Roles of serum uric acid on the association between arsenic exposure and incident metabolic syndrome in an older Chinese population.

Growing evidences showed that heavy metals exposure may be associated with metabolic diseases. Nevertheless, the mechanism underlying arsenic (As) exposure and metabolic syndrome (MetS) risk has not been fully elucidated. So we aimed to prospectively investigate the role of serum uric acid (SUA) on the association between blood As exposure and incident MetS. A sample of 1045 older participants in a community in China was analyzed. We determined As at baseline and SUA concentration at follow-up in the Yiwu Elderly Cohort. MetS events were defined according to the criteria of the International Diabetes Federation (IDF). Generalized linear model with log-binominal regression model was applied to estimate the association of As with incident MetS. To investigate the role of SUA in the association between As and MetS, a mediation analysis was conducted. In the fully adjusted log-binominal model, per interquartile range increment of As, the risk of MetS increased 1.25-fold. Compared with the lowest quartile of As, the adjusted relative risk (RR) of MetS in the highest quartile was 1.42 (95% confidence interval, CI: 1.03, 2.00). Additionally, blood As was positively associated with SUA, while SUA had significant association with MetS risk. Further mediation analysis demonstrated that the association of As and MetS risk was mediated by SUA, with the proportion of 15.7%. Our study found higher As was remarkably associated with the elevated risk of MetS in the Chinese older adults population. Mediation analysis indicated that SUA might be a mediator in the association between As exposure and MetS.

Ilex cornuta leaves extracts ameliorate hyperuricemia by modulating uric acid transporters.

ETHNOPHARMACOLOGICAL RELEVANCE: Ilex cornuta is a valuable species of the Holly genus (Aquifoliaceae), and mainly distributed in eastern China. It is not only made into tea, namely Kudingcha, but also used as traditional medicine to relieve cough, headache, gout, and nourish liver and kidney. AIM OF THE STUDY: The purpose of this study was to explore the exact efficacy of different extracts from Ilex cornuta in the treatment of hyperuricemia in vitro and in vivo, and to explore its pharmacological mechanism, so as to bring new ideas for the development of new drugs for reducing uric acid (UA) and anti-gout. MATERIALS AND METHODS: Five crude extracts from Ilex cornuta leaves were extracted by different methods. Then, the xanthine oxidase inhibitory activity and antioxidant capacity of 5 extracts in vitro were compared to screen the extract with the most UA regulating potential. In vivo experiment, hyperuricemia model of mice was established by intragastric administration of potassium oxonate and feeding high yeast diet. Biochemical indexes such as serum UA level, xanthine oxidase activity, liver and kidney index of mice in each group were detected. The pathological sections of kidney and liver tissues were also observed and compared. The mechanism of Ilex cornuta leaves (western blotting, and RT-qPCR) in the treatment of hyperuricemia was further explored by targeting UA transporters ABCG2, GLUT9, and URAT1. RESULTS: The in vitro results of inhibitory activity of xanthine oxidase showed that the crude saponin extract was the best, followed by crude flavonoids extract. Then, the in vivo results reflected that both crude saponins and crude flavonoids extracts could significantly reduce the serum UA level, inhibit the activity of xanthine oxidase in serum and liver, and maintain serum urea nitrogen and creatinine at normal level. Meanwhile, there was no liver and kidney injury in mice. Through the comparison of the mechanism results, it was found that both extracts could up-regulate the expression of ABCG2 protein and mRNA related to UA excretion, and down-regulate the expression of GLUT9 and URAT1 protein and mRNA. CONCLUSION: The crude flavonoids and saponins of Ilex cornuta leaves not only inhibited XOD activity in vitro, but also significantly controlled XOD activity and reduced UA level in hyperuricemia mice in vivo. One of the potential mechanisms was to regulate UA level in vivo by regulating ABCG2, GLUT9, and URAT1 transporters directly related to UA transport, thus achieving the effect of intervening hyperuricemia. This study provided a preliminary experimental basis for the development of new drugs of Ilex cornuta leaves for treating hyperuricemia.

Associations of polycyclic aromatic hydrocarbons exposure with serum uric acid and hyperuricemia in US adults: The role of systemic inflammation.

The associations of polycyclic aromatic hydrocarbon (PAH) exposure with serum uric acid (SUA) or hyperuricemia have been rarely assessed. We aimed to investigate the relationships between urinary PAH metabolites and SUA or hyperuricemia among US adults and to explore the mediating role of systemic inflammation in the associations. A total of 10,307 US adults were conducted to assess the associations of seven urinary hydroxy­PAH with SUA and hyperuricemia and evaluate the role of C-reactive protein (CRP), a biomarker of systemic inflammation, in such associations. Results showed that each 1-unit increase in ln-transformed 2-hydroxynaphthalene (2-OHNa), 1-hydroxyphenanthrene (1-OHPh), 2&3-hydroxyphenanthrene (2&3-OHPh) and total hydroxyphenanthrene (ΣOHPh) was associated with a 1.68 (95% confidence interval (CI): 0.19 to 3.17), 2.46 (0.78 to 4.13), 3.34 (1.59 to 5.09), and 2.99 (1.23 to 4.75) µmol/L increase in SUA, and a 8% (odds ratio (OR): 1.08, 1.02 to 1.15), 9% (OR: 1.09, 1.02 to 1.18), 13% (OR: 1.13, 1.05 to 1.22), and 12% (OR: 1.12, 95% CI: 1.03, 1.21) increase in hyperuricemia, respectively. Co-exposure of seven PAHs was positively associated with SUA and hyperuricemia, with 2&3-OHPh showing the highest weight (components weights: 0.83 and 0.78, respectively). The CRP mediated 11.47% and 10.44% of the associations of ΣOHPh and 2&3-OHPh with SUA and mediated 8.60% and 8.62% in associations of ΣOHPh and 2&3-OHPh with hyperuricemia, respectively. In conclusion, internal levels of PAH metabolites were associated with elevated SUA levels and the increased risk of hyperuricemia among US adults, and CRP played a mediating role in the associations.

Sex and Age Differences in the Effects of Food Frequency on Metabolic Parameters in Japanese Adults.

Owing to differences in dietary preferences between men and women, the associations between dietary intake frequency and metabolic parameters may differ between the sexes. A retrospective observational study of the checkup findings of 3147 Japanese individuals (968 men, 2179 women) aged 20-59 years was conducted to examine differences in dietary habits and associations between food frequency and blood parameters (eGFR, HbA1c, uric acid, and lipids) by sex and age. Males were more likely to consume meat, fish, soft drinks, and alcohol, whereas women were more likely to consume soybeans, dairy products, vegetables, fruits, and snacks. Multivariate linear regression models adjusted for age and BMI revealed that meat intake frequency was positively associated with HbA1c (ß = 0.007, p = 0.03) and negatively associated with eGFR (ß = -0.3, p = 0.01) only in males, whereas fish intake frequency was positively associated with eGFR (ß = 0.4, p = 0.005) only in females. Egg and soy intake frequencies were positively and negatively associated with non-HDL-C (egg: ß = 0.6, p = 0.02; soy: ß = -0.3, p = 0.03) only in females. Alcohol consumption frequency was associated with uric acid (M: ß = 0.06, p < 0.001; F: ß = 0.06, p < 0.001) and HDL-C (M: ß = 1.0, p < 0.001; F: ß = 1.3, p < 0.001) in both sexes. Future research is needed to determine whether varying the emphasis of dietary guidance by sex and age group is effective, since the effects of dietary preferences on metabolic parameters vary by age and sex.

Pyrazinamide-induced Hyperuricemia in Pulmonary Tuberculosis Patients.

BACKGROUND: Pyrazinamide is one of the antitubercular drugs used for 2 months in the intensive phase. One of the adverse effects of pyrazinamide is hyperuricemia, with a symptom of arthralgia. This study aims to analyze the incidence of hyperuricemia and arthralgia and their causality in pulmonary tuberculosis (TB) patients undergoing treatment in the intensive phase. METHODS: It was an analytic observational study with a prospective cohort design. Three ml of blood from each pulmonary TB patient was withdrawn to examine uric acid levels before and after 2 months of treatment with pyrazinamide. The Wilcoxon test was used to analyze changes in uric acid levels and the Chi-square test to analyze the association between uric acid levels and arthralgia. Naranjo algorithm is used to analyze the causality of hyperuricemia. RESULTS: Twenty pulmonary TB patients met the inclusion criteria in this study. Eight out of 12 (60%) TB patients showed uric acid levels ≥7 mg/dl and 8 of them (66.6%) showed symptoms of arthralgia. The median uric acid level increased significantly before (5.14 mg/dl) and after 2 months of treatment (7.74 mg/dl), P-value = 0.001. Uric acid levels ≥7 mg/dl were significantly associated with arthralgia (P-value = 0.017; odds ratio 14.00; 95% confidence interval 1.25-156.61). Based on the Naranjo algorithm, those with hyperuricemia, eight and four patients had a total score of 7 and 8, respectively, which are classified as probable. CONCLUSION: Uric acid levels significantly increased during the intensive phase. Pulmonary TB patients with hyperuricemia are a risk factor for arthralgia.

Association between 25 hydroxyvitamin D and serum uric acid level in the Chinese general population: a cross-sectional study.

BACKGROUD: The relationship between serum uric acid (SUA) and 25-hydroxyvitamin D (25(OH)D) has been variably characterized in existing literature, with inconsistent results regarding its nature and implications in the Chinese population. This study aims to clarify this association, considering the potential impact of vitamin D levels on SUA. METHODS: This cross-sectional study involved 7,086 individuals from the Second Affiliated Hospital of Zhejiang University School of Medicine, screened throughout 2020. We collected data on 25(OH)D, SUA, and other metabolic markers. Logistic regression models adjusted for confounding factors were utilized to analyze the relationships. RESULTS: Our findings illustrate a statistically significant inverted U-shaped relationship between 25(OH)D and SUA. The identified threshold effect at 28.82 ng/ml is pivotal; with 25(OH)D levels below this point associated with an increased risk of hyperuricemia (odds ratio: 1.0146, p = 0.0148), and levels above it offering protective benefits (odds ratio: 0.9616, p = 0.0164). CONCLUSIONS: Our findings confirm a nonlinear, inverted U-shaped correlation between 25(OH)D and SUA, emphasizing the importance of maintaining vitamin D levels within a specific range to effectively manage hyperuricemia. These results support the implementation of personalized vitamin D supplementation strategies to optimize metabolic health outcomes, highlighting the complex interplay between vitamin D status and uric acid levels.

Investigating artificial intelligence models for predicting joint pain from serum biochemistry.

OBJECTIVE: The study used machine learning models to predict the clinical outcome with various attributes or when the models chose features based on their algorithms. METHODS: Patients who presented to an orthopedic outpatient department with joint swelling or myalgia were included in the study. A proforma collected clinical information on age, gender, uric acid, C-reactive protein, and complete blood count/liver function test/renal function test parameters. Machine learning decision models (Random Forest and Gradient Boosted) were evaluated with the selected features/attributes. To categorize input data into outputs of indications of joint discomfort, multilayer perceptron and radial basis function-neural networks were used. RESULTS: The random forest decision model outperformed with 97% accuracy and minimum errors to anticipate joint pain from input attributes. For predicted classifications, the multilayer perceptron fared better with an accuracy of 98% as compared to the radial basis function. Multilayer perceptron achieved the following normalized relevance: 100% (uric acid), 10.3% (creatinine), 9.8% (AST), 5.4% (lymphocytes), and 5% (C-reactive protein) for having joint pain. Uric acid has the highest normalized relevance for predicting joint pain. CONCLUSION: The earliest artificial intelligence-based detection of joint pain will aid in the prevention of more serious orthopedic complications.

Dietary Carbohydrates, Genetic Susceptibility, and Gout Risk: A Prospective Cohort Study in the UK.

This study aimed to investigate the associations between carbohydrate intake and gout risk, along with interactions between genetic susceptibility and carbohydrates, and the mediating roles of biomarkers. We included 187,387 participants who were free of gout at baseline and completed at least one dietary assessment in the UK Biobank. Cox proportional hazard models were used to estimate the associations between carbohydrate intake and gout risk. Over a median follow-up of 11.69 years, 2548 incident cases of gout were recorded. Total carbohydrate intake was associated with a reduced gout risk (Q4 vs. Q1: HR 0.67, 95% CI 0.60-0.74), as were total sugars (0.89, 0.80-0.99), non-free sugars (0.70, 0.63-0.78), total starch (0.70, 0.63-0.78), refined grain starch (0.85, 0.76-0.95), wholegrain starch (0.73, 0.65-0.82), and fiber (0.72, 0.64-0.80), whereas free sugars (1.15, 1.04-1.28) were associated with an increased risk. Significant additive interactions were found between total carbohydrates and genetic risk, as well as between total starch and genetic risk. Serum urate was identified as a significant mediator in all associations between carbohydrate intake (total, different types, and sources) and gout risk. In conclusion, total carbohydrate and different types and sources of carbohydrate (excluding free sugars) intake were associated with a reduced risk of gout.

Fetoplacental unit involvement in uric acid production in women with severe preeclampsia: a prospective case control pilot study.

PURPOSE: Preeclampsia (PE) is a common complication of pregnancy that carries significant risks for both the mother and the fetus, and is frequently accompanied by hyperuricemia, yet the exact source of elevated uric acid (UA) levels remains partially elucidated. Several potential origins for increased UA levels include abnormal renal function, increased tissue breakdown, and increased activity of the enzyme Xanthine Oxidase (XO). The aim of the study was to determine serum levels of UA and XO not only in maternal serum, but also in umbilical vein (UV) and umbilical artery (UA) and explore their possible role in PE development. METHODS: A prospective case-control pilot study was conducted in women who were found positive for PE with severe features, and had elevated UA levels above 6 mg/dL, with normotensive pregnant women serving as controls. Renal function, UA and XO levels were measured in maternal, UV and UA serums immediately after delivery. They were then compared between PE (n = 21) and control (n = 18) groups, as well as across all mediums (maternal, UV and UA) among the total study sample (N = 39). Diastolic blood pressure (DBP) was also measured immediately following delivery. RESULTS: The mean serum maternal creatinine levels did not differ significantly between groups (0.65 ± 0.03 vs 0.6 ± 0.07, p = 0.13). Both mean maternal serum UA and XO concentrations were higher in PE group than in control (7.3 ± 1.2 vs 4.2 ± 0.9, p < 0.01 and 3.6 ± 3.5 Vs 1.7 ± 0.8, p < 0.01, respectively). The mean UV and UA serum XO concentrations were significantly higher in PE group compared to control (4.2 ± 3.6 vs 2.2 ± 1.4, p < 0.01 and 4.2 ± 3.6 vs 2.1 ± 1.5, p < 0.01, respectively). Polynomial fit correlation test demonstrated a significant association between maternal DBP and UV XO concentration for all the total study participants (p = 0.03). CONCLUSION: Despite preserved renal functions, UA and XO levels were elevated in women with PE. Importantly, this pattern was found to be applied to the feto-placental unit as well, which may indicate an active involvement of the fetus in the hypoxic process. Further study is needed to clarify the possible role of the feto-placental unit in pregnancies complicated by PE.

Empowering probiotics with high xanthine transport for effective hyperuricemia management.

Hyperuricemia, a prevalent metabolic disorder, poses a susceptibility to various complications. The conventional pharmacotherapeutic approaches for hyperuricemia often entail notable adverse effects, posing substantial clinical challenges. Hence, the imperative lies in the development of novel, safe and effective strategies for preventing and treating hyperuricemia. Here, we developed a probiotic Escherichia coli Nissle 1917 strain, designated as YES301, which contains a rationally designed xanthine importer XanQ, enabling efficient uptake of xanthine and hypoxanthine, consequently leading to reduced serum uric acid concentrations and amelioration of renal impairments in a murine model of hyperuricemia. Importantly, YES301 exhibited a therapeutic efficacy comparable to allopurinol, a conventional uric acid-lowering agent, and manifesting fewer adverse effects and enhanced biosafety. These findings highlight the promising potential of engineered probiotics in the management of hyperuricemia through reducing intestinal purine levels.

Association between cardiovascular health assessed by life's essential 8 and hyperuricemia in U.S. adults: the NHANES 2009-2020.

Background: This study presented the new Life's Essential 8 (LE8) framework for examining cardiovascular health (CVH) to analyze the potential relationship between the latter and hyperuricemia (HUA) in the U.S. population. Methods: Data on individuals aged at least 20 years were collected from the National Health and Nutrition Examination Survey (NHANES) 2009-2020. Smoothed curve fitting and multivariate logistic regression analyses were then performed on a sample of 25,681 adults to explore the association between LE8 and HUA. A sensitivity analysis was conducted to examine the robustness of the research findings. Results: The study found a strong negative association between LE8 and HUA, with an odds ratio (OR) of 0.71 and a 95% confidence interval (CI) from 0.69 to 0.73 after adjusting for multiple confounding factors. The sensitivity analysis further validated the robustness of this association. This analysis consistently showed negative associations across different genders, ages, races, and education levels (p < 0.05), but there were no significant relationships with marital status. The association between uric acid levels and LE8 displayed an inverted L-shaped curve, with an inflection point around 41.43. Conclusions: The findings indicate a strong negative relationship between LE8 and HUA among the U.S. population, suggesting that higher scores on the LE8, which assesses CVH, were associated with reduced uric acid levels. The consistent negative association underscores the LE8 framework's potential as a valuable tool for understanding and managing HUA in CVH.

Identifying reliable obesity indices for hyperuricemia among middle-aged and elderly populations: a longitudinal study.

BACKGROUND: Given the established link between obesity and hyperuricemia (HUA), the research want to investigate the relationship between different obesity indices and HUA, and further analyze which obesity index can better predict HUA. METHODS: The data were obtained from a longitudinal study involving middle-aged and elderly populations in Dalian, China. The research encompassed individuals who exhibited typical uric acid levels initially and tracked their progress over a three-year period. 8 obesity indices were evaluated retrospectively. Subgroup analyses were conducted to identify susceptible populations. Restricted cubic splines (RCS) were utilized to model the dose-response relationships between obesity indices and HUA. Receiver operating characteristic (ROC) curves were applied to visualize and compare the predictive value of both traditional and new obesity indices for HUA. RESULTS: Among 4,112 individuals with normal baseline uric acid levels, 950 developed HUA. Significant associations with HUA were observed for body mass index (BMI), waist circumference (WC), body roundness index (BRI), cardiometabolic index (CMI), visceral adiposity index (VAI), Chinese visceral adiposity index (CVAI), lipid accumulation product (LAP), and abdominal volume index (AVI). Subgroup analysis indicated that all obesity indices proved more effective in assessing the onset of HUA in women without Metabolic Syndrome (MetS). Further analysis using RCS revealed non-linear dose-response relationships between LAP, CMI, VAI, and HUA in males, with similar non-linear relationships observed for all indices in females. The results from the ROC curves indicate that LAP may serve as a better predictor of HUA in males, and CVAI may serve as a better predictor in females. CONCLUSION: HUA is closely associated with obesity indices. Among females, CVAI emerges as the preferred predictive index for HUA. In males, LAP emerges as the preferred predictive index for HUA.

Association of serum uric acid to all-cause and cardiovascular mortality in patients with cardiovascular disease.

Serum uric acid (SUA) has been linked to mortality in heart failure, hypertension, diabetes, hyperlipidemia, obstructive sleep apnea, and metabolic dysfunction-associated fatty liver disease. However, data are lacking on how it affects the mortality risk of patients with cardiovascluar disease (CVD). This study evaluated the data of 4 308 individuals from the National Health and Nutrition Examination Survey 1999-2008 using multivariate Cox proportional hazards regression, trend, restricted cubic splines (RCS), subgroup and inflection point analyses. All-cause and cardiovascular mortality accounted for 42.8% and 17.6% of cases, respectively, over a median 80- month follow-up. Upon control for confounding variables, no linear trend was seen in the Cox proportional hazards regression analysis between SUA and all-cause (P = 0.001) or cardiovascular death (P = 0.007) mortality. On the RCS analysis, SUA showed an L-shaped connection with all-cause (non-linear P < 0.001) and cardiovascular mortality (non-linear P = 0.003) mortality. On the inflection point analysis, patients with CVD and an SUA ≥ 6.127 mg/dL had an all-cause mortality hazard ratio of 1.146 (95% confidence interval, 1.078-1.217; P < 0.001), while those with CVD and an SUA ≥ 5.938 mg/dL had a cardiovascular mortality hazard ratio of 1.123 (95% confidence interval, 1.03-1.225; P = 0.007). In patients with CVD, higher SUA was non-linearly correlated with all-cause and cardiovascular mortality.

Association between serum uric acid levels and cardio-ankle vascular index stratified by circulating level of CD34-positive cells among elderly Japanese men: a cross-sectional study.

Although serum uric acid (UA) has been reported to be positively associated with increased arterial stiffness as evaluated by cardio-ankle vascular index (CAVI), UA also has an antioxidative effect that prevents endothelial damage. Therefore, the status of endothelial repair induced by endothelial damage might affect the correlation between UA and CAVI. To clarify the correlation between UA and CAVI in relation to endothelial repair activity, we performed a cross-sectional study with 246 Japanese men aged 60-69 years undergoing a general health check-up. The analysis was stratified by the median circulating level of CD34-positive cells because circulating levels of CD34-positive cells could indicate the degree of endothelial repair activity. Independent of known cardiovascular risk factors, among participants with high circulating levels of CD34-positive cells (0.95 cells/µL ≤), UA was significantly positively correlated with CAVI (standardized parameter estimate ß = 0.23, p = 0.009), but not among participants with low circulating levels of CD34-positive cells (< 0.95 cells/µL) (ß = 0.07, p = 0.445). Independent of established cardiovascular risk factors, UA levels were significantly positively correlated with increased arterial stiffness only among participants with aggressive endothelial repair as evaluated by circulating levels of CD34-positive cells. These results might help clarify some background mechanisms related to endothelial activity.

Mendelian randomization reveals the causal association between gout and hearing impairment in older adults.

With the global aging trend escalating, the holistic well-being of the elderly has become a paramount concern within public health. Traditional observational studies often struggle with confounding factors and establishing causality, leaving the relationship between age-related hearing loss (ARHL) and gout largely unexplored. Employing bidirectional two-sample Mendelian randomization (MR) analysis, this investigation elucidated the genetic underpinnings associated with age-related hearing impairment, gout, and urate levels within the IEU Open-GWAS database, thereby uncovering potential causal connections that underlie the intricate interplay between gout, serum urate concentrations, and auditory decline in the geriatric demographic. In the forward MR phase, a cohort of 30 single nucleotide polymorphisms was leveraged to dissect the causal dynamics between ARHL and both gout and urate concentrations. Conversely, in the reverse MR phase, gout and urate levels were posited as the exposome to delineate their impact on hearing acuity, employing an array of models for rigorous validation and sensitivity scrutiny. In the forward MR analysis, a statistically significant correlation was discerned between ARHL and gout (P = .003, odds ratio = 1.01, 95% confidence interval: 1.00-1.02), alongside a notable association with serum urate levels (P = .031, odds ratio = 1.39, 95% confidence interval: 1.03-1.88), intimating that ARHL could potentially influence the incidence of gout and urate concentrations. Conversely, the reverse MR investigation revealed that neither gout nor serum urate levels exerted significant impact on auditory degradation (P > .05), insinuating that these factors might not predominantly contribute to hearing loss. Sensitivity analyses concurred with this inference. This study enriches the comprehension of geriatric health intricacies and unveils that ARHL potentially influences gout and serum urate concentrations. This suggests that monitoring ARHL may play a crucial role in the early identification and management of gout and hyperuricemia, potentially contributing to a comprehensive approach to improving geriatric health outcomes.

Metabolic signatures of metabolites of the purine degradation pathway in human plasma using HILIC UHPLC-HRMS.

The metabolic disorders in the purine degradation pathway have proven to be closely associated with several human diseases. However, the etiology is not yet fully understood. Profile assay of purine intermediates and uric acid involved in the metabolic pathway can provide additional insight into the nature and severity of related diseases. Purine metabolites are endogenous chemicals with high hydrophilicity, polarity, and similar structures, thus there is a great need for a specific method to quantify them directly in biological fluids with a short running time. Herein, eight purine degradation pathway metabolites, including xanthine, hypoxanthine, guanine, xanthosine, inosine, guanosine, adenosine and uric acid, in human plasma were quantitatively measured using hydrophilic interaction chromatography-tandem high-resolution mass spectrometry (HILIC-HRMS) in a short running time of 10 min. The method was systematically validated for specificity, linearity of the calibration curve, the limit of detection, the limit of quantification, the lower limit of quantification, precision, accuracy, extraction recovery, matrix effect, and stability. The results showed that the method was linear (R2 > 0.99), accurate (the intra- and inter-day recoveries of all analytes ranged from 90.0 % to 110.0 %), and precise (the intra- and inter-day precisions were less than 6.7 % and 8.9 %, respectively) with the lower limits of quantification ranging from 3 to 10,000 ng/mL. The extraction recoveries and matrix effects were repeatable and stable. All the analytes were stable in the autosampler and could be subject to three freeze-thaw cycles. The developed method was ultimately applied to 100 plasma specimens from healthy individuals. The results showed that the concentrations of different purine metabolites varied dramatically in plasma specimens. Diet and body mass index (BMI) were the most significant factors determining purine levels, followed by drinking and sex. Age, smoking and bedtime showed a very weak correlation with purine metabolism. The findings of the present work reveal the characteristics of purine metabolism in human plasma under non-pathological conditions. The results also highlight the factors that can cause changes in purine metabolism, which are useful in developing effective treatment strategies for metabolic disorders of purines, particularly for those caused by lifestyle factors.

LACK OF AGREEMENT BETWEEN A POINT-OF-CARE BLOOD URIC ACID METER AND A BENCHTOP CHEMISTRY ANALYZER IN EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA).

Uric acid (UA) is excreted as an end product of protein metabolism in many reptiles, including some chelonians. Elevated plasma UA concentrations can occur due to many physiologic and pathologic changes, and determining plasma UA concentrations is part of a complete general health assessment in this taxon. UA concentrations are typically measured using benchtop chemistry analyzers, but point-of-care (POC) UA meters have also been developed for human use. However, these POC UA meters have not been investigated for use in any reptile species. The purpose of this study was to assess agreement between UA measurements produced by a standard benchtop chemistry analyzer and a POC UA meter in free-living eastern box turtles (Terrapene carolina carolina). UA concentrations were measured with a POC meter using fresh whole blood and frozen-thawed plasma and with a standard benchtop chemistry analyzer using frozen-thawed plasma. Poor-to-moderate agreement was present between each of the three methods as evidenced by mixed models, Passing-Bablok regression, Bland-Altman plots, and Cohen's κ. Differences between methods fell outside of clinically acceptable limits, indicating that the POC UA meter should not be used in eastern box turtles.

Is cardiac function associated with the clinical course of disease in patients with gout? A prospective study.

OBJECTIVE: To analyze the function of the left heart in patients with different courses of gout, the independent influencing factors for left heart functional changes, and interactions between left atrial and left ventricular functions. METHODS: Patients with gout (n = 171) were selected; 87 patients with a disease course <10 years were included in Group I, and 84 patients with a disease course ≥10 years were included in Group II. Ninety-four healthy volunteers comprised the control group. RESULTS: The intergroup differences in cardiac strain parameters were statistically significant (p < .05). Moreover, the differences gradually declined with disease progression. Multivariate logistic regression analysis showed that uric acid was an independent predictor of decreased left ventricular global longitudinal strain (LVGLS). Moreover, LVGLS had a positive effect on the left atrial systolic rate (LASr) and the left atrial systolic contraction time (LASct) but no interaction with the left atrial systolic contraction duration (LAScd). CONCLUSION: The course of the disease significantly affected the function of the left heart in gout patients, and uric acid was observed to be an independent predictor of decreased LVGLS in gout patients.

Effect of low-purine diet on the serum uric acid of gout patients in different clinical subtypes: a prospective cohort study.

BACKGROUND: The pathogenic causes of primary gout include urate overproduction and/or renal or extra-renal urate underexcretion. The aim of this study was to evaluate the association of gout subtypes with the response to low-purine diet (LPD). METHODS: This is a single-center prospective clinical study. Gout patients visiting from 2019 to 2022, from Shandong Gout Clinic Center at the Affiliated Hospital of Qingdao University, China, assigned to three groups according to clinical subtypes, were enrolled and all treated with 2-week low-purine diet. General characteristics, serum uric acid (sUA) and other clinical biochemical variables before and after the diet were evaluated. RESULTS: A total of 626 gout patients (age 41.20 ± 13.41 years, male 98.0%) were included. Of these, 69 (11.0%) were overproduction type, 428 (68.37%) were underexcretion type, and 129 (20.61%) were combined type. Overall, there was a substantial decrease in sUA after a 2-week LPD (p < 0.001). In addition, systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST), serum triglycerides (TG), serum total cholesterol (TC), blood urea nitrogen (BUN) and serum creatinine (Scr) levels were lower than those at baseline (p < 0.05). On the other hand, there were significant differences in the reduction of sUA among different types, the rank order being overproduction type (- 88.81 ± 63.01 µmol/L) > combined type (- 65.22 ± 44.13 µmol/L) > underexcretion type (- 57.32 ± 61.19 µmol/L). After adjusting for age, BMI and baseline sUA and eGFR, there were still significant differences in the decline of serum uric acid among different types. Higher baseline sUA (95%CI - 0.285, - 0.191; p < 0.001) and BUN (95%CI - 6.751, - 0.602; p < 0.001) were correlated with greater decrease of sUA. CONCLUSIONS: Our findings support the protective role of low-purine diet on sUA levels in gout patients, especially overproduction type. Furthermore, LPD could exert a beneficial effect on gout patients' blood pressure, BMI, blood lipid, BUN and Scr levels. Trial registration Registered with ChiCTR, No. ChiCTR1900022981 at 06/05/2019.