High-fat diet causes lipotoxicity responses in cumulus-oocyte complexes and decreased fertilization rates

The epoxiconazole and tebuconazole fungicides impair granulosa cells functions partly through the aryl hydrocarbon receptor (AHR) signalling with contrasted effects in obese, normo-weight and polycystic ovarian syndrome (PCOS) patients

Polycystic ovarian syndrome (PCOS), frequently associated to obesity, is the main reproductive disorder in women in age to procreate. Some evidence suggests that pesticides can result in alterations of the female reproductive system, including polycystic ovary syndrome (PCOS). Here, we detected two fungicides, Tebuconazole (Tb) and Epoxiconazole (Epox) in the soils and waters of French area. Our hypothesis is that these two triazoles could be associated to the etiology of PCOS. We used the human KGN cell line and primary human granulosa cells (hGCs) from different group of patients: normal weight non PCOS (NW), normal weight PCOS (PCOS NW), obese (obese) and obese PCOS (PCOS obese). We exposed in vitro these cells to Tb and Epox from 0 up to 10 mM for 24 and 48 h and analysed cell viability and steroidogenesis. In hGCs NW, cell viability was reduced from 12.5 µM for Tb and 75 µM for Epox. In hGCs NW, Epox decreased progesterone (Pg) and estradiol (E2) secretions and inhibited STAR, HSD3B and CYP19A1 mRNA expressions from 25 µM and increased AHR mRNA expression from 75 µM. Tb exposure also reduced steroid secretion and STAR and CYP19A1 mRNA expressions and increased AHR mRNA expression but at cytotoxic concentrations. Silencing of AHR in KGN cells reduced inhibitory effects of Tb and Epox on steroid secretion. Tb and Epox exposure decreased more steroid secretion in hGCs from obese, PCOS NW and PCOS obese groups than in NW group. Moreover, we found a higher gene expression of AHR within these three groups. Taken together, both Epox and Tb reduced steroidogenesis in hGCs through partly AHR and Tb was more cytotoxic than Epox. These triazoles alter more strongly PCOS and/or obese hGCs suggesting that human with reproductive disorders are more sensitive to triazoles exposure.

A combination of gliclazide and metformin attenuates obesity-induced polycystic ovary syndrome in female Wistar rats

Presently, it is known that the progression of obesity concomitantly leads to polycystic ovary syndrome and infertility. This study aimed to evaluate the potential effects of metformin (M; insulin secretagogues) and gliclazide (G; insulin sensitizer) alone and their combination at different doses to treat obesity-induced PCOS. High high-fat diet was given to all female Wistar rats for nine weeks to induce obesity except for the normal control group which received a normal chow diet. Estradiol valerate (0.8 mg/kg) was also given to all obese rats to induce polycystic ovarian syndrome. After the induction, M (100, 300 mg/kg) and G (5, 10 mg/kg) were given orally either individually or in combination for 28 days. The notable (p < 0.0001) reduction in body weight and blood glucose level was observed in treatment groups in contrast to disease control (DCG). The marked (p < 0.05-0.0001) decrease in hemocylated hemoglobin, serum insulin, cholesterol, triglycerides, and testosterone was observed in treated groups, notably in combination groups (M100+G10 mg/kg) in contrast to DCG. There was a considerable (p < 0.01-0.0001) increase in progesterone E2, estradiol, luteinizing, and follicle-stimulating hormones in treated groups as compared to DCG. Treatment with M and G treated groups also exhibited marked (p < 0.05-0.0001) increases in SOD, CAT, and GSH while decreased in NO and MDA levels in ovary tissue as evidenced by the histological study of the ovary. Treatment with M and G alone and in combination significantly (p < 0.0001) restored the serum IL-6, NrF2, and NF-κB levels as compared to DCG. The results inveterate that the M and G combination (M100+G10, and M300+G10) was useful in treating obesity-induced infertility due to antioxidant properties, hypolipidemic effects, and modulation of inflammatory markers.

Establishment and validation of a nomogram model for predicting ovulation in the PCOS women

BACKGROUND

The mechanisms underlying ovulatory dysfunction in PCOS remain debatable. This study aimed to identify the factors affecting ovulation among PCOS patients based on a large sample-sized randomized control trial.

METHODS

Data were obtained from a multi-centered randomized clinical trial, the PCOSAct, which was conducted between 2011 and 2015. Univariate and multivariate analysis using binary logistic regression were used to construct a prediction model and nomogram. The accuracy of the model was assessed using receiver operating characteristic (ROC) curves and calibration curves.

RESULTS

The predictive variables included in the training dataset model were luteinizing hormone (LH), free testosterone, body mass index (BMI), period times per year, and clomiphene treatment. The ROC curve for the model in the training dataset was 0.81 (95% CI [0.77, 0.85]), while in the validation dataset, it was 0.7801 (95% CI [0.72, 0.84]). The model showed good discrimination in both the training and validation datasets. Decision curve analysis demonstrated that the nomogram designed for ovulation had clinical utility and superior discriminative ability for predicting ovulation.

CONCLUSIONS

The nomogram composed of LH, free testosterone, BMI, period times per year and the application of clomiphene may predict the ovulation among PCOS patients.

Follicular metabolic alterations are associated with obesity in mares and can be mitigated by dietary supplementation

Obesity is a growing concern in human and equine populations, predisposing to metabolic pathologies and reproductive disturbances. Cellular lipid accumulation and mitochondrial dysfunction play an important role in the pathologic consequences of obesity, which may be mitigated by dietary interventions targeting these processes. We hypothesized that obesity in the mare promotes follicular lipid accumulation and altered mitochondrial function of oocytes and granulosa cells, potentially contributing to impaired fertility in this population. We also predicted that these effects could be mitigated by dietary supplementation with a combination of targeted nutrients to improve follicular cell metabolism. Twenty mares were grouped as: Normal Weight [NW, n = 6, body condition score (BCS) 5.7 ± 0.3], Obese (OB, n = 7, BCS 7.7 ± 0.2), and Obese Diet Supplemented (OBD, n = 7, BCS 7.7 ± 0.2), and fed specific feed regimens for ≥ 6 weeks before sampling. Granulosa cells, follicular fluid, and cumulus-oocyte complexes were collected from follicles ≥ 35 mm during estrus and after induction of maturation. Obesity promoted several mitochondrial metabolic disturbances in granulosa cells, reduced L-carnitine availability in the follicle, promoted lipid accumulation in cumulus cells and oocytes, and increased basal oocyte metabolism. Diet supplementation of a complex nutrient mixture mitigated most of the metabolic changes in the follicles of obese mares, resulting in parameters similar to NW mares. In conclusion, obesity disturbs the equine ovarian follicle by promoting lipid accumulation and altering mitochondrial function. These effects may be partially mitigated with targeted nutritional intervention, thereby potentially improving fertility outcomes in the obese female.

High Fat Diet and Polycystic Ovary Syndrome (PCOS) in Adolescence: An Overview of Nutritional Strategies

Polycystic ovary syndrome (PCOS) is a multifaceted and heterogeneous disorder, linked with notable reproductive, metabolic, and psychological outcomes. During adolescence, key components of PCOS treatment involve weight loss achieved through lifestyle and dietary interventions, subsequently pursued by pharmacological or surgical therapies. Nutritional interventions represent the first-line therapeutic approach in adolescents affected by PCOS, but different kinds of dietary protocols exist, so it is necessary to clarify the effectiveness and benefits of the most well-known nutritional approaches. We provided a comprehensive review of the current literature concerning PCOS definition, pathophysiology, and treatment options, highlighting nutritional strategies, particularly those related to high-fat diets. The high-fat nutritional protocols proposed in the literature, such as the ketogenic diet (KD), appear to provide benefits to patients with PCOS in terms of weight loss and control of metabolic parameters. Among the different types of KD studies, very low-calorie ketogenic diets (VLCKD), can be considered an effective dietary intervention for the short-term treatment of patients with PCOS. It rapidly leads to weight loss alongside improvements in body composition and metabolic profile. Even though extremely advantageous, long-term adherence to the KD is a limiting factor. Indeed, this dietary regimen could become unsustainable due to the important restrictions required for ketosis development. Thus, a combination of high-fat diets with more nutrient-rich nutritional regimens, such as the Mediterranean diet, can amplify positive effects for individuals with PCOS.

Dietary Patterns and Fertility

Diet has a key role in the reproductive axis both in males and females. This review aims to analyze the impacts of different dietary patterns on fertility. It appears that the Mediterranean diet has a predominantly protective role against infertility, while the Western diet seems to be a risk factor for infertility. Moreover, we focus attention also on dietary patterns in different countries of the World (Middle Eastern diet, Asian diet). In particular, when analyzing single nutrients, a diet rich in saturated fatty acids, cholesterol, animal proteins, and carbohydrates with high glycemic index is highly associated with male and female infertility. Finally, we evaluate the effects of vegetarian, vegan, and ketogenic diets on fertility, which seem to be still unclear. We believe that comprehension of the molecular mechanisms involved in infertility will lead to more effective and targeted treatments for infertile couples.

Infertility Improvement after Medical Weight Loss in Women and Men: A Review of the Literature

Infertility is a modern health problem. Obesity is another expanding health issue associated with chronic diseases among which infertility is also included. This review will focus on the effects of weight loss by medical therapy on fertility regarding reproductive hormonal profile, ovulation rates, time to pregnancy, implantation rates, pregnancy rates, normal embryo development, and live birth rates. We comprised medicine already used for weight loss, such as orlistat and metformin, and emerging medical treatments, such as Glucagon-Like Peptide-1 receptor agonists (GLP-1 RA). Their use is not recommended during a planned pregnancy, and they should be discontinued in such cases. The main outcomes of this literature review are the following: modest weight loss after medication and the duration of the treatment are important factors for fertility improvement. The fecundity outcomes upon which medical-induced weight loss provides significant results are the female reproductive hormonal profile, menstrual cyclicity, ovulation and conception rates, and pregnancy rates. Regarding the male reproductive system, the fertility outcomes that feature significant alterations after medically induced weight loss are as follows: the male reproductive hormonal profile, sperm motility, movement and morphology, weight of reproductive organs, and sexual function. The newer promising GLP-1 RAs show expectations regarding fertility improvement, as they have evidenced encouraging effects on improving ovulation rates and regulating the menstrual cycle. However, more human studies are needed to confirm this. Future research should aim to provide answers about whether medical weight loss therapies affect fertility indirectly through weight loss or by a possible direct action on the reproductive system.

Redox Biomarkers and Matrix Remodeling Molecules in Ovarian Cancer

Ovarian cancer (OC) has emerged as the leading cause of death due to gynecological malignancies among women. Oxidative stress and metalloproteinases (MMPs) have been shown to influence signaling pathways and afflict the progression of carcinogenesis. Therefore, the assessment of matrix-remodeling and oxidative stress intensity can determine the degree of cellular injury and often the severity of redox-mediated chemoresistance. The study group comprised 27 patients with serous OC of which 18% were classified as Federation of Gynecology and Obstetrics (FIGO) stages I/II, while the rest were diagnosed grades III/IV. The control group comprised of 15 ovarian tissue samples. The results were compared with genetic data from The Cancer Genome Atlas. Nitro-oxidative stress, inflammation and apoptosis biomarkers were measured colorimetrically/fluorometrically or via real-time PCR in the primary ovarian tumor and healthy tissue. Stratification of patients according to FIGO stages revealed that high-grade carcinoma exhibited substantial alterations in redox balance, including the accumulation of protein glycoxidation and lipid peroxidation products. TCGA data demonstrated only limited prognostic usefulness of the studied genes. In conclusion, high-grade serous OC is associated with enhanced tissue oxidative/nitrosative stress and macromolecule damage that could not be overridden by the simultaneously augmented measures of antioxidant defense. Therefore, it can be assumed that tumor cells acquire adaptive mechanisms that enable them to withstand the potential toxic effects of elevated reactive oxygen species.

Maternal High-Fat Diet Affects the Contents of Eggs and Causes Abnormal Development in the Medaka Fish

Maternal nutritional status can affect development and metabolic phenotypes of progeny in animals. The effects of maternal diet are thought to be mediated mainly by changes inside oocytes such as organelles, maternal RNAs, and metabolites. However, to what extent each factor contributes to offspring phenotypes remains uncertain, especially in viviparous mammalian systems, where factors other than oocytes, such as placenta and milk, need to be considered. Here, using the medaka fish as an oviparous vertebrate model, we examined whether maternal high-fat diet (mHFD) feeding affects offspring development and what kind of changes occur in the contents of mature eggs. We found that mHFD caused the high frequency of embryonic deformities of offspring, accompanied by downregulation of transcription- and translation-related genes and zygotic transcripts at the blastula stage. Transcriptomic and metabolomic analyses of mature eggs suggested decreased catabolism of amino acids and glycogen, moderate upregulation of endoplasmic reticulum stress-related genes, and elevated lipid levels in mHFD eggs. Furthermore, high-fat diet females showed a higher incidence of oocyte atresia and downregulation of egg protein genes in the liver. These data suggest that attenuated amino acid catabolism triggered by decreased yolk protein load/processing, as well as elevated lipid levels inside eggs, are the prime candidates that account for the higher incidence of embryonic deformities in mHFD offspring. Our study presents a comprehensive data on the changes inside eggs in a mHFD model of nonmammalian vertebrates and provides insights into the mechanisms of parental nutritional effects on offspring.

Obesity and its impact on female reproductive health: unraveling the connections

In the modern era, the escalating global prevalence of obesity has profound implications on female reproductive health. Obesity, transcending mere lifestyle choices, has evolved into a complex disorder affecting physiological and metabolic functions. Concurrently, female infertility is rising as a significant global health issue. Obesity, with its extensive systemic effects, is pinpointed as a major disruptor. The convergence of these health challenges reveals a multifaceted scenario: on one hand, obesity directly impacts female reproductive health, particularly in the context of conditions like polycystic ovary syndrome (PCOS) and menstrual disturbances; on the other, the psychosocial consequences of infertility might intensify weight-gain patterns, forming a challenging cycle. Additionally, the economic implications of treating obesity-related infertility are considerable. This review delves into the myriad ways obesity affects female reproductive health, drawing insights from epidemiological, clinical, and molecular studies. It explores the epidemiological relationship between obesity and PCOS, the influence of obesity on menstrual disturbances, and the broader impact of obesity on female infertility. Weight loss, through pharmacological interventions, surgical methods, or lifestyle adjustments, emerges as a promising strategy. Lastly, the efficacy of assisted reproductive technologies, such as IVF, is influenced by obesity, underscoring the importance of an optimal body mass index. The review also highlights the molecular and physiological mechanisms underlying the impact of obesity on female reproductive health, including the disruption of the hypothalamic-pituitary-ovary axis, altered adipokine secretion, and the role of chronic inflammation and oxidative stress.

Effect of lipotoxicity on mitochondrial function and epigenetic programming during bovine in vitro embryo production

Maternal metabolic disorders may cause lipotoxic effects on the developing oocyte. Understanding the timing at which this might disrupt embryo epigenetic programming and how this is linked with mitochondrial dysfunction is crucial for improving assisted reproductive treatments, but has not been investigated before. Therefore, we used a bovine in vitro model to investigate if pathophysiological palmitic acid (PA) concentrations during in vitro oocyte maturation and in vitro embryo culture alter embryo epigenetic patterns (DNA methylation (5mC) and histone acetylation/methylation (H3K9ac/H3K9me2)) compared to control (CONT) and solvent control (SCONT), at the zygote and morula stage. Secondly, we investigated if these epigenetic alterations are associated with mitochondrial dysfunction and changes in ATP production rate, or altered expression of epigenetic regulatory genes. Compared to SCONT, H3K9ac and H3K9me2 levels were increased in PA-derived zygotes. Also, 5mC and H3K9me2 levels were increased in PA-exposed morulae compared to SCONT. This was associated with complete inhibition of glycolytic ATP production in oocytes, increased mitochondrial membrane potential and complete inhibition of glycolytic ATP production in 4-cell embryos and reduced SOD2 expression in PA-exposed zygotes and morulae. For the first time, epigenetic alterations in metabolically compromised zygotes and morulae have been observed in parallel with mitochondrial dysfunction in the same study.

The impact of a maternal and offspring obesogenic diet on daughter's oocyte mitochondrial ultrastructure and bioenergetic responses. Insights from an outbred mouse model

Obesity affects oocyte mitochondrial functions and reduces oocyte quality and fertility. Obesity may also increase the risk of metabolic disorders in the offspring. Children are likely to follow their parents lifestyle and diet, which also contributes to the increased prevelance of obesity across generations. We hypothesise that the impact of obesogenic (OB) diet and obesity on oocyte mitochondrial functions is different in offspring born to obese mothers compared to those born to healthy mothers. To test this hypothesis, we fed a control (C, 10% fat, 7% sugar) or an OB diet (60% fat, 20% sugar) to female mice (for 7 weeks (w)) and then to their female offspring (for 7w after weaning) in a 2 × 2 factorial design (C » C, n = 35, C » OB, n = 35, OB » C n = 49 and OB » OB, n = 50). Unlike many other studies, we used an outbred Swiss mouse model to increase the human pathophysiological relevance. Offspring were sacrificed at 10w and their oocytes were collected. Offspring OB diet increased oocyte lipid droplet content, mitochondrial activity and reactive oxygen species (ROS) levels, altered mitochondrial ultrastructure and reduced oocyte pyruvate consumption. Mitochondrial DNA copy numbers and lactate production remained unaffected. Mitochondrial ultrastructure was the only factor where a significant interaction between maternal and offspring diet effect was detected. The maternal OB background resulted in a small but significant increase in offspring's oocyte mitochondrial ultrastructural abnormalities without altering mitochondrial inner membrane potential, active mitochondrial distribution, mitochondrial DNA copy numbers, or ROS production. This was associated with reduced mitochondrial complex III and V expression and reduced pyruvate consumption which may be compensatory mechanisms to control mitochondrial inner membrane potential and ROS levels. Therefore, in this Swiss outbred model, while offspring OB diet had the largest functional impact on oocyte mitochondrial features, the mitochondrial changes due to the maternal background appear to be adaptive and compensatory rather than dysfunctional.

The Effect of Maternal Exposure to a Diet High in Fats and Cholesterol on the Placental Function and Phenotype of the Offspring in a Rabbit Model: A Summary Review of About 15 Years of Research

The rates of obesity and being overweight are increasing all around the world, especially among women of childbearing age, in part due to overconsumption of lipids. The aim of this summary review was to present the cellular and molecular effects of a hyperlipidic high-cholesterol (H) diet on the maternal and offspring phenotype at the early embryonic, neonatal, weaning and adult stages while considering the effects of sex and to identify the window(s) of vulnerability linked to this exposure in a rabbit model. Before breeding, the H diet induced dyslipidemia and aortic atherosclerosis lesions and increased the number of atretic follicles. In the offspring, the H diet disrupted the embryonic phenotype and induced fetal hypotrophy associated with sex-specific disturbances of the feto-placental unit. In adulthood, the offspring of the H dams were heavier and hyperphagic and had increased blood pressure associated with disturbed gonadal development in both sexes. Vulnerability windows were explored via embryo transfers. The maternal gestational diet was shown to play a key role in the feto-placental phenotype, and preconception programming was unquestionably also observed. These two periods could represent windows of intervention in the context of obesity or being overweight to limit fetal and placental consequences.

Influence of maternal obesity on embryonic vitrification injury and subsequent pregnancy outcomes: A retrospective cohort study

Background

We previously reported that obese mice had significantly high lipid content in embryos, and excessive lipids are detrimental to embryonic development. However, whether maternal obesity has an effect on embryonic vitrification injury and subsequent pregnancy outcomes is still controversial. This study was conducted to clarify the influence of maternal obesity on embryonic vitrification injury and subsequent pregnancy outcomes by in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI).

Methods

We retrospectively collected medical record of IVF/ICSI patients from reproductive medicine centers in two tertiary hospitals. The patients were classified into a low-weight group (<18.5 kg/m2), normal-weight group (18.5-23.9 kg/m2), overweight group (24.0-27.9 kg/m2) and obese group (≥28.0 kg/m2) according to their body mass index (BMI). Multivariable logistic regression analysis was performed to compare pregnancy outcomes in fresh and frozen embryo transfer among different BMI groups to define the correlation between BMI and embryonic vitrification injury.

Results

A total of 44 773 women among 20-40 years old were recruited in this study, of which 27 797 underwent their first fresh embryo transfer and 16 976 underwent their first frozen embryo transfer. For fresh embryo transfer, there was no significant difference in the clinical pregnancy rate, live birth rate, and miscarriage rate of 4 BMI groups. For frozen-thawed embryo transfer, there was a significant increase in the clinical pregnancy rate of the overweight group (AOR = 1.14, 95% CI: 1.05-1.25) and the obese group (AOR = 1.24, 95% CI: 1.03-1.50), while the miscarriage rate (AOR = 1.42, 95% CI: 1.05-1.92) also showed a significant increase in the obese group compared to the normal-weight group.

Conclusion

This study provided a new understanding of the effect of maternal obesity on embryonic vitrification injury. Maternal obesity does not worsen the outcome of IVF/ICSI, particularly in the frozen-thawed group.

Use of green microalgae Chlorella as a nutritional supplement to support oocyte and embryo production in goats

This study aimed to evaluate the use of green microalgae as a nutritional supplement for oocyte and embryo production in goats. Two experiments were performed on adult goats to obtain oocytes (EVO; n = 14) and in vivo embryos (IVD; n = 14). In both, the donors were divided into control (n = 7) and Chlorella (n = 7) groups. All goats received a base diet, and donors were orally supplemented with Chlorella pyrenoidosa (CH) in the Chlorella groups. For EVO, donors received 10 g CH for 14 days, and for IVD, 20 g CH was given for six days before embryo recovery. In EVO and IVD, food intake in the CH group was comparatively low, and it showed relatively high subcutaneous adipose deposition. In addition, the CH group exhibited an increase in triglyceride, cholesterol, and plasma glucose levels. In IVD, a significant increase in peripheral glutathione peroxidase levels was noticed. In EVO, the CH group showed relatively large follicular size and an increase in intrafollicular levels of triglycerides, glucose, and glutathione peroxidase. No differences were observed in the oocyte collected, and CH oocytes showed a low intensity of MitoTracker fluorescence (MT). In IVD, the CH group had a high proportion of transferable embryos, and these structures exhibited high fluorescence intensities for MT and H2DCFDA probes. We concluded that under these conditions, CH did not enhance the quality of the recovered oocytes. However, a daily dose of 20 g CH improved the quality of embryos and stimulated their mitochondrial functionality.

The Role of Lifestyle and Dietary Factors in the Development of Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI) is a condition that arises from dysfunction or early depletion of the ovarian follicle pool accompanied by an earlier-than-normal loss of fertility in young women. Oxidative stress has been suggested as an important factor in the decline of fertility in women and POI. In this review, we discuss the mechanisms of oxidative stress implicated in ovarian ageing and dysfunction in relation to POI, in particular mitochondrial dysfunction, apoptosis and inflammation. Genetic defects, autoimmunity and chemotherapy, are some of the reviewed hallmarks of POI that can lead to increased oxidative stress. Additionally, we highlight lifestyle factors, including diet, low energy availability and BMI, that can increase the risk of POI. The final section of this review discusses dietary factors associated with POI, including consumption of oily fish, mitochondria nutrient therapy, melatonin, dairy and vitamins that can be targeted as potential interventions, especially for at-risk women and in combination with personalised nutrition. Understanding the impact of lifestyle and its implications for POI and oxidative stress holds great promise in reducing the burden of this condition.

Correlation between abnormal energy metabolism of ovarian granulosa cells and in vitro fertilization-embryo transfer outcomes in patients with polycystic ovary syndrome and obesity

CONTEXT

Granulosa cells (GCs) that surround oocytes in mammalian reproduction play an active role in oocyte differentiation through proliferation and energy production.

AIMS

This study aimed to investigate the characteristics of the energy metabolism of ovarian GCs and the influence of GCs on the early embryonic development in polycystic ovary syndrome (PCOS).

METHODS

The clinical characteristics and in vitro fertilization-embryo transfer treatment outcomes of 39 patients with PCOS and 68 patients with simple tubal factor infertility who underwent controlled ovarian hyperstimulation were analyzed and summarized. The mitochondrial function and glucose metabolism level of the GCs were determined, as well as the content of oxidative stress markers in the follicular fluid (FF) of patients with and without PCOS.

KEY RESULTS

When compared to the non-PCOS group, patients with PCOS had a significantly increased number of retrieved oocytes but a significantly decreased number of high-quality embryos, available embryos, and high-quality blastocyst formation (P < 0.05). Furthermore, the mitochondrial membrane potential, adenosine triphosphate level, and mitochondrial DNA (mtDNA) copy number decreased in the GCs, whereas the levels of reactive oxygen species increased (P < 0.01). The levels of malondialdehyde and 8-oxo-deoxyguanosine (8-OHdG) in the follicular fluid (FF) of the patients with PCOS were higher than those of the control group (P < 0.05), and superoxide dismutase was increased by compensation (P < 0.05). In the PCOS group, the expressions of GLUT1, LDHA, and PFKP were lower than those in the non-PCOS group, and glucose levels were higher.

CONCLUSIONS

The low oocyte competence of PCOS may be associated with mitochondrial dysfunction and abnormal glycolysis.

IMPLICATIONS

This research offers explanations for the possible connections influencing human ovarian folliculogenesis.

Mitochondrial dysfunction in the offspring of obese mothers and it's transmission through damaged oocyte mitochondria: Integration of mechanisms

In vivo and in vitro studies demonstrate that mitochondria in the oocyte, are susceptible to damage by suboptimal pre/pregnancy conditions, such as obesity. These suboptimal conditions have been shown to induce mitochondrial dysfunction (MD) in multiple tissues of the offspring, suggesting that mitochondria of oocytes that pass from mother to offspring, can carry information that can programme mitochondrial and metabolic dysfunction of the next generation. They also suggest that transmission of MD could increase the risk of obesity and other metabolic diseases in the population inter- and trans-generationally. In this review, we examined whether MD observed in offspring tissues of high energetic demand, is the result of the transmission of damaged mitochondria from obese mothers' oocytes to the offspring. The contribution of genome-independent mechanisms (namely mitophagy) in this transmission were also explored. Finally, potential interventions aimed at improving oocyte/embryo health were investigated, to see if they may provide an opportunity to halter the generational effects of MD.

The effect of maternal consumption of high-fat diet on ovarian development in offspring

The environment encountered by the fetus during its development exerts a profound influence on its physiological function and disease risk in adulthood. Women's intake of high-fat diet during pregnancy and lactation has gradually become an issue of widespread concern. Maternal high-fat diet will not only cause abnormal neurological development and metabolic syndrome symptoms in the offspring, but also affect the fertility of female offspring. Maternal high-fat diet affects the expression of genes related to follicle growth in offspring, such as AAT, AFP and GDF-9, which reduces the number of follicles and impairs follicle development. Additionally, maternal high-fat diet also affects ovarian health by inducing ovarian oxidative stress and cell apoptosis, which collectively can impair the reproductive potential of female offspring. Reproductive potential carries significant importance for both humans and animals. Therefore, this review aims to describe the effect of maternal exposure to high-fat diet on the ovarian development of offspring and to discuss possible mechanisms by which maternal diet affects the growth and metabolism of offspring.

Effect of High Fat Diet on Disease Development of Polycystic Ovary Syndrome and Lifestyle Intervention Strategies

Polycystic ovary syndrome (PCOS) is a prevalent endocrine and metabolic disorder that affects premenopausal women. The etiology of PCOS is multifaceted, involving various genetic and epigenetic factors, hypothalamic-pituitary-ovarian dysfunction, androgen excess, insulin resistance, and adipose-related mechanisms. High-fat diets (HFDs) has been linked to the development of metabolic disorders and weight gain, exacerbating obesity and impairing the function of the hypothalamic-pituitary-ovarian axis. This results in increased insulin resistance, hyperinsulinemia, and the release of inflammatory adipokines, leading to heightened fat synthesis and reduced fat breakdown, thereby worsening the metabolic and reproductive consequences of PCOS. Effective management of PCOS requires lifestyle interventions such as dietary modifications, weight loss, physical activity, and psychological well-being, as well as medical or surgical interventions in some cases. This article systematically examines the pathological basis of PCOS and the influence of HFDs on its development, with the aim of raising awareness of the connection between diet and reproductive health, providing a robust approach to lifestyle interventions, and serving as a reference for the development of targeted drug treatments.

Ovarian inflammation mediated by Toll-like receptor 4 increased transcripts of maternal effect genes and decreased embryo development†

Obese women are subfertile and have reduced assisted reproduction success, which may be due to reduced oocyte competence. We hypothesize that consumption of a high-fat/high-sugar diet induces ovarian inflammation, which is a primary contributor to decreased oocyte quality and pre-implantation embryo development. To test this hypothesis, C57BL/6 (B6) mice with a normal inflammatory response and C3H/HeJ (C3H) mice with a dampened inflammatory response due to dysfunctional Toll-like receptor 4 were fed either normal chow or high-fat/high-sugar diet. In both B6 and C3H females, high-fat/high-sugar diet induced excessive adiposity and hyperglycemia compared to normal chow-fed counterparts. Conversely, ovarian CD68 levels and oocyte expression of oxidative stress markers were increased when collected from B6 high-fat/high-sugar but not C3H high-fat/high-sugar mice. Following in vitro fertilization of in vivo matured oocytes, blastocyst development was decreased in B6-high-fat/high-sugar but not C3H high-fat/high-sugar mice. Expression of cumulus cell markers of oocyte quality were altered in both B6 high-fat/high-sugar and C3H high-fat/high-sugar. However, there were no diet-dependent differences in spindle abnormalities in either B6 or C3H mice, suggesting potential defects in cytoplasmic maturation. Indeed, there were significant increases in the abundance of maternal effect gene mRNAs in oocytes from only B6 high-fat/high-sugar mice. These differentially expressed genes encode proteins of the subcortical maternal complex and associated with mRNA metabolism and epigenetic modifications. These genes regulate maternal mRNA degradation at oocyte maturation, mRNA clearance at the zygotic genome activation, and methylation of imprinted genes suggesting a mechanism by which inflammation induced oxidative stress impairs embryo development.

Maternal obesity and ovarian failure: is leptin the culprit?

At the time of its discovery and characterization in 1994, leptin was mostly considered a metabolic hormone able to regulate body weight and energy homeostasis. However, in recent years, a great deal of literature has revealed leptin's pleiotropic nature, through its involvement in numerous physiological contexts including the regulation of the female reproductive tract and ovarian function. Obesity has been largely associated with infertility, and leptin signalling is known to be dysregulated in the ovaries of obese females. Hence, the disruption of ovarian leptin signalling was shown to contribute to the pathophysiology of ovarian failure in obese females, affecting transcriptional programmes in the gamete and somatic cells. This review attempts to uncover the underlying mechanisms contributing to female infertility associated with obesity, as well as to shed light on the role of leptin in the metabolic dysregulation within the follicle, the effects on the oocyte epigenome, and the potential long-term consequence to embryo programming.

Effect of apple vinegar on folliculogenesis and ovarian kisspeptin in a high-fat diet-induced nonalcoholic fatty liver disease in rat

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) adversely affects reproduction. We aimed to study the effect of a high-fat diet (HFD), supplemented with apple vinegar, on folliculogenesis in a rat model of NAFLD.

METHODS

Female rats were randomly divided into four groups (N = 28): Standard diet (SD), SD + vinegar, HFD, and HFD + vinegar groups. At the end of the study, biochemical tests were assessed in serum. HOMA-IR (Homeostatic model assessment-Insulin resistance) was calculated. Sex hormones were determined using an ELISA kit; ovary follicle counts were studied using histological methods. The proliferation index of granulosa cells was determined using immunohistochemistry. Kisspeptin expression in the ovary was detected using RT-PCR.

RESULTS

The HFD induced steatohepatitis and NAFLD. The ovaries in the rat model of NAFLD were atrophied. The ovaries had less count of developing follicles and corpus luteum, and more degenerated and cystic follicles in comparison with the SD group. Vinegar + HFD consumption decreased ALT, compared to the HFD group (P = 0.004). Steatohepatitis was reduced in the Vinegar + HFD group (P = 0.001). Vinegar + HFD considerably reduced HOMA-IR (p = 0.01). The HFD + vinegar diet could increase estradiol (P = 0.001), without significantly affecting progesterone or testosterone. In addition, an increase of primordial follicles as an ovarian reserve and also primary follicles were determined in the HFD + vinegar group. There were no statistical differences in the granulosa cell proliferation index in various follicle types between groups. HFD + vinegar significantly enhanced ovarian kisspeptin expression (p = 0.04).

CONCLUSIONS

The vinegar diet in a rat model of NAFLD raises estradiol, primordial, and small primary follicles, and increases ovarian kisspeptin expression indirectly. Insulin resistance and obesity were improved by apple vinegar, and anti-glycemic and anti-lipidemic effects were also determined. The supplementation of apple vinegar in NAFLD might be useful for ovary. However, it requires further investigation.

Long-term changes in the diurnal temporal regulation and set points of metabolic parameters associated with chronic maternal overnutrition in rabbits

Metabolic syndrome (MS) and obesity have become a worldwide epidemic with an alarming prevalence in women of reproductive age. Maternal metabolic condition is considered a risk factor for adverse birth outcomes and long-term MS. In this study, we developed a rabbit model of maternal overnutrition via the chronic intake of a high-fat and carbohydrate diet (HFCD), and we determined the effects of this diet on maternal metabolism and offspring metabolic set points and temporal metabolic regulation in adult life. Before and during pregnancy, the female rabbits that consumed the HFCD exhibited significant changes in body weight, serum levels of analytes associated with carbohydrate and lipid metabolism, levels of liver and kidney damage markers, and liver histology. Our data suggest that rabbits are a valuable model for studying the development of MS associated with the chronic intake of unbalanced diets and fetal metabolic programming. Furthermore, the offspring of overnourished dams exhibited considerable changes in 24-h serum metabolite profiles in adulthood, with notable sexual dimorphism. These data suggest that maternal nutritional conditions due to the chronic intake of an HFCD adversely impact key elements related to the development of circadian rhythmicity in offspring.NEW & NOTEWORTHY Maternal overnutrition previous and during pregnancy leads to long-term changes in the 24-h regulation and setpoint of metabolic profiles of the offspring.

Maternal metabolic health and fertility: we should not only care about but also for the oocyte!

Metabolic disorders due to obesity and unhealthy lifestyle directly alter the oocyte's microenvironment and impact oocyte quality. Oxidative stress and mitochondrial dysfunction play key roles in the pathogenesis. Acute effects on the fully grown oocytes are evident, but early follicular stages are also sensitive to metabolic stress leading to a long-term impact on follicular cells and oocytes. Improving the preconception health is therefore of capital importance but research in animal models has demonstrated that oocyte quality is not fully recovered. In the in vitro fertilisation clinic, maternal metabolic disorders are linked with disappointing assisted reproductive technology results. Embryos derived from metabolically compromised oocytes exhibit persistently high intracellular stress levels due to weak cellular homeostatic mechanisms. The assisted reproductive technology procedures themselves form an extra burden for these defective embryos. Minimising cellular stress during culture using mitochondrial-targeted therapy could rescue compromised embryos in a bovine model. However, translating such applications to human in vitro fertilisation clinics is not simple. It is crucial to consider the sensitive epigenetic programming during early development. Research in humans and relevant animal models should result in preconception care interventions and in vitro strategies not only aiming at improving fertility but also safeguarding offspring health.

Obese outbred mice only partially benefit from diet normalization or calorie restriction as preconception care interventions to improve metabolic health and oocyte quality

STUDY QUESTION

Can diet normalization or a calorie-restricted diet for 2 or 4 weeks be used as a preconception care intervention (PCCI) in Western-type diet-induced obese Swiss mice to restore metabolic health and oocyte quality?

SUMMARY ANSWER

Metabolic health and oocyte developmental competence was already significantly improved in the calorie-restricted group after 2 weeks, while obese mice that underwent diet normalization showed improved metabolic health after 2 weeks and improved oocyte quality after 4 weeks.

WHAT IS KNOWN ALREADY

Maternal obesity is linked with reduced metabolic health and oocyte quality; therefore, infertile obese women are advised to lose weight before conception to increase pregnancy chances. However, as there are no univocal guidelines and the specific impact on oocyte quality is not known, strategically designed studies are needed to provide fundamental insights in the importance of the type and duration of the dietary weight loss strategy for preconception metabolic health and oocyte quality.

STUDY DESIGN, SIZE, DURATION

Outbred female Swiss mice were fed a control (CTRL) or high-fat/high-sugar (HF/HS) diet. After 7 weeks, some of the HF mice were put on two different PCCIs, resulting in four treatment groups: (i) only control diet for up to 11 weeks (CTRL_CTRL), (ii) only HF diet for up to 11 weeks (HF_HF), (iii) switch at 7 weeks from an HF to an ad libitum control diet (HF_CTRL) and (iv) switch at 7 weeks from an HF to a 30% calorie-restricted control diet (HF_CR) for 2 or 4 weeks. Metabolic health and oocyte quality were assessed at 2 and 4 weeks after the start of the intervention (n = 8 mice/treatment/time point).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Changes in body weight were recorded. To study the impact on metabolic health, serum insulin, glucose, triglycerides, total cholesterol and alanine aminotransferase concentrations were measured, and glucose tolerance and insulin sensitivity were analyzed at PCCI Weeks 2 and 4. The quality of in vivo matured oocytes was evaluated by assessing intracellular lipid droplet content, mitochondrial activity and localization of active mitochondria, mitochondrial ultrastructure, cumulus cell targeted gene expression and oocyte in vitro developmental competence.

MAIN RESULTS AND THE ROLE OF CHANCE

Significant negative effects of an HF/HS diet on metabolic health and oocyte quality were confirmed (P < 0.05). HF_CTRL mice already showed restored body weight, serum lipid profile and glucose tolerance, similar to the CTRL_CTRL group after only 2 weeks of PCCI (P < 0.05 compared with HF_HF) while insulin sensitivity was not improved. Oocyte lipid droplet volume was reduced at PCCI Week 2 (P < 0.05 compared with HF_HF), while mitochondrial localization and activity were still aberrant. At PCCI Week 4, oocytes from HF_CTRL mice displayed significantly fewer mitochondrial ultrastructural abnormalities and improved mitochondrial activity (P < 0.05), while lipid content was again elevated. The in vitro developmental capacity of the oocytes was improved but did not reach the levels of the CTRL_CTRL mice. HF_CR mice completely restored cholesterol concentrations and insulin sensitivity already after 2 weeks. Other metabolic health parameters were only restored after 4 weeks of intervention with clear signs of fasting hypoglycemia. Although all mitochondrial parameters in HF_CR oocytes stayed aberrant, oocyte developmental competence in vitro was completely restored already after 2 weeks of intervention.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

In this study, we applied a relevant HF/HS Western-type diet to induce obesity in an outbred mouse model. Nevertheless, physiological differences should be considered when translating these results to the human setting. However, the in-depth study and follow-up of the metabolic health changes together with the strategic implementation of specific PCCI intervals (2 and 4 weeks) related to the duration of the mouse folliculogenesis (3 weeks), should aid in the extrapolation of our findings to the human setting.

WIDER IMPLICATIONS OF THE FINDINGS

Our study results with a specific focus on oocyte quality provide important fundamental insights to be considered when developing preconception care guidelines for obese metabolically compromised women wishing to become pregnant.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Flemish Research Fund (FWO-SB grant 1S25020N and FWO project G038619N). The authors declare there are no conflicts of interest.

Impact of elevated body mass index on cumulative live birth rate and obstetric safety in women undergoing assisted reproductive technology

This study evaluated the impact of elevated body mass index (BMI) on short- and long-term outcomes of in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatments. A total of 7229 patients undergoing IVF/ICSI fresh cycles and subsequent frozen embryo transfer cycles from 2014 to 2020 were divided into normal (18.5-24.9 kg/m²) and high BMI (≥ 25 kg/m²) groups. Ovarian response, pregnancy outcomes, and safety of both mother and fetus were the main outcome measures. Furthermore, multivariate analysis was used to determine whether BMI was associated with cumulative live birth rate (CLBR). Results showed that for younger women (< 38 year), CLBR was significantly reduced in the high BMI group compared with the normal BMI control and was accompanied by fewer retrieved oocytes and available embryos. Additionally, the incidence of hypertensive disorders of pregnancy, fetal macrosomia, and cleft lip and palate birth defects resulting from cumulative live births was significantly higher compared with the normal BMI group. No differences were observed among older women (≥ 38 year). Multivariate analysis revealed that high BMI was a risk factor for CLBR. Our study suggested that elevated BMI has a greater adverse impact on younger women.

High-Fat Diet and Female Fertility across Lifespan: A Comparative Lesson from Mammal Models

Female reproduction focuses mainly on achieving fully grown follicles and competent oocytes to be successfully fertilized, as well as on nourishing the developing offspring once pregnancy occurs. Current evidence demonstrates that obesity and/or high-fat diet regimes can perturbate these processes, leading to female infertility and transgenerational disorders. Since the mechanisms and reproductive processes involved are not yet fully clarified, the present review is designed as a systematic and comparative survey of the available literature. The available data demonstrate the adverse influences of obesity on diverse reproductive processes, such as folliculogenesis, oogenesis, and embryo development/implant. The negative reproductive impact may be attributed to a direct action on reproductive somatic and germinal compartments and/or to an indirect influence mediated by the endocrine, metabolic, and immune axis control systems. Overall, the present review highlights the fragmentation of the current information limiting the comprehension of the reproductive impact of a high-fat diet. Based on the incidence and prevalence of obesity in the Western countries, this topic becomes a research challenge to increase self-awareness of dietary reproductive risk to propose solid and rigorous preventive dietary regimes, as well as to develop targeted pharmacological interventions.

Parental Programming of Offspring Health: The Intricate Interplay between Diet, Environment, Reproduction and Development

As adults, our health can be influenced by a range of lifestyle and environmental factors, increasing the risk for developing a series of non-communicable diseases such as type 2 diabetes, heart disease and obesity. Over the past few decades, our understanding of how our adult health can be shaped by events occurring before birth has developed into a well-supported concept, the Developmental Origins of Health and Disease (DOHaD). Supported by epidemiological data and experimental studies, specific mechanisms have been defined linking environmental perturbations, disrupted fetal and neonatal development and adult ill-health. Originally, such studies focused on the significance of poor maternal health during pregnancy. However, the role of the father in directing the development and well-being of his offspring has come into recent focus. Whereas these studies identify the individual role of each parent in shaping the long-term health of their offspring, few studies have explored the combined influences of both parents on offspring well-being. Such understanding is necessary as parental influences on offspring development extend beyond the direct genetic contributions from the sperm and oocyte. This article reviews our current understanding of the parental contribution to offspring health, exploring some of the mechanisms linking parental well-being with gamete quality, embryo development and offspring health.

Lower Plasmatic Levels of Saturated Fatty Acids and a Characteristic Fatty Acid Composition in the Ovary Could Contribute to the High-Fertility Phenotype in Dummerstorf Superfertile Mice

In recent decades, fertility traits in humans as well as in farm animals have decreased worldwide. As such, it is imperative to know more about the genetics and physiology of increased or high fertility. However, most of the current animal models with reproductive phenotypes describe lower fertility or even infertility (around 99%). The “Dummerstorf high-fertility lines” (FL1 and FL2) are two unique mouse lines selected for higher reproductive performances, more specifically for higher number of pups per litter. We recently described how those superfertile mice managed to increase their reproductive phenotype by doubling the ovulation rate and consequently the litter size compared to the unselected mice of the same founder population. FLs show an unusual estrous cycle length and atypical levels of hormones that link reproduction and metabolism, such as insulin in FL1 and leptin in FL2. Moreover, we described that their higher ovulation rate is mostly due to a higher quality of their oocytes rather than their sheer quantity, as they are characterized by a higher quantity of high-quality oocytes in antral follicles, but the quantity of follicles per ovary is not dissimilar compared to the control. In the present study, we aimed to analyze the lipid composition of the fertility lines from plasma to the gonads, as they can connect the higher reproductive performances with their metabolic atypicalities. As such, we analyzed the fat content of FLs and fatty acid composition in plasma, liver, fat, oocytes of different quality, and granulosa cells. We demonstrated that those mice show higher body weight and increased body fat content, but at the same time, they manage to decrease the lipid content in the ovarian fat compared to the abdominal fat, which could contribute to explaining their ovarian quality. In addition, we illustrate the differences in fatty acid composition in those tissues, especially a lower level of saturated fatty acids in plasma and a different lipid microenvironment of the ovary. Our ongoing and future research may be informative for farm animal biology as well as human reproductive medicine, mostly with cases that present characteristics of lower fertility that could be reversed following the way-of-managing of Dummerstorf high-fertility lines.

Optical imaging detects metabolic signatures associated with oocyte quality

Oocyte developmental potential is intimately linked to metabolism. Existing approaches to measure metabolism in the cumulus oocyte complex (COC) do not provide information on the separate cumulus and oocyte compartments. Development of an assay that achieves this may lead to an accurate diagnostic for oocyte quality. Optical imaging of the autofluorescent cofactors NAD(P)H and FAD provides a spatially resolved indicator of metabolism via the optical redox ratio ($\mathrm{FAD}/\left[\mathrm{NAD}\left(\mathrm{P}\right)\mathrm{H}+\mathrm{FAD}\right]$). This may provide an assessment of oocyte quality. Here, we determined whether the optical redox ratio is a robust methodology for measuring metabolism in the cumulus and oocyte compartments compared with oxygen consumption in the whole COC. We also determined whether optical imaging could detect metabolic differences associated with poor oocyte quality (etomoxir-treated). We used confocal microscopy to measure NAD(P)H and FAD, and extracellular flux to measure oxygen consumption. We found that the optical redox ratio was an accurate reflection of metabolism in the oocyte compartment when compared with oxygen consumption (whole COC). Etomoxir-treated COCs showed significantly lower levels of NAD(P)H and FAD compared to control. While confocal imaging demonstrated the premise, we validated this approach using hyperspectral imaging, which is clinically compatible due to its low energy dose. This confirmed lower NAD(P)H and FAD in etomoxir-treated COCs. When comparing imaged vs non-imaged COCs, subsequent preimplantation development and post-transfer viability were comparable. Collectively, these results demonstrate that label-free optical imaging of metabolic cofactors is a safe and sensitive assay for measuring metabolism and has potential to assess oocyte developmental competence.

Rescue of obesity-induced infertility in female mice by silencing AgRP neurons

Obesity impacts multiple sites of the hypothalamus-pituitary gland-ovary axis (HPO axis) and has become a leading cause of female infertility. However, the critical hypothalamic neurons that participate in the development of obesity-induced infertility have not been well defined yet. Previous studies suggested that metabolic-sensing agouti-related peptide-expressing (AgRP) neurons in the arcuate nucleus (ARC) are hyperactive in diet-induced obesity (DIO) mice. We hypothesize that these neurons may convey metabolic dysfunction onto the HPO axis and contribute to obesity-induced infertility's pathophysiological process. To determine if AgRP neurons in obesity play a necessary role in the development of reproductive impairment in obesity, we used the chemogenetic method to normalize the neuronal activity of AgRP neurons in DIO female mice and test if their fertility can be restored. Our results indicated that chemogenetic inhibition of AgRP neurons could fully rescue the reproductive performance of DIO female mice, as manifested by recovered sex hormonal levels, ovulation, and fecundity. Moreover, we assayed serum AgRP levels in normal-weight and obese women and found elevated AgRP levels in obese subjects, suggesting the correlation between obesity and AgRP neuronal hyperactivity. Our results indicated that AgRP neurons constitute a central node connecting metabolism and reproduction, and dysfunctions of these neurons play a crucial role in reproductive impairment induced by metabolic abnormalities.

Overweight and Fertility: What We Can Learn from an Intergenerational Mouse Obesity Model

The aim of this study was to evaluate the effects of being overweight on the ability to conceive, fertilization rate, and in vivo development of embryos in regularly cycling, spontaneously ovulating, and naturally mated female mice. The study was based on statistical analysis of data collected during 14 experiments with identical design, performed on 319 control and 327 obese mice, developed in an intergenerational model of obesity induction which eliminates the impact of aging and high-fat feeding. Six-week-old mice with a vaginal sperm plug were slaughtered on embryonic days 2, 3, or 4, and the flushed contents of the oviducts and uteri were assessed by stereomicroscopy. The results showed no association between being overweight and the proportion of ovulating or fertilized females. On the other hand, a strong association was found between being overweight and ovulation yield. On embryonic day 2, significantly higher numbers of eggs were recovered from the oviducts of fertilized obese mice. Maternal overweight status was also associated with higher developmental capacities of preimplantation embryos. In conclusion, contrary to studies based on the high-fat-diet model, in female mice fed regular chow, being overweight was associated with an increased ovulation quota and higher developmental rate of fertilized oocytes. Being overweight did not impact ability to conceive. On the other hand, as documented in our previous studies, the quality of oocytes and blastocysts recovered from overweight mice developed in an intergenerational model of obesity was low.

Maladaptation to the transition period and consequences on fertility of dairy cows

After parturition, dairy cows undergo a plethora of metabolic, inflammatory, and immunologic changes to adapt to the onset of lactation. These changes are mainly due to the homeorhetic shift to support milk production when nutrient demand exceeds dietary intake, resulting in a state of negative energy balance. Negative energy balance in postpartum dairy cows is characterized by upregulated adipose tissue modelling, insulin resistance, and systemic inflammation. However, half of the postpartum cows fail to adapt to these changes and develop one or more types of clinical and subclinical disease within 5 weeks after calving, and this is escorted by impaired reproductive performance in the same lactation. Maladaptation to the transition period exerts molecular and structural changes in the follicular and reproductive tract fluids, the microenvironment in which oocyte maturation, fertilization, and embryo development occur. Although the negative effects of transition diseases on fertility are well-known, the involved pathways are only partially understood. This review reconstructs the mechanism of maladaptation to lactation in the transition period, explores their key (patho)physiological effects on reproductive organs, and briefly describes potential carryover effects on fertility in the same lactation.

Impact of obesity on medically assisted reproductive treatments

Increasing evidence has demonstrated that obesity impairs female fertility and negatively affects human reproductive outcome following medically assisted reproduction (MAR) treatment. In the United States, 36.5% of women of reproductive age are obese. Obesity results not only in metabolic disorders including type II diabetes and cardiovascular disease, but might also be responsible for chronic inflammation and oxidative stress. Several studies have demonstrated that inflammation and reactive oxygen species (ROS) in the ovary modify steroidogenesis and might induce anovulation, as well as affecting oocyte meiotic maturation, leading to impaired oocyte quality and embryo developmental competence. Although the adverse effect of female obesity on human reproduction has been an object of debate in the past, there is growing evidence showing a link between female obesity and increased risk of infertility. However, further studies need to clarify some gaps in knowledge. We reviewed the recent evidence on the association between female obesity and infertility. In particular, we highlight the association between fat distribution and reproductive outcome, and how the inflammation and oxidative stress mechanisms might reduce ovarian function and oocyte quality. Finally, we evaluate the connection between female obesity and endometrial receptivity.

Suppressive Role of Lactoferrin in Overweight-Related Female Fertility Problems

The secretory glycoprotein lactoferrin (LF) is suggested to ameliorate overweight regardless of non-genetic or genetic mechanisms. Although maternal overweight represents a key predictor of offspring growth, the efficacy of LF on fertility problems in overweight and obese mothers remains unknown. To address this issue, we examined the effect of LF ingestion by analyzing overweight mice (Institute of Cancer Research (ICR) mice with high-fat diets; HF mice) and obese mice (leptin-deficient mice with type II diabetes; ob/ob mice). Plasma insulin, leptin, glucose, and cholesterol levels were measured, and thermal imaging and histological analysis were employed. The litter size of HF females was reduced due to miscarriage, which was reversed by LF ingestion. In addition, LF ingestion suppressed overweight prevalence in their offspring. The component analysis of the maternal blood demonstrated that glucose concentration in both HF females and their offspring was normalized by LF ingestion, which further standardized the concentration of insulin, but not leptin. LF ingestion was unable to reverse female infertility in ob/ob mice, although their obesity and uterine function were partially improved. Our results indicate that LF upregulates female fertility by reinforcing ovarian and uterine functions in females that are overweight due to caloric surplus.

The Key Role of Peroxisomes in Follicular Growth, Oocyte Maturation, Ovulation, and Steroid Biosynthesis

The absence of peroxisomes can cause disease in the human reproductive system, including the ovaries. The available peroxisomal gene-knockout female mouse models, which exhibit pathological changes in the ovary and reduced fertility, are listed in this review. Our review article provides the first systematic presentation of peroxisomal regulation and its possible functions in the ovary. Our immunofluorescence results reveal that peroxisomes are present in all cell types in the ovary; however, peroxisomes exhibit different numerical abundances and strong heterogeneity in their protein composition among distinct ovarian cell types. The peroxisomal compartment is strongly altered during follicular development and during oocyte maturation, which suggests that peroxisomes play protective roles in oocytes against oxidative stress and lipotoxicity during ovulation and in the survival of oocytes before conception. In addition, the peroxisomal compartment is involved in steroid synthesis, and peroxisomal dysfunction leads to disorder in the sexual hormone production process. However, an understanding of the cellular and molecular mechanisms underlying these physiological and pathological processes is lacking. To date, no effective treatment for peroxisome-related disease has been developed, and only supportive methods are available. Thus, further investigation is needed to resolve peroxisome deficiency in the ovary and eventually promote female fertility.

Cellular Stress Responses in Oocytes: Molecular Changes and Clinical Implications

The oocyte may be exposed to several sources of stress during its growth and maturation, which may lead to reduced fertility. Unfolded protein responses (UPRs) play a central role to maintain cell survival and repair. Transcription of heat shock proteins (HSPs) is a key element to facilitate reestablishment of cellular homeostasis. Unlike somatic cells, cellular mechanisms by which oocytes can sense and respond to stress are not well described. In here, we provide an overview about the impact of cellular stress, particularly due to lipotoxicity, oxidative stress, and heat stress on oocyte developmental competence. Next, we focus on the expression of HSPs in oocytes and their potential role in UPRs in oocytes and embryos. This is based on a comprehensive shotgun proteomic analysis of mature bovine oocytes performed in our laboratory, as well as a literature review. The topic is discussed in light of our understanding of similar mechanisms in other cell types and the limited transcriptional activity in oocytes. More fundamental research is needed both at the transcriptomic and proteomic levels to further understand cell stress response mechanisms in oocytes and early developing embryos, their critical interactions, and their long-term effects. Strategies to provide targeted external support to prevent or reduce cell stress levels during oocyte maturation or early embryo development under maternal metabolic stress conditions should be developed to maximize the odds of producing good quality embryos and guarantee optimal viability.

Obesity and oocyte quality: Significant implications for ART and Emerging mechanistic insights

The prevalence of obesity in adults worldwide, and specifically in women of reproductive age, is concerning given the risks to fertility posed by the increased risk of type 2 diabetes, metabolic syndrome and other non-communicable diseases. Obesity has a multi-systemic impact in female physiology that is characterized by the presence of oxidative stress, lipotoxicity, and the activation of pro-inflammatory pathways, inducing tissue-specific insulin resistance and ultimately conducive to abnormal ovarian function. A higher body mass is linked to Polycystic Ovary Syndrome, dysregulated menstrual cycles, anovulation, and longer time to pregnancy, even in ovulatory women. In the context of ART, compared to women of normal BMI, obese women have worse outcomes in every step of their journey, resulting in reduced success measured as live birth rate. Even after pregnancy is achieved, obese women have a higher chance of miscarriage, gestational diabetes, pregnancy complications, birth defects, and most worryingly, a higher risk of stillbirth and neonatal death. The potential for compounding effects of ART on pregnancy complications and infant morbidities in obese women has not been studied. There is still much debate in the field on whether these poorer outcomes are mainly driven by defects in oocyte quality, abnormal embryo development or an unaccommodating uterine environment, however the clinical evidence to date suggests a combination of all three are responsible. Animal models of maternal obesity shed light on the mechanisms underlaying the effects of obesity on the peri-conception environment, with recent findings pointing to lipotoxicity in the ovarian environment as a key driver of defects in oocytes that have not only reduced developmental competence but long-lasting effects in offspring health.

Dietary Fatty Acid Intakes and the Outcomes of Assisted Reproductive Technique in Infertile Women

Background

The purpose of this study was evaluating the relationship between fatty acid (FA) intakes and the Assisted Reproductive Technique (ART) outcomes in infertile women.

Methods

In this descriptive longitudinal study, a validated food frequency questionnaire (FFQ) was used to measure dietary intakes among 217 women with primary infertility seeking ART treatments at Isfahan Fertility and Infertility Center, Isfahan, Iran. The average number of total and metaphase II (MII) oocytes, the fertilization rate, the ratio of good and bad quality embryo and biochemical and clinical pregnancy were assessed. Analyses were performed using mean, standard deviation, Chi-square test, ANOVA, ANCOVA, logistic regression.

Results

A total of 140 women were finally included in the study. There was a positive relationship between the average number of total and MII oocytes and the amount of total fatty acids (TFAs), saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), linoleic acids, linolenic acids, and oleic acids intakes, while eicosapentaenoic acids (EPAs) and docosahexaenoic acids (DHAs) intakes had an inverse relationship. Consuming more amounts of TFAs, SFAs, PUFAs, MUFAs, linoleic acids, and oleic acids was associated with the lower fertilization rate, whereas the consumption of linolenic acids and EPAs increased the fertilization rate. The ratio of good quality embryo was directly affected by the amount of PUFAs intakes. Additionally, there was a negative correlation between the amount of SFAs intakes and the number of pregnant women.

Conclusion

TFAs, SFA, PUFA, and MUFA intakes could have both beneficial and adverse impacts on ART outcomes.

Uncovering the important role of mitochondrial dynamics in oogenesis: impact on fertility and metabolic disorder transmission

Oocyte health is tightly tied to mitochondria given their role in energy production, metabolite supply, calcium (Ca2+) buffering, and cell death regulation, among others. In turn, mitochondrial function strongly relies on these organelle dynamics once cyclic events of fusion and fission (division) are required for mitochondrial turnover, positioning, content homogenization, metabolic flexibility, interaction with subcellular compartments, etc. Importantly, during oogenesis, mitochondria change their architecture from an "orthodox" elongated shape characterized by the presence of numerous transversely oriented cristae to a round-to-oval morphology containing arched and concentrically arranged cristae. This, along with evidence showing that mitochondrial function is kept quiescent during most part of oocyte development, suggests an important role of mitochondrial dynamics in oogenesis. To investigate this, recent works have downregulated/upregulated in oocytes the expression of key effectors of mitochondrial dynamics, including mitofusins 1 (MFN1) and 2 (MFN2) and the dynamin-related protein 1 (DRP1). As a result, both MFN1 and DRP1 were found to be essential to oogenesis and fertility, while MFN2 deletion led to offspring with increased weight gain and glucose intolerance. Curiously, neither MFN1/MFN2 deficiency nor DRP1 overexpression enhanced mitochondrial fragmentation, indicating that mitochondrial size is strictly regulated in oocytes. Therefore, the present work seeks to discuss the role of mitochondria in supporting oogenesis as well as recent findings connecting defective mitochondrial dynamics in oocytes with infertility and transmission of metabolic disorders.

Influence of maternal and paternal pre-conception overweight/obesity on offspring outcomes and strategies for prevention

Overweight, obesity, and their comorbidities remain global health challenges. When established early in life, overweight is often sustained into adulthood and contributes to the early onset of non-communicable diseases. Parental pre-conception overweight and obesity is a risk factor for overweight and obesity in childhood and beyond. This increased risk likely is based on an interplay of genetic alterations and environmental exposures already at the beginning of life, although mechanisms are still poorly defined. In this narrative review, potential routes of transmission of pre-conceptional overweight/obesity from mothers and fathers to their offspring as well as prevention strategies are discussed. Observational evidence suggests that metabolic changes due to parental overweight/obesity affect epigenetic markers in oocytes and sperms alike and may influence epigenetic programming and reprogramming processes during embryogenesis. While weight reduction in overweight/obese men and women, who plan to become pregnant, seems advisable to improve undesirable outcomes in offspring, caution might be warranted. Limited evidence suggests that weight loss in men and women in close proximity to conception might increase undesirable offspring outcomes at birth due to nutritional deficits and/or metabolic disturbances in the parent also affecting gamete quality. A change in the dietary pattern might be more advisable. The data reviewed here suggest that pre-conception intervention strategies should shift from women to couples, and future studies should address possible interactions between maternal and paternal contribution to longitudinal childhood outcomes. Randomized controlled trials focusing on effects of pre-conceptional diet quality on long-term offspring health are warranted.

Leptin Signaling in the Ovary of Diet-Induced Obese Mice Regulates Activation of NOD-Like Receptor Protein 3 Inflammasome

Obesity leads to ovarian dysfunction and the establishment of local leptin resistance. The aim of our study was to characterize the levels of NOD-like receptor protein 3 (NLRP3) inflammasome activation in ovaries and liver of mice during obesity progression. Furthermore, we tested the putative role of leptin on NLRP3 regulation in those organs. C57BL/6J female mice were treated with equine chorionic gonadotropin (eCG) or human chorionic gonadotropin (hCG) for estrous cycle synchronization and ovary collection. In diet-induced obesity (DIO) protocol, mice were fed chow diet (CD) or high-fat diet (HFD) for 4 or 16 weeks, whereas in the hyperleptinemic model (LEPT), mice were injected with leptin for 16 days (16 L) or saline (16 C). Finally, the genetic obese leptin-deficient ob/ob (+/? and −/−) mice were fed CD for 4 week. Either ovaries and liver were collected, as well as cumulus cells (CCs) after superovulation from DIO and LEPT. The estrus cycle synchronization protocol showed increased protein levels of NLRP3 and interleukin (IL)-18 in diestrus, with this stage used for further sample collections. In DIO, protein expression of NLRP3 inflammasome components was increased in 4 week HFD, but decreased in 16 week HFD. Moreover, NLRP3 and IL-1β were upregulated in 16 L and downregulated in ob/ob. Transcriptome analysis of CC showed common genes between LEPT and 4 week HFD modulating NLRP3 inflammasome. Liver analysis showed NLRP3 protein upregulation after 16 week HFD in DIO, but also its downregulation in ob/ob−/−. We showed the link between leptin signaling and NLRP3 inflammasome activation in the ovary throughout obesity progression in mice, elucidating the molecular mechanisms underpinning ovarian failure in maternal obesity.

Diet normalization or caloric restriction as a preconception care strategy to improve metabolic health and oocyte quality in obese outbred mice

BACKGROUND

Maternal metabolic disorders are linked to reduced metabolic health and oocyte quality. Obese women are advised to lose weight before conception to increase pregnancy chances. However, as human studies show no univocal guidelines, more research is necessary to provide fundamental insights in the consequences of dietary weight loss on oocyte quality. Therefore, we investigated the impact of diet normalization or calorie restricted diet for two, four or six weeks, as preconception care intervention (PCCI), in obese mice on metabolic health and oocyte quality.

METHODS

Outbred female mice were fed a control (CTRL) or high-fat (HF) diet for 7 weeks (7w). Afterwards, HF-mice were put on different PCCIs, resulting in four treatment groups: 1) control diet up to 13w, 2) HF diet up to 13w (HF_HF), switch from a HF (7w) to 3) an ad libitum control diet (HF_CTRL) or 4) 30% calorie restricted control diet (HF_CR) for two, four or six weeks. Body weight, metabolic health, oocyte quality and overall fertility results were assessed.

RESULTS

Negative effects of HF diet on metabolic health, oocyte quality and pregnancy rates were confirmed. HF_CTRL mice progressively improved insulin sensitivity, glucose tolerance, serum insulin and cholesterol from PCCI w2 to w4. No further improvements in metabolic health were present at PCCI w6. However, PCCI w6 showed best oocyte quality improvements. Mature oocytes still showed elevated lipid droplet volume and mitochondrial activity but a significant reduction in ROS levels and ROS: active mitochondria ratio compared with HF_HF mice. HF_CR mice restored overall insulin sensitivity and glucose tolerance by PCCI w4. However, serum insulin, cholesterol and ALT remained abnormal. At PCCI w6, glucose tolerance was again reduced. However, only at PCCI w6, oocytes displayed reduced ROS levels and restored mitochondrial activity compared with HF_HF mice. In addition, at PCCI w6, both PCCI groups showed decreased mitochondrial ultrastructural abnormalities compared with the HF_HF group and restored pregnancy rates.

CONCLUSIONS

Diet normalization for 4 weeks showed to be the shortest, most promising intervention to improve metabolic health. Most promising improvements in oocyte quality were seen after 6 weeks of intervention in both PCCI groups. This research provides fundamental insights to be considered in developing substantiated preconception guidelines for obese women planning for pregnancy.

Postpartum cows showed high oocyte triacylglycerols concurrently with high plasma free fatty acids

Impaired oocyte quality is one of the main causes of low fertility in modern high-yielding dairy cows. One of the potential factors of the impaired oocyte quality is the effects of free fatty acids (FFA). In fact, high FFA supplementation to culture media exacerbated oocyte developmental competence in vitro. Meanwhile, artificially induced high blood FFA levels in heifers did not affect the lipid composition of oocytes in vivo; however, the oocyte lipid profile of postpartum cows has not yet been investigated. Therefore, the profile of lipids involved in energy metabolism, including FFA and triacylglycerols (TAG), and their relationship between plasma and oocytes were compared among cows at different lactation stages. Heifers were used as a control group that was not affected by lactation. Plasma and oocytes were collected from heifers (n = 4) and 14 Holstein cows categorized to the early lactation stage: 25-47 days in milk (DIM) (n = 6), peak lactation stage: 61-65 DIM (n = 4), and middle lactation stage: 160-202 DIM (n = 4). The FFA and TAG profiles of plasma and oocytes were examined by liquid chromatography mass spectrometry. Plasma FFA positively correlated with oocyte TAG (P < 0.05). Plasma FFA and oocyte TAG were significantly higher in cows in the early lactation stage than in heifers (P < 0.05), while the peak and middle lactation stage groups had intermediate levels. The proportion of oleic acid in plasma increased concurrently with elevations in total FFA, while the compositions of oocyte FFA and TAG fatty acyls were constant regardless of plasma FFA concentration or oocyte TAG content. The present results suggest that high postpartum plasma FFA concentrations affect the quantity of oocyte TAG. Taken together with the adverse effects of high FFA concentrations on oocyte developmental competence in vitro, oocyte quality in postpartum cows may be impaired due to high circulating FFA concentrations. These results provide a more detailed understanding of the effects of postpartum high circulating FFA concentrations on the low fertility of cows.

Obesity induces morphological and functional changes in female reproductive system through increases in NF-κB and MAPK signaling in mice

BACKGROUND

Recently, human infertility incidence is increasing in obese women causing it to become an emerging global health challenge requiring improved treatment. There is extensive evidence that obesity caused female reproductive dysfunction is accompanied by an endocrinological influence. Besides, systemic and tissue-specific chronic inflammatory status are common characteristics of obesity. However, the underlying molecular mechanism is unclear linking obesity to infertility or subfertility.

METHODS

To deal with this question, we created an obese mouse model through providing a high fat diet (HFD) and determined the fertility of the obese mice. The morphological alterations were evaluated in both the reproductive glands and tracts, such as uterus, ovary and oviduct. Furthermore, to explore the underlying mechanism of these functional changes, the expressions of pro-inflammatory cytokines as well as the activations of MAPK signaling and NF-κB signaling were detected in these reproductive tissues.

RESULTS

The obese females were successful construction and displayed subfertility. They accumulated lipid droplets and developed morphological alterations in each of their reproductive organs including uterus, ovary and oviduct. These pathological changes accompanied increases in pro-inflammatory cytokine expression levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in all of these sites. Such effects also accompanied increases in nuclear factor kappa B (NF-kB) expression and mitogen-activated protein kinase (MAPK) signaling pathway stimulation based on uniform time dependent increases in the NF-κB (p-NF-κB), JNK (p-JNK), ERK1/2 (p-ERK) and p38 (p-p38) phosphorylation status.

CONCLUSIONS

These HFD-induced increases in pro-inflammatory cytokine expression levels and NF-κB and MAPKs signaling pathway activation in reproductive organs support the notion that increases of adipocytes resident and inflammatory status are symptomatic of female fertility impairment in obese mice.

Dyslipidemia Is Negatively Associated With the Cumulative Live-Birth Rate in Patients Without PCOS Following IVF/ICSI

Objective: To evaluate the effect of dyslipidemia on the cumulative live-birth rate (cLBR) in patients without polycystic ovary syndrome (PCOS) undergoing in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET) cycles. Methods: A total of 1,132 patients from the Yantai Yuhuangding Hospital Affiliated to Qingdao University from January 2016 to December 2017 were retrospectively included. The subjects were distributed into two groups based on their lipid profiles, namely, dyslipidemia group (n = 195) and control group (n = 937). The clinical and laboratory parameters of the two groups were analyzed, and a multivariate logistic regression analysis of the cLBR was conducted. In addition, subgroup analysis was carried out to avoid deviation according to the body mass index (BMI). Results: Patients with dyslipidemia had significantly greater BMI and longer duration of infertility, as well as lower antral follicle count and basal follicle-stimulating hormone level compared with patients without dyslipidemia. Stratified analysis showed that dyslipidemia was associated with a significantly higher total gonadotrophin dosage required for ovarian stimulation as well as lower number of oocytes retrieved, independent of obesity. The live-birth rate in fresh cycle and cLBR were higher in the control group, although the difference between the groups was not significant (54.9% vs. 47.3%, p = 0.116; 67.6% vs. 62.1%, p = 0.138). However, multivariate logistic regression analysis adjusting for potential confounders showed that dyslipidemia was negatively associated with cLBR (OR, 0.702, 95% CI, 0.533-0.881, p = 0.044). Conclusion: Our findings demonstrate for the first time that dyslipidemia has a deleterious impact on cLBR, independent of obesity, in non-PCOS population considered to have good prognosis. Assessment of serum lipid profiles as well as the provision of nutritional counseling is essential for increasing successful outcomes in assisted reproductive techniques.

Pathophysiology and management of classic galactosemic primary ovarian insufficiency

Classic galactosemia is an inborn error of carbohydrate metabolism associated with early-onset primary ovarian insufficiency (POI) in young women. Our understanding of the consequences of galactosemia upon fertility and fecundity of affected women is expanding, but there are important remaining gaps in our knowledge and tools for its management, and a need for continued dialog so that the special features of the condition can be better managed. Here, we review galactosemic POI and its reproductive endocrinological clinical sequelae and summarize current best clinical practices for its management. Special consideration is given to the very early-onset nature of the condition in the pediatric/adolescent patient. Afterward, we summarize our current understanding of the reproductive pathophysiology of galactosemia, including the potential action of toxic galactose metabolites upon the ovary. Our work establishing that ovarian cellular stress reminiscent of endoplasmic reticulum (ER) stress is present in a mouse model of galactosemia, as well as work by other groups, are summarized.

LAY SUMMARY

Patients with the condition of classic galactosemia need to maintain a strict lifelong diet that excludes the sugar galactose. This is due to having mutations in enzymes that process galactose, resulting in the buildup of toxic metabolic by-products of the sugar. Young women with classic galactosemia often lose the function of their ovaries very early in life (termed 'primary ovarian insufficiency'), despite adherence to a galactose-restricted diet. This means that in addition to the consequences of the disease, these women also face infertility and the potential need for hormone replacement therapy. This article summarizes current strategies for managing the care of galactosemic girls and women and also what is known of how the condition leads to early primary ovarian insufficiency.

Albumin used in human IVF contain different levels of lipids and modify embryo and fetal growth in a mouse model

PURPOSE

Different commercial human embryo culture mediums can alter embryo quality and change birthweight. One component that could be contributing to variations but is not widely investigated is human serum albumin (HSA). HSA plays a multitude of roles during embryo culture and is a carrier for molecules including lipids. It remains unclear if lipid composition of HSA varies among commercial products and its effects on embryo quality, implantation, and fetal outcomes are relatively unknown.

METHODS

Utilizing a mouse model of embryo culture, we cultured zygotes until the blastocyst stage (72-h culture) in G1/G2 containing either Vitrolife HSA, Sage HSA, or Recombinant HSA at 10%. Blastocyst quality (development, total cell number, superoxide generation), blastocyst lipid content (neutral lipids, non-esterified fatty acids, phospholipids, and triglycerides), implantation, and fetal lengths and weights were assessed. Fatty acid quantification of HSA source was assessed by standard thin-layer chromatography.

RESULTS

Sage HSA had the greatest fatty acid composition, with an eightfold increase in saturated fatty acids. This coincided with reduced blastocyst development, increased superoxide generation, neutral lipids and triglycerides levels of blastocysts, and decreased implantation rates (p < 0.05). Unexpectedly, while Recombinant HSA had the lowest overall lipids it had 70-fold increase in palmitoleic acid and the lowest fetal weights (p < 0.05).

CONCLUSION

Indicates the importance of a balance between different types/amount of lipids, and an "optimal ratio" required for embryo and fetal development. Therefore, the lipid content of HSA should be considered when choosing a suitable HSA source for use in clinical IVF.

Revisiting the Impact of Local Leptin Signaling in Folliculogenesis and Oocyte Maturation in Obese Mothers

The complex nature of folliculogenesis regulation accounts for its susceptibility to maternal physiological fitness. In obese mothers, progressive expansion of adipose tissue culminates with severe hyperestrogenism and hyperleptinemia with detrimental effects for ovarian performance. Indeed, maternal obesity is associated with the establishment of ovarian leptin resistance. This review summarizes current knowledge on potential effects of impaired leptin signaling throughout folliculogenesis and oocyte developmental competence in mice and women.