH in accelerating the rate of progression of non-growing and primary follicles to the preantral/antral stage. Hypogonadotropic hypogonadism, together with other clinical conditions of pituitary suppression, has been associated with reduced functional ovarian reserve. The reduction in LH serum concentration is associated with a low concentration of anti-Müllerian hormone. This is the case in hypothalamic amenorrhoea, pregnancy, long-term GnRH-analogue therapy and hormonal contraception. The effect seems to be reversible, such that after pregnancy and after discontinuation of drugs, the functional ovarian reserve returns to the baseline level. Evidence suggests that women with similar primordial follicle reserves could present with different numbers of antral follicles, and that gonadotrophins may play a fundamental role in permitting a normal rate of progression of follicles through non-cyclic folliculogenesis. The precise role of gonadotrophins in early folliculogenesis, as well as their use to modify the functional ovarian reserve, must be investigated.

Insulin-like growth factor (IGF) performance in ovarian function and applications in reproductive biotechnologies

The role of the insulin-like growth factor (IGF) system has attracted close attention. The activity of IGF binding proteins (IGFBPs) within the ovary has not been fully elucidated to date. These proteins bind to IGF with an equal, or greater, affinity than to the IGF1 receptor, thus being in the main position to regulate IGF signalling, in addition to extending the half-life of IGFs within the bloodstream and promoting IGF storage in specific tissue niches. IGF1 has an important part in cell proliferation, differentiation and apoptosis. Considering the importance of IGFs in oocyte maturation, this review sought to elucidate aspects including: IGF production mechanisms; constituent members of their family and their respective functions; the role that these factors play during folliculogenesis, together with their functions during oocyte maturation and apoptosis, and their performance during luteal development. This review also explores the role of IGFs in biotechnological applications, focusing specifically on animal genetic gain.

Effects of melatonin on development and hormone secretion of sheep theca cells in vitro

Theca cells (TCs) play a unique role in the structure and function of the ovary. They are not only the structural basis of the follicle but also the androgen-secreting cells in female mammals, which can affect the normal development and atresia of the follicle. The results showed that melatonin receptor (MTR) MT1 and MT2 were expressed on sheep TCs. In the present study, the effects of different concentrations of MT at 0, 10^-10, 10^-8, 10^-6 and 10^-4 M/L on sheep TCs with regards to the antioxidant levels, proliferation, apoptosis and steroid hormone secretion were investigated. The results showed that in sheep TCs, all concentrations of MT significantly decreased reactive oxygen species (ROS) concentration and BAX expression; increased Cat, Sod1, and BCL-2 expression. The proliferation viability of TCs was significantly inhibited in all groups except for 10^-10 M/L MT, and the expression of cyclin D1 and CDK4 was significantly reduced. MT significantly increased StAR expression and progesterone secretion in TCs, but there was no significant effect on androgen secretion and CYP11A1, CYP17A1 and 3β-HSD expression in all groups. MT-induced progesterone secretion was completely inhibited by Luzindole (a nonspecific MT1 and MT2 inhibitor) and partially inhibited by 4p-PDOT (specific MT2 inhibitor). MT-induced progesterone secretion can be inhibited by LY294002 (PI3K/AKT pathway inhibitor). This study indicated that MT inhibits apoptosis and proliferation of in vitro cultured sheep TCs, which has implications for slowing ovarian atresia and aging. MT activates the PI3K/Akt pathway to mediate the synthesis and secretion of progesterone by TCs. This study provides a basis for further exploration of the role of TCs on follicle development and ovarian steroid hormone secretion.

Polycystic ovary syndrome and obesity: a modern paradigm

Polycystic ovary syndrome is a heterogeneous endocrine disease that affects women of childbearing age. The pathogenesis of polycystic ovary syndrome has not been fully studied to date, its paradigm considers the genetic determinism of the manifestation of hormonal and metabolic disorders, which are considered to be criteria for the verification of the disease (hyperandrogenism, oligo/anovulation and/or polycystic ovarian transformation during ultrasound examination (ultrasound). This review discusses the main ways of interaction between hyperandrogenism, insulin resistance and obesity and their role in the pathogenesis of polycystic ovary syndrome, as well as possible methods of treatment for this category of patients. The review analyzes the role of hyperandrogenism and insulin resistance in the implementation of the genetic scenario of polycystic ovary syndrome and finds out the reasons why women with polycystic ovary syndrome often demonstrate the presence of a «metabolic trio» - hyperinsulinemia, insulin resistance and type 2 diabetes mellitus. It is noted that obesity is not included in the criteria for the diagnosis of polycystic ovary syndrome, but epidemiological data confirm the existence of a relationship between these diseases. Obesity, especially visceral, which is often found in women with polycystic ovary syndrome, enhances and worsens metabolic and reproductive outcomes with polycystic ovary syndrome, as well as increases insulin resistance and compensatory hyperinsulinemia, which, in turn, stimulates adipogenesis and suppresses lipolysis. Obesity increases the sensitivity of tech cells to luteinizing hormone stimulation and enhances functional hyperandrogenism of the ovaries, increasing the production of androgens by the ovaries. Excess body weight is associated with a large number of inflammatory adipokines, which, in turn, contribute to the growth of insulin resistance and adipogenesis. Obesity and insulin resistance exacerbate the symptoms of hyperandrogenism, forming a vicious circle that contributes to the development of polycystic ovary syndrome. These data allow us to conclude that bariatric surgery can become an alternative to drugs (metformin, thiazolidinedione analogs of glucagon-like peptide-1), which has shown positive results in the treatment of patients with polycystic ovary syndrome and obesity.

Extended LH administration as a strategy to increase the pool of recruitable antral follicles in hypothalamic amenorrhea: evidence from a case series

New evidence is indicating a growing role of LH in promoting ovarian follicular growth and maturation, even at the early stages. LH seems to enhance the transition of follicles to the antral stage hence leading to an increase in the so-called functional ovarian reserve (recruitable antral follicles). Hypogonadotropic hypogonadism is characterized by low, and sometimes undetectable, serum LH and FSH levels, which may indeed explain the low anti-Müllerian hormone (AMH) levels and antral follicle count (AFC) found in patients affected by this condition. We report here the cases of two young women affected by hypothalamic amenorrhea (HA) that presented for fertility treatment with very low functional ovarian reserve. The two patients were treated with exogenous LH for 1 and 2 months (extended LH administration: ELHA) at the dose of 187.5 IU LH every day and 150 IU LH every other day, respectively. In both the cases there was an increase in serum AMH levels and in the AFC. In one patient, the AMH and AFC increased from a baseline 1.3 ng/ml and 8 to 2.3 ng/ml and 14 at end of treatment, respectively. In the second case, serum AMH and AFC increased from 0.4 ng/ml and 6 to 1.6 ng/ml and 13, respectively. One patient underwent ovarian stimulation before and after ELHA, showing an increase in the number of mature oocytes recruited (3 versus 8 metaphase II (MII) oocytes before and after, respectively). The second patient underwent an IVF cycle after ELHA resulting in the retrieval of six MII oocytes and an ongoing pregnancy following transfer of a single blastocyst. Women with HA are characterized by chronic, low levels of gonadotrophins, which may impact not only on the cyclic recruitment of follicles but also the progression of small growing follicles through the first stages of folliculogenesis. Some women with HA may in fact show very low serum AMH and AFC. Our case series shows that the administration of LH at a dose of at least 150–187.5 IU every day or every other day may contribute to a clinically evident increase in the functional ovarian reserve (AFC), and probably accounts for a positive effect of LH on the progression of follicles throughout the early stages of folliculogenesis.

Association of Insulin Resistance and Elevated Androgen Levels with Polycystic Ovarian Syndrome (PCOS): A Review of Literature

The polycystic ovary syndrome (PCOS) is the disease featured by elevated levels of androgens, ovulatory dysfunction, and morphological abnormalities. At reproductive stage of women, the rate of PCOS occurrence is measured as 6–10% and the prevalence rate may be double. There are different pathophysiological factors involved in PCOS, and they play a major role in various abnormalities in individual patient. It is clear that there is noteworthy elevation of androgen in PCOS, causing substantial misery and infertility problems. The overexposure of androgen is directly linked with insulin resistance and hyperinsulinaemia. It has been reported previously that PCOS is related to cardiac metabolic miseries and potently increases the risk of heart diseases. Endometrial cancer is also a serious concern which is reported with exceedingly high incidence in women with PCOS. However, the overexposure of androgen has direct and specific influence on the development of insulin resistance. Although many factors are involved, resistance to the insulin and enhanced level of androgen are considered the major causes of PCOS. In the present review, we have focused on the pathophysiology and major revolutions of insulin resistance and excessive levels of androgen in females with PCOS.

Prevention of Premature Ovulation by Administration of Gonadotropin Releasing Hormone Antagonist the day After Ovulation Triggering in Diminished Ovarian Reserve Patients

OBJECTIVE

 The aim of the present retrospective study was to investigate the effectiveness of single-dose gonadotropin releasing hormone (GnRH) antagonist administration, the day after human chorionic gonadotropin (hCG) triggering for final oocyte maturation, on the prevention of premature luteinization in patients with diminished ovarian reserve in in-vitro fertilization (IVF) cycles. The secondary objective of the study was to search the effect of this protocol on pregnancy outcomes.

METHODS

 This is a retrospective study including 267 infertile patients who have single antral follicle seen with ultrasonography on the 2^nd or 3^rd day of the menstrual cycle before starting IVF treatment. We randomized patients into two groups. The case group comprised patients who had single-dose GnRH antagonist injection the day after hCG triggering formed, and the patients who had the standard treatment regime formed the control group. In both groups, the oocytes were collected 36 hours after hCG injection.

RESULTS

 The premature ovulation rate was significantly low in the case group compared with the control group (6.86 versus 20.6% per scheduled cycle) (p = 0.022). Also, the oocyte retrieval rate (93.14 versus 67.87% per scheduled cycle) (p = 0.013), the oocyte maturity rate (79.42 versus 47.87%) (p = 0.041), the fertilization rate (65.68 versus 34.54%) (p = 0.018), and the embryo transfer rate per scheduled cycle (44.11 versus 18.78%) (p = 0.003) were higher in the GnRH antagonist group than in the control group.

CONCLUSION

 The administration of GnRH antagonist the day after hCG trigger in IVF treatments of patients with diminished ovarian reserve enabled a significant decrease in the rate of premature ovulation but had no effect on live birth rate.

An altered expression of components of the IGF system could contribute to follicular persistence in Holstein cows

In dairy cows, reproductive diseases such as cystic ovarian disease (COD) represent a major problem that impacts on dairy production. It has been postulated that the insulin-like growth factor (IGF) system may contribute to follicular persistence and development of COD. Thus, the aim of the present study was to analyze relevant members of the IGF system in a critical period immediately after the expected time of ovulation, to obtain information about their role in follicular persistence in dairy cows. Proteins of the IGF system were evaluated at 0 (expected day of ovulation), 5, 10 and 15 days of follicular persistence to determine whether the changes previously detected in cows with COD occur early in COD pathogenesis. The serum concentration of IGF1 was higher in cows with 10 and 15 days of follicular persistence than in control cows. IGF1 expression in granulosa cells was similar in the follicles analyzed. In contrast, in theca cells, persistent follicles of days 5 and 10 showed the lowest IGF1 expression. IGF binding protein (IGFBP) 2 and 3 expression was lower in persistent follicles than in dominant follicles of the control group. Although IGF receptor (IGFR) 1 expression was similar in the groups analyzed, p-IGFR1 expression was significantly higher in dominant follicles of the control group than in persistent follicles. These data suggest alterations in the IGF system at the early stages of follicular persistence. The evidences obtained allow supporting that the IGF system could plays a key role in dairy cattle reproduction.

Arachidonic Acid in Follicular Fluid of PCOS Induces Oxidative Stress in a Human Ovarian Granulosa Tumor Cell Line (KGN) and Upregulates GDF15 Expression as a Response

Polycystic ovarian ovary syndrome (PCOS) is the main cause of ovulatory infertility and a common reproductive endocrine disease of women in reproductive age. In addition, nearly half of PCOS patients are associated with obesity, and their total free fatty acids tend to increase. Arachidonic acid (AA) is a polyunsaturated fatty acid. Oxidation products of AA reacting with various enzymes[cyclooxygenases (COX), lipoxygenases (LOX), cytochrome P450s (CYP)] can change cellular mitochondrial distribution and calcium ion concentration, and increase reactive oxygen species (ROS) production. In this study, we analyzed the follicular fluid fatty acids and found higher levels of C20:4n6 (AA) in PCOS patients than in normal control subjects. Also, to determine whether AA induces oxidative stress (OS) in the human ovarian granulosa tumor cell line (KGN) and affects its function, we treated KGN cells with or without reduced glutathione (GSH) and then stimulated them with AA. The results showed that AA significantly reduced the total antioxidant capacity (TAC) and activity of antioxidant enzymes and increased the malondialdehyde (MDA), ROS and superoxide anion(O_2-)levels in KGN cells. In addition, AA was also found to impair the secretory and mitochondrial functions of KGN cells and induce their apoptosis. We further investigated the downstream genes affected by AA in KGN cells and its mechanism of action. We found that AA upregulated the expression of growth differentiation factor 15 (GDF15), which had a protective effect on inflammation and tissue damage. Therefore, we investigated whether AA-induced OS in KGN cells upregulates GDF15 expression as an OS response.Through silencing of GDF15 and supplementation with recombinant GDF15 (rGDF15), we found that GDF15, expressed as an OS response, protected KGN cells against AA-induced OS effects, such as impairment of secretory and mitochondrial functions and apoptosis. Therefore, this study suggested that AA might induce OS in KGN cells and upregulate the expression of GDF15 as a response to OS.

Luteinizing hormone-based modified GnRH antagonist protocol in normal responders undergoing in vitro fertilization treatment: A multi-center randomized controlled trial

OBJECTIVE

To study the clinical efficacy and cost-effectiveness of a modified gonadotrophin-releasing hormone (GnRH) antagonist protocol based on luteinizing hormone (LH) levels through one complete assisted reproductive technology (ART) cycle in normal responders.

DESIGN

Non-inferiority, multicenter randomized controlled trial.

SETTING

University-based hospitals and an academic medical center.

PATIENTS

A total of 372 patients fulfilled the inclusion criteria and were eligible to participate.

INTERVENTIONS

Participants were randomized at a 1:1 ratio and stimulated with the conventional flexible GnRH antagonist protocol (control group) or LH-based modified GnRH antagonist protocol (study group).

MAIN OUTCOME MEASURES

The primary outcome was the cumulative ongoing pregnancy rate per aspiration. The secondary outcomes were number of oocytes retrieved, number of good quality embryos, cumulative positive βhCG rate, cumulative clinical pregnancy rate, pregnancy loss rate, moderate and severe ovarian hyperstimulation syndrome (OHSS), and financial expenditure.

RESULTS

The cumulative ongoing pregnancy rate was 65.1% in the study group and 70.1% in the control group (odds ratio, 0.79; 95% confidence interval, 0.50-1.26; P = 0.33). The multivariate regression analyses results showed that the number of retrieved oocytes was positively associated with the odds for a higher cumulative ongoing pregnancy rate (adjusted odds ratio, 1.11, 95% confidence interval, 1.06-1.17, P < 0.001). The treatment protocol, female age, and body mass index were not independent predictors. The incremental cost-effectiveness ratio for luteinizing hormone-based gonadotrophin releasing hormone antagonist protocol versus the conventional flexible gonadotrophin releasing hormone antagonist protocol was estimated at 3568.6 USD for each additional ongoing pregnancy.

CONCLUSION

The luteinizing hormone-based gonadotrophin releasing hormone antagonist protocol had clinical efficacy similar to the conventional flexible gonadotrophin releasing hormone antagonist protocol in normal responders undergoing in vitro fertilization treatment but was more cost-effective considering the cumulative ongoing pregnancy rate in the entire assisted reproductive technology cycle.

CLINICAL TRIAL REGISTRATION

www.chictr.org.cn, identifier: ChiCTR1800018077.

URL OF THE REGISTRATION SITE

http://www.chictr.org.cn/edit.aspx?pid=27389&htm=4.

TRIAL REGISTRATION DATE

29 August 2018.

DATE OF FIRST PATIENT ENROLLMENT

1 September 2018.

Follicular development in livestock: Influencing factors and underlying mechanisms

Livestock farming development has become increasingly important in recent years. It not only provides us with meat nutrition and pet feeding but also increases the economic value by providing numerous employment opportunities, which improves our life quality. The livestock farming development depends on successful animal reproduction. As a vital process in animal reproduction, folliculogenesis and its influencing factors as well as their underlying mechanisms need to be understood thoroughly. This review is aimed at summarizing the factors such as cellular processes, gene regulation, noncoding RNAs and other endocrine or paracrine regulatory factors that affect follicular development, and their underlying mechanisms of action in livestock in order to provide novel insights for future studies. The above factors were found as significant determinants influencing the follicular development in livestock through various signaling pathways.

Monocyte perturbation modulates the ovarian response to an immune challenge

Our recent findings indicate that an acute depletion of monocytes has no sustained effects on ovarian follicle health. Here, we utilised a Cx3cr1-Dtr transgenic Wistar rat model to transiently deplete monocytes and investigated the impact of an acute immune challenge by lipopolysaccharide (LPS) on ovarian follicle health and ovulatory capacity relative to wt once the monocytes had repopulated. Monocyte depletion and repopulation exacerbated the effects of LPS in several domains. As such, monocyte perturbation decreased the numbers of secondary follicles in those challenged with LPS. Monocyte perturbation was also associated with reduced antral follicle numbers and circulating luteinising hormone (LH) levels, as well as potential changes in ovarian sensitivity to LH, exacerbated by LPS. These data suggest that monocyte depletion and repopulation induce a transient suppression of ovulatory capacity in response to a subsequent immune challenge, but this is likely to be restored once the pro-inflammatory environment is resolved.

ERβ Regulation of Gonadotropin Responses during Folliculogenesis

Gonadotropins are essential for regulating ovarian development, steroidogenesis, and gametogenesis. While follicle stimulating hormone (FSH) promotes the development of ovarian follicles, luteinizing hormone (LH) regulates preovulatory maturation of oocytes, ovulation, and formation of corpus luteum. Cognate receptors of FSH and LH are G-protein coupled receptors that predominantly signal through cAMP-dependent and cAMP-independent mechanisms that activate protein kinases. Subsequent vital steps in response to gonadotropins are mediated through activation or inhibition of transcription factors required for follicular gene expression. Estrogen receptors, classical ligand-activated transcriptional regulators, play crucial roles in regulating gonadotropin secretion from the hypothalamic-pituitary axis as well as gonadotropin function in the target organs. In this review, we discuss the role of estrogen receptor β (ERβ) regulating gonadotropin response during folliculogenesis. Ovarian follicles in Erβ knockout (Erβ^KO) mutant female mice and rats cannot develop beyond the antral state, lack oocyte maturation, and fail to ovulate. Theca cells (TCs) in ovarian follicles express LH receptor, whereas granulosa cells (GCs) express both FSH receptor (FSHR) and LH receptor (LHCGR). As oocytes do not express the gonadotropin receptors, the somatic cells play a crucial role during gonadotropin induced oocyte maturation. Somatic cells also express high levels of estrogen receptors; while TCs express ERα and are involved in steroidogenesis, GCs express ERβ and are involved in both steroidogenesis and folliculogenesis. GCs are the primary site of ERβ-regulated gene expression. We observed that a subset of gonadotropin-induced genes in GCs, which are essential for ovarian follicle development, oocyte maturation and ovulation, are dependent on ERβ. Thus, ERβ plays a vital role in regulating the gonadotropin responses in ovary.

Death Processes in Bovine Theca and Granulosa Cells Modelled and Analysed Using a Systems Biology Approach

In this paper, newly discovered mechanisms of atresia and cell death processes in bovine ovarian follicles are investigated. For this purpose the mRNA expression of receptor interacting protein kinases 1 and 3 (RIPK1 and RIPK3) of the granulosa and theca cells derived from healthy and atretic follicles are studied. The follicles were assigned as either healthy or atretic based on the estradiol to progesterone ratio. A statistically significant difference was recorded for the mRNA expression of a RIPK1 and RIPK3 between granulosa cells from healthy and atretic follicles. To further investigate this result a systems biology approach was used. The genes playing roles in necroptosis, apoptosis and atresia were chosen and a network was created based on human genes annotated by the IMEx database in Cytoscape to identify hubs and bottle-necks. Moreover, correlation networks were built in the Cluepedia plug-in. The networks were created separately for terms describing apoptosis and programmed cell death. We demonstrate that necroptosis (RIPK—dependent cell death pathway) is an alternative mechanism responsible for death of bovine granulosa and theca cells. We conclude that both apoptosis and necroptosis occur in the granulosa cells of dominant follicles undergoing luteinisation and in the theca cells from newly selected follicles.

Does LH supplementation in poor responders affect granulosa cells apoptosis rate in ART? A prospective randomised controlled trial

The aim was to compare granulosa cell's (GCs) apoptosis rate with (group A) or without (group B) luteinising hormone (LH) supplementation in poor ovarian responders (PORs) during controlled ovarian stimulation (COS). After oocyte retrieval, the follicular fluid was analysed by cytoflowmetry. Primary outcomes were GCs apoptosis rate in terms of viability, early apoptosis, late apoptosis and necrosis. Secondary outcome was clinical pregnancy rate. The viability was 96.7{IQR: 8} and 83.5{IQR: 20} for groups A and B, respectively (p < .001). Late apoptosis rates were significantly lower in group A (median 1.5, {IQR: 3.1}) than group B (median 9.5, {IQR: 20.6}) (p < .001). Median early apoptosis rates were 1.4 {IQR: 2.9} and 5.2 {IQR: 6.5} for group A and B respectively (p = .04). No significant difference was observed in the clinical pregnancy rate. Although LH seems necessary in PORs to decrease late granulosa apoptosis rates, this does not improve clinical pregnancy rates.IMPACT STATEMENTWhat is already known on this subject? LH supplementation during COS has long been an issue in PORs to overcome the rFSH responsiveness due to the LH polymorphism. LH receptors have also been on GCs and their expression increases in preovulatory follicles. GCs apoptosis rates may show the oocyte quality and reproductive potential of oocyte retrieved and the requirement for LH supplementation.What do the results of this study add? The present study shows that LH supplementation during COS for PORs promotes the GC viability and reduces early/late apoptosis rates. Similarly, the number of MII oocytes was significantly higher in the LH regimen group. However, there was no significant difference in terms of clinical pregnancy rates.What are the implications of these findings for clinical practice and/or further research? The oocyte quality parameters such as higher GC viability and lower GC early/late apoptosis rates verify the LH supplementation in PORs during COS. However, the limited size of this study requires further multi-centre research in a larger cohort of patients. Results obtained with a sensitive and validated method will help clinicians to make better decisions in patient care.

The role of pituitary gonadotropins and intraovarian regulators in follicle development: A mini-review

BACKGROUND

The process of follicle development is tightly regulated by pituitary gonadotropins (follicle-stimulating hormone [FSH] and luteinizing hormone [LH]) and intraovarian regulators (eg, steroids, growth factors, and cytokines).

METHODS

This review outlines recent findings on the mechanisms of human follicle development, based on the research on animal models such as mice, rats, cows, and sheep.

MAIN FINDINGS

Phosphatidylinositol 3-kinase/protein kinase B signaling pathway and anti-Müllerian hormone are involved in primordial follicle activation during the gonadotropin-independent phase. The intraovarian regulators, such as androgen, insulin-like growth factor system, activin, oocyte-derived factors (growth differentiation factor-9 and bone morphogenetic protein 15), and gap junction membrane channel protein (connexin), play a central role in the acquisition of FSH dependence in preantral follicles during the gonadotropin-responsive phase. Antral follicle development can be divided into FSH-dependent growth and LH-dependent maturation. The indispensable tetralogy for follicle selection and final maturation of antral follicles involves (a) acquisition of LH dependence, (b) greater capacity for E2 production, (c) activation of the IGF system, and (d) an antiapoptotic follicular microenvironment.

CONCLUSION

We reproductive endocrinologists should accumulate further knowledge from animal model studies to develop methods that promote early folliculogenesis and connect to subsequent gonadotropin therapy in infertile women.

In vitro development of mechanically and enzymatically isolated cat ovarian follicles

Isolation of ovarian follicles is a key step in culture systems for large mammalian species to promote the continued growth of follicles beyond the preantral stage in fertility preservation efforts. Still, mechanical isolation methods are user-skill dependent and time-consuming, whereas enzymatic strategies carry increased risk of damaging theca cell layers and the basement membranes. Here, we sought to determine an optimal method to rescue domestic cat (Felis catus) early antral and antral stage follicles from ovarian tissue and to evaluate the influence of isolation strategy on follicle development, survival, and gene expression during 14 days of in vitro culture in alginate hydrogel. Mechanical isolation was compared with 90 min digestion in 0.7 and 1.4 Wünsch units/mL Liberase blendzyme (0.7L and 1.4L, respectively). Mechanical isolation resulted in improved follicle growth and survival, and better antral cavity and theca cell maintenance in vitro, compared with 1.4L (P < 0.05) but displayed higher levels of apoptosis after incubation compared with enzymatically isolated follicles. However, differences in follicle growth and survival were not apparent until 7+ days in vitro. Expressions of CYP19A1, GDF9, LHR, or VEGFA were similar among isolation-strategies. Cultured follicles from all isolation methods displayed reduced STAR expression compared with freshly isolated follicles obtained mechanically or via 0.7L, suggesting that prolonged culture resulted in loss of theca cell presence and/or function. In sum, early antral and antral stage follicle development in vitro is significantly influenced by isolation strategy but not necessarily observable in the absence of extended culture. These results indicate that additional care must be taken in follicle isolation optimizations for genome rescue and fertility preservation efforts.

Patients With Deep Ovarian Suppression Following GnRH Agonist Long Protocol May Benefit From a Modified GnRH Antagonist Protocol: A Retrospective Cohort Study

OBJECTIVE

To verify if patients with deep ovarian suppression following gonadotropin releasing hormone (GnRH) agonist long protocol may benefit from a modified GnRH antagonist protocol based on luteinizing hormone (LH) levels.

DESIGN

Retrospective cohort study.

SETTING

University-based hospital.

PATIENTS

110 patients exhibited ultra-low LH levels during ovarian stimulation using GnRH agonist long protocol.

INTERVENTIONS

As all the embryos in the first cycle were exhausted without being pregnant, these patients proposed to undergo a second cycle of ovarian stimulation. 74 of them were treated with a modified GnRH antagonist protocol based on LH levels. Other 36 patients were still stimulated following GnRH agonist long protocol.

MAIN OUTCOME MEASURE

The primary outcome was live birth rate (LBR). The second outcomes were biochemical pregnancy rate, clinical pregnancy rate (CPR), ongoing pregnancy rate (OPR) and cancellation rate.

RESULTS

Reproductive outcomes were much better in the modified GnRH antagonist protocol. The OPR and LBR were much higher in the GnRH antagonist protocol group than in the GnRH agonist long protocol group [odds ratio (OR) 3.82, 95% confidence interval (CI) 1.47, 10.61, P=0.018; OR 4.33, 95% CI 1.38, 13.60, P=0.008; respectively]. Meanwhile, the cancellation rate was much lower in the GnRH antagonist protocol group (OR 0.13, 95% CI 0.02, 0.72; P=0.014). Mean LH level during stimulation did not have a predictive value on live birth. However, it was independently associated with the occurrence of ongoing pregnancy (OR 2.70, 95% CI 1.25, 5.85; P=0.01). The results of sensitivity analyses were consistent with the data mentioned above. The patients got completely different and excellent clinical outcomes in their second cycles stimulated with the modified GnRH antagonist protocol.

CONCLUSION

Patients with deep ovarian suppression following GnRH agonist long protocol may benefit from a modified GnRH antagonist protocol based on LH levels.

Possible role of n-hexane as an endocrine disruptor in occupationally exposed women at reproductive age

Human exposure to n-hexane has been associated with subfertility and, experimentally, with a decrease in follicular development. In order to assess occupational exposure to n-hexane on ovarian function and gonadotropic hormones, we studied Mexican women labouring in a leather shoe factory (n = 34). Individual environmental levels for seven solvents, n-hexane included, were measured; also, urinary 2,5-hexanedione (2,5-HD) was determined. For ovarian function and hormonal status, FSH, LH, oestradiol and anti-Müllerian hormone (AMH) levels were determined. We performed all determinations also in a reference group, administrative workers with no exposure to solvents (n = 32). Results: N-hexane and urinary 2,5-HD levels were higher in exposed group (p < 0.001). More cases of oligomenorrhea as well as longer time for getting pregnant were observed in exposed women compared with controls; a positive association was found between menstrual cycle length and "time for getting pregnant" (p = 0.010); significant associations between FSH serum levels and 2,5-HD urinary levels (post-shift sample) were observed in non-smokers participants presenting oligomenorrhea from exposed group. Also, we found a trend for lower oestradiol levels in exposed participants with current smoking habit (p = 0.059). Conclusions: 2,5-HD urinary levels are associated with decreased gonadotropins levels; hence, n-hexane should be considered an endocrine disruptor in reproductive-age women.

Cumulus cell gene expression in luteal-phase-derived oocytes after double stimulation in one menstrual cycle

RESEARCH QUESTION

Does double stimulation (DuoStim) affect cumulus cell gene expression in luteal-phase-derived oocytes?

DESIGN

This prospective observational study included 39 patients with reduced ovarian reserve. Fifteen patients (group 1) underwent IVF with a gonadotrophin-releasing hormone antagonist in the follicular phase and 24 patients (group 2) underwent DuoStim. A total of 149 cumulus cell samples were divided into two groups according to the phase of the cycle: group 1 included 55 follicular-phase-derived oocytes and group 2 included 94 luteal-phase-derived oocytes. The expression levels of the following genes were assessed using quantitative polymerase chain reaction: HAS2, VCAN, ALCAM, PTGS2, GREM1, ITPKA, TRPM7, SDC4, CALM2, SPSB2, TP53I3, PGR and PFKP.

RESULTS

The expression of 10 out of 13 genes in cumulus cells was similar between DuoStim luteal-phase-derived oocytes and follicular-phase-derived oocytes. A significant increase in the mRNA levels of VCAN (15.542 ± 6.8 versus 20.353 ± 10.58; P = 0.001), SDC4 (1.016 ± 0.65 versus 1.318 ± 0.97; P = 0.013), and TP53I3 (0.185 ± 0.09 versus 0.270 ± 0.11; P = 1.19E-05) was observed in group 2. The number of oocytes collected (5.57 ± 2.3 versus 5.7 ± 2.7; P > 0.05) and the number of blastocysts were comparable between the groups (2.1 ± 2.1 versus 2.7 ± 2.2; P > 0.05).

CONCLUSIONS

The DuoStim approach leads to changes in the follicular environment. It affects the expression levels of VCAN, SDC4, and TP53I3 in the cumulus cells of luteal-phase-derived oocytes. These results, however, did not correlate with oocyte maturation, embryo quality and pregnancy rate.

Reproductive biology and biotechnologies in wild felids

Conservation strategies in natural habitats as well as in breeding centers are necessary for maintaining and reinforcing viable populations of wild felids. Among the fundamental knowledge that is required for conservation breeding, a solid understanding of reproductive biology is critical for improving natural breeding and enhance genetic diversity. Additionally, it offers the opportunity to develop assisted reproductive technologies (ARTs) in threatened and endangered species. Conservation breeding and reproductive biotechnologies of wild felids have advanced in the past decade. It has been clearly shown that female felids have species and individual patterns of reproductive cycles and respond differently to exogenous hormones. In males, several species still have poor semen quality often due to the loss of genetic diversity in small populations. To overcome the challenges of natural breeding (incompatibility between individuals or suboptimal environment) and mitigate inbreeding, artificial insemination, embryo production and embryo transfer have been further developed in 24 wild cat species. Major factors limiting ART success are inconsistent responses to ovarian stimulation, variable quality of gametes and embryos, and preparation of recipient females. Additional approaches including stem cell technologies have been explored for future medical applications. However, there still is a critical need for better knowledge of feline reproductive biology and improvement of ARTs efficiency to increase the genetic diversity and create sustainable populations of wild felids.

Polycystic ovarian syndrome: Correlation between hyperandrogenism, insulin resistance and obesity

Polycystic ovary syndrome (PCOS) is a complex and heterogeneous endocrine disease characterized by clinical or laboratorial hyperandrogenism, oligo-anovulation and metabolic abnormalities, including insulin resistance, excessive weight or obesity, type II diabetes, dyslipidemia and an increased risk of cardiovascular disease. The most significant clinical manifestation of PCOS is hyperandrogenism. Excess androgen profoundly affects granulosa cell function and follicular development via complex mechanisms that lead to obesity and insulin resistance. Most PCOS patients with hyperandrogenism have steroid secretion defects that result in abnormal folliculogenesis and failed dominant follicle selection. Hyperandrogenism induces obesity, hairy, acne, and androgenetic alopecia. These symptoms can bring great psychological stress to women. Drugs such as combined oral contraceptive pills, metformin, pioglitazone and low-dose spironolactone help improve pregnancy rates by decreasing androgen levels in vivo. Notably, PCOS is heterogeneous, and hyperandrogenism is not the only pathogenic factor. Obesity and insulin resistance aggravate the symptoms of hyperandrogenism, forming a vicious cycle that promotes PCOS development. Although numerous studies have been conducted, the definitive pathogenic mechanisms of PCOS remain uncertain. This review summarizes and discusses previous and recent findings regarding the relationship between hyperandrogenism, insulin resistance, obesity and PCOS.

LH Levels May Be Used as an Indicator for the Time of Antagonist Administration in GnRH Antagonist Protocols-A Proof-Of-Concept Study

Objective: To investigate whether circulating LH levels could be used as an indicator for the timing of antagonist addition in GnRH antagonist protocol. Design: Retrospective cohort study. Setting: University-based hospital. Patients: A total of 567 women stimulated with recombinant FSH monotherapy in a GnRH antagonist protocol were studied. Among them, 256 patients showed relatively low LH levels [highest LH level (LHmax) < 4 IU/L] during the entire ovarian stimulation process; 88 (Group A) and 168 patients (Group B) were stimulated without and with antagonist co-treatment, respectively. The remaining 311 patients had LHmax≥4 IU/L and were stimulated with a modified flexible antagonist protocol based on LH levels (Group C). Intervention(s): Patients in Group B and C received antagonist during ovarian stimulation, whereas patients in Group A did not. Main outcome measure: Clinical pregnancy rate and ongoing pregnancy rate. Results: The clinical and ongoing pregnancy rates were significantly higher in group A than group B (69.3 vs. 54.7%, P = 0.03 and 62.5 vs. 48.2%, P = 0.04, respectively), but the primary outcome measures did not differ between groups B and C. There were no significant differences in terms of patient demographics, LH levels, total dosage of gonadotrophin, duration of stimulation, follicular output rate between groups A and B, and between groups B and C. Also, there were no significant differences in laboratory and clinical outcomes in pairwise group comparisons. No canceled cycles due to premature ovulation was reported among the treated patients. Conclusion: LH levels may be used as an indicator for the time of antagonist addition. Patients with sustained low LH levels (LHmax<4 IU/L) during controlled ovarian stimulation (COS) might not require antagonist administration. Although further well-designed randomized controlled trials (RCTs) are needed to confirm our results, a novel treatment regimen based on LH measurements during COS might provide clinicians new insights about when to start antagonist administration in the GnRH antagonist protocol.