FSH/AMH Ratio and Adipocyte Size are Linked to Ovarian Dysfunction

Impact of bariatric surgery on ovarian reserve markers and its correlation with nutritional parameters and adipokines

Introduction

A reduction in anti-müllerian hormone (AMH) levels at short-term after bariatric surgery (BS) has been previously described. However, an assessment of ovarian reserve at longer-follow up, and a comprehensive evaluation of the potentially implicated factors has not been reported.

Design

Prospective cohort study.

Materials and methods

Twenty women aged 18-40 years with BMI 43.95 kg/m2 undergoing BS were studied at baseline (BS0), and at 1 month (BS1), 4 months (BS2), 12 months (BS3), and 24-36 months (BS4) after the surgery. Anthropometrics, reproductive hormones (AMH, FSH, LH, estradiol, testosterone, SHBG, androstenedione), metabolic parameters (adiponectin, leptin, ghrelin, insulin), and nutritional blood parameters (markers of nutritional status, vitamins, and minerals) were obtained at each study time point. Antral follicular count (AFC) was assessed by ultrasonography at BS0, BS3, and BS4. Mixed models were used for analysis of longitudinal data.

Results

The mean AMH level was 3.88 ng/mL at BS0, decreased at BS3 (mean= 2.59 ng/mL; p=0.009), and remained stable between BS3 and BS4 (mean= 2.96 ng/mL; p=0.409). We also observed a non-significant decrease in AFC at BS3 (mean=26.14 at BS0, mean 16.81 at BS3; p=0.088) that remained stable at BS4 (mean= 17.86; p=0.731). Mixed models analysis showed: (a) a decrease in 10 kg of body weight was associated with an average decrease of 0.357 ng/mL in AMH (p=0.014); (b) a decrease in 1 BMI point was associated with an average decrease of 0.109 ng/mL in AMH (p=0.005); (c) an increase in 1 µg/mL of adiponectin was associated with an average decrease of 0.091 ng/ml in AMH (p=0.041) Significant positive correlations were found between the AMH levels after BS and plasma concentrations of testosterone, free androgen index, insulin and HOMA index. No significant correlations were detected between AMH levels and nutritional parameters.

Conclusions

Our results were in line with previous observations, showing that AMH levels decreased significantly at 12 months after bariatric surgery, in parallel with a non-significant reduction in AFC. Both ovarian reserve markers showed a later stabilization up to the end of the study. Of note, postoperative AMH levels were positively correlated with key androgen and insulin resistance-related parameters.

Association between environmental pollutants and the FSH/AMH ratio as a marker of ovarian reserve

The ovarian function decreases with age, and various markers, such as follicle stimulating hormone, inhibin B, antral follicle count, and anti-Müllerian hormone, are used for its evaluation. Recently, exposure to various environmental pollutants in daily life has been reported as an important cause of ovarian function decline. Therefore, the present study aimed to confirm the effect of environmental pollutants on the relationship between age and decline in ovarian function. The exposure levels of 16 environmental pollutants were evaluated in women aged 26-40 years, and the AMH levels and FSH/AMH ratios were used as markers for the decline of ovarian function. The participants were divided into two groups: low-level or high-level for each environmental pollutant if their exposure level was below or above the median respectively. The slope of the decrease or increase in the AMH level and FSH/AMH ratio of each group with age was evaluated. The FSH/AMH ratio better presented the difference in the rate of change with age in each group than did AMH alone. In particular, the rate of change in the FSH/AMH ratio increased 5.2 and 3.7 times (p<0.05) in the group exposed to high levels of the volatile organic compound metabolite, trans, trans-muconic acid and the polycyclic aromatic hydrocarbons metabolite, 2-hydroxynaphthalene, respectively, than in the low-level exposure groups for those metabolites. This study confirmed that environmental pollutants influenced the rate of change in the FSH/AMH ratio with age. Further studies on larger populations are necessary in the future.

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.

A Systematic Review of the Effects of High-Fat Diet Exposure on Oocyte and Follicular Quality: A Molecular Point of View

Worldwide, infertility affects between 10 and 15% of reproductive-aged couples. Female infertility represents an increasing health issue, principally in developing countries, as the current inclinations of delaying pregnancy beyond 35 years of age significantly decrease fertility rates. Female infertility, commonly imputable to ovulation disorders, can be influenced by several factors, including congenital malformations, hormonal dysfunction, and individual lifestyle choices, such as smoking cigarettes, stress, drug use and physical activity. Moreover, diet-related elements play an important role in the regulation of ovulation. Modern types of diet that encourage a high fat intake exert a particularly negative effect on ovulation, affecting the safety of gametes and the implantation of a healthy embryo. Identifying and understanding the cellular and molecular mechanisms responsible for diet-associated infertility might help clarify the confounding multifaceted elements of infertility and uncover novel, potentially curative treatments. In this view, this systematic revision of literature will summarize the current body of knowledge of the potential effect of high-fat diet (HFD) exposure on oocyte and follicular quality and consequent female reproductive function, with particular reference to molecular mechanisms and pathways. Inflammation, oxidative stress, gene expression and epigenetics represent the main mechanisms associated with mammal folliculogenesis and oogenesis.

Tributyltin and high-refined carbohydrate diet lead to metabolic and reproductive abnormalities, exacerbating premature ovary failure features in the female rats

Exposure to the obesogen tributyltin (TBT) alone or high carbohydrate diet (HCD) alone leads to obesity and reproductive complications, such as premature ovary failure (POF) features. However, little is known about interactions between TBT and nutrition and their combined impact on reproduction. In this study, we assessed whether acute TBT and HCD exposure results in reproductive and metabolic irregularities. Female rats were treated with TBT (100 ng/kg/day) and fed with HCD for 15 days and metabolic and reproductive outcomes were assessed. TBT and HCD rats displayed metabolic impairments, such as increased adiposity, abnormal lipid profile and triglyceride and glucose (TYG) index, worsening adipocyte hypertrophy in HCD-TBT rats. These metabolic consequences were linked with reproductive disorders. Specifically, HCD-TBT rats displayed irregular estrous cyclicity, high follicle-stimulating hormone (FSH) levels, low anti-Müllerian hormone (AMH) levels, reduction in ovarian reserve, and corpora lutea (CL) number, with increases in atretic follicles, suggesting that HCD-TBT exposure exacerbated POF features. Further, strong negative correlations were observed between adipocyte hypertrophy and ovarian reserve, CL number and AMH levels. HCD-TBT exposure resulted in reproductive tract inflammation and fibrosis. Collectively, these data suggest that TBT plus HCD exposure leads to metabolic and reproductive abnormalities, exacerbating POF features in female rats.

Whole-slide image analysis outperforms micrograph acquisition for adipocyte size quantification

The distinction between biological processes of adipose tissue expansion is crucial to understanding metabolic derangements, but a robust method for quantifying adipocyte size has yet to be standardized. Here, we compared three methods for histological analysis in situ: one conventional approach using individual micrographs acquired by digital camera, and two with whole-slide image analysis pipelines involving proprietary (Visiopharm) and open-source software (QuPath with a novel ImageJ plugin). We found that micrograph analysis identified 10–40 times fewer adipocytes than whole-slide methods, and this small sample size resulted in high variances that could lead to statistical errors. The agreement of the micrograph method to measure adipocyte area with each of the two whole-slide methods was substantially less (R² of 0.6644 and 0.7125) than between the two whole-slide methods (R² of 0.9402). These inconsistencies were more pronounced in samples from high-fat diet fed mice. While the use of proprietary software resulted in the highest adipocyte count, the lower cost, ease of use, and minimal variances of the open-source software provided a distinct advantage for measuring the number and size of adipocytes. In conclusion, we recommend whole-slide image analysis methods to consistently measure adipocyte area and avoid unintentional errors due to small sample sizes.