Adipokines: new emerging roles in fertility and reproduction

Possible role of apelin on the ovarian steroidogenesis and uterine apoptosis of infantile mice: An in vitro study

The expression of adipokines is well-known in the ovary and uterus. Recently we have shown that apelin and its receptor, APJ are developmentally regulated in the ovary and uterus of mice with elevation at postnatal day 14 (PND14). However, its role in the ovary and uterus of PND14 has not been investigated. Thus, we aimed to unravel the role of the apelin system (by APJ antagonist, ML221) on ovarian steroid secretion, proliferation, and apoptosis along with its role in uterine apoptosis in PND14 mice by in vitro approaches. The treatment of ML221 decreased estrogen, testosterone, and androstenedione secretion while increasing the progesterone secretion from the infantile ovary. These results suggest that apelin signaling would be important for ovarian estrogen synthesis in infantile mice (PND14). The abundance of 3β-HSD, 17β-HSD, aromatase, and active caspase3 increased in the infantile ovary after ML221 treatment. The expression of ERs and BCL2 were also down-regulated by ML221 treatment. The decreased BCL2 and increased active caspase3 by ML221 suggest the suppressive role of apelin on ovarian apoptosis. The APJ antagonist treatment also down-regulated the ER expression in the uterus along with increased active caspase3 and decreased BCL2 expression. In conclusion, apelin signaling inhibits the ovarian and uterine apoptosis via estrogen signaling in the ovary and uterus.

Circulating levels of cytokines (IL-6, IL-10 and TGF- β) and CD4+CD25+FOXP3+Treg cell population in recurrent pregnancy loss

Recurrent pregnancy loss (RPL), a serious reproductive health issue, characterized by two or more pregnancy losses before 20th week of gestation. Globally, it affects 2-5% couples and the basis of the crisis is still unknown in 50% cases. Successful pregnancy is associated with pro and anti-inflammatory gestational phases that tolerate the semi-allogenic foetus, and disturbance leads to pregnancy complications like RPL. This case-control study aimed to assess the inflammatory status in the mid-gestation of ongoing pregnancy of women with (RPL) and without (NRPL) the history of RPL. Blood samples were processed for PBMC isolation, subjected to Flow-cytometry for CD4+CD25+FOXP3+Treg-cell population count and serum samples for IL-6, TGF-β, IL-10 cytokine levels (ELISA). Significant reduction in the percentage of Treg cells, and elevated values for IL-6/TGF-β and IL-6/IL-10 ratios were observed in RPL over NRPL group (p = 0.0001). Opposing results were seen with respect to the magnitude of history of RPL (2 vs. >2 losses). ROC curve analysis showed the superior discriminatory ability of cytokine ratios (IL-6/TGF-β > IL-6/IL-10) for RPL over Treg cells. Our findings are suggestive of pro-inflammatory dominance in mid-gestation of pregnant women with a history of RPL in general and greater than normal anti-inflammatory milieu in cases with > 2 pregnancy loss. As both sterile and infection related inflammation plays a role in pregnancy loss, studies enrolling women with favourable and unfavourable ongoing pregnancies may shed light on the importance of the present study for developing better management/therapeutic strategies.

Effect of bovine myosin heavy chain 3 on proliferation and differentiation of myoblast

The myosin heavy chain 3 (MYH3) gene is an essential gene that affects muscle development. This study aimed to discuss the expression characteristics of the MYH3 gene and its effect on the proliferation and differentiation of bovine myoblasts. Quantitative real time-PCR results display that the expression level of MYH3 was higher in muscle tissue, and the expression increased in the early stage of myoblast differentiation. Interfering with the MYH3 gene in myoblasts resulted in fewer EDU-positive cells and decreased expression of proliferation marker genes. Interference with MYH3 can also affect the differentiation process of myoblasts. Regarding phenotype, myotube differentiation in the interference group was slowed or even stopped. Interference with the expression of MYH3 could significantly reduce the expression of myogenic differentiation marker genes. The above results show that MYH3 is mainly expressed in muscle tissue and is highly expressed in the early stage of differentiation of bovine myoblasts, and interfering with the MYH3 can promote the proliferation and inhibit the differentiation of bovine myoblasts. This study provides a theoretical basis for revealing the regulatory process of bovine myoblast proliferation and differentiation and bovine molecular breeding.

Bile acids ameliorates lipopolysaccharide-induced endometritis in mice by inhibiting NLRP3 inflammasome activation

AIMS

Endometritis is a common inflammatory disorder affecting the reproductive health in both humans and livestock. The NLR family pyrin domain containing 3 (NLRP3) inflammasome has recently been identified as a possible therapeutic target for several inflammatory disorders. Bile acids (BAs) have been shown to possess anti-inflammatory properties by inhibiting the activation of the NLRP3 inflammasome. However, whether BAs ameliorate endometritis by targeting NLRP3 inflammasome remain poorly understood.

MAIN METHODS

Female NLRP3+/+ and NLRP3-/- mice were subjected to uterine perfusion with lipopolysaccharide (LPS) to establish the endometritis model. For BAs pre-treatment, wild-type mice were administered oral gavage of BAs for seven days followed by uterine perfusion with LPS. All mice were euthanized and the uterine tissues were collected for analysis.

KEY FINDINGS

The abundances of NLRP3 and interleukin-1 beta (IL-1β) were significantly upregulated in the uterine tissues of endometritis mice. NLRP3 deficiency led to a reduction in the inflammatory response, neutrophil infiltration, and myeloperoxidase (MPO) activity in the uterus, as well as an inhibition of IL-1β secretion. Moreover, BAs pre-treatment successfully decreased LPS-induced upregulation of NLRP3, ASC, and Caspase1, lessened histopathological alteration in the uterus, and notably reduced MPO activity and secretion of IL-1β.

SIGNIFICANCE

NLRP3 inflammasome is a promising target for endometritis treatment and BAs exhibit anti-inflammatory properties by repressing NLRP3 inflammasome activation, making them a possible novel therapeutic strategy for endometritis.

The association between body mass index and live birth and maternal and perinatal outcomes after in-vitro fertilization: a national cohort study

Objective

To investigate the association between female body mass index (BMI) and live birth rates and maternal and perinatal outcomes after in-vitro fertilization (IVF).

Methods

We performed a national, population-based cohort study including women undergoing IVF between 2002 and 2020. The cohort included 126,620 fresh cycles and subsequent frozen embryo transfers between 2007 and 2019 (subpopulation 1) and 58,187 singleton deliveries between 2002 and 2020 (subpopulation 2). Exposure was female BMI (kg/m2) categorized according to the World Health Organization as underweight (<18.5), normal weight (18.5-24.9, reference), overweight (25.0-29.9), class I obesity (30.0-34.9), class II obesity (35.0-39.9), and class III obesity (≥40.0). The primary outcome in subpopulation 1 was cumulative live birth per started fresh IVF cycle, including fresh and subsequent frozen embryo transfers. Primary outcomes in subpopulation 2 were hypertensive disorders of pregnancy and preterm birth at less than 37 weeks. Risk ratios (RRs) with 95% confidence intervals (CIs) for the association between BMI class and outcomes were calculated using generalized linear models after adjustment for relevant confounders.

Results

The cumulative live birth rate decreased significantly with increasing BMI from 32.6% in normal-weight women to 29.4% in overweight women, 27.0% in women in obesity class I, 21.8% in women in obesity class II, and 7.6% in women in obesity class III. The risk of hypertensive disorders of pregnancy increased significantly and progressively with increasing BMI, from 4.6% in normal-weight women to 7.8% in overweight women and 12.5%, 17.9%, and 20.3% in women in obesity classes I, II, and III. The risk of preterm birth followed a similar pattern, from 6.3% in normal-weight women to 7.5% in overweight women and 8.9%, 9.9%, and 15.3% in women in obesity classes I, II, and III. The risks of other perinatal complications, such as perinatal death, showed an even more pronounced increase.

Conclusion

Using a large and complete national cohort of women undergoing IVF, we demonstrate a dose-dependent decrease in live birth rate and a substantial increase in maternal and perinatal complications with increasing BMI. Strategies to improve this situation are warranted.

Obesity and recurrent miscarriage: The interconnections between adipose tissue and the immune system

Currently, obesity is considered a global public health problem. It is the main risk factor for noncommunicable diseases and reproductive complications, such as recurrent miscarriage (RM). RM affects approximately 1% of couples of reproductive age, and recent studies suggest that its prevalence is increasing. Immunological abnormalities may be responsible for a significant number of cases of unexplained RM. Obesity is recognized as a chronic low-grade inflammatory condition. The accumulation of fat in obese adipose tissue promotes changes in the local and systemic immune response. Adipokines, exosomes, micro-RNAs, lipids, and other factors released or secreted by adipose tissue are responsible for the interconnection between obesity and the immune system. Obesity-induced dysregulation of the innate and acquired immune response is also involved in the immunopathology of pregnancy loss in patients with unexplained RM. Therefore, understanding the communication pathways between maternal adipose tissue and the immune response in women living with obesity and RM is an important objective. Thus, diagnostic tools and new immunomodulatory therapies may be proposed for the management of patients with concurrent obesity and RM.

Alpha Lipoic Acid Efficacy in PCOS Treatment: What Is the Truth?

Polycystic ovary syndrome (PCOS) is among the most common female endocrinopathies, affecting about 4-25% of women of reproductive age. Women affected by PCOS have an increased risk of developing metabolic syndrome, type 2 diabetes mellitus, cardiovascular diseases, and endometrial cancer. Given the pivotal role of insulin resistance (IR) in the pathogenesis of PCOS, in the last years, many insulin-sensitizing factors have been proposed for PCOS treatment. The first insulin sensitizer recommended by evidence-based guidelines for the assessment and treatment of PCOS was metformin, but the burden of side effects is responsible for treatment discontinuation in many patients. Inositols have insulin-mimetic properties and contribute to decreasing postprandial blood glucose, acting by different pathways. ALA is a natural amphipathic compound with a very strong anti-inflammatory and antioxidant effect and a very noteworthy role in the improvement of insulin metabolic pathway. Given the multiple effects of ALA, a therapeutic strategy based on the synergy between inositols and ALA has been recently proposed by many groups with the aim of improving insulin resistance, reducing androgen levels, and ameliorating reproductive outcomes in PCOS patients. The purpose of this study is to review the existing literature and to evaluate the existing data showing the efficacy and the limitation of a treatment strategy based on this promising molecule. ALA is a valid therapeutic strategy applicable in the treatment of PCOS patients: Its multiple actions, including antinflammatory, antioxidant, and insulin-sensitizing, may be of utmost importance in the treatment of a very complex syndrome. Specifically, the combination of MYO plus ALA creates a synergistic effect that improves insulin resistance in PCOS patients, especially in obese/overweight patients with T2DM familiarity. Moreover, ALA treatment also exerts beneficial effects on endocrine patterns, especially if combined with MYO, improving menstrual regularity and ovulation rhythm. The purpose of our study is to review the existing literature and to evaluate the data showing the efficacy and the limitations of a treatment strategy based on this promising molecule.

Obesity and In Vitro Fertilization

Obesity is a highly prevalent chronic disease with a significant effect on reproductive-age women. The clinical implications of obesity on fertility and pregnancy are well studied citing ovulatory dysfunction, hormonal imbalances, higher miscarriage rates, and increased maternal and neonatal risks. For this reason, many patients with obesity seek reproductive specialists to help build their families. Despite this literature base, the effect of weight loss interventions prior to assisted reproductive technology (ART) is lacking. This review aims to outline the impact of obesity on ART, specifically in vitro fertilization (IVF). Response differences to treatment protocols compared with normal weight counterparts, limitations of access to care, and the mixed results of weight-reduction strategies prior to fertility treatment will be addressed. The known data surrounding benefits of lifestyle modification, pharmacologic therapies, and surgical interventions for obesity prior to IVF are outlined and found to emphasize a need for further research to determine the optimal approach for infertility patients with obesity.

Postnatal developmental expression and localization of apelin and apelin receptor protein in the ovary and uterus of mice

Postnatal ovarian and uterine development is crucial to accomplished female fertility. Thus, the investigations of factors that present in pre-pubertal stages are important as it might be responsible for the regulation of ovarian and uterine function. Apelin, an adipokine and its receptor (APJ) are present in female reproductive organs. However, no study has reported its postnatal expression in uterus and ovary. Thus, we investigated the postnatal developmental changes in expression and localization of apelin and APJ in the ovary and uterus of mice. Postnatal ovary and uterus were collected from postnatal day (PND) 1, 7, 14, 21, 42, 65 and performed western blot analysis and immunohistochemistry. Uterine APJ is elevated in PND14 and PND65, whereas, ovarian APJ elevated in PND7, PND14, and PND65. Apelin expression in both ovary and uterus showed intense staining at PND65 and PND14. Our results showed that apelin and APJ abundance was lower at PND21 in uterus and ovary. In conclusion, apelin and APJ are developmentally regulated in the ovary and uterus, and its localization in the different compartments of ovary and uterus suggest its distribution specific physiological role in the uterus and ovary.

The Complex Roles of Adipokines in Polycystic Ovary Syndrome and Endometriosis

Polycystic ovary syndrome (PCOS) and endometriosis are frequent diseases of the female reproductive tract causing high morbidity as they can significantly affect fertility and quality of life. Adipokines are pleiotropic signaling molecules secreted by white or brown adipose tissues with a central role in energy metabolism. More recently, their involvement in PCOS and endometriosis has been demonstrated. In this review article, we provide an update on the role of adipokines in both diseases and summarize previous findings. We also address the results of multi-omics approaches in adipokine research to examine the role of single nucleotide polymorphisms (SNPs) in genes coding for adipokines and their receptors, the secretome of adipocytes and to identify epigenetic alterations of adipokine genes that might be conferred from mother to child. Finally, we address novel data on the role of brown adipose tissue (BAT), which seems to have notable effects on PCOS. For this review, original research articles on adipokine actions in PCOS and endometriosis are considered, which are listed in the PubMed database.

Reproductive roles of novel adipokines apelin, visfatin, and irisin in farm animals

The adipose tissue has a substantial impact on reproduction in mammals, specifically in females. As an energy depository organ, it is precisely associated with the reproductive success of mammals. Adipose tissue secretes many single molecules that are called 'adipokines' which mainly act as endocrine hormones. Adipokines homeostasis is fundamental to energy regulation, metabolic and cardiovascular diseases. The endocrine function of adipokines is influential for the long-term control of energy metabolism and performs an important function in metabolic state and fertility modulation. During the last years, new roles for adipokines have been appearing in the field of fertility. The adipokines have functions in reproduction at levels of the hypothalamus, the pituitary, and the gonads in humans, rodents, and other animals. Normal levels of adipokines are indispensable to protect the integrity of the hypothalamus-hypophysis-gonadal axis, regular ovulatory processes, and successful embryo implantation. Leptin and adiponectin are the most studied adipokines, but also the novel adipokines; apelin, visfatin, and irisin are important adipokines having several functions within the reproductive tract. Due to the known and unknown effects of these novel adipokines in the reproduction of farm animals, in this review, we will highlight the reproductive functions of apelin, visfatin, and irisin and summarize the known reproductive effects in farm animals to introduce the gaps for future studies in farm animals.

Role of adipokines in the ovarian function: Oogenesis and steroidogenesis

Adipokines are mainly produced by adipose tissue; however, their expression has been reported in other organs including female reproductive tissues. Therefore, adipokines have opened new avenues of research in female fertility. In this regard, studies reported different roles for certain adipokines in ovarian function, although the role of other recently identified adipokines is still controversial. It seems that adipokines are essential for normal ovarian function and their abnormal levels could be associated with ovarian-related disorders. The objective of this study is to review the available information regarding the role of adipokines in ovarian functions including follicular development, oogenesis and steroidogenesis and also their involvement in ovary-related disorders.

Effect of Neudesin Neurotrophic Factor on Differentiation of Bovine Preadipocytes and Myoblasts in a Co-Culture System

Simple Summary

Marbling beef refers to the red and white beef formed by depositing fat between muscle fibers, and “marbling” is an important factor affecting beef quality. Therefore, we established a co-culture system of adipocytes and myocytes to mimic the microenvironment of marbling beef in vivo. However, Neudesin neurotrophic factor (NENF) was not detected in the co-culture system, but was detected in both adipocytes and myoblasts cultured separately. Further studies revealed that NENF knockdown inhibits adipogenesis and promotes myogenesis in separately cultured preadipocytes and myoblasts. However, because the monoculture system does not include the interaction of bovine adipocytes and myoblasts in the formation of marbling beef, in this study we investigated the effect of recombinant protein NENF on the differentiation of adipocytes and myoblasts in the co-culture system. The addition of NENF inhibited the formation of lipid droplets in co-cultured adipocytes but had no significant effect on myotube formation. These results were different from, and even conflicted with, those in the monocultures, which suggested that regulation of NENF expression in the same cell type changed along with the cell microenvironment and the molecular mechanism of marbling beef formation cannot be fully revealed through studies on the monoculture system.

Abstract

In this study, we successfully established a co-culture system of bovine preadipocytes and myoblasts to explore the effect of exogenous addition of Neudesin neurotrophic factor (NENF) recombinant protein on the differentiation of adipocytes and myoblasts in co-culture. The optimal concentration of NENF recombinant protein was 100 pg/mL. NENF promoted the differentiation of bovine preadipocytes and inhibited the differentiation of bovine myoblasts when the cells were cultured separately. After adding NENF recombinant protein to the co-culture system, the accumulation of lipid droplets in bovine preadipocytes decreased, but the differentiation of bovine myoblasts did not change significantly. The results of real-time quantitative PCR (RT-qPCR) and Western blot showed that the expression levels of adipogenesis-related factors such as PPARγ, FABP4 and FASN were significantly down-regulated at the mRNA and protein levels in adipocytes, while myogenic marker genes such as MYOD1, MYOG and MYHC had no significant changes at the mRNA or protein levels in myoblasts. This differs from, and potentially conflicts with, the monoculture system, where NENF expression in each cell type changed with the cell microenvironment. Consequently, the molecular mechanism of marbling beef formation cannot be fully revealed using monocultures of adipocytes or myocytes.

Impact of maternal obesity on the risk of preterm delivery: insights into pathogenic mechanisms

PURPOSE

Preterm delivery (PTD) represents the leading cause of neonatal death and disability. Among risk factors for PTD, maternal obesity (MO) is becoming an ever more relevant condition in developed countries, although the mechanisms relating this condition to higher risk of PTD is not clear. Aim of this narrative review is to summarize evidences from clinical and translational research showing how MO might negatively impact on pregnancy and neonatal outcomes, particularly, by increasing the risk of PTD.

METHODS

We performed comprehensive review of the literature in PubMed and Google Scholar databases for studies from 1998 to 2018 linking MO to PTD and inflammation.

RESULTS

Chronic inflammatory status associated to increased synthesis of adipokines and cytokines from fat tissue has been shown in obesity. Obese women have a higher risk of both spontaneous and medically induced PTD. In about 50% of cases of spontaneous PTD, an infection-induced chorion amnionitis can be detected while in the remaining 50% a sterile inflammatory response has been described. Activation of uterine innate immunity system in intra-amniotic cavity and in chorioamniotic membranes might represent the missing link between MO and the pathogenesis of PTD.

CONCLUSION

Tissue inflammation might represent the pathogenic link between MO and increased occurrence of PTD. The achievement of pre-pregnancy normal maternal weight and body mass index is a fundamental aim of public health to reduce the incidence of PTD and get optimal reproductive outcomes.

Neudesin Neurotrophic Factor Promotes Bovine Preadipocyte Differentiation and Inhibits Myoblast Myogenesis

Simple Summary

Neudesin neurotrophic factor (NENF) is a secreted protein that was significantly inhibited in the fat-muscle co-culture system in our previous study. However, studies on NENF regulation of bovine muscle development and involvement in the cross-talk between adipose tissue and skeletal muscle have not been reported. Hence, the aim of this study was to clarify the roles of NENF in bovine myoblast and preadipocyte differentiation. In this study, we first examined the spatial expression patterns of NENF in different tissues and found that NENF was highly expressed in the muscle of four-day-old and 24-month-old Qinchuan cattle. Compared with 4-day-old Qinchuan cattle, the expression level of NENF was significantly up-regulated in 24-month-old bovine adipose tissue. Then, we detected the expression pattern of the NENF gene in bovine preadipocyte and myoblast differentiation and found that the expression of NENF mRNA peaks at day 6 during preadipocyte differentiation and peaks at day 4 during myoblast differentiation. Furthermore, we found that the endogenous knockdown of NENF inhibited the differentiation of preadipocytes and promoted the differentiation of myoblasts. These findings not only lay the foundation for the construction of regulatory pathways during fat and muscle differentiation but also provide a theoretical basis for molecular breeding of beef cattle.

Abstract

Neudesin neurotrophic factor (NENF) is a secreted protein that is essential in multiple biological processes, including neural functions, adipogenesis, and tumorigenesis. In our previous study, NENF was significantly inhibited in the bovine adipocytes-myoblasts co-culture system. However, studies on NENF regulation of bovine muscle development and involvement in the cross-talk between adipose tissue and skeletal muscle have not been reported. Hence, the aim of this study was to clarify the functional roles of NENF in bovine preadipocytes and myoblasts. Real-time quantitative PCR (RT-qPCR) was performed to examine the spatial expression patterns of NENF in different tissues, and the results showed that NENF was highly expressed in the muscle of four-day-old and 24-month-old Qinchuan cattle. Compared with four-day-old Qinchuan cattle, the expression level of NENF was significantly up-regulated in 24-month-old bovine adipose tissue. To explore the roles of NENF in bovine myoblast and preadipocyte differentiation, small interfering RNA (siRNA) targeting the NENF gene were transfected into bovine preadipocytes and myoblasts to knock down the expression of the NENF gene. The results showed that the knockdown of NENF in differentiating adipocytes attenuated lipid accumulation, decreased the mRNA expression of adipogenic key marker genes PPARγ, CEBPα, CEBPβ, FASN, and SCD1, and decreased the protein expression of PPARγ, CEBPα, and FASN. The formation of myotubes was significantly accelerated, and the mRNA expression levels of myogenic marker genes MYOD1, MYF5, MYF6, MEF2A, MEF2C, and CKM, and the protein expression levels of MYOD1, MYF6, MEF2A, and CKM were up-regulated in myoblasts where NENF was knocked down. In short, the knockdown of NENF inhibited preadipocyte differentiation and promoted myoblast myogenesis.

Is DPP4 activity increased in PCOS?

AIMS

Dipeptidyl peptidase-4 (DPP4) is an adipokine with greater expression in visceral fat and related with insulin resistance (IR). Polycystic ovary syndrome (PCOS) is also associated with IR. Our study aims to evaluate DPP4 activity in PCOS.

MATERIALS AND METHODS

Thirty PCOS patients were compared to 28 healthy women. Body composition by dual X-ray absorptiometry (DXA), plasma activity of DPP4 and biochemical variables were performed. All participants underwent an oral glucose tolerance test for insulin and glucose analysis.

RESULTS

DPP4 activity was similar in both groups (PCOS 5823 ± 926 vs Control 5501.8 ± 975; p = 0.20). PCOS patients were more IR with lower levels of SHBG (32 vs 47, p = 0.02) and Matsuda index (15.6 vs 20.4, p = 0.03) and higher HOMA-IR (2.8 vs 1.7, p < 0.01), in addition to increased levels of testosterone (55 vs 25, p < 0.01). DPP4 was correlated to HbA1c (r = 0.279, p = 0.03), HDL-c (r = -0.28, p = 0.03) and SHBG (r = -0.256, p = 0.05).

CONCLUSIONS

Although PCOS was well characterized as IR and hyperandrogenic, DPP4 was not different in this group. However, a relationship between DPP4 and markers of IR were found. More studies are warranted.

Visfatin and resistin in gonadotroph cells: expression, regulation of LH secretion and signalling pathways

Visfatin and resistin appear to interfere with reproduction in the gonads, but their potential action at the hypothalamic-pituitary level is not yet known. The aim of the present study was to investigate the mRNA and protein expression of these adipokines in murine gonadotroph cells and to analyse the effects of different concentrations of recombinant mouse visfatin and resistin (0.01, 0.1, 1 and 10ngmL^-1) on LH secretion and signalling pathways in LβT2 cells and/or in primary female mouse pituitary cells. Both visfatin and resistin mRNA and protein were found in vivo in gonadotroph cells. In contrast with resistin, the primary tissue source of visfatin in the mouse was the skeletal muscle, and not adipose tissue. Visfatin and resistin both decreased LH secretion from LβT2 cells after 24h exposure of cells (P<0.03). These results were confirmed for resistin in primary cell culture (P<0.05). Both visfatin (1ngmL^-1) and resistin (1ngmL^-1) increased AMP-activated protein kinase α phosphorylation in LβT2 cells after 5 or 10min treatment, up to 60min (P<0.04). Extracellular signal-regulated kinase 1/2 phosphorylation was transiently increased only after 5min resistin (1ngmL^-1) treatment (P<0.01). In conclusion, visfatin and resistin are expressed in gonadotroph cells and they may affect mouse female fertility by regulating LH secretion at the level of the pituitary.

Effects of synbiotic supplementation on metabolic parameters and apelin in women with polycystic ovary syndrome: a randomised double-blind placebo-controlled trial

Polycystic ovary syndrome (PCOS) is one of the most common causes of infertility in women of reproductive age. Insulin resistance is a main pathophysiologic feature in these patients. According to some studies, the intake of probiotic bacteria may improve glucose homoeostasis. The aim of this study was to investigate the effect of synbiotics on metabolic parameters and apelin in PCOS patients. This randomised double-blind placebo-controlled trial was conducted on eighty-eight PCOS women aged 19–37 years old. The participants were randomly assigned to two groups receiving (1) synbiotic supplement (n44), and (2) placebo (n44) for 12 weeks. Fasting blood samples were taken at baseline and after 12 weeks. The two groups showed no difference in fasting blood sugar (adjusted mean difference: 0·60; 95 % CI −3·80, 5·00,P=0·727), plasma glucose fasting 2-h (adjusted mean difference 2·09; 95 % CI −9·96, 14·15,P=0·134), HbA1c (adjusted mean difference 0·06; 95 % CI −0·09, 0·22,P=0·959), homoeostatic model assessment-insulin resistance (HOMA-IR) (adjusted mean difference: 0·02; 95 % CI −0·99, 1·03,P=0·837), quantitative insulin sensitivity check index (QUICKI) (adjusted mean difference: −0·02; 95 % CI −0·33, 0·29,P=0·940) and C-reactive protein (CRP) (adjusted mean difference: 0·24; 95 % CI −1·61, 2·08,P=0·141) by the end of the intervention. A significant difference was observed in the mean apelin 36 before and after the intervention between synbiotic and placebo groups (adjusted mean difference: −4·05; 95 % CI −7·15, −0·96,P=0·004). A 12-week synbiotic supplementation has no significant beneficial effects on HOMA-IR and CRP in PCOS patients, whereas the level of apelin 36 significantly decreased.

KIRREL is differentially expressed in adipose tissue from 'fertil+' and 'fertil-' cows: in vitro role in ovary?

We have previously shown that dairy cows carrying the 'fertil-' haplotype for one quantitative trait locus affecting female fertility located on the bovine chromosome three (QTL-F-Fert-BTA3) have a significantly lower conception rate and body weight after calving than cows carrying the 'fertil+' haplotype. Here, we compared by Tiling Array the expression of genes included in the QTL-F-Fert-BTA3 in 'fertil+' and 'fertil-' adipose tissue one week after calving when plasma non-esterified fatty acid concentrations were greater in 'fertil-' animals. We observed that thirty-one genes were overexpressed whereas twelve were under-expressed in 'fertil+' as compared to 'fertil-' cows (P < 0.05). By quantitative PCR and immunoblot we confirmed that adipose tissue KIRREL mRNA and protein were significantly greater expressed in 'fertil+' than in 'fertil-'. KIRREL mRNA is abundant in bovine kidney, adipose tissue, pituitary, and ovary and detectable in hypothalamus and mammary gland. Its expression (mRNA and protein) is greater in kidney of 'fertil+' than 'fertil-' cows (P < 0.05). KIRREL (mRNA and protein) is also present in the different ovarian cells with a greater expression in granulosa cells of 'fertil+' than 'fertil-' cows. In cultured granulosa cells, recombinant KIRREL halved steroid secretion in basal state (P < 0.05). It also decreased cell proliferation (P < 0.05) and in vitro oocyte maturation (P < 0.05). These results were associated to a rapid increase in MAPK1/3 and MAPK14 phosphorylation in granulosa cells and to a decrease in MAPK1/3 phosphorylation in oocyte. Thus, KIRREL could be a potential metabolic messenger linking body composition and fertility.

Oral Quercetin Supplementation Enhances Adiponectin Receptor Transcript Expression in Polycystic Ovary Syndrome Patients: A Randomized Placebo-Controlled Double-Blind Clinical Trial

OBJECTIVES

Polycystic ovary syndrome (PCOS), an ovarian-pituitary axis androgen disorder, is a common endocrine disease in women. Obesity-induced androgenesis and imbalance of adipokine secretion may lead to some metabolic features of PCOS. The beneficial effects of polyphenolic compounds such as quercetin have been reported, however, the underlying molecular mechanism is not entirely understood. In the present study, we investigated the effect of quercetin supplementation on the expression of adiponectin receptors at the transcript level in peripheral blood mononuclear cells (PBMC) samples of PCOS patients.

MATERIALS AND METHODS

In this randomized clinical trial, 84 PCOS subjects were randomly assigned to two groups; the treatment group received 1 g quercetin (two 500 mg capsules) daily for 12 weeks and the control group received placebo. To examine the effect of quercetin supplementation on PCOS patients in addition to biochemical and anthropometric assessments, the expression of ADIPOR1 and ADIPOR2 at the transcript level and AMPK level were determined by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and ELISA assays respectively.

RESULTS

Oral quercetin supplementation significantly increased ADIPOR1 and ADIPOR2 transcript expression by 1.32- and 1.46-fold respecetively (P<0.01). In addition, quercetin supplementation enhanced AMPK level by 12.3% compared with the control group (P<0.05).

CONCLUSIONS

Oral quercetin supplementation improves the metabolic features of PCOS patients by upregulating the expression of adiponectin receptors and AMPK (Registration Number: IRCT2013112515536N1).

Ovarian hormones and obesity

BACKGROUND

Obesity is caused by an imbalance between energy intake, i.e. eating and energy expenditure (EE). Severe obesity is more prevalent in women than men worldwide, and obesity pathophysiology and the resultant obesity-related disease risks differ in women and men. The underlying mechanisms are largely unknown. Pre-clinical and clinical research indicate that ovarian hormones may play a major role.

OBJECTIVE AND RATIONALE

We systematically reviewed the clinical and pre-clinical literature on the effects of ovarian hormones on the physiology of adipose tissue (AT) and the regulation of AT mass by energy intake and EE.

SEARCH METHODS

Articles in English indexed in PubMed through January 2016 were searched using keywords related to: (i) reproductive hormones, (ii) weight regulation and (iii) central nervous system. We sought to identify emerging research foci with clinical translational potential rather than to provide a comprehensive review.

OUTCOMES

We find that estrogens play a leading role in the causes and consequences of female obesity. With respect to adiposity, estrogens synergize with AT genes to increase gluteofemoral subcutaneous AT mass and decrease central AT mass in reproductive-age women, which leads to protective cardiometabolic effects. Loss of estrogens after menopause, independent of aging, increases total AT mass and decreases lean body mass, so that there is little net effect on body weight. Menopause also partially reverses women's protective AT distribution. These effects can be counteracted by estrogen treatment. With respect to eating, increasing estrogen levels progressively decrease eating during the follicular and peri-ovulatory phases of the menstrual cycle. Progestin levels are associated with eating during the luteal phase, but there does not appear to be a causal relationship. Progestins may increase binge eating and eating stimulated by negative emotional states during the luteal phase. Pre-clinical research indicates that one mechanism for the pre-ovulatory decrease in eating is a central action of estrogens to increase the satiating potency of the gastrointestinal hormone cholecystokinin. Another mechanism involves a decrease in the preference for sweet foods during the follicular phase. Genetic defects in brain α-melanocycte-stimulating hormone-melanocortin receptor (melanocortin 4 receptor, MC4R) signaling lead to a syndrome of overeating and obesity that is particularly pronounced in women and in female animals. The syndrome appears around puberty in mice with genetic deletions of MC4R, suggesting a role of ovarian hormones. Emerging functional brain-imaging data indicates that fluctuations in ovarian hormones affect eating by influencing striatal dopaminergic processing of flavor hedonics and lateral prefrontal cortex processing of cognitive inhibitory controls of eating. There is a dearth of research on the neuroendocrine control of eating after menopause. There is also comparatively little research on the effects of ovarian hormones on EE, although changes in ovarian hormone levels during the menstrual cycle do affect resting EE.

WIDER IMPLICATIONS

The markedly greater obesity burden in women makes understanding the diverse effects of ovarian hormones on eating, EE and body adiposity urgent research challenges. A variety of research modalities can be used to investigate these effects in women, and most of the mechanisms reviewed are accessible in animal models. Therefore, human and translational research on the roles of ovarian hormones in women's obesity and its causes should be intensified to gain further mechanistic insights that may ultimately be translated into novel anti-obesity therapies and thereby improve women's health.

Role of the PI3K-Akt Signaling Pathway in the Pathogenesis of Polycystic Ovary Syndrome

This review aimed to focus on the recent progress of the understanding of the role of phosphatidylinositol 3-kinase (PI3K) in polycystic ovary syndrome (PCOS). In recent years, it has been increasingly recognized that PI3K plays an important role in PCOS whose pathogenesis is unclear. However, research continues into revealing the details of how PI3Ks are involved in developing PCOS. Previous studies have shown that activation of the PI3K-protein kinase B (Akt) signaling pathway has important effects on insulin resistance and endometrial cancer. Knowledge of the action of PI3K in PCOS might provide valuable information to further validate the pathogenesis of PCOS and suggest new methods of treatment.

Could gestational diabetes mellitus be managed through dietary bioactive compounds? Current knowledge and future perspectives

Gestational diabetes mellitus (GDM) is a serious problem growing worldwide that needs to be addressed with urgency in consideration of the resulting severe complications for both mother and fetus. Growing evidence indicates that a healthy diet rich in fruit, vegetables, nuts, extra-virgin olive oil and fish has beneficial effects in both the prevention and management of several human diseases and metabolic disorders. In this review, we discuss the latest data concerning the effects of dietary bioactive compounds such as polyphenols and PUFA on the molecular mechanisms regulating glucose homoeostasis. Several studies, mostly based on in vitro and animal models, indicate that dietary polyphenols, mainly flavonoids, positively modulate the insulin signalling pathway by attenuating hyperglycaemia and insulin resistance, reducing inflammatory adipokines, and modifying microRNA (miRNA) profiles. Very few data about the influence of dietary exposure on GDM outcomes are available, although this approach deserves careful consideration. Further investigation, which includes exploring the ‘omics’ world, is needed to better understand the complex interaction between dietary compounds and GDM.

History of infertility and risk of type 2 diabetes mellitus: a prospective cohort study

AIMS/HYPOTHESIS

We sought to evaluate the relationship between delayed conception and type 2 diabetes risk, given that there are plausible underlying mechanisms linking the two, including inflammation and insulin resistance.

METHODS

Participants of the Nurses' Health Study II prospective cohort were included if they were free of chronic disease (cardiovascular disease, type 2 diabetes, cancer) at baseline. Biennial questionnaires updated information on infertility status (>12 months attempted pregnancy), lifestyle characteristics and several health-related outcomes. Self-reported cases of diabetes were confirmed using a follow-up questionnaire. Multivariable Cox proportional hazards models were used to compute the HRs and 95% CIs.

RESULTS

Incident type 2 diabetes occurred in 5,993 of the 112,106 participants over 24 years of follow-up (1989-2013). A history of infertility was reported in 27,774 (24.8%) women and was associated with a 20% greater risk of developing diabetes, compared with those never reporting infertility (HR 1.20 [95% CI 1.14, 1.28]), after adjusting for age, lifestyle factors, marital status, oral contraceptive use, family history of diabetes and BMI. Compared with women without a history of infertility, the causes of infertility associated with a higher diabetes risk were ovulation disorders (HR 1.43 [95% CI 1.29, 1.58]) and tubal factor (HR 1.34 [95% CI 1.13, 1.58]). Cervical factor (HR 1.06 [95% CI 0.81, 1.40]) and endometriosis (HR 1.06 [95% CI 0.89, 1.27]) were not associated, while male factor infertility was associated with a modestly higher diabetes risk (HR 1.15 [95% CI 1.00, 1.33]).

CONCLUSIONS/INTERPRETATION

These novel findings suggest a history of infertility, particularly that related to ovulation disorders and tubal blockage, is significantly associated with a higher risk of type 2 diabetes.

Plasma omentin and adiponectin levels as markers of adipose tissue dysfunction in normal weight and obese women with polycystic ovary syndrome

OBJECTIVE

It is suggested that disturbed adipokines release plays a role in PCOS pathogenesis. The aim of this study was to assess plasma levels of omentin and adiponectin as well as the omentin to adiponectin ratio, as markers of adipose tissue dysfunction in relation to hormonal or metabolic changes in PCOS.

STUDY DESIGN, PATIENTS AND MEASUREMENTS

A cross-sectional study involved 87 PCOS (48 obese) and 72 non-PCOS women (41 obese). Anthropometric parameters and body composition were determined, and serum glucose, hormones, omentin-1 and adiponectin levels were measured.

RESULTS

The adiponectin level was similar in PCOS and non-PCOS groups, but, in both, was significantly lower in obese compared with normal weight subgroups, while the omentin-1 level was significantly lower in the PCOS compared with the non-PCOS group, and not related to body mass. The adiponectin to omentin-1 ratio (AOR) was significantly higher in the PCOS than non-PCOS group. Moreover, AOR was significantly higher in the normal weight than in obese subgroups in both PCOS and non-PCOS groups. Multiple regression analyses revealed that AOR variability is explained by oestradiol level and all anthropometric parameters as well as FAI, but not LH to FSH and HOMA-IR values.

CONCLUSIONS

Our results suggest secondary to insulin resistance and hyperandrogenism impairment of hormonal stroma adipose tissue function in PCOS, independent of nutritional status. Contrarily, the adipocyte hormonal dysfunction is primarily dependent on excessive fat accumulation. It seems that the AOR may be useful in the assessment of adipose tissue dysfunction not only in PCOS.

The effect of nutrition and metabolic status on the development of follicles, oocytes and embryos in ruminants

The impact of nutrition and energy reserves on the fertility of ruminants has been extensively described. However, the metabolic factors and the molecular mechanisms involved in the interactions between nutrition and ovarian function are still poorly understood. These factors could be hormonal (either reproductive and/or metabolic) and/or dietary and metabolic (glucose, amino acids and fatty acids). In this review, we briefly summarize the impact of those nutrients (fatty acids, glucose and amino acids) and metabolic hormones (insulin/IGF-I, growth hormone, T3/4, ghrelin, apelin and the adipokines (leptin, adiponectin and resistin)) implicated in the development of ovarian follicles, oocytes and embryos in ruminants. We then discuss the current hypotheses on the mechanisms of action of these factors on ovarian function. We particularly describe the role of some energy sensors including adenosine monophosphate-activated kinase and peroxisome proliferator-activated receptors in the ovarian cells.

Expression of chemerin and its receptors in rat testes and its action on testosterone secretion

The novel adipokine chemerin plays a role in the regulation of lipid and carbohydrate metabolism, and recent reports of elevated chemerin levels in polycystic ovarian syndrome and preeclampsia have pointed to an emerging role of chemerin in reproduction. We hypothesised that chemerin, like other adipokines, may function to regulate male gonadal steroidogenesis. In this study, we show that chemerin and its three receptors chemokine-like receptor 1 (CMKLR1), G-protein-coupled receptor 1 (GPR1) and chemokine (C-C motif) receptor-like 2 were expressed in male reproductive tracts, liver and white adipose tissue. CMKLR1 and GPR1 proteins were localised specifically in the Leydig cells of human and rat testes by immunohistochemistry. The expression of chemerin and its receptors in rat testes was developmentally regulated and highly expressed in Leydig cells. In vitro treatment with chemerin suppressed the human chorionic gonadotropin (hCG)-induced testosterone production from primary Leydig cells, which was accompanied by the inhibition of 3β-hydroxysteroid dehydrogenase gene and protein expression. The hCG-activated p44/42 MAPK (Erk1/2) pathway in Leydig cells was also inhibited by chemerin cotreatment. Together, these data suggest that chemerin is a novel regulator of male gonadal steroidogenesis.

Molecular heterogeneities of adipose depots - potential effects on adipose-muscle cross-talk in humans, mice and farm animals

Adipose tissue is considered as a major endocrine organ that secretes numerous proteins called adipokines. The heterogeneous nature of adipose tissue in different parts of the body suggests respective heterogeneity of proteomes and secretomes. This review consolidates knowledge from recent studies targeting the diversity of different adipose depots affecting the pattern of secreted adipokines and discusses potential consequences for the cross-talk between adipose and skeletal muscle in humans, rodent models and farm animals. Special attention is paid to muscle-associated fat depots like inter- and intramuscular fat that become focus of attention in the context of the rather new notion of skeletal muscle as a major endocrine organ. Understanding the complexity of communication between adipocytes and skeletal muscle cells will allow developing strategies for improvement of human health and for sustainable production of high quality meat.

Adipokines and the female reproductive tract

It is well known that adipose tissue can influence puberty, sexual maturation, and fertility in different species. Adipose tissue secretes molecules called adipokines which most likely have an endocrine effect on reproductive function. It has been revealed over the last few years that adipokines are functionally implicated at all levels of the reproductive axis including the gonad and hypothalamic-pituitary axis. Many studies have shown the presence and the role of the adipokines and their receptors in the female reproductive tract of different species. These adipokines regulate ovarian steroidogenesis, oocyte maturation, and embryo development. They are also present in the uterus and placenta where they could create a favorable environment for embryonic implantation and play a key role in maternal-fetal metabolism communication and gestation. Reproductive functions are strongly dependent on energy balance, and thereby metabolic abnormalities can lead to the development of some pathophysiologies such as polycystic ovary syndrome (PCOS). Adipokines could be a link between reproduction and energy metabolism and could partly explain some infertility related to obesity or PCOS.

Management of reproduction and pregnancy complications in maternal obesity: which role for dietary polyphenols?

Obesity is a global and dramatic public health problem; maternal obesity represents one of the main risk factors of infertility and pregnancy complications as it is associated with adverse maternal and offspring outcomes. In the last few years, adipose tissue dysfunction associated with altered adipocytokine secretion has been suggested to play a critical role in all the phases of reproductive process. Obesity is a nutrition-related disorder. In this regard, dietary intervention strategies, such as high intake of fruit and vegetables, have shown significant effects in both preserving health and counteracting obesity-associated diseases. Evidence has been provided that polyphenols, important constituents of plant-derived food, can influence developmental program of oocyte and embryo, as well as pregnancy progression by modulating several cellular pathways. This review will examine the controversial results so far obtained on adipocytokine involvement in fertility impairment and pregnancy complications. Furthermore, the different effects exerted by polyphenols on oocyte, embryo, and pregnancy development will be also taken in account.

History of infertility and risk of gestational diabetes mellitus: a prospective analysis of 40,773 pregnancies

Studies of delayed conception and risk of gestational diabetes (GDM) are sparse, although common underlying mechanisms are plausible, including insulin resistance and inflammation. The association between a history of infertility and GDM was assessed prospectively among 40,773 eligible pregnancies in the US Nurses' Health Study II cohort (1989-2001). Biennial questionnaires provided updated information on infertility and several lifestyle and health-related characteristics. Multivariable log-binomial models with generalized estimating equations were used to compute risk ratios and 95% confidence intervals, adjusting for age, prepregnancy body mass index (weight (kg)/height (m)(2)), and additional potential confounders. GDM occurred among 1,405 (5.2%) women. A prepregnancy history of infertility was reported by 5,497 (20.5%) participants and was significantly associated with a 39% greater risk of GDM (risk ratio (RR) = 1.39, 95% confidence interval (CI): 1.24, 1.57; P < 0.001). Underlying reasons for infertility associated with GDM included ovulation disorders (RR = 1.52, 95% CI: 1.23, 1.87; P < 0.001) and tubal blockage (RR = 1.83, 95% CI: 1.20, 2.77; P = 0.005). The association of cervical mucus disorder with GDM was of borderline significance (RR = 1.70, 95% CI: 0.88, 3.30; P = 0.11). Endometriosis (RR = 1.27, 95% CI: 0.70, 2.31; P = 0.43) and male factor infertility (RR = 1.12, 95% CI: 0.78, 1.61; P = 0.55) were not associated with GDM risk. These novel findings suggest that infertility, particularly from ovulation disorders and tubal blockage, is associated with an increased GDM risk. Further research is needed to identify mechanisms or common underlying metabolic dysfunction explaining these observations.

Circulating apelin level in relation to nutritional status in polycystic ovary syndrome and its association with metabolic and hormonal disturbances

OBJECTIVE

The aim of the study was to analyse relationships between plasma apelin-36 and apelin-12 levels, nutritional status, insulin resistance and hormonal disturbances, as well as plasma adiponectin, leptin and resistin concentrations in PCOS women.

STUDY DESIGN PATIENTS AND MEASUREMENTS

A cross-sectional study involving 87 PCOS (48 obese) and 67 non-PCOS women (36 obese). Anthropometric parameters and body composition were determined. Serum glucose, androgens, FSH, LH, SHBG, insulin, apelin-36, apelin-12, adiponectin, leptin and resistin were measured in the fasting state.

RESULTS

Plasma apelin-36 and apelin-12 levels were significantly higher in normal weight women than in the obese women with PCOS (3·1 ± 2·2 vs 1·2 ± 0·7 μg/l, P < 0·001; 2·9 ± 2·4 vs 0·5 ± 0·7 μg/l; P < 0·001 respectively). Both plasma apelin-36 and -12 levels correlated positively with adiponectin levels, and inversely with leptin or resistin levels. There was a negative correlation between plasma apelin-36, apelin-12 and serum LH levels. In addition, an inverse correlation between apelin-12 level and LH to FSH ratio was found. In multiple regression analysis 9% of LH variability was explained by apelin-12 levels (β = -0·14; P < 0·001).

CONCLUSIONS

Nutritional status seems to have different effects on apelin release, particularly, its active isoform, in women with PCOS compared with women without PCOS. This may be partially caused by changes in leptin and resistin secretion and may enhance pituitary-ovarian axis disturbances. The association between both isoforms of apelin and insulin resistance seems to be bidirectional.

Integrative control of energy balance and reproduction in females

There is a strong association between nutrition and reproduction. Chronic dietary energy deficits as well as energy surpluses can impair reproductive capacity. Metabolic status impacts reproductive function at systemic level, modulating the hypothalamic GnRH neuronal network and/or the pituitary gonadotropin secretion through several hormones and neuropeptides, and at the ovarian level, acting through the regulation of follicle growth and steroidogenesis by means of the growth hormone-IGF-insulin system and local ovarian mediators. In the past years, several hormones and neuropeptides have been emerging as important mediators between energy balance and reproduction. The present review goes over the main sites implicated in the control of energy balance linked to reproductive success and summarizes the most important metabolic and neuroendocrine signals that participate in reproductive events with special emphasis on the role of recently discovered neuroendocrine peptides. Also, a little overview about the effects of maternal nutrition, affecting offspring reproduction, has been presented.

Psychological disturbances and quality of life in obese and infertile women and men

Anovulatory cycles and endometriosis are the main causes of female infertility. The most frequently anovulatory cycles are related to polycystic ovary syndrome (PCOS) commonly associated with obesity and hormonal disturbances in the course of obesity. Recently published studies revealed that infertility affects about one in six couples during their lifetime and is more frequent in obese. Obesity is also associated with male infertility related to erectile dysfunction, hormonal disturbances and lower semen quality. Any of these above mentioned disorder is the important risk factor of psychological disturbances and poor quality of life among women and men in the reproductive age. On the other hand the mood disorders may exacerbate the hormonal disturbances and worsen the effectiveness of infertility management. Infertility, its therapy with accompanying psychological disturbances may also significantly affect the partners relationships. The review summarize the results described in the current literature on the association between obesity and infertility and psychological disturbances as well as their impact on quality of life and sexual functioning in women and men. Moreover, the impact of infertility and psychological disturbances on partners relationships is discussed.