Association of uric acid and fructose levels in polycystic ovary syndrome.

STUDY QUESTION: Is there a relationship between serum uric acid and fructose levels in polycystic ovary syndrome (PCOS)? SUMMARY ANSWER: Elevated serum uric acid levels in women with PCOS positively correlate with serum fructose levels, and elevated serum fructose levels are an independent risk factor for hyperuricemia in women with PCOS. WHAT IS KNOWN ALREADY: Our previous study suggested a link between elevated serum fructose levels and PCOS. Fructose is unique as it generates uric acid during metabolism, and high uric acid levels are associated with metabolic disorders and an increased risk of anovulation. However, the relationship between serum uric acid and fructose levels in women with PCOS remains unclear. STUDY DESIGN, SIZE, DURATION: In a case-control study of 774 women (482 controls and 292 patients with PCOS) between May and October 2020 at the Shengjing Hospital of China Medical University, the relationship between uric acid and fructose levels in women with PCOS was examined. Participants were divided into subgroups based on various factors, including BMI, insulin resistance, dyslipidemia, metabolic syndrome, and hyperuricemia. PARTICIPANTS/MATERIALS, SETTING, METHODS: Serum uric acid concentrations were measured using enzymatic assays, and serum fructose levels were determined using a fluorescent enzyme immunoassay. Dietary fructose data were collected through a validated food-frequency questionnaire of 81 food items. We applied restricted cubic splines to a flexibly model and visualized the linear/nonlinear relationships between serum uric acid and fructose levels in PCOS. Multivariate logistic analysis was executed to assess the association between serum fructose levels and hyperuricemia in PCOS. Human granulosa cell and oocyte mRNA profile sequencing data were downloaded for mapping uric acid and fructose metabolism genes in PCOS. Further downstream analyses, including Gene Ontology, Kyoto Encyclopedia of Genes and Genomes analysis, and protein-protein interactions were then carried out on the differentially expressed genes (DEGs). The correlation between uric acid and fructose metabolism genes was calculated using the Pearson correlation coefficient. The GeneCards database was used to identify DEGs related to uric acid and fructose metabolism in PCOS, and then several DEGs were confirmed by quantitative real-time PCR. MAIN RESULTS AND THE ROLE OF CHANCE: Both serum fructose and uric acid levels were significantly increased in women with PCOS compared with the control women (P < 0.001), and there was no statistically significant difference in dietary fructose intake between PCOS and controls, regardless of metabolic status. There was a positive linear correlation between serum uric acid and fructose levels in women with PCOS (Poverall < 0.001, Pnon-linear = 0.30). In contrast, no correlation was found in control women (Poverall = 0.712, Pnon-linear = 0.43). Additionally, a non-linear association was observed in the obese subgroup of patients with PCOS (Poverall < 0.001, Pnon-linear = 0.02). Serum uric acid levels were linearly and positively associated with serum fructose levels in patients with PCOS with insulin resistance, dyslipidemia, and metabolic syndrome. Furthermore, even after adjusting for confounding factors, elevated serum fructose levels were an independent risk factor for hyperuricemia in patients with PCOS (P = 0.001; OR, 1.380; 95% CI, 1.207-1.577). There were 28 uric acid and 25 fructose metabolism genes which showed a significant correlation in PCOS. Seven upregulated genes (CAT, CRP, CCL2, TNF, MMP9, GCG, and APOB) related to uric acid and fructose metabolism in PCOS ovarian granulosa cells were ultimately successfully validated using quantitative real-time PCR. LIMITATIONS, REASONS FOR CAUTION: Due to limited conditions, more possible covariates (such as smoking and ethnicity) were not included, and the underlying molecular mechanism between fructose and uric acid levels in women with PCOS remains to be further investigated. WIDER IMPLICATIONS OF THE FINDINGS: The results of this study and our previous research indicate that the high uric acid status of PCOS may be mediated by fructose metabolism disorders, highlighting the importance of analyzing fructose metabolism, and especially its metabolic byproduct uric acid, during the clinical diagnosis of PCOS. These results suggest the adverse effects of high uric acid in PCOS, and the importance of taking early interventions regarding uric acid levels to reduce the occurrence and development of further clinical signs, such as metabolic disorders in women with PCOS. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by: the National Natural Science Foundation of China (No. 82371647, No. 82071607, and No. 32100691); LiaoNing Revitalization Talents Program (No. XLYC1907071); Fok Ying Tung Education Foundation (No. 151039); and Outstanding Scientific Fund of Shengjing Hospital (No. 202003). No competing interests were declared. TRIAL REGISTRATION NUMBER: N/A.

Serum fructose concentrations are positively correlated with dyslipidaemia in women with polycystic ovary syndrome.

RESEARCH QUESTION: Is there an association between fructose and dislipidaemia in polycystic ovary syndrome (PCOS)? DESIGN: Serum fructose levels were measured in 250 women with PCOS (113 with dislipidaemia, 137 with normolipidaemia) and 460 controls (70 with dislipidaemia, 390 with normolipidaemia). Logistic regression was used to model the relationship between serum fructose levels and dyslipidaemia. Receiver operating characteristic curve analysis was used to assess the ability of serum fructose levels to predict dislipidaemia in women with PCOS, and PCOS in women with dislipidaemia. RESULTS: Patients with PCOS and dislipidaemia had higher serum fructose levels. Triglycerides, total cholesterol and low-density lipoprotein cholesterol increased with increasing serum fructose quartiles in patients with PCOS, whereas high-density lipoprotein cholesterol decreased (all P < 0.001). Among the lipid metabolism-related indicators, triglycerides were most associated with fructose (R = 0.626, P < 0.001). Serum fructose at a cut-off value of 9.79 pmol/µl had a sensitivity of 83.2% and specificity of 66.4% for predicting dislipidaemia in women with PCOS. Lower serum fructose levels were strongly associated with a decreased risk of dislipidaemia in women with PCOS (P < 0.001; OR 0.067; 95% CI 0.027 to 0.170). Moreover, high fructose levels are predictive of PCOS in women with dislipidaemia, with a better diagnostic performance than the androgens typically used as markers. CONCLUSION: Serum fructose levels are significantly correlated with dislipidaemia in women with PCOS, highlighting the importance of investigating the role of fructose in lipid metabolism of PCOS.

Demonstration of polarization mode selection and coupling efficiency of optofluidic ring resonator lasers.

We demonstrate the polarization mode selection and the dependence of coupling efficiency on polarization state of pump light for an optofluidic ring resonator (OFRR) laser. An optical fiber is chosen to serve as the ring resonator and surrounded by rhodamine 6G dye solution of lower refractive index as the fluidic gain medium. When the ring resonator is pumped by a linearly s-polarized laser, the emitted whispering gallery mode (WGM) lasing is of parallel polarization (TM mode), while p-polarized laser excitation generates a vertically polarized lasing emission (TE mode), both TM and TE mode lasing emission coexist simultaneously if the ring resonator is pumped by the s- and p-mixed polarized light. Further investigation reveals that the lasing intensity of the TM mode is approximately twice that of the TE mode for the same pump energy density, meaning an obvious difference of coupling efficiency on the polarization state of pump light; the experimental results of coupling efficiency are well explained by an induced dipole model.

Controllable Synthesis of PtIrCu Ternary Alloy Ultrathin Nanowires for Enhanced Ethanol Electrooxidation.

Rational design and controllable synthesis of catalysts with unique structure and composition are effective ways to promote electrocatalytic ethanol oxidation, thus contributing the direct ethanol fuel cells to gain ground. Herein, 2.5 nm-thin PtIrCu ternary alloy ultrathin nanowires (UNWs) with high-density planar defects are synthesized via oriented attachment with the assistance of H2. By adjusting the contents of Ir and Cu atoms, we find that the structure of the products changed from nanowires (NWs) to nanoparticles with the increase of Ir content. Density functional theory calculations show that when Cu atoms are replaced by Ir atoms, the vacancy formation energy of Pt atoms is increased, making the Pt atoms difficult to be activated by H2, which is not conducive to the formation of a one-dimensional structure. The optimal Pt43Ir32Cu25 UNWs achieve excellent ethanol electrooxidation reaction activity (1.05 A·mg-1Pt and 1.67 mA·cm-2), for it can significantly reduce the onset potential and improve the ability of CO anti-poisoning. The significant improvement in catalytic performance is attributed to the synergistic effect of the alloy and the NW structure with high-density planar defects.

Mode I Fatigue of Fibre Reinforced Polymeric Composites: A Review.

Composites are macroscopic combinations of chemically dissimilar materials preferred for new high-tech applications where mechanical performance is an area of interest. Mechanical apprehensions chiefly include tensile, creep, and fatigue loadings; each loading comprises different modes. Fatigue is cyclic loading correlated with stress amplitude and the number of cycles while defining the performance of a material. Composite materials are subject to various modes of fatigue loading during service life. Such loadings cause micro invisible to severe visible damage affecting the material's performance. Mode I fatigue crack propagates via opening lamina governing a visible tear. Recently, there has been an increasing concern about finding new ways to reduce delamination failure, a life-reducing aspect of composites. This review focuses on mode I fatigue behaviours of various preforms and factors determining failures considering different reinforcements with respect to fibres and matrix failures. Numerical modelling methods for life prediction of composites while subjected to fatigue loading are reviewed. Testing techniques used to verify the fatigue performance of composite under mode I load are also given. Approaches for composites' life enhancement against mode I fatigue loading have also been summarized, which could aid in developing a well-rounded understanding of mode I fatigue behaviours of composites and thus help engineers to design composites with higher interlaminar strength.

Global Trends in Research on Cell-Free Nucleic Acids in Obstetrics and Gynecology during 2017-2021.

OBJECTIVES: The objectives of this study were to identify global trends in research on cell-free deoxyribonucleic acid (cfDNA) from a bibliometric perspective and provide researchers with new research hotspots. METHODS: In all, we extracted 5038 pieces of literature from PubMed and 527 articles from the Web of Science Core Collection (WoSCC) database related to cfDNA published from 1 January 2017 to 31 December 2021. For PubMed literature, we employed co-word, biclustering, and strategic diagram analysis to describe the trends in research on cfDNA in the said five years. Then, we used VOSviewer analysis for the WoSCC database to display the trends in research on cfDNA in obstetrics and gynecology during 2017-2021. RESULTS: Strategy diagram analysis of 95 major Medical Subject Headings terms extracted from 5038 pieces of literature indicated that cfDNA sequence analysis for non-invasive prenatal and genetic testing and its application in the fields of neoplasm genetics and diagnosis is a newly emerging immature theme of cfDNA. VOSviewer analysis of 527 articles showed the global trends in research on cfDNA in obstetrics and gynecology, for example, in terms of most influential authors, institutions, countries, journals, and five research hotspots: (1) cfDNA application in prenatal screening and prenatal diagnosis, (2) cfDNA application in assisted reproductive technology, (3) cfDNA application in pre-eclampsia, DNA methylation, etc., (4) cfDNA application in placental dysfunction and fetal growth restriction, and (5) cfDNA application in fetal chromosomal abnormalities (fetal aneuploidy). CONCLUSIONS: Comprehensive visual analysis provides information regarding authors, organizations, countries/regions, journals, research hotspots, and emerging topics in the field of cfDNA for obstetrics and gynecology research. This comprehensive study could make it easier to find a partner for project development and build a network of knowledge on this emerging topic.

Elevated Serum Leptin Levels as a Predictive Marker for Polycystic Ovary Syndrome.

Background: Leptin may have important implications in polycystic ovary syndrome (PCOS)-related metabolic disorders. However, the changes in serum leptin levels in patients with PCOS and its predictive value for PCOS remain obscure. We intend to analyze the association between leptin and PCOS in this study. Materials and Methods: The study comprised 89 patients with PCOS and 139 individuals without PCOS. Each group was stratified as either normal- or hyper-fasting serum insulin (FSI), and lean or overweight/obese; and the patients were further categorized as normal- or hyper-androgenic. The validity of leptin toward the diagnosis of PCOS, or leptin combined with total testosterone, dehydroepiandrosterone sulfate (DHEAS), and free testosterone was estimated by receiver operating characteristic (ROC) curves, and correlations between paired variables was estimated by Spearman's rank correlation coefficient. Associations between the clinical and metabolic variables and PCOS were analyzed via logistic regression. Results: The serum leptin levels of patients with PCOS were significantly higher than that of the control, and especially the PCOS in hyper-FSI, hyperandrogenimic and overweight/obese subgroups. The area under the ROC curve (AUC) of leptin was 74%, with cutoff value, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) 11.58 ng/mL, 77.5%, 62.6%, 57.0%, and 81.3%, respectively. Combined leptin and anti-Müllerian hormone (AMH) had the highest AUC (92.3%), excellent sensitivity (93.3%), moderate specificity (78.3%), PPV (73.5%) and NPV (94.8%). Serum leptin levels of the patients were correlated with the FSI, fasting plasma glucose (FPG), homeostasis model assessment of insulin resistance (HOMA-IR), body mass index (BMI), and total testosterone levels. Elevated serum leptin was associated with a high risk of PCOS [P = 0.015; OR (95% CI) 1.128 (1.024-1.244)]. Conclusion: Substantially elevated serum leptin is significantly associated with PCOS. These findings warrant further investigations into the function of leptin in the pathogenesis of PCOS.

RING-finger E3 ligases regulatory network in PI3K/AKT-mediated glucose metabolism.

The phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway plays an essential role in glucose metabolism, promoting glycolysis and resisting gluconeogenesis. PI3K/AKT signaling can directly alter glucose metabolism by phosphorylating several metabolic enzymes or regulators of nutrient transport. It can indirectly promote sustained aerobic glycolysis by increasing glucose transporters and glycolytic enzymes, which are mediated by downstream transcription factors. E3 ubiquitin ligase RING-finger proteins are mediators of protein post-translational modifications and include the cullin-RING ligase complexes, the tumor necrosis factor receptor-associated family, the tripartite motif family and etc. Some members of the RING family play critical roles in regulating cell signaling and are involved in the development and progression of various metabolic diseases, such as cancer, diabetes, and dyslipidemia. And with the progression of modern research, as a negative or active regulator, the RING-finger adaptor has been found to play an indispensable role in PI3K/AKT signaling. However, no reviews have comprehensively clarified the role of RING-finger E3 ligases in PI3K/AKT-mediated glucose metabolism. Therefore, in this review, we focus on the regulation and function of RING ligases in PI3K/AKT-mediated glucose metabolism to establish new insights into the prevention and treatment of metabolic diseases.