Uric acid metabolism in polycystic ovary syndrome

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.

A nomogram to predict the risk of insulin resistance in Chinese women with polycystic ovary syndrome

Background

Insulin resistance (IR) is considered a major driver of the pathophysiology of polycystic ovary syndrome (PCOS), mediating the progression of hyperandrogenism and metabolic and reproductive dysfunction in patients with PCOS. Early detection of the risk of concurrent IR is essential for women with PCOS. To address this need, this study developed a predictive nomogram for assessing the risk of IR in women with PCOS, aiming to provide a tool for risk stratification and assist in clinical decision-making.

Methods

Patients with untreated PCOS-IR diagnosed in a single-center retrospective cohort study from January 2023 to December 2023 were included for nomogram construction and validation. The area under the ROC curve (AUC), calibration curve, Hosmer-Lemeshow (H-L) goodness-of-fit test, and decision curve analysis (DCA) were used to evaluate the nomogram's discrimination, calibration, and clinical decision performance. A risk stratification model based on the nomogram was then developed.

Results

A total of 571 patients were included in the study; 400 patients enrolled before September 2023 were divided into the training and validation sets, and 171 patients enrolled later were used as the external validation set. The variables identified by logistic regression and the random forest algorithm-body mass index (BMI, OR 1.43), triglycerides (TG, OR 1.22), alanine aminotransferase (ALT, OR 1.03), and fasting plasma glucose (FPG, OR 5.19)-were used to build the nomogram. In the training, internal validation, and external validation sets, the AUCs were 0.911 (95% CI 0.878-0.911), 0.842 (95% CI 0.771-0.842), and 0.901 (95% CI 0.856-0.901), respectively. The nomogram showed good agreement between predicted and observed outcomes, and patients were categorized into low-, medium-, and high-risk groups based on their scores.

Conclusions

Independent predictors of untreated PCOS-IR risk were incorporated into a nomogram that effectively classifies patients into risk groups, providing a practical tool for guiding clinical management and early intervention.

Effect of serum uric acid level on reproductive outcome in women without polycystic ovary syndrome undergoing in vitro fertilization

BACKGROUND

Prior research showed that elevated serum uric acid (SUA) levels in women with polycystic ovary syndrome (PCOS) before in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) treatment can lead to a lower rate of live birth and an increased risk for low birthweight. Nonetheless, it is not known whether elevated SUA results in similar reproductive outcome in women without PCOS. This study aimed to exploring the relationship between pre-pregnancy SUA levels and reproductive outcomes in non-PCOS women undergoing IVF/ICSI treatment.

METHODS

This single-center, retrospective study included 13,325 women without PCOS undergoing their first IVF/ICSI fresh embryo transfer cycles from January 2014 to December 2022 at a university-affiliated reproductive medicine center in China. The trends for pregnancy, obstetric and perinatal outcomes across quartiles of SUA levels were assessed. A logistic regression analysis was applied to control for baseline and cycle characteristics. Generalized addition model was used to draw spline smoothing plot.

RESULTS

There was no significant decreasing or increasing trend in the clinical pregnancy rate and live birth rate with the increase in quartiles of SUA levels. For Obstetric and perinatal outcomes following a single live birth, the percentage of hypertensive disorders in pregnancy (1.6-4.1%, Ptrend<0.001), gestational diabetes mellitus (5.9-13.9%, Ptrend<0.001), premature rupture of membranes (0.6-1.5%, Ptrend=0.016), preterm birth (6.3-9.2%, Ptrend=0.009), macrosomia (2.3-5.5%, Ptrend<0.001), large for gestational age (10.8-14.9%, Ptrend=0.002) all increased significantly from the lowest quartile to the highest. Logistic regression results showed that compared with those in quartile 1, the risk of maternal and infant complications mentioned above was still significantly higher in quartile 4 after adjusting for reproductive related factors. When further confounding factors were added, including body mass index (BMI), blood pressure, fasting blood glucose, and blood lipids related indicators, only gestational diabetes mellitus and macrosomia showed a significant increase.

CONCLUSION

In women without PCOS, SUA levels before IVF/ICSI treatment do not affect the probabilities of clinical pregnancy and live birth. An elevated SUA level is associated with an increased risk for hypertensive disorders in pregnancy, gestational diabetes mellitus, premature rupture of membranes, preterm birth, macrosomia, and large for gestational age. For gestational diabetes mellitus and macrosomia, the association is independent of BMI, blood pressure, blood glucose, and blood lipid.

The Causal Effect of Urate Level on Female Infertility: A Mendelian Randomization Study

BACKGROUND/OBJECTIVE

This study aimed to investigate the causal relationship between urate level and female infertility using Mendelian randomization (MR) analysis.

METHODS

To identify instrumental variables, we selected independent genetic loci associated with serum urate levels in individuals of European ancestry, utilizing data from large-scale genome-wide association studies (GWAS). The GWAS dataset included information on serum urate levels from 288,649 CKDGen participants. Female infertility data, including different etiologic classifications, consisted of 13,142 female infertility patients and 107,564 controls. We employed four MR methods, namely inverse variance weighted (IVW), MR-Egger, weighted median, and weighted model, to investigate the causal relationship between urate levels and female infertility. The Cochran Q-test was used to assess heterogeneity among single nucleotide polymorphisms (SNPs), and the MR-Egger intercept test was employed to evaluate the presence of horizontal pleiotropy. Additionally, a "leave-one-out" sensitivity analysis was conducted to examine the influence of individual SNPs on the MR study.

RESULTS

The IVW analysis demonstrated that elevated serum urate levels increased the risk of female infertility (odds ratio [OR] = 1.18, 95% confidence interval [CI]: 1.07-1.33). Furthermore, serum urate levels were found to be associated with infertility due to cervical, vaginal, or other unknown causes (OR = 1.16, 95% CI: 1.06-1.26), also confirmed by other methods. Heterogeneity among instrumental variables was assessed using Cochran's Q-test (p < 0.05), so a random-effects IVW approach was employed in the effects model. The MR-Egger intercept test indicated no presence of horizontal pleiotropy. A "leave-one-out" sensitivity analysis was conducted, demonstrating that no individual SNP had a substantial impact on the overall findings.

CONCLUSIONS

In the European population, the urate level is significantly and causally associated with an increased risk of female infertility.

Association of serum uric acid with women's ovarian reserve: observational study and Mendelian randomization analyses

OBJECTIVE

To investigate the association between serum uric acid and women's ovarian reserve.

DESIGN

Retrospective observational study and Mendelian randomization study.

SETTING

University-affiliated in vitro fertilization center.

PATIENTS

Observational analyses were undertaken using data from 8,257 women with infertility who finished their first in vitro fertilization treatments between May 2017 and December 2021. Mendelian randomization analyses were based on genome-wide association summary statistics from several biobanks of predominantly European ancestries.

INTERVENTIONS

Observational study involved testing log2 transformed serum uric acid levels (for linear, negative regression, and logistic regression analyses); original uric acid levels (for nonlinear association analyses). Mendelian randomization study involved testing genetically predicted uric acid levels.

MAIN OUTCOME MEASURES

Biomarkers including antimüllerian hormone, basal antral follicle count, follicle-stimulating hormone, luteinizing hormone, ratio of follicle-stimulating hormone to luteinizing hormone, estradiol; indices of ovarian response to stimulation including poor ovarian response according to different criteria and oocyte yield.

RESULTS

In retrospective observational study, all ovarian reserve-related outcomes demonstrated significant differences across serum uric acid quartiles. A two-fold uric acid increase was associated with increased antimüllerian hormone (adjusted β = 0.69; 95% confidence interval [CI], 0.43-0.95), antral follicle count (adjusted incidence rate ratio = 1.10, 95% CI, 1.05-1.14), luteinizing hormone (adjusted β = 0.53, 95% CI, 0.28-0.78), decreased risks of Bologna poor ovarian response (adjusted odds ratio = 0.97; 95% CI, 0.95-0.99) and groups 2-4 Poseidon poor ovarian response (group 2: 0.63, 0.56-0.71; group 3: 0.71, 0.65-0.78; group 4: 0.50, 0.46-0.55), whereas an increased risk of group 1 (1.26, 1.13-1.41). Nonlinear analyses showed a common inflection point at 320-340 μmol/L of uric acid. Interactions between uric acid and antimüllerian hormone and antral follicle count were presented in association with oocyte yield. Mendelian randomization results suggested a significant association between genetically predicted uric acid levels and antimüllerian hormone levels (β = 0.08; 95% CI, 0.04-0.12) but none for uric acid in relation to polycystic ovarian syndrome or other related hormones.

CONCLUSION

Higher uric acid levels were associated with better ovarian reserve and increased levels of antimüllerian hormone albeit an increased risk of unexpected poor ovarian response.

Decoding connections in the European population: serum uric acid, sex hormone-binding globulin, total testosterone, estradiol, and female infertility - advanced bidirectional and mediative Mendelian randomization

Background

Despite observational links between serum uric acid (SUA), sex hormone-related phenotypes, and female infertility, the causality behind these associations remains uncertain.

Objective

This study utilizes Bidirectional Two-Sample and Mediation Mendelian Randomization to explore the causal relationships and mediation effects of sex hormone-binding globulin (SHBG), total testosterone (TT), and estradiol on these associations.

Methods

We analyzed single-nucleotide polymorphisms (SNPs) associated with SUA and sex hormone levels using data from large-scale GWAS of European populations. Female infertility data were sourced from 6,481 cases and 75,450 controls in the FinnGen Consortium. We employed methods including Inverse Variance Weighted (IVW), Weighted Median, and MR-Egger regression to assess causality.

Results

We found that elevated SUA levels causally increase the risk of female infertility (IVW OR: 1.13, P=0.047). Elevated SUA levels significantly decrease SHBG levels (β=-0.261; P=2.177e-04), with SHBG mediating 27.93% of the effect of SUA on infertility (OR=0.854; 95%CI, 0.793-0.920; P=2.853e-05). Additionally, elevated TT levels, which were associated with decreased SUA levels (β=-0.127), showed an indirect effect on infertility mediated by SUA (β=-0.0187; 95% CI, -0.041 to -0.003; P=0.046).

Conclusion

Our findings demonstrate causal links between high SUA and increased risk of female infertility mediated by hormonal factors such as SHBG and TT. These insights suggest new avenues for infertility treatment and highlight the need for further research into these mechanisms.

Association of Free Radical Product and Polycystic Ovary Syndrome: A Systematic Review and Meta-analysis

PURPOSE

Polycystic ovary syndrome (PCOS) is an endocrine disorder that primarily affects women of reproductive age. It is recognized as the leading cause of infertility due to anovulation. This research aims to evaluate the diagnostic potential of oxidative stress biomarkers, including advanced oxidation protein products (AOPP), malondialdehyde (MDA), uric acid (UA), and nitric oxide (NO), in identifying PCOS.

METHODS

A literature search was conducted in the EMBASE, PubMed, Cochrane Library, and Scopus databases. The standardized mean difference (SMD) and 95% confidence interval (CI) were employed to assess the correlation between free radical product and PCOS. Moreover, the presence of heterogeneity among the studies was assessed utilizing the I2 statistic and Cochran Q test. The methodological rigor of the incorporated studies was assessed through the application of the Newcastle-Ottawa Scale. Furthermore, the presence of publication bias was determined via Begg and Egger tests.

RESULTS

This meta-analysis reviewed 38 observational studies, including 17,845 women. The results revealed a significant association between PCOS in women and alterations in free radical levels. The study revealed that the PCOS group had significantly higher levels of AOPP (SMD = 3.193; 95% CI, 2.86 to 3.25), UA (SMD = 0.68; 95% CI, 0.24 to 1.13), and MDA (SMD = 1.16; 95% CI, 0.77 to 1.56) compared to the healthy control group. Furthermore, the analysis found a significantly lower level of NO (SMD = (- 0.59); 95% CI, - 1.15 to - 0.03) in the PCOS patient.

CONCLUSION

Screening of specific biomarkers associated with free radical products could provide valuable benefits in the prognosis and diagnosis of PCOS.

Serum uric acid did not affect embryonic and pregnancy outcomes in women without PCOS during IVF procedures

Objectives

Serum uric acid (UA) levels are associated with many systemic diseases. A previous study confirmed the association between high serum uric acid levels and poor prognosis of in vitro fertilization (IVF) treatment in polycystic ovary syndrome (PCOS) patients. This study aimed to explore the correlation between serum uric acid levels and reproductive outcomes in patients without PCOS.

Methods

A retrospective study that included 1057 patients who underwent pre-implantation genetic testing for monogenic disorders (PGT-M) treatment from January 2013 to December 2020 was conducted. The study population was further divided into 3 groups according to serum UA levels: the ≤250 μmol/L group, the 251-360 μmol/L group, and the >360 μmol/L group. The controlled ovarian hyperstimulation (COH) treatment outcomes, embryonic treatment outcomes and pregnancy outcomes of the first frozen embryo transfer (FET) cycle were compared among groups. Multivariable linear regression and binary regression were applied to detect the association between IVF outcomes and serum uric acid levels.

Results

The number of retrieved oocytes, fertilization rate, viable embryo rate, blastocyst formation rate and euploid rate were not associated with serum uric acid levels. The mature oocyte rate was negatively correlated with serum uric acid levels. The pregnancy outcomes of the first FET cycle were also not associated with serum uric acid levels. After adjustment for BMI, the perinatal outcomes were not associated with serum uric acid levels.

Conclusion

IVF treatment outcomes were not associated with serum uric acid levels in patients without PCOS.

Elevated serum uric acid is associated with infertility in women living in America

Excessive uric acid levels may affect several organs and systems in the body. There is limited evidence of the effects of high serum uric acid levels on the female reproductive system. This study used the National Health and Nutrition Examination Survey (NHANES) database to explore the relationship between serum uric acid and female infertility. This cross-sectional study included a total of 2197 eligible subjects using data from NHANES 2013-March 2020 pre-pandemic data. Self-reported infertility (ever experiencing an inability to conceive after 12 months of trying to become pregnant) was the main outcome. Logistic regression models and restricted cubic spline were used to analyze the relationship between serum uric acid and female infertility, and stratified analysis was carried out. A total of 295 women self-reported infertility (13.43%). The median uric acid level for all study subjects was 4.4 mg/dL (interquartile range [IQR]: 3.7, 5.1). Serum uric acid levels were higher in the infertility group than in the control group (4.7 mg/dL [IQR: 4.0, 5.3] vs. 4.4 mg/dL [IQR: 3.7, 5.1], P < 0.001). After adjusting for age, race, marital status, smoking, alcohol, history of pregnancy, history of diabetes, history of hypertension, fasting glucose, total cholesterol, creatinine in refrigerated serum, low-density lipoprotein cholesterol, direct high-density lipoprotein cholesterol, glycohemoglobin, and body mass index confounders, women with serum uric acid levels at Q3 (4.4-5.1 mg/dL) had a 73% (odds ratio [OR] = 1.73, 95% confidence interval [CI] 1.18, 2.54, P = 0.005) higher risk of infertility, and women with uric acid levels at Q4 (5.1-18.0 mg/dL) had an 83% (OR = 1.83, 95% CI 1.22, 2.75, P = 0.003) increased risk of infertility compared to women at Q1 (1.6-3.7 mg/dL). The restricted cubic spline also showed that when serum uric acid levels exceeded the reference value, the risk of infertility gradually increased. We also performed a sensitivity analysis based on the complete dataset and found that the results were robust. Higher serum uric acid levels were significantly associated with an increased risk of female infertility. Women planning a pregnancy should have increased serum uric acid monitoring.

Association between serum uric acid and female infertility: a cross-sectional study of National Health and Nutrition Examination Survey (NHANES) 2013-2018

BACKGROUND

Female infertility is a major problem for women of reproductive-age worldwide. Oxidative stress and inflammation are involved in processes related to female infertility. Serum uric acid levels, an indicator of oxidative stress and inflammation, have rarely been reported to be associated with female infertility. This study aimed to investigate the relationship between serum uric acid levels and female infertility.

METHODS

This cross-sectional study included women aged 18-44 years from the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2018. All data were extracted from NHANES questionnaires and laboratory measurements. Weighted univariable and multivariable logistic regression analyses were utilized to explore the relationship between serum uric acid and female infertility. Stratified analyses were performed based on body mass index (BMI, < 25 kg/m² and ≥ 25 kg/m²) and age (≤ 30 years and > 30 years). The odds ratio (OR) with 95% confidence interval (CI) was used to report associations.

RESULTS

A total of 2,884 women were included, of which 352 (13.30%) had infertility. Women with high serum uric acid concentrations were related to higher odds of infertility (OR = 1.20, 95%CI: 1.03-1.39) after adjusting for confounders. Compared with serum uric acid concentrations ≤ 3.72 mg/dL, women with uric acid concentrations of 4.43-5.13 mg/dL (OR = 1.65, 95%CI: 1.02-2.67) and > 5.13 mg/dL (OR = 1.86, 95%CI: 1.10-3.13) were related to higher odds of infertility. Stratified analyses showed that high serum uric acid concentrations were associated with higher odds of infertility in women with a BMI < 25 kg/m² (OR = 1.41, 95%CI: 1.04-1.93), but not in women with a BMI ≥ 25 kg/m² (P = 0.056). In addition, high serum uric acid concentrations were associated with higher odds of infertility in women aged > 30 years (OR = 1.23, 95%CI: 1.04-1.45), but not in women aged ≤ 30 years (P = 0.556).

CONCLUSION

Women with high serum uric acid concentrations were associated with higher odds of infertility, and this association may vary by BMI and age.

Elevated serum uric acid level is associated with adverse reproductive outcomes in women with polycystic ovary syndrome undergoing in vitro fertilization or intracytoplasmic sperm injection embryo transfer cycles: a retrospective cohort study

BACKGROUND

Serum uric acid levels are elevated in polycystic ovary syndrome, however, the relationship between serum uric acid level and reproductive outcomes in women with polycystic ovary syndrome remains unclear.

OBJECTIVE

This study aimed to investigate the association between serum uric acid level and the reproductive outcomes in women with polycystic ovary syndrome undergoing in vitro fertilization or intracytoplasmic sperm injection embryo transfer cycles.

STUDY DESIGN

This was a retrospective cohort study performed at a university-affiliated reproductive medicine center. A total of 1903 women with polycystic ovary syndrome undergoing their first in vitro fertilization or intracytoplasmic sperm injection embryo transfer cycles between January 2010 and January 2021 were initially included. The trends for reproductive outcomes in polycystic ovary syndrome across quartiles of serum uric acid levels were assessed. A logistic regression analysis was performed to obtain the odds ratios for in vitro fertilization outcomes based on the quartiles of serum uric acid with or without adjusting for potential confounding variables. Using generalized additive models, serum uric acid was further treated as its original continuous property to visualize its nonlinear relationship with in vitro fertilization outcomes. The live birth rate was the main outcome.

RESULTS

After exclusions, a total of 883 women with polycystic ovary syndrome with their first fresh-embryo transfer cycles were included. In quartiles of serum uric acid levels, there was a significant decreasing trend in the live birth rate from the lowest quartile (Q1: 61.8%) to the highest (Q4: 45.9%) (P_trend=.002). The percentage of low birthweight increased from Q1 (22.3%) to Q4 (31.7%) (P_trend=.049). Compared with those in Q1, women in Q4 showed a significant lower probability of live birth and clinical pregnancy and a higher risk for low birthweight (all P<.05). Both the unadjusted and adjusted generalized additive models indicated that as the serum uric acid level increased, the probability of clinical pregnancy and the live birth rate exhibited an overall decreasing profile, and the risk for low birthweight showed an increasing profile.

CONCLUSION

An elevated serum uric acid level is associated with decreased probabilities of live birth and clinical pregnancy and an increased risk for low birthweight in women with polycystic ovary syndrome. However, these associations may be confounded by other factors and more well-designed studies are needed to confirm these findings in the future.

Uric acid participating in female reproductive disorders: a review

Uric acid (UA) is the end metabolic product of purine metabolism. Early on, UA was considered to be a metabolite with a certain antioxidant capacity. As research has progressed, other properties of UA have been explored, and its association with many diseases has been found. The association between UA and kidney disease and cardiovascular disease is well established; however, there is still a paucity of reviews on the association between UA and the female reproductive system. An increasing number of epidemiological studies have shown elevated serum UA levels in patients with polycystic ovary syndrome (PCOS), endometriosis, etc. Additionally, serum UA can be used as a predictor of pregnancy complications and adverse foetal outcomes. An increasing number of animal experiments and clinical studies have revealed possible mechanisms related to the involvement of UA in certain female reproductive disorders: oxidative stress, chronic inflammation, mitochondrial dysfunction, etc. This article reviews the current mainstream mechanisms regarding the pathogenesis of UA and the role of UA in certain specific female reproductive disorders (direct involvement in the development of certain diseases or enhancement of other risk factors) in the hope of contributing to clinical prevention, diagnosis, treatment and improvement in prognosis.

Correlation Between Serum Uric Acid and Body Fat Distribution in Patients With Polycystic Ovary Syndrome

OBJECTIVE

This study aims to investigate the correlation between serum uric acid levels and body fat distribution in patients with polycystic ovary syndrome (PCOS).

METHODS

Between May 2017 and March 2021, a total of 199 patients with PCOS were recruited from the Department of Endocrinology and Metabolism at the Shanghai Tenth People's Hospital. Anthropometric characteristics, metabolic parameters, and reproductive hormones were measured. Hyperuricemia was defined as serum uric acid (SUA) greater than 420 μmol/l. Dual-energy X-ray absorptiometry (DEXA) was used to measure body fat distribution.

RESULTS

The prevalence of hyperuricemia in patients with PCOS was 28.64%. PCOS patients with hyperuricemia are more obese and have a higher waist-to-hip ratio (WHR) and worse lipid metabolism than those without hyperuricemia. According to SUA quartiles, patients in the highest quartile had higher total testosterone (TT), body fat accumulation, and lower sex hormone-binding globulin (SHBG) than patients in the lowest quartile. SUA was correlated with percentage of total body fat, arm fat mass, leg fat mass, trunk fat mass, android/gynoid (A/G) ratio, and visceral adipose tissue (VAT) mass. After controlling possible confounders, logistic regression analysis found that only excessive VAT mass could significantly increase the risk of hyperuricemia in patients with PCOS.

CONCLUSION

In patients with PCOS, a high level of VAT mass, but not other fat compartments, will exacerbate the risk of hyperuricemia. Attention should be paid to the role of excessive VAT in the occurrence and development of PCOS with hyperuricemia.