Obesity and female fertility: a primary care perspective

High-fat diet-negative impact on female fertility: from mechanisms to protective actions of antioxidant matrices

Introduction

Excessive calorie intake poses a significant threat to female fertility, leading to hormonal imbalances and reproductive challenges. Overconsumption of unhealthy fats exacerbates ovarian dysfunction, with an overproduction of reactive oxygen species causing oxidative stress, impairing ovarian follicle development and leading to irregular ovulation and premature ovarian failure. Interest in biological matrices with high antioxidant properties to combat diet-related oxidative stress has grown, as they contain various bioactive factors crucial for neutralizing free radicals potentially preventing female reproductive health. This systematic review evaluates the female reproductive impact of biological matrices in mitigating oxidative damages induced by over calory habits and, in particular, high fat diets.

Methods

A comparative approach among mammalian models was utilized to interpret literature available data. This approach specifically investigates the antioxidant mechanisms of biological matrices on early and late ovarian folliculogenesis, under physiological and hormone-induced female reproductive cycle. Adhering to the PRISMA 2020 guidelines, only English-language publications from peer-reviewed international indexes were considered.

Results

The analysis of 121 publications meeting the inclusion criteria facilitated the identification of crucial components of biological matrices. These components, including carbocyclic sugars, phytonutrients, organosulfur compounds, and vitamins, were evaluated for their impact on ovarian follicle resilience, oocyte quality, and reproductive lifespan. The detrimental effects of oxidative stress on female fertility, particularly exacerbated by high saturated fat diets, are well-documented. In vivo studies across mammalian preclinical models have underscored the potential of antioxidants derived from biological matrices to mitigate diet-induced conditions. These antioxidants enhance steroidogenesis and ovarian follicle development, thereby improving oocyte quality. Additionally, discussions within these publications emphasized the clinical significance of these biological matrices, translating research findings into practical applications for female health.

Conclusion

Further research is essential to fully exploit the potential of these matrices in enhancing female reproduction and mitigating the effects of diets rich in fatty acids. This requires intensified in vitro studies and comprehensive collection of in vivo data before clinical trials. The promotion of ovarian resilience offers promising avenues for enhancing understanding and advancing female reproductive health world-wide.

The Silent Threat to Women's Fertility: Uncovering the Devastating Effects of Oxidative Stress

Oxidative stress (OS), which arises through an imbalance between the formation of reactive oxygen species (ROS) and antioxidant defenses, plays a key role in the pathophysiology of female infertility, with the latter constituting just one of a number of diseases linked to OS as a potential cause. The aim of the present article is to review the literature regarding the association between OS and female infertility. Among the reproductive diseases considered are endometriosis and polycystic ovary syndrome (PCOS), while environmental pollutants, lifestyle variables, and underlying medical conditions possibly resulting in OS are additionally examined. Current evidence points to OS likely contributing to the pathophysiology of the above reproductive disorders, with the amount of damage done by OS being influenced by such variables as duration and severity of exposure and the individual's age and genetic predisposition. Also discussed are the processes via which OS may affect female fertility, these including DNA damage and mitochondrial dysfunction. Finally, the last section of the manuscript contains an evaluation of treatment options, including antioxidants and lifestyle modification, capable of minimizing OS in infertile women. The prime message underlined by this review is the importance of considering OS in the diagnosis and treatment of female infertility. Further studies are, nevertheless required to identify the best treatment regimen and its ideal duration.

Obesogenic diet in mice compromises maternal metabolic physiology and lactation ability leading to reductions in neonatal viability

AIMS

Diets containing high-fat and high sugar (HFHS) lead to overweight/obesity. Overweight/obesity increases the risk of infertility, and of the pregnant mother and her child for developing metabolic conditions. Overweight/obesity has been recreated in mice, but most studies focus on the effects of chronic, long-term HFHS diet exposure. Here, we exposed mice to HFHS from 3 weeks prior to pregnancy with the aim of determining impacts on fertility, and gestational and neonatal outcomes.

METHODS

Time-domain NMR scanning was used to assess adiposity, glucose, and insulin tolerance tests were employed to examine metabolic physiology, and morphological and proteomic analyses conducted to assess structure and nutrient levels of maternal organs and placenta.

RESULTS

Fertility measures of HFHS dams were largely the same as controls. HFHS dams had increased adiposity pre-pregnancy, however, exhibited exacerbated lipolysis/hyper-mobilization of adipose stores in late pregnancy. While there were no differences in glucose or insulin tolerance, HFHS dams were hyperglycemic and hyperinsulinemic in pregnancy. HFHS dams had fatty livers and altered pancreatic islet morphology. Although fetuses were hyperglycemic and hyperinsulinemic, there was no change in fetal growth in HFHS dams. There were also reductions in placenta formation. Moreover, there was increased offspring loss during lactation, which was related to aberrant mammary gland development and milk protein composition in HFHS dams.

CONCLUSIONS

These findings are relevant given current dietary habits and the development of maternal and offspring alterations in the absence of an increase in maternal weight and adiposity during pregnancy, which are the current clinical markers to determine risk across gestation.

Fertility, pregnancy and post partum management after bariatric surgery: a narrative review

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Of the women who gave birth in Australia in 2018, 47% had overweight or obesity, with obesity being associated with both maternal and fetal complications.

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Bariatric surgery improves fertility and some pregnancy‐related outcomes.

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Following bariatric surgery, pregnancy should be delayed by at least 12–18 months due to adverse pregnancy outcomes associated with rapid weight loss.

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Contraception should be prescribed after bariatric surgery, although the effectiveness of the oral contraceptive pill may be reduced due to malabsorption and contraceptive devices such as intrauterine devices should be considered as first line therapy.

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After bariatric surgery, women should undergo close monitoring for nutritional insufficiencies before, during and after pregnancy. Expert opinion recommends these women undergo dietary assessment and supplementation to prevent micronutrient deficiencies.

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Bariatric surgeons, bariatric medical practitioners, bariatric dieticians, the patient’s usual general practitioner, obstetricians, and maternity specialists should be involved to assist in the multidisciplinary management of these complex patients.

DLK1 and Nesfatin-1 levels and the relationship with metabolic parameters in polycystic ovary syndrome: Prospective, controlled study

Objective

Delta-like 1 (DLK1) is known to inhibit adipocyte differentiation and nesfatin-1 is a neuropeptide that plays a role in the regulation of nutrition and metabolism. We aimed to assess both the levels of DLK1 and nesfatin-1 in polycystic ovary syndrome (PCOS) and determine the association of DLK1 and nesfatin-1 with metabolic parameters.

Materials and Methods

Forty-four patients with PCOS and 40 healthy women as the control group were included in this study. Venous blood samples of the participants were collected, and hormonal, metabolic parameters, DLK1 and nesfatin-1 blood levels were determined. Anthropometric parameters were also determined. For a double comparison, the Mann-Whitney U test was used for non-parametric numerical data, and Student's t-test was used for parametric numerical data. Bivariate correlations were investigated using Spearman's correlation analysis. The diagnostic performance of the parameters was evaluated using receiver operating characteristic curve analysis.

Results

The findings showed that DLK1 and nesfatin-1 levels were lower among the PCOS group, and the differences in these values were found to be statistically significant. A significant negative correlation was found between DLK1 levels and body mass index (BMI), waist/hip ratio, visceral adiposity index (VAI), fasting serum insulin (FSI), homeostasis model of assessment-insulin resistance (HOMA-IR) and triglyceride levels. A significant negative correlation was found between nesfatin-1 levels and BMI, VAI, FSI, HOMA-IR and triglyceride.

Conclusion

The findings showed that DLK1 and nesfatin-1 levels were lower in PCOS. Based on this study, DLK1 may be culpable for metabolic disorders in PCOS and can be a novel marker for PCOS in the future.

Nesfatin-1 levels and metabolic markers in polycystic ovary syndrome

Nesfatin-1 is a novel hormone synthesized in hypothalamus and several other specific organs to regulate eating habits, appetite and is thought to be related to ovarian functions. In our study, we aimed to evaluate the nesfatin-1 levels with other metabolic parameters in polycystic ovary syndrome (PCOS), a condition that is known to be related to both ovarian functions and obesity. Study subjects were chosen from the women attended to the Obstetrics and Gynecology Department of Istanbul Bilim University, Avrupa Florence Nightingale Hospital. Thirty-five healthy control subjects and 55 PCOS patients were included. Blood samples were obtained on the 3rd day of the menstrual cycle. Luteinizing hormone (LH), follicle stimulating hormone (FSH), free testosterone (FT), dehydroepiandrosterone sulfate (DHEA-S), insulin, fasting blood glucose (FBG), high density lipoprotein (HDL), low density lipoprotein (LDL), triglycerides (TG), sex hormone binding globulin (SHBG) levels were measured; homeostatic model assessment-insulin resistance (HOMA-IR) value was calculated. The nesfatin-1 levels were measured by competitive inhibition ELISA method. Due to our results, PCOS patients were having lower nesfatin-1 levels compared to the control group and this was not seemed to be related to body mass index (BMI) levels. This is an important result to be investigated in larger study groups and is related to other metabolic markers.

Prior caloric restriction increases survival of prepubertal obese- and PCOS-prone rats exposed to a challenge of time-limited feeding and physical activity

We hypothesized that a polycystic ovary syndrome (PCOS) background associated with obese-prone genotype, coupled with preconditioning by caloric restriction, would confer a survival benefit in genetically prepubertal obese/PCOS (O/PCOS)-prone rats faced with an unpredictable challenge of food shortage. Female, juvenile JCR:LA-cp rats, O/PCOS- and lean-prone, were exposed to 1.5 h of daily meals and 22.5 h of voluntary wheel-running, a procedure that leads to activity anorexia (AA). One week before the AA challenge (AAC), O/PCOS-prone rats were freely fed (O/PCOS-FF) or pair fed (O/PCOS-FR) to lean-prone, free-feeding animals (Lean-FF). O/PCOS-FR and lean-prone, food-restricted (Lean-FR) groups were matched on relative average caloric intake. Animals were removed from protocol at 75% of initial body weight (starvation criterion) or after 14 days (survival criterion). The AAC induced weight loss in all rats, but there were significant effects of both genotype and feeding history on weight loss (lean-prone rats exhibited a higher rate of weight loss than O/PCOS-prone; P < 0.001), and rats with prior caloric restriction retained more weight than those free fed previously (90.68 ± 0.59% vs. 85.47 ± 0.46%; P < 0.001). The daily rate of running was higher in lean-prone rats compared with O/PCOS-prone. This difference in running rate correlated with differences in mean days of survival. All O/PCOS-FR rats survived at day 14. O/PCOS-FF rats survived longer (10.00 ± 0.97 days) than Lean-FR (6.17 ± 1.58 days) and Lean-FF (4.33 ± 0.42 days) rats (P < 0.05). Thus preconditioning by caloric restriction induces a substantial survival advantage, beyond genotype alone, in prepubertal O/PCOS-prone rats.

The endocannabinoid pathway and the female reproductive organs

Endocannabinoids are endogenous ligands of cannabinoid, vanilloid and peroxisome proliferator-activated receptors that activate multiple signal transduction pathways. Together with their receptor and the enzymes responsible for their synthesis and degradation, these compounds constitute the endocannabinoid system that has been recently shown to play, in humans, an important role in modulating several central and peripheral functions including reproduction. Given the relevance of the system, drugs that are able to interfere with the activity of endocannabinoids are currently considered as candidates for the treatment of various diseases. In this review, we will summarise the current knowledge regarding the effects of endocannabinoids in female reproductive organs. In particular, we will focus on some newly reported mechanisms that can affect endometrial plasticity both in physiological and in pathological conditions.

High fat diet affects reproductive functions in female diet-induced obese and dietary resistant rats

The incidence of ovulatory disorders is common in obese animal models. The mechanism behind this effect is unclear. We hypothesised that a high-fat (HF) diet induces alterations in neuroendocrine mechanisms resulting in anovulation in diet-induced obese (DIO) animals. Adult female DIO and diet-resistant (DR) rats were fed either chow or a HF diet (45% calories from fat) for 6 weeks. Oestrous cyclicity and body weight were monitored regularly. At the end of treatment, rats were implanted with a jugular catheter to monitor luteinising hormone (LH) levels on the day of pro-oestrous. Rats were sacrificed on the next pro-oestrous, and their brains and ovaries were collected. Plasma from trunk blood was analysed for oestradiol and leptin concentrations. Ovaries were fixed and sectioned for histological analysis. Brains were removed, frozen and sectioned, and norepinephrine (NE) concentrations in discrete hypothalamic areas were measured using high-performance liquid chromatography with electrochemical detection. A HF diet exposure affected oestrous cyclicity in both DIO and DR rats, with the effect being more pronounced in DIO animals. HF diet exposure increased leptin levels in both DIO and DR rats. Oestradiol levels were low in the DIO-HF group. NE levels in the hypothalamus were unaffected by HF diet or genotype. A normal LH surge was observed in DR-Chow rats and LH levels were low in the remaining groups. These results lead to the conclusion that DIO rats have an inherently reduced reproductive capacity and exposure to a HF diet decreases it further. A reduction in oestradiol and LH surge levels could contribute to this effect; however, the underlying mechanisms need to be investigated further.

Endocannabinoids and pregnancy

Acylethanolamides such as anandamide (AEA), and monoacylglycerols like 2-arachidonoylglycerol are endocannabinoids that bind to cannabinoid, vanilloid and peroxisome proliferator-activated receptors. These compounds, their various receptors, the purported membrane transporter(s), and related enzymes that synthesize and degrade them are collectively referred to as the "endocannabinoid system (ECS)". Poorly defined cellular and molecular mechanisms control the biological actions of the ECS. Over the last decade evidence has been emerging to suggest that the ECS plays a significant role in various aspects of human reproduction. In this review, we summarize our current understanding of this role especially the involvement of AEA and related ECS elements in regulating oogenesis, embryo oviductal transport, blastocyst implantation, placental development and pregnancy outcomes, and sperm survival, motility, capacitation and acrosome reaction. Additionally, the possibility that plasma and tissue AEA and other cannabinoids may represent reliable diagnostic markers of natural and assisted reproduction and pregnancy outcomes in women will be discussed.