Amino acid signatures in relation to polycystic ovary syndrome and increased risk of different metabolic disturbances

Neuroendocrine mechanisms responsible for elevated gonadotrophin-releasing hormone and luteinising hormone pulses in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the leading cause of anovulatory infertility in premenopausal individuals with ovaries worldwide. Despite the diagnostic features of anovulation, ovarian cysts, and hyperandrogenemia, which indicate that ovary dysfunction is the cause of the syndrome, changes in central neuroendocrine circuits are a significant cause of PCOS pathology. Specifically, cells in the hypothalamus have a diminished ability to transmit negative feedback signals from gonadal sex steroid hormones to gonadotropin-releasing hormone (GnRH) neurons. This results in an elevated frequency of pulsatile hypothalamic GnRH and pituitary luteinizing hormone (LH) secretion, leading to ovarian hyperandrogenism and ovulatory dysfunction. In recent years, preclinical research in animal models has rapidly advanced our understanding of the neural mechanisms underlying GnRH pulse generation with the identification of KNDy cells-a unique cell population in the hypothalamus expressing the neuropeptides kisspeptin, neurokinin B and dynorphin. As a result, therapeutics targeting KNDy cell signaling have emerged as a promising avenue for treating GnRH/LH hypersecretion in PCOS patients. However, the precise central changes underpinning impaired negative feedback regulation of GnRH pulse generation in PCOS patients are still unclear. Evidence from both the clinic and animal models suggests that changes in the regulation of KNDy cells may be directly responsible for elevated GnRH and LH pulse frequency in PCOS. However, other cell populations regulating GnRH secretion may also be involved. This review provides an overview of our current understanding of the aetiology and contribution of neuroendocrine dysfunction in PCOS pathology. It also examines the evidence for neural mechanisms underlying GnRH/LH hypersecretion, which may serve as central targets in developing novel treatments. Finally, this review highlights key knowledge gaps that are hindering the development of preventive and curative interventions.

The Role of Aromatic Amino Acids in Polycystic Ovary Syndrome through Patients' Blood Metabolic Profiling: A Systematic Review of the Past Five Years

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in women of reproductive age that encompasses a multitude of signs and symptoms, including hyperandrogenism, polycystic ovarian morphology, ovulatory dysfunction, and insulin resistance. The study aims to explore the role of aromatic amino acid (AAA) disorders in the syndrome. A systematic search on the databases Scopus, PubMed, and Google Scholar until 20 July 2024 over the past 5 years regarding metabolomic studies on PCOS patients' blood and the status of AAAs resulted in 12 related papers. Our review showed that AAA metabolic pathways are dysregulated, and their levels in the blood serum and plasma of PCOS patients in most studies are elevated due to inflammation and oxidative stress which, assisted by gut dysbiosis, give rise to insulin resistance that develops into PCOS. AAA abnormalities can also directly induce the defining symptoms of the syndrome through diminished neurotransmitter availability and impaired signaling. According to our review, AAA perturbations are detected in every stage of PCOS pathophysiology, making them valuable biomarkers for early diagnosis and management of the syndrome. Further investigation of the biological function, role, and impact of AAAs, probably alongside other metabolites, including BCAAs, could lead to the discovery of new tools for preventing and managing PCOS symptoms.

Branched-chain and Aromatic Amino Acids in Blood and Seminal Plasma are Associated with Sperm Parameters; A Practice within a Fertility Clinic Considering the Metabolic Syndrome

The metabolomic approach has recently been used in the assessment of semen quality and male fertility. Additionally, the crucial roles of branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) in metabolic syndrome (MetS) were reported. However, little information exists about the association between BCAAs and AAAs with semen parameters, particularly in men with and without MetS. Our objective was to explore the association between BCAAs and AAAs in blood and seminal plasma and sperm parameters in men with MetS (MetS +) and without MetS (MetS-). In a cross-sectional study between January-July 2022, we investigated 98 men (age: 25-42 years; MetS + : n = 28 and MetS-: n = 70) at Royan Institute, Tehran, Iran. All participants underwent anthropometric indices measurements using standard protocols. From each participant, a single fasting blood sample was collected on the same day that the semen sample was collected. The BCAAs and AAAs in blood and seminal plasma were measured using high-performance liquid chromatography (HPLC). The aromatase activity (total testosterone/ estradiol ratio) was significantly lower in MetS + (0.16) than MetS- (0.35) (p = 0.016). Semen parameters were similar between the MetS + and the MetS- groups. All BCAA and AAA family members, except tryptophan, were higher in the blood plasma of men with metabolic syndrome. Meanwhile, the seminal plasma of BCAA and AAAs were similar. Intriguingly, Valine in blood (r = -0.329; p < 0.001) and seminal (r = -0.237; p < 0.05) plasma were correlated with abnormal sperm morphology in patients without metabolic syndrome (MetS-). Further research is necessary to validate these findings and to explore the underlying mechanisms and interactions between the plasma BCAAs and AAAs and sperm parameters.

The impact of GABA and GABAergic pathway in polycystic ovary syndrome: a systematic review

Emerging evidence indicates that dysfunction of the gamma-aminobutyric acid (GABA)ergic pathway may contribute to the pathophysiology of polycystic ovary syndrome (PCOS), and GABA demonstrates potential in the management of PCOS symptoms. This systematic review aimed to determine the role of the GABAergic pathway in PCOS and evaluate the impact of GABA on improving the condition. Web of Science, Embase, Scopus, Cochrane, and PubMed databases were systematically searched for experimental studies, clinical trials, animal studies, and cellular investigations. The search was conducted for relevant English-language manuscripts, published up to February 2024, using keywords, such as "polycystic ovary syndrome", PCOS, "gamma-aminobutyric acid" and GABA. Quality assessment of the included studies was performed using the Cochrane Collaboration's tool and the Newcastle-Ottawa scale. The results indicate that GABAergic dysfunction adversely affects gonadotrophin-releasing hormone neuronal activity, leading to hormonal imbalances and reproductive issues. Prenatal androgen exposure and kisspeptin signaling influence GABAergic transmission to GnRH neurons, thereby linking GABA to the pathogenesis of PCOS. Additionally, GABAergic signaling affects peripheral tissues relevant to PCOS, including the immune system, gut-brain axis, and ovaries. GABA supplementation has demonstrated potential benefits in enhancing metabolic and reproductive health, such as reducing insulin resistance and modulating sex hormone levels, as supported by animal models and clinical studies involving females with PCOS. The GABAergic signaling pathway may represent a promising therapeutic target for the management of PCOS. Nevertheless, further studies are required to validate these findings and deepen our understanding of the role of GABA in the pathogenesis and treatment of PCOS.

Polycystic Ovarian Syndrome: A Review of Multi-omics Analyses

Polycystic Ovary Syndrome (PCOS) is among the most prevalent endocrinological abnormalities of young females, posing a grave public health challenge to the society. The objective of the present literature review is to analyze the enormous amount of information available by way of numerous multi-omic studies, and to explore a meaningful relationship between various factors such as genetic, proteomic, environmental etc. to understand the multifactorial metabolic disorder in a proper manner. Detailed literature search was done in various science article repositories and biomedical databases such as PubMed, Google Scholar, BioMed Central, Embase etc. by using several keywords in whole gamut of combinations. PCOS is a heritable disease. It manifests as a result of a combination of several intricately inter-linked symptoms such as anovulation, obesity, type II diabetes, hyperandrogenism, polycystic ovaries etc., the last one being the main manifestation of the disease, thus leading to infertility among several other complications. Such a multifactorial metabolic disorder with extreme symptomatic heterogeneity cannot be fully explained solely based on symptoms or genetic variations; thus, giving some space of thought to other factors such as epigenetic, microbiomic factors etc. playing a role in the causation of the disease. The present scientific survey of literature extensively reviews various aspects of PCOS by critically looking into the vast multi-omic data, and concluded with suggesting treatment options as well as lifestyle changes required to deal with the psychological/ emotional impacts of the condition on affected women.

Cadmium alters the cellular metabolome of human ovarian granulosa cells

Cadmium (Cd) is a toxic heavy metal that has been extensively implicated in disordered folliculogenesis, but the mechanisms underlying the ovarian toxicity of Cd remain to be explored fully. Granulosa cells are key players in ovarian follicular development and are the primary cells affected by Cd exposure-induced damage and dysfunction. In this study, we investigated how various levels of exposure of Cd (3 and 10 μM) to human granulosa cells (KGN cells) impacted the metabolism of the KGN cells utilizing a non-targeted metabolomics methodology. In vitro cell experiments revealed that Cd exposure dose-dependently diminished the viability of KGN cells. Metabolomics analysis revealed the presence of 296 (182 elevated and 114 reduced) and 397 (244 elevated and 153 reduced) differentially expressed metabolites after exposure to 3 and 10 μM, respectively. Cd exposure was found to significantly enrich nucleotide metabolism, sphingolipid metabolism, and ABC transporters in both groups. Although amino acid metabolic pathways exhibited significant enrichment across all groups, only glutathione, cysteine, and methionine metabolism were notably enriched in KGN cells exposed to 3 μM Cd, while glutathione and tryptophan metabolism were significantly enriched in the 10 μM Cd exposure cohort. The outcomes of this study provide mechanistic clues for elucidating Cd's cytotoxic impact on granulosa cells, and deepen our understanding of the ovarian toxicity of Cd.

Metabolic Profiles of Pregnancy with Polycystic Ovary Syndrome: Insights into Maternal-Fetal Metabolic Communication

CONTEXT

PCOS pregnancies are linked to metabolic disorders affecting maternal and fetal outcomes, with maternal metabolites differing from those in normal pregnancies.

OBJECTIVE

To investigate the metabolic communication at the maternal-fetal interface in PCOS pregnancies.

DESIGN

Placenta and umbilical cord serum were analyzed using gas chromatography-mass spectrometry. In-depth analysis was performed with clinical characteristics.

SETTING

Placenta and umbilical cord serum were analyzed using gas chromatography-mass spectrometry, alongside clinical characteristics.

PARTICIPANTS

45 uncomplicated PCOS pregnancies and 50 normal pregnancies.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The metabolic characteristics at the maternal-fetal interface in PCOS pregnancies and the underlying mechanisms.

RESULTS

A total of 79 metabolites in the placenta and 25 in umbilical cord serum showed significant differences between polycystic ovary syndrome (PCOS) and normal pregnancies. The 10 most significant placental metabolites were identified through receiver operating characteristic (ROC) analysis, 9 of which correlated significantly with maternal serum testosterone levels. Lasso regression analysis identified 4 key placental metabolite combinations: gamma-aminobutyric acid, proline, glycine, and isoleucine, achieving an area under the curve (AUC) of 93.24%. In umbilical cord serum, 6 metabolites differed significantly between PCOS and normal pregnancies, with the highest AUC reaching 76.07%, and 5 of these metabolites showed significant correlations with maternal serum testosterone levels. Nine differential metabolites were shared between the placenta and umbilical cord serum, which also shared metabolic pathways, including ABC transporters and aminoacyl-tRNA biosynthesis, potentially influencing maternal-fetal interactions.

CONCLUSION

This study identifies the metabolomic profile and key pathways in maternal-fetal communication during PCOS pregnancies.

Genetically predicted serum metabolites mediate the association between inflammatory proteins and polycystic ovary syndrome: a Mendelian randomization study

Objective

To investigate the association between polycystic ovary syndrome (PCOS) and inflammatory proteins, and to identify and quantify the role of serum metabolites as potential mediators.

Methods

Utilizing summary-level data from a genome-wide association study (GWAS), we conducted a two-sample Mendelian Randomization (MR) analysis, a genetic approach that uses genetic variants as instrumental variables to assess the causal relationships between risk factors and outcomes. This analysis involved genetically predicted PCOS (1,639 cases and 218,970 controls) and inflammatory proteins (14,824 participants of primarily European descent). Additionally, a two-step MR analysis was performed to quantify the proportion of the effect of serum metabolites-mediated inflammatory proteins on PCOS. The Inverse Variance Weighted (IVW) method, a statistical technique used within MR to combine data from multiple genetic variants, was used to estimate the causal effects.

Results

The IVW method revealed that the inflammatory proteins IFN-γ (p-value = 0.037, OR = 1.396, 95% CI = 1.020-1.910) and CCL7 (p-value = 0.033, OR = 1.294, 95% CI = 1.021-1.641) were associated with an increased risk of PCOS, while IL-6 (p-value = 0.015, OR = 0.678, 95% CI = 0.495-0.929) and MMP-10 (p-value = 0.025, OR = 0.753, 95% CI = 0.587-0.967) were associated with a decreased risk. No significant evidence suggested an effect of genetically predicted PCOS on inflammatory proteins. The serum metabolite X-11444 was found to mediate 5.44% (95% CI: 10.8-0.0383%) of the effect of MMP-10 on PCOS.

Conclusion

This study not only introduces novel causal associations between inflammatory proteins and PCOS but also highlights the mediating role of serum metabolites in these associations. By applying MR, we were able to minimize confounding and reverse causality, offering robust insights into the biological mechanisms underlying PCOS. These findings advance the understanding of PCOS pathogenesis, particularly in relation to inflammatory pathways and serum metabolite interactions, and suggest potential therapeutic targets that could inform future clinical interventions aimed at mitigating inflammation-related PCOS risks.

TIGAR relieves PCOS by inhibiting granulosa cell apoptosis and oxidative stress through activating Nrf2

This study aimed to elucidate the role of TP53-induced glycolysis and apoptosis regulator (TIGAR) in polycystic ovary syndrome (PCOS). A rat model PCOS was constructed by subcutaneous injection with dehydroepiandrosterone (DHEA). Follicular atresia and reduced granular cells (GCs) in ovaries suggested successful modeling. The low expression of TIGAR was observed in ovarian tissue of PCOS rat. To explore the role of TIGAR in PCOS, lentivirus carrying the TIGAR were used to up-regulate TIGAR expression. TIGAR overexpression reduced the DHEA-induced increase of ovarian weight, the levels of estradiol (E2), and the ratio of luteinizing hormone/follicle-stimulating hormone (LH/FSH) in the serum, as well as improved the morphology of the follicle, especially increased the thickness of the GC layer, which attributed to the inhibition of apoptosis by TIGAR. In addition, high expression of TIGAR inhibited oxidative stress in ovaries of PCOS rat, as evidenced by decreased level of malondialdehyde (MDA), and reactive oxygen species (ROS), and enhanced activity of glutathione peroxidase (GPX) and superoxide dismutase (SOD). Mechanically, Nrf2/OH-1 signal pathway was activated by TIGAR. The effect of TIGAR on PCOS were verified in the primary rat GCs treated with dihydrotestosterone, but also the rescue experiment was performed. Downregulation of Nrf2 reversed the effects of TIGAR, indicating that TIGAR suppressed oxidative stress and GC apoptosis by activating Nrf2/OH-1 pathway in PCOS. Finally, non-targeted metabolomics revealed that TIGAR might affect the energy metabolic pathway, thereby altering the metabolic profile of primary rat GCs. This study provided new insights into the prevention and treatment of PCOS.

Fueling the fight against cancer: Exploring the impact of branched-chain amino acid catalyzation on cancer and cancer immune microenvironment

Metabolism of Branched-chain amino acids (BCAAs) is essential for the nutrient necessities in mammals. Catalytic enzymes serve to direct the whole-body BCAAs oxidation which involve in the development of various metabolic disorders. The reprogrammed metabolic elements are also responsible for malignant oncogenic processes, and favor the formation of distinctive immunosuppressive microenvironment surrounding different cancers. The impotent immune surveillance related to BCAAs dysfunction is a novel topic to investigate. Here we focus on the BCAA catalysts that contribute to metabolic changes and dysregulated immune reactions in cancer progression. We summarize the current knowledge of BCAA catalyzation, highlighting the interesting roles of BCAA metabolism in the treatment of cancers.

Impact of Dietary Patterns and Serum Amino Acid Profile on Metabolic Syndrome Development in Mexican Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the main endocrine disorder in women of reproductive age worldwide. This condition is often associated with various metabolic alterations that contribute to the development of metabolic syndrome (MetS). Recent research suggests that branched-chain amino acid (BCAA) dysregulation is observed in PCOS. This study aims to investigate the relationship between dietary patterns, body composition, metabolic analytes, and serum amino acid levels in Mexican women with PCOS. Utilizing a cross-sectional design, we found that both study groups, PCOS (n = 24) and PCOS + MetS (n = 21), exhibited increased relative fat mass and dietary habits characterized by high simple sugar intake and low protein consumption, correlating with levels of relative fat mass and leptin. Notably, serum concentrations of BCAAs and glutamic acid were significantly elevated in the PCOS + MetS group. Our findings suggest that a metabolic approach may enhance the prediction and management of MetS in women with PCOS, highlighting the importance of dietary interventions in this population.

Epoxiconazole disturbed metabolic balance and gut microbiota homeostasis in juvenile zebrafish

Epoxiconazole (EPX) is a broad-spectrum fungicide extensively used in agricultural pest control. Emerging evidence suggests that EPX can adversely affect different endpoints in non-target organisms. Here, the toxicity of EPX was assessed using earlier developmental stage of zebrafish as a model to investigate its effects on metabolism and intestinal microbiota after 21 days of exposure. Our findings indicated that EPX exposure resulted in physiological alterations in juvenile zebrafish, including increase in triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), and glycose (Glu). Nile red staining demonstrated enhanced lipid accumulation in juvenile, accompanied by a marked upregulation in the expression of genes associated with TG synthesis. Moreover, EPX led to alterations in amino acids and carnitines levels in 21 dpf (days post fertilization) zebrafish. We also observed that EPX disrupted intestinal barrier function in juvenile zebrafish, manifested by decreasing mucus secretion and changing in genes related to tight junctions. Moreover, for a more comprehensive analysis of the intestinal microbiota in 21 dpf zebrafish, the intestine tissues were dissected under a microscope for 16S rRNA sequencing analysis. The results revealed that EPX altered the structure and abundance of intestinal microflora in zebrafish, including decreased alpha diversity indices and shifted in bacteria at phylum and genus levels. Notably, the correlation analysis demonstrated strong associations between alterations in various pathogenic bacterial genera and levels of amino acids and carnitines. Overall, these findings confirm that the fungicide EPX promotes metabolic disorders and alterations in the intestinal micro-environment in 21 dpf zebrafish, shedding light on the toxicologic effects of chemicals to aquatic organisms during the development stage.

Investigating GABA Neuron-Specific Androgen Receptor Knockout in two Hyperandrogenic Models of PCOS

Androgen excess is a hallmark feature of polycystic ovary syndrome (PCOS), the most common form of anovulatory infertility. Clinical and preclinical evidence links developmental or chronic exposure to hyperandrogenism with programming and evoking the reproductive and metabolic traits of PCOS. While critical androgen targets remain to be determined, central GABAergic neurons are postulated to be involved. Here, we tested the hypothesis that androgen signaling in GABAergic neurons is critical in PCOS pathogenesis in 2 well-characterized hyperandrogenic mouse models of PCOS. Using cre-lox transgenics, GABA-specific androgen receptor knockout (GABARKO) mice were generated and exposed to either acute prenatal androgen excess (PNA) or chronic peripubertal androgen excess (PPA). Females were phenotyped for reproductive and metabolic features associated with each model and brains of PNA mice were assessed for elevated GABAergic input to gonadotropin-releasing hormone (GnRH) neurons. Reproductive and metabolic dysfunction induced by PPA, including acyclicity, absence of corpora lutea, obesity, adipocyte hypertrophy, and impaired glucose homeostasis, was not different between GABARKO and wild-type (WT) mice. In PNA mice, acyclicity remained in GABARKO mice while ovarian morphology and luteinizing hormone secretion was not significantly impacted by PNA or genotype. However, PNA predictably increased the density of putative GABAergic synapses to GnRH neurons in adult WT mice, and this PNA-induced plasticity was absent in GABARKO mice. Together, these findings suggest that while direct androgen signaling in GABA neurons is largely not required for the development of PCOS-like traits in androgenized models of PCOS, developmental programming of GnRH neuron innervation is dependent upon androgen signaling in GABA neurons.

Metabolic landscape and pathogenic insights: a comprehensive analysis of high ovarian response in infertile women undergoing in vitro fertilization

BACKGROUND

In the realm of assisted reproduction, a subset of infertile patients demonstrates high ovarian response following controlled ovarian stimulation (COS), with approximately 29.7% facing the risk of Ovarian Hyperstimulation Syndrome (OHSS). Management of OHSS risk often necessitates embryo transfer cancellation, leading to delayed prospects of successful pregnancy and significant psychological distress. Regrettably, these patients have received limited research attention, particularly regarding their metabolic profile. In this study, we aim to utilize gas chromatography-mass spectrometry (GC-MS) to reveal these patients' unique serum metabolic profiles and provide insights into the disease's pathogenesis.

METHODS

We categorized 145 infertile women into two main groups: the CON infertility group from tubal infertility patients and the Polycystic Ovary Syndrome (PCOS) infertility group. Within these groups, we further subdivided them into four categories: patients with normal ovarian response (CON-NOR group), patients with high ovarian response and at risk for OHSS (CON-HOR group) within the CON group, as well as patients with normal ovarian response (PCOS-NOR group) and patients with high ovarian response and at risk for OHSS (PCOS-HOR group) within the PCOS group. Serum metabolic profiles were analyzed using GC-MS. The risk criteria for OHSS were: the number of developing follicles > 20, peak Estradiol (E2) > 4000pg/mL, and Anti-Müllerian Hormone (AMH) levels > 4.5ng/mL.

RESULTS

The serum metabolomics analysis revealed four different metabolites within the CON group and 14 within the PCOS group. Remarkably, 10-pentadecenoic acid emerged as a discernible risk metabolite for the CON-HOR, also found to be a differential metabolite between CON-NOR and PCOS groups. cysteine and 5-methoxytryptamine were also identified as risk metabolites for the PCOS-HOR. Furthermore, KEGG analysis unveiled significant enrichment of the aminoacyl-tRNA biosynthesis pathway among the metabolites differing between PCOS-NOR and PCOS-HOR.

CONCLUSION

Our study highlights significant metabolite differences between patients with normal ovarian response and those with high ovarian response and at risk for OHSS within both the tubal infertility control group and PCOS infertility group. Importantly, we observe metabolic similarities between patients with PCOS and those with a high ovarian response but without PCOS, suggesting potential parallels in their underlying causes.

Metabolome implies increased fatty acid utilization and histone methylation in the follicles from hyperandrogenic PCOS women

Well-balanced metabolism is essential for the high-quality of oocytes, and metabolic fluctuations of follicular microenvironment potentially encourage functional changes in follicle cells, ultimately impacting the developmental potential of oocytes. Here, the global metabolomic profiles of follicular fluid from PCOS women with ovarian hyperandrogenism and nonhyperandrogenism were depicted by untargeted metabolome and transcriptome. In parallel, functional methods were employed to evaluate the possible impact of dysregulated metabolites on oocyte and embryo development. Our findings demonstrated that PCOS women exhibited distinct metabolic features in follicles, such as the increase in fatty acid utilization and the downregulation in amino acid metabolism. And intrafollicular androgen levels were positively correlated with contents of multiple fatty acids, suggesting androgen as one of the contributing factors to the metabolic abnormalities in PCOS follicles. Moreover, we further demonstrated that elevated levels of α-linolenic acid and H3K27me3 could hinder oocyte maturation, fertilization, and early embryo development. Hopefully, our data serve as a broad resource on the metabolic abnormalities of PCOS follicles, and advances in the relevant knowledge will allow the identification of biomarkers that predict the progression of PCOS and its poor pregnancy outcomes.

High-fat and high-sucrose diet impairs female reproduction by altering ovarian transcriptomic and metabolic signatures

BACKGROUND

Excessive energy intake in modern society has led to an epidemic surge in metabolic diseases, such as obesity and type 2 diabetes, posing profound threats to women's reproductive health. However, the precise impact and underlying pathogenesis of energy excess on female reproduction remain unclear.

METHODS

We established an obese and hyperglycemic female mouse model induced by a high-fat and high-sucrose (HFHS) diet, then reproductive phenotypes of these mice were evaluated by examing sexual hormones, estrous cycles, and ovarian morphologies. Transcriptomic and precise metabolomic analyses of the ovaries were performed to compare the molecular and metabolic changes in HFHS mice. Finally, orthogonal partial least squares discriminant analysis was performed to compare the similarities of traits between HFHS mice and women with polycystic ovary syndrome (PCOS).

RESULTS

The HFHS mice displayed marked reproductive dysfunctions, including elevated serum testosterone and luteinizing hormone levels, irregular estrous cycles, and impaired folliculogenesis, mimicking the clinical manifestations of women with PCOS. Precise metabolomic overview suggested that HFHS diet disrupted amino acid metabolism in the ovaries of female mice. Additionally, transcriptional profiling revealed pronounced disturbances in ovarian steroid hormone biosynthesis and glucolipid metabolism in HFHS mice. Further multi-omics analyses unveiled prominent aberration in ovarian arginine biosynthesis pathway. Notably, comparisons between HFHS mice and a cohort of PCOS patients identified analogous reproductive and metabolic signatures.

CONCLUSIONS

Our results provide direct in vivo evidence for the detrimental effects of overnutrition on female reproduction and offer insights into the metabolic underpinnings of PCOS.

Serum and follicular fluid metabolome and markers of ovarian stimulation

STUDY QUESTION

What metabolic pathways and metabolites in the serum and follicular fluid are associated with peak estradiol levels and the number of mature oocytes?

SUMMARY ANSWER

In the serum metabolome, mostly fatty acid and amino acid pathways were associated with estradiol levels and mature oocytes while in the follicular fluid metabolome, mostly lipid, vitamin, and hormone pathways were associated with peak estradiol levels and mature oocytes.

WHAT IS KNOWN ALREADY

Metabolomics has identified several metabolic pathways and metabolites associated with infertility but limited data are available for ovarian stimulation outcomes.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study of women undergoing IVF from 2009 to 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 125 women undergoing a fresh IVF cycle at a fertility clinic in the Northeast United States who provided a serum and follicular fluid sample. Untargeted metabolomics profiling was conducted using liquid chromatography with high-resolution mass spectrometry in two chromatography columns (C18 and hydrophilic interaction chromatography (HILIC)). The main ovarian stimulation outcomes were peak serum estradiol levels and number of mature oocytes. We utilized adjusted generalized linear regression models to identify significant metabolic features. Models were adjusted for age,BMI, initial infertility diagnosis, and ovarian stimulation protocol. We then conducted pathway analysis using mummichog and metabolite annotation using level-1 evidence.

MAIN RESULTS AND ROLE OF CHANCE

In the serum metabolome, 480 and 850 features were associated with peak estradiol levels in the C18 and HILIC columns, respectively. Additionally, 437 and 538 features were associated with mature oocytes in the C18 and HILIC columns, respectively. In the follicular fluid metabolome, 752 and 929 features were associated with peak estradiol levels in the C18 and HILIC columns, respectively, Additionally, 993 and 986 features were associated with mature oocytes in the C18 and HILIC columns, respectively. The most common pathways associated with peak estradiol included fatty acids (serum and follicular fluid), hormone (follicular fluid), and lipid pathways (follicular fluid). The most common pathways associated with the number of mature oocytes retrieved included amino acids (serum), fatty acids (serum and follicular fluid), hormone (follicular fluid), and vitamin pathways(follicular fluid). The vitamin D3 pathway had the strongest association with both ovarian stimulation outcomes in the follicularfluid. Four and nine metabolites were identified using level-1 evidence (validated identification) in the serum and follicular fluid metabolomes, respectively.

LIMITATIONS, REASONS FOR CAUTION

Our sample was majority White and highly educated and may not be generalizable to thewider population. Additionally, residual confounding is possible and the flushing medium used in the follicular fluid could have diluted our results.

WIDER IMPLICATIONS OF THE FINDINGS

The pathways and metabolites identified by our study provide novel insights into the biologicalmechanisms in the serum and follicular fluid that may underlie follicular and oocyte development, which could potentially be used to improve ovarian stimulation outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the following grants from the National Institute of Environmental Health Sciences (P30-ES019776, R01-ES009718, R01-ES022955, P30-ES000002, R00-ES026648, and T32-ES012870), and National Institute of Diabetes and Digestive and Kidney Diseases (P30DK046200). The authors have no competing interests to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Berberine interacts with gut microbiota and its potential therapy for polycystic ovary syndrome

Berberine (BBR) is an isoquinoline alkaloid extracted from Chinese medicinal plants showing a tight correlation with gut microbiota. Polycystic ovary syndrome (PCOS) is a prevalent reproductive and endocrine disorder syndrome among women of childbearing age. Dysbiosis, the imbalance of intestinal microorganisms, is a potential factor that takes part in the pathogenesis of PCOS. Recent evidence indicates that berberine offers promise for treating PCOS. Here, we review the recent research on the interaction between berberine and intestinal microorganisms, including the changes in the structure of gut bacteria, the intestinal metabolites after BBR treatment, and the effect of gut microbiota on the bioavailability of BBR. We also discuss the therapeutic effect of BBR on PCOS in terms of gut microbiota and its potential mechanisms.

Alteration of Branched-Chain and Aromatic Amino Acid Profile as a Novel Approach in Studying Polycystic Ovary Syndrome Pathogenesis

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects reproductive-age women and predisposes them to the development of metabolic disturbances. Recent research has shown that several metabolic factors may play a role in PCOS pathogenesis, and it has been suggested that an alteration in the amino acid profile might be a predictive sign of metabolic disorders. Metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) are concepts that have attracted scientific attention; however, a universal definition has not been established yet for these terms. Already existing definitions of MHO involve the coexistence of obesity with the absence or minimal presence of other metabolic syndrome parameters. A group of 326 women, 209 diagnosed with PCOS and 117 healthy individuals, participated in this study. Multiple parameters were assessed, including anthropometrical, biochemical, and hormonal ones, and gas-liquid chromatography, combined with tandem mass spectrometry, was used to investigate the amino acid profile. Statistical analysis revealed noticeably higher levels of all aromatic amino acids in PCOS women compared to the control group: phenylalanine 47.37 ± 7.0 vs. 45.4 ± 6.09 nmol/mL (p = 0.01), tyrosine 61.69 ± 9.56 vs. 58.08 ± 8.89 nmol/mL (p < 0.01), and tryptophan 53.66 ± 11.42 vs. 49.81 ± 11.18 nmol/mL (p < 0.01); however, there was no significant difference in the "tryptophan ratio" between the PCOS and control group (p = 0.88). A comparison of MHO and MUO PCOS women revealed that LAP, leucine, and isoleucine concentrations were significantly higher among the MUO subgroup: respectively, 101.98 ± 34.74 vs. 55.80 ± 24.33 (p < 0.001); 153.26 ± 22.26 vs. 137.25 ± 25.76 nmol/mL (p = 0.04); and 92.92 ± 16.09 vs. 82.60 ± 18.70 nmol/mL (p = 0.02). No significant differences in BMI, fasting glucose, and HOMA-IR between MHO and MUO were found: respectively, 35.0 ± 4.8 vs. 36.1 ± 4.6 kg/m2 (p = 0.59); 88.0 ± 6.0 vs. 87.73 ± 6.28 mg/dL (p = 0.67); and 3.36 ± 1.70 vs. 4.17 ± 1.77 (p = 0.1). The identification of altered amino acid profiles in PCOS holds potential clinical implications. Amino acids may serve as biomarkers for diagnosing and monitoring the metabolic status of individuals with PCOS. The alteration of BCAAs and AAAs may be involved in PCOS pathogenesis, but the underlying mechanism should be further investigated.

Alterations in glycine metabolism in obesity and chronic metabolic diseases - an update on new advances

PURPOSE OF REVIEW

The metabolic signature associated with obesity is characterized by a decrease in plasma glycine concentration, a feature closely associated with insulin resistance and highly predictive of the risk of developing chronic metabolic diseases. This review presents recent advances in understanding the causes of decreased glycine availability and in targeting strategies to replenish the glycine pool and especially to improve insulin resistance.

RECENT RESULTS

Recent literature has made progress in understanding host and gut microbiota mechanisms in determining circulating glycine levels. It has also explored new clinical pathways to restore circulating glycine levels and insulin resistance in obesity-related metabolic diseases.

SUMMARY

Recent findings suggest that glycine metabolism must now be considered in close interaction with branched-chain amino acid (BCAA) metabolism. Thus, strategies that decrease BCAAs seem to be the best to restore glycine. Furthermore, recent literature has confirmed that lifestyle strategies aimed at inducing weight loss are effective in replenishing the glycine pool. It also confirms that correcting the dysbiosis of the gut microbiota associated with obesity may be a valuable means of achieving this goal. However, it remains unclear whether dietary glycine is an effective strategy for correcting cardiometabolic disorders in obesity.

Specific Alteration of Branched-Chain Amino Acid Profile in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies in reproductive age women; it is a complex health issue with numerous comorbidities. Attention has recently been drawn to amino acids as they are molecules essential to maintain homeostasis. The aim of the study was to investigate the branch chain amino acid (BCAA) profile in women with PCOS. A total of 326 women, 208 diagnosed with PCOS and 118 healthy controls, participated in the study; all the patients were between 18 and 40 years old. Anthropometrical, biochemical and hormonal parameters were assessed. Gas-liquid chromatography combined with tandem mass spectrometry was used to investigate BCAA levels. Statistical analysis showed significantly higher plasma levels of BCAAs (540.59 ± 97.23 nmol/mL vs. 501.09 ± 85.33 nmol/mL; p < 0.001) in women with PCOS. Significant correlations (p < 0.05) were found between BCAA and BMI, HOMA-IR, waist circumference and total testosterone levels. In the analysis of individuals with abdominal obesity, there were significant differences between PCOS and controls in BCAA (558.13 ± 100.51 vs. 514.22 ± 79.76 nmol/mL) and the concentrations of all the analyzed amino acids were higher in the PCOS patients. Hyperandrogenemia in PCOS patients was associated with significantly higher leucine, isoleucine and total BCAA levels. The increase of BCAA levels among PCOS patients in comparison to healthy controls might be an early sign of metabolic alteration and a predictive factor for other disturbances.

Present and Future: Crosstalks Between Polycystic Ovary Syndrome and Gut Metabolites Relating to Gut Microbiota

Polycystic ovary syndrome (PCOS) is a common disease, affecting 8%-13% of the females of reproductive age, thereby compromising their fertility and long-term health. However, the pathogenesis of PCOS is still unclear. It is not only a reproductive endocrine disease, dominated by hyperandrogenemia, but also is accompanied by different degrees of metabolic abnormalities and insulin resistance. With a deeper understanding of its pathogenesis, more small metabolic molecules, such as bile acids, amino acids, and short-chain fatty acids, have been reported to be involved in the pathological process of PCOS. Recently, the critical role of gut microbiota in metabolism has been focused on. The gut microbiota-related metabolic pathways can significantly affect inflammation levels, insulin signaling, glucose metabolism, lipid metabolism, and hormonal secretions. Although the abnormalities in gut microbiota and metabolites might not be the initial factors of PCOS, they may have a significant role in the pathological process of PCOS. The dysbiosis of gut microbiota and disturbance of gut metabolites can affect the progression of PCOS. Meanwhile, PCOS itself can adversely affect the function of gut, thereby contributing to the aggravation of the disease. Inhibiting this vicious cycle might alleviate the symptoms of PCOS. However, the role of gut microbiota in PCOS has not been fully explored yet. This review aims to summarize the potential effects and modulative mechanisms of the gut metabolites on PCOS and suggests its potential intervention targets, thus providing more possible treatment options for PCOS in the future.