Physiology of Hyperuricemia and Urate-Lowering Treatments

New drug targets for the treatment of gout arthritis: what's new?

INTRODUCTION

Gout arthritis (GA) is an intermittent inflammatory disease affecting approximately 10% of the worldwide population. Symptomatic phases (acute flares) are timely spaced by asymptomatic periods. During an acute attack, redness, joint swelling, limited movement, and excruciating pain are common symptoms. However, the current available therapies are not fully effective in reducing symptoms and offer numerous side effects. Therefore, unveiling new drug targets and effector molecules are required in developing novel GA therapeutics.

AREAS COVERED

This review discusses the pathophysiological mechanisms of GA and explores potential pharmacological targets to ameliorate disease outcome. In addition, we listed promising pre-clinical studies demonstrating effector molecules with therapeutical potential. Among those, we emphasized the importance of natural products, including traditional Chinese medicine formulas and their multitarget mechanisms of action.

EXPERT OPINION

In our search, we observed that there is a massive gap between pre-clinical and clinical knowledge. Only a minority (4.4%) of clinical trials aimed to intervene by applying natural products or current hot targets described herein. In this sense, we envisage four possibilities for GA therapeutics, which include the repurposing of existing therapies, ALX/FPR2 agonism for improvement in disease outcome, the use of multitarget drugs (e.g. natural products), and targeting the neuroinflammatory component of GA.

Serum uric acid levels in kidney transplant recipients: A cause for concern? A review of recent literature

The impact of elevated serum uric acid levels i.e., hyperuricemia, on native and transplant chronic kidney disease progression has been debated. This literature review presents an analysis of multiple studies exploring the relationship between serum uric acid levels and kidney transplant outcomes. The review includes a summary of the pathophysiology of hyperuricemia and gout, a review of urate-lowering therapies, and an appraisal of multiple studies examining the association or lack thereof between serum uric acid level and kidney transplant outcomes. Based on these studies, elevated serum uric acid levels may contribute to CKD progression in kidney transplant recipients. In this review, we also summarize current literature to highlight risk factors associated with hyperuricemia as well as the need for further investigation to monitor and manage hyperuricemia in kidney transplant recipients.

Investigating the Vital Role of the Identified Abietic Acid from Helianthus annuus L. Calathide Extract against Hyperuricemia via Human Embryonic Kidney 293T Cell Model

To explore the anti-hyperuricemia components in sunflower (Helianthus annuus L.) calathide extract (SCE), we identified abietic acid (AA) via liquid chromatography-mass spectrometry and found an excellent inhibitor of xanthine oxidase (IC₅₀ = 10.60 µM, Ki = 193.65 nM) without cytotoxicity. Based on the transcriptomics analysis of the human embryonic kidney 293T cell model established using 1 mM uric acid, we evaluated that AA showed opposite modulation of purine metabolism to the UA group and markedly suppressed the intensity of purine nucleoside phosphorylase, ribose phosphate pyrophosphokinase 2, and ribose 5-phosphate isomerase A. Molecular docking also reveals the inhibition of purine nucleoside phosphorylase and ribose phosphate pyrophosphokinase 1. The SCE exhibits similar regulation of these genes, so we conclude that AA was a promising component in SCE against hyperuricemia. This present study provided a novel cell model for screening anti-hyperuricemia natural drugs in vitro and illustrated that AA, a natural diterpenoid, is a potential inhibitor of purine biosynthesis or metabolism.

Association between dietary approaches to stop hypertension (DASH) diet and hyperuricemia among Chinese adults: findings from a nationwide representative study

BACKGROUND

Certain foods and food groups could positively or negatively impact serum uric acid (SUA) levels. However, evidence on the holistic dietary strategy to prevent and control hyperuricemia (HUA) development remains limited.

OBJECTIVE

The aim of this research work was to explore the association of dietary approaches to stop hypertension (DASH) diet with SUA levels and odds of HUA among Chinese adults.

METHODS

This research premise included 66,427 Chinese adults aged 18 and above who were part of the China Adult Chronic Disease and Nutrition Surveillance in 2015. Dietary consumptions were assessed via the household condiment weighing approach and a three-day, 24-hour dietary recall. Total fat, saturated fat, calcium, protein, potassium, cholesterol, magnesium, fiber, and sodium were all adopted to calculate the DASH score (score range, 0-9). The associations of DASH score with SUA levels and odds of HUA were evaluated using multiple linear and logistic regression models, respectively.

RESULTS

We established that a higher DASH score was linked with a lower SUA levels (β = - 0.11; 95% CI: - 0.12, - 0.1; p < 0.001) and odds of HUA (OR = 0.85; 95% CI: 0.83, 0.87; p < 0.001) after adjustment for age, sex, ethnicity, education status, marital status, health behaviours and health factors. The association of the DASH diet with odds of HUA was stronger among men (p-interaction = 0.009), non-Han Chinese (p-interaction< 0.001) as well as rural residents (p-interaction< 0.001).

CONCLUSIONS

Our results illustrate that the DASH diet was remarkably negatively with SUA levels and odds of HUA in the Chinese adult population.

Smart Bandaid Integrated with Fully Textile OECT for Uric Acid Real-Time Monitoring in Wound Exudate

Hard-to-heal wounds (i.e., severe and/or chronic) are typically associated with particular pathologies or afflictions such as diabetes, immunodeficiencies, compression traumas in bedridden people, skin grafts, or third-degree burns. In this situation, it is critical to constantly monitor the healing stages and the overall wound conditions to allow for better-targeted therapies and faster patient recovery. At the moment, this operation is performed by removing the bandages and visually inspecting the wound, putting the patient at risk of infection and disturbing the healing stages. Recently, new devices have been developed to address these issues by monitoring important biomarkers related to the wound health status, such as pH, moisture, etc. In this contribution, we present a novel textile chemical sensor exploiting an organic electrochemical transistor (OECT) configuration based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) for uric acid (UA)-selective monitoring in wound exudate. The combination of special medical-grade textile materials provides a passive sampling system that enables the real-time and non-invasive analysis of wound fluid: UA was detected as a benchmark analyte to monitor the health status of wounds since it represents a relevant biomarker associated with infections or necrotization processes in human tissues. The sensors proved to reliably and reversibly detect UA concentration in synthetic wound exudate in the biologically relevant range of 220-750 μM, operating in flow conditions for better mimicking the real wound bed. This forerunner device paves the way for smart bandages integrated with real-time monitoring OECT-based sensors for wound-healing evaluation.

Alleviation of Hyperuricemia by Strictinin in AML12 Mouse Hepatocytes Treated with Xanthine and in Mice Treated with Potassium Oxonate

Hyperuricemia, an abnormally high level of blood uric acid, is a major risk factor for gout. Although xanthine oxidase inhibitors were clinically used to lower blood uric acid level, the concerned side effects restricted their utilization. In this study, strictinin, an abundant polyphenol in Pu'er tea, was evaluated for its preventive effects on hyperuricemia. The results showed that the xanthine oxidase activity, uric acid production, and inflammation in AML12 mouse hepatocytes treated with xanthine were significantly reduced by the supplementation of strictinin. Detailed analyses revealed that strictinin inhibited xanthine-induced NLRP3 inflammasome activation. Consistently, the elevated blood uric acid level and the enhanced xanthine oxidase activity in mice treated with potassium oxonate were effectively diminished by strictinin supplementation. Moreover, for the first time, strictinin was found to promote healthy gut microbiota. Overall, strictinin possesses a great potential to be utilized as a functional ingredient for the prevention of hyperuricemia.

Exploration of the anti-hyperuricemia effect of TongFengTangSan (TFTS) by UPLC-Q-TOF/MS-based non-targeted metabonomics

BACKGROUND

TongFengTangSan (TFTS) is a commonly used Tibetan prescription for gout treatment. Previously, TFTS (CF) was confirmed to have a significant uric acid-lowering effect. However, the anti-hyperuricemia mechanisms and the main active fractions remain unclear. The current study aimed to investigate the anti-hyperuricemia mechanism using metabolomics and confirm the active CF fraction.

METHODS

The hyperuricemia model was established through intraperitoneal injection containing 100 mg/kg potassium oxonate and 150 mg/kg hypoxanthine by gavage. We used serum uric acid (sUA), creatinine (CRE), blood urea nitrogen (BUN), xanthine oxidase (XOD) activity, interleukin-6 (IL-6) and interleukin-1β (IL-1β) as indicators to evaluate the efficacy of CF and the four fractions (SX, CF30, CF60, and CF90). The anti-hyperuricemia mechanism of CF was considered through non-targeted metabolomics depending on the UPLC-Q-TOF-MS technology. Principle component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) helped explore the potential biomarkers in hyperuricemia. Moreover, the differential metabolites and metabolic pathways regulated by CF and four fractions were also assessed.

RESULTS

CF revealed a significant anti-hyperuricemia effect by down-regulating the level of sUA, sCRE, sIL-1β, and XOD. SX, CF30, CF60, and CF90 differed in the anti-hyperuricemia effect. Only CF60 significantly lowered the sUA level among the four fractions, and it could be the main efficacy fraction of TFTS. Forty-three differential metabolites were identified in hyperuricemia rats from plasma and kidney. Pathway analysis demonstrated that seven pathways were disrupted among hyperuricemia rats. CF reversed 19 metabolites in hyperuricemia rats and exerted an anti-hyperuricemia effect by regulating purine metabolism. CF60 was the main active fraction of TFTS and exerted a similar effect of CF by regulating purine metabolism.

CONCLUSIONS

CF and CF60 could exert an anti-hyperuricemia effect by regulating the abnormal purine metabolism because of hyperuricemia while improving intestinal and renal function. CF60 could be the main active fraction of TFTS.

A randomized pilot trial assessing the reduction of gout episodes in hyperuricemic patients by oral administration of Ligilactobacillus salivarius CECT 30632, a strain with the ability to degrade purines

Introduction

Hyperuricemia and gout are receiving an increasing scientific and medical attention because of their relatively high prevalence and their association with relevant co-morbidities. Recently, it has been suggested that gout patients have an altered gut microbiota. The first objective of this study was to investigate the potential of some Ligilactobacillus salivarius strains to metabolize purine-related metabolites. The second objective was to evaluate the effect of administering a selected potential probiotic strain in individuals with a history of hyperuricemia.

Methods

Inosine, guanosine, hypoxanthine, guanine, xanthine, and uric acid were identified and quantified by high-performance liquid chromatography analysis. The uptake and biotransformation of these compounds by a selection of L. salivarius strains were assessed using bacterial whole cells and cell-free extracts, respectively. The efficacy of L. salivarius CECT 30632 to prevent gout was assessed in a pilot randomized controlled clinical trial involving 30 patients with hyperuricemia and a history of recurrent gout episodes. Half of the patients consumed L. salivarius CECT 30632 (9 log₁₀ CFU/day; probiotic group; n = 15) for 6 months while the remaining patients consumed allopurinol (100-300 mg/daily; control group; n = 15) for the same period. The clinical evolution and medical treatment received by the participants were followed, as well as the changes in several blood biochemical parameters.

Results

L. salivarius CECT 30632 was the most efficient strain for inosine (100%), guanosine (100%) and uric acid (50%) conversion and, therefore, it was selected for the pilot clinical trial. In comparison with the control group, administration of L. salivarius CECT 30632 resulted in a significant reduction in the number of gout episodes and in the use of gout-related drugs as well as an improvement in some blood parameters related to oxidative stress, liver damage or metabolic syndrome.

Conclusion

Regular administration of L. salivarius CECT 30632 reduced serum urate levels, the number of gout episodes and the pharmacological therapy required to control both hyperuricemia and gout episodes in individuals with a history of hyperuricemia and suffering from repeated episodes of gout.

A metabonomic study to explore potential markers of asymptomatic hyperuricemia and acute gouty arthritis

BACKGROUND

Acute gouty arthritis (AGA) is a metabolic disease with acute arthritis as its main manifestation. However, the pathogenesis of asymptomatic hyperuricemia (HUA) to AGA is still unclear, and metabolic markers are needed to early predict and diagnose. In this study, gas chromatography (GC)/liquid chromatography (LC)-mass spectrometry (MS) was used to reveal the changes of serum metabolites from healthy people to HUA and then to AGA, and to find the pathophysiological mechanism and biological markers.

METHODS

Fifty samples were included in AGA, HUA, and healthy control group, respectively. The metabolites in serum samples were detected by GC/LC-MS. According to the statistics of pairwise grouping, the statistically significant differential metabolites were obtained by the combination of multidimensional analysis and one-dimensional analysis. Search the selected metabolites in KEGG database, determine the involved metabolic pathways, and draw the metabolic pathway map in combination with relevant literature.

RESULTS

Using metabonomics technology, 23 different serum metabolic markers related to AGA and HUA were found, mainly related to uric acid metabolism and inflammatory response caused by HUA/AGA. Three of them are completely different from the previous gout studies, nine metabolites with different trends from conventional inflammation.

CONCLUSIONS

In conclusion, we analyzed 150 serum samples from AGA, HUA, and healthy control group by GC/LC-MS to explore the changes of these differential metabolites and metabolic pathways, suggesting that the disease progression may involve the changes of biomarkers, which may provide a basis for disease risk prediction and early diagnosis.

Purine catabolism by enterobacteria

Purines are abundant among organic nitrogen sources and have high nitrogen content. Accordingly, microorganisms have evolved different pathways to catabolize purines and their metabolic products such as allantoin. Enterobacteria from the genera Escherichia, Klebsiella and Salmonella have three such pathways. First, the HPX pathway, found in the genus Klebsiella and very close relatives, catabolizes purines during aerobic growth, extracting all four nitrogen atoms in the process. This pathway includes several known or predicted enzymes not previously observed in other purine catabolic pathways. Second, the ALL pathway, found in strains from all three species, catabolizes allantoin during anaerobic growth in a branched pathway that also includes glyoxylate assimilation. This allantoin fermentation pathway originally was characterized in a gram-positive bacterium, and therefore is widespread. Third, the XDH pathway, found in strains from Escherichia and Klebsiella spp., at present is ill-defined but likely includes enzymes to catabolize purines during anaerobic growth. Critically, this pathway may include an enzyme system for anaerobic urate catabolism, a phenomenon not previously described. Documenting such a pathway would overturn the long-held assumption that urate catabolism requires oxygen. Overall, this broad capability for purine catabolism during either aerobic or anaerobic growth suggests that purines and their metabolites contribute to enterobacterial fitness in a variety of environments.

Urinary levels of kidney injury molecule-1 (KIM-1) and interleukin-18 (IL-18) in children and adolescents with hyperuricemia

PURPOSE

Hyperuricemia may lead to silent tissue damage and increase the risk of some diseases, including kidney diseases. Increased serum uric acid concentration induces inflammatory pathways and promotes kidney damage. This study aimed to determine whether hyperuricemia influences the levels of urinary kidney injury markers in children and adolescents with hyperuricemia, assessed by the urinary concentrations of interleukin-18, a biomarker of inflammation, and kidney injury molecule-1 (KIM-1), a biomarker of kidney injury.

MATERIAL AND METHODS

The study included 73 children and adolescents (32 males and 41 females) aged 2-18 years. They were divided into two groups: hyperuricemia (HU) group (n ​= ​48) and normouricemia - reference group (R) (n ​= ​25). The concentrations of urinary interleukin-18 and KIM-1 were measured using an ELISA kit and were normalized for urinary creatinine (cr.) concentration.

RESULTS

The median interleukin-18/cr. Levels in the HU group were significantly higher than in the R group (median, Q1-Q3) 21.83 (11.32-35.96) and 12.68 (7.11-24.04), respectively, (p ​< ​0.05). The KIM-1/cr. in the HU group and the R group were (median, Q1-Q3) 0.79 (0.45-1.03) and 0.81 (0.59-1.01), respectively, and the difference was not significant. KIM-1/cr. did not differ between the groups. Interleukin-18/cr. ratio correlated positively with serum uric acid concentration (r ​= ​0.24, p ​< ​0.05).

CONCLUSIONS

Interleukin-18/cr., but not KIM-1/cr. was higher in children with hyperuricemia. Hyperuricemia results in increased IL-18 in urine, in absence of other markers of kidney injury, suggesting inflammation in the kidney. Additional studies on the adults should be done, to confirm this hypothesis.

The risk of ischemic cerebrovascular disease associated with benzbromarone use in gout people: A retrospective cohort study in Taiwan

Epidemiological studies have shown that people having hyperuricemia are at increased risk of ischemic cerebrovascular disease. This research aimed to study the relation of ischemic cerebrovascular disease with benzbromarone use among persons with gout-related disorders. This was a retrospective cohort design utilizing a 2003 to 2015 national health insurance database in Taiwan. Subjects aged 20 to 99 years who already had suffered from gout-related disorders were included as eligible subjects. Eligible persons who had the benzbromarone prescription alone were selected into the benzbromarone group. Sex-matched and age-matched eligible persons who never used any urate-lowering agents were selected into the control group. An index date was set as a date of benzbromarone being prescribed. The end-point was defined as ischemic cerebrovascular disease being newly diagnosed. A hazard ratio was applied to measure the association strength between benzbromarone use and ischemic cerebrovascular disease. Totally, there were 13,398 persons in the benzbromarone group and 13,398 persons in the control group. The incidence rate of ischemic cerebrovascular disease seemed to be modestly higher in the benzbromarone group than the control group, but it did not achieve statistical significance (0.78 vs 0.75 every 100 person-years, incidence rate ratio = 1.05, 95% confidence interval = 0.94-1.16). A crude hazard ratio of ischemic cerebrovascular disease showed 1.05 in the benzbromarone group (95% confidence interval = 0.94-1.17, P = .373) comparing with the control group. No significant association can be detected between benzbromarone use and the probability of ischemic cerebrovascular disease among persons with gout-related disorders. We think that reduction of the serum uric acid by use of benzbromarone could not be related to the probability of ischemic cerebrovascular disease. Further research is suggested to clarify this issue.

The Association between Water Consumption and Hyperuricemia and Its Relation with Early Arterial Aging in Middle-Aged Lithuanian Metabolic Patients

BACKGROUND

Hyperuricemia is well-known as an independent risk factor for the development of hypertension, metabolic syndrome, and cardiovascular disease. Water is essential to most bodily functions, and its consumption rates appear to decline with age. The aim was to evaluate the influence of water intake on early vascular aging in metabolic middle-aged patients with hyperuricemia.

MATERIALS AND METHODS

The study included 241 men aged 40-55 years and 420 women aged 50-65 years from the Lithuanian High Cardiovascular Risk (LitHiR) primary prevention program. Anthropometric characteristics, blood pressure, laboratory testing, and the specialized nutrition profile questionnaire were evaluated. Carotid-femoral pulse wave velocity (cfPWV), assessed using applanation tonometry, was evaluated as an early vascular aging parameter in patients with hyperuricemia and with normal serum uric acid (sUA) levels.

RESULTS

72.6% of men and 83.1% of women drink insufficient amounts of water (less than 1.5 L per day). However, our results showed statistically significant relationships only among a group of women. The women in the hyperuricemic group had a higher cfPWV than women with normal sUA levels. In hyperuricemic women, drinking less than 0.5 L per day in combination with other risk factors, such as age, increasing fasting glucose, and systolic blood pressure, was statistically significantly associated with an increased cfPWV (R² = 0.45, Adj. R² = 0.42, p < 0.001).

CONCLUSION

Drinking an insufficient amount of water daily is associated with increased arterial stiffness and has a negative effect on vascular health in metabolic women with hyperuricemia.

Wuling San Based on Network Pharmacology and in vivo Evidence Against Hyperuricemia via Improving Oxidative Stress and Inhibiting Inflammation

Background

Hyperuricemia (HUA) is a major public health issue with a high prevalence worldwide. Wuling San (WLS) is an effective treatment for HUA. However, the active compounds and the related mechanism are unclear. In this study, we aimed to explore the active compounds and the underlying pharmacological mechanisms of WLS against HUA.

Methods

First, a network pharmacology approach was used to detect active compounds of WLS, and potential targets and signaling pathways involved in the treatment of HUA were predicted. Then, a molecular docking strategy was used to predict the affinity between active compounds and key targets. Finally, to verify the prediction, the HUA rat model was established.

Results

49 active compounds with 108 common targets were obtained. Besides, cerevisterol, luteolin, ergosterol peroxide, beta-sitosterol, and sitosterol were identified as key active compounds. In PPI analysis, TNF, IL6, CASP3, PPARG, STAT3, and other 12 core targets were obtained. GO enrichment analysis indicated that WLS was likely to interfere with oxidative stress in the treatment of HUA, and KEGG enrichment analysis indicated multiple inflammation-related signaling pathways possibly involved in the treatment of HUA by WLS, including TNF, and NOD-like receptor, HIF-1, PI3K-Akt, and IL-17 signaling pathways. The results of molecular docking indicated that the active compounds had good binding properties to their key targets. In the validation experiments, WLS significantly reduced the levels of serum uric acid (SUA) and serum malondialdehyde (MDA). Moreover, WLS not only significantly increased the levels of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD), but also inhibited the expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6).

Conclusion

In the present study, we demonstrate that WLS has multicomponent, multitarget, and multi-pathway properties in the treatment of HUA. Its potential capability to reduce SUA could be ascribed to oxidative stress improvement and inflammation inhibition.

Research Progress of Natural Active Substances with Uric-Acid-Reducing Activity

Hyperuricemia is a metabolic disease caused by the accumulation of uric acid in the body. Allopurinol, benzbromarone, and febuxostat, which are available in the market, have reduced the circulating urate levels; however, they exhibit serious side effects. Therefore, it is reasonable to develop a new active antihyperuricemia drug with few side effects. With the deepening of research, numerous kinds of literature have shown that natural active substances are effective in the treatment of hyperuricemia with a variety of sources and few side effects, which have become the focus of research in recent years. This review focuses on natural active substances with uric-acid-reducing activity and discusses their pharmacological effects. More specifically, the bioactive compounds of natural active substances are divided into five categories: natural extracts, monomer compounds extracted from plants, natural protease hydrolysates, peptides, and probiotic bacteria. In addition, the mechanisms by which these bioactive compounds exhibit hypouricemic effects can be divided into four classes: inhibition of key enzyme activities, promotion of uric acid excretion and inhibition of reabsorption in the kidney, promotion of decomposing uric acid precursors, and promotion of decomposing uric acid. Overall, this current and comprehensive review examines the role of natural active substances in the treatment of hyperuricemia.

Interaction of Colloidal Gold Nanoparticles with Urine and Saliva Biofluids: An Exploratory Study

The use of gold nanoparticles for drug delivery, photothermal or photodynamic therapy, and biosensing enhances the demand for knowledge about the protein corona formed on the surface of nanoparticles. In this study, gold nanospheres (AuNSs), gold nanorods (AuNRs), and gold nanoflowers (AuNFs) were incubated with saliva or urine. After the interaction, the surface of gold nanoparticles was investigated using UV-VIS spectroscopy, zeta potential, and dynamic light scattering. The shifting of the localized surface plasmon resonance (LSPR) band, the increase in hydrodynamic diameter, and the changes in the surface charge of nanoparticles indicated the presence of biomolecules on the surface of AuNSs, AuNRs, and AuNFs. The incubation of AuNFs with saliva led to nanoparticle aggregation and minimal protein adsorption. AuNSs and AuNRs incubated in saliva were analyzed through liquid chromatography with tandem mass spectrometry (LC-MS/MS) to identify the 96 proteins adsorbed on the surface of the gold nanoparticles. Among the 20 most abundant proteins identified, 14 proteins were common in both AuNSs and AuNRs. We hypothesize that the adsorption of these proteins was due to their high sulfur content, allowing for their interaction with gold nanoparticles via the Au-S bond. The presence of distinct proteins on the surface of AuNSs or AuNRs was also investigated and possibly related to the competition between proteins present on the external layers of corona and gold nanoparticle morphology.

Superiority of Low-Dose Benzbromarone to Low-Dose Febuxostat in a Prospective, Randomized Comparative Effectiveness Trial in Gout Patients With Renal Uric Acid Underexcretion

OBJECTIVE

The predominant mechanism driving hyperuricemia in gout is renal uric acid underexcretion; however, the standard urate-lowering therapy (ULT) recommendation is first-line xanthine oxidase inhibitor (XOI), irrespective of the cause of hyperuricemia. This comparative effectiveness clinical trial was undertaken to compare first-line nontitrated low-dose benzbromarone (LDBen) uricosuric therapy to XOI ULT with low-dose febuxostat (LDFeb) in gout patients with renal uric acid underexcretion.

METHODS

We conducted a prospective, randomized, single-center, open-label trial in men with gout and renal uric acid underexcretion (defined as fractional excretion of urate <5.5% and uric acid excretion ≤600 mg/day/1.73 m2 ). A total of 196 participants were randomly assigned to receive LDBen 25 mg daily or LDFeb 20 mg daily for 12 weeks. All participants received daily urine alkalization with oral sodium bicarbonate. The primary end point was the rate of achieving the serum urate target of <6 mg/dl.

RESULTS

More participants in the LDBen group achieved the serum urate target than those in the LDFeb group (61% compared to 32%, P < 0.001). Rates of adverse events, including gout flares and urolithiasis, did not differ between groups, with the exception of greater transaminase elevation in the LDFeb group (4% for LDBen compared to 15% for LDFeb, P = 0.008).

CONCLUSION

Compared to LDFeb, LDBen has superior urate-lowering efficacy and similar safety in treating relatively young and healthy patients with renal uric acid underexcretion-type gout.

Extract of Aster glehni ameliorates potassium oxonate-induced hyperuricemia by modulating renal urate transporters and renal inflammation by suppressing TLR4/MyD88 signaling

Recent studies suggest that Aster glehni extract (AGE) reduces hyperuricemia by preventing xanthine oxidase activity. However, its effect on renal urate transporters responsible for modulating urate excretion has not been examined. This study investigated whether AGE affects gene expressions of urate transporters using potassium oxonate (PO)-induced hyperuricemia rats. Furthermore, the underlying mechanisms of AGE were explored to ameliorate renal inflammation and injury by PO. AGE effectively restored PO-induced dysregulation of renal urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), ATP-binding cassette transporter subfamily G member 2 (ABCG2), organic anion transporter 1 (OAT1), and organic cation transporter 1 (OCT1), resulting in increasing urate excretion. Additionally, AGE suppressed toll-like receptor 4/myeloid differentiation factor 88 (TLR4/MyD88) signaling, phosphorylation of nuclear factor kappa B (NF-κB), and renal production of IFN-γ, IL-1β, TNF-α, and IL-6. These results suggest that AGE may ameliorate PO-induced hyperuricemia by modulating renal transporters, and further renal inflammation via inhibiting the TLR4/MyD88/NF-κB signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01153-5.

Screening of lactic acid bacteria strains with urate-lowering effect from fermented dairy products

Hyperuricemia is a well-known cause of gout and also a risk factor for various comorbidities. Current agents like xanthine oxidase inhibitors prevent hyperuricemia, but usually induce severe side effects. Alternative strategies, such as novel dietary supplementations, are necessary for the management of hyperuricemia. Lactic acid bacteria (LAB) have been used in human diet for a long time with a good safety record. In this study, 345 LAB strains isolated from traditional fermented dairy products were tested for assimilating abilities of guanosine. Two LAB strains, Lacticaseibacillus rhamnosus 1155 (LR1155) and Limosilactobacillus fermentum 2644 (LF2644), showing great capacities of guanosine transformation and degradation were selected. Compared to LR1155, LF2644 showed a better effect with 100.00% transforming rate and 55.10% degrading rate. In an in vivo test, a hyperuricemic rat model was established and the results showed that administration of LR1155 (p < 0.01) or LF2644 (p < 0.01) prevented the rise of serum uric acid with more than 20% decrease when compared with the hyperuricemia rats. In addition, an increased fecal uric acid level was observed in LF2644 or LR1155 treated rats (LR1155-M p < 0.05, others p < 0.01). This study proved that LR1155 and LF2644 can be promising candidates of dietary supplements for prevention or improvement of hyperuricemia. PRACTICAL APPLICATION: The LAB strains tested in this study could be considered as good potential probiotic candidates for dietary supplements because of their urate-lowering effects, which provide a novel antihyperuricemic strategy with advantages of safety and sustainability.

Probiotic effects of Lacticaseibacillus rhamnosus 1155 and Limosilactobacillus fermentum 2644 on hyperuricemic rats

Hyperuricemia is the main cause of gout and involved in the occurrence of multiple diseases, such as hypertension, metabolic disorders and chronic kidney disease. Emerging evidence suggests that lactic acid bacteria (LAB) have shown the beneficial effects on the prevention or treatment of hyperuricemia. In this study, the urate-lowering effect of two LAB strains, Lacticaseibacillus rhamnosus 1155 (LR1155) and Limosilactobacillus fermentum 2644 (LF2644) on hyperuricemic rats were investigated. A hyperuricemic rat model was induced by the intragastric treatment of potassium oxonate, combined with a high purine diet. The oral administration of LR1155, LF2644, or a combination of LR1155 and LF2644 for 4 weeks significantly prevented the rise of the serum uric acid (UA) induced by hyperuricemia. LR1155 and LF2644 significantly elevated the fecal UA levels, increased the UA content and up-regulated gene expression of UA transporter, ATP-binding cassette subfamily G-2 (ABCG2), in colon and jejunum tissues, suggesting the accelerated UA excretion from the intestine. Besides, LR1155 significantly inhibited the activity of xanthine oxidase (XOD) in liver and serum, benefited the reduce of UA production. In addition, LF2644 strengthened the gut barrier functions through an up-regulation of the gene expressions for occluding and mucin2, accompanied with the reduced inflammatory indicators of lipopolysaccharide (LPS) and interleukin-1β (IL-1β) in hyperuricemic rat. Moreover, using 16s rDNA high-throughput sequencing of feces, LR1155 was shown to improve the hyperuricemia induced gut microbial dysbiosis. The genera Roseburia, Butyricicoccus, Prevotella, Oscillibacter, and Bifidobacterium may associate with the effect of LR1155 on microbiota in hyperuricemic rats. Collectively, the results indicated that LR1155 and LF2644 exhibit urate-lowering effects and could be used alone or in combination as a new adjuvant treatment for hyperuricemia.

Hypouricemic effect of gallic acid, a bioactive compound from Sonneratia apetala leaves and branches, on hyperuricemic mice

As a tropical medicinal plant, Sonneratia apetala is mainly distributed in the southeast coastal areas of China. Recently, the hypouricemic effect of Sonneratia apetala leaves and branches (SAL) has been reported, but the active compound and its mechanism are unclear. Thus, this study aims to explore the effective fraction of SAL and the mechanism of its active compound on uric acid formation and excretion. SAL was extracted with ethyl acetate and concentrated to obtain solvent-free extracts (SAL-EA). The remains fraction (SAL-E) and the supernatant fraction (SAL-S) of SAL resulting from water extraction and alcohol precipitation were collected and dried. The effects of different fractions were explored on hyperuricemic mice. SAL-S showed excellent activities in decreasing the levels of uric acid (UA), blood urea nitrogen (BUN), and creatinine (CRE) in serum and in attenuating kidney damage. Then, the active compound gallic acid (GA) identified by HPLC was assayed for its mechanism of regulating uric acid metabolism in hyperuricemic mice. The hypouricemic effect of GA was probably associated with the downregulation of URAT1 and GLUT9, upregulation of ABCG2 and decreased activities of adenosine deaminase (ADA) and xanthine oxidase (XOD). Moreover, GA suppressed the level of MDA, IL-6, IL-1β, TNF-α, TGF-β1, COX-2 and cystatin-C (Cys-C), and enhanced the activities of SOD, GSH-Px, CAT, and Na⁺-K⁺-ATPase (NKA) in the kidneys. These results indicated that GA protects against hyperuricemia-induced kidney injury via suppressing oxidative stress and inflammation as well as decreasing the serum levels of UA by regulating urate transporters.

Sex Difference in the Associations among Hyperuricemia with New-Onset Chronic Kidney Disease in a Large Taiwanese Population Follow-Up Study

The global prevalence and incidence of chronic kidney disease (CKD) continue to increase. Whether hyperuricemia is an independent risk factor for renal progression and whether there are sex differences in the relationships between serum uric acid (UA) and a decline in renal function are unclear. Therefore, in this longitudinal study, we aimed to explore these relationships in a large cohort of around 27,000 Taiwanese participants in the Taiwan Biobank (TWB), and also to identify serum UA cutoff levels in men and women to predict new-onset CKD. A total of 26,942 participants with a median 4 years of complete follow-up data were enrolled from the TWB. We excluded those with CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2) at baseline (n = 297), and the remaining 26,645 participants (males: 9356; females: 17,289) were analyzed. The participants who developed CKD during follow-up were defined as having incident new-onset CKD, and those with a serum UA level >7 mg/dL in males and >6 mg/dL in females were classified as having hyperuricemia. After multivariable analysis, hyperuricemia (odds ratio [OR], 2.541; 95% confidence interval [CI], 1.970−3.276; p < 0.001) was significantly associated with new-onset CKD. Furthermore, in the male participants (n = 9356), hyperuricemia (OR, 1.989; 95% CI, 1.440−2.747; p < 0.001), and quartile 4 of UA (vs. quartile 1; OR, 2.279; 95% CI, 1.464−3.547; p < 0.001) were significantly associated with new-onset CKD, while in the female participants (n = 17,289), hyperuricemia (OR, 3.813; 95% CI, 2.500−5.815; p < 0.001), quartile 3 of UA (vs. quartile 1; OR, 3.741; 95% CI, 1.250−11.915; p = 0.018), and quartile 4 of UA (vs. quartile 1; OR, 12.114; 95% CI, 14.278−34.305; p < 0.001) were significantly associated with new-onset CKD. There were significant interactions between hyperuricemia and sex (p = 0.024), and quartiles of serum UA and sex (p = 0.010) on new-onset CKD. Hyperuricemia was associated with new-onset CKD in the enrolled participants, and the interactions between hyperuricemia and sex were statistically significant. Hyperuricemia was more strongly associated with new-onset CKD in the women than in the men.

Lifestyle-Related Risk Factors for the Incidence and Progression of Chronic Kidney Disease in the Healthy Young and Middle-Aged Population

The prevalence of chronic kidney disease (CKD) increased by 88% from 1990 to 2016. Age of onset of lifestyle-related diseases (such as hypertension, diabetes mellitus, obesity, dyslipidemia, and hyperuricemia), which are risk factors for incident CKD, is lower now compared with the past. Thus, we aimed to evaluate the risk factors for the incidence and progression of CKD in the young and middle-aged population. There are differences in the risk for CKD among the young, middle-aged, and elderly populations. We aimed to assess obesity (which is basic component of metabolic syndrome), waist circumference, and abdominal adiposity, which are predictive factors of CKD in the younger population. Furthermore, we described the management and clinical evidence of hypertension, diabetes mellitus, dyslipidemia, and hyperuricemia for young and middle-aged patients, along with diet management and nutrients associated with kidney function. Kidney function in the young and middle-aged population is mostly normal, and they are considered a low-risk group for incident CKD. Thus, we expect this review to be useful in reducing the prevalence of CKD.

Raised total methylated arginine load in patients with gout

Aim: The aim of this study was to measure serum levels of methylarginine derivatives and related metabolites in patients with gout. Materials & methods: This study enrolled 100 patients with gout and 80 patients in the control group. Serum asymmetric dimethylarginine, symmetric dimethylarginine, L-N-monomethylarginine, arginine, homoarginine, citrulline and ornithine levels were measured with tandem mass spectrometry. Results: Serum ornithine, citrulline and total methylated arginine load levels were statistically significantly higher in patients with gout compared with the control group, while serum arginine and homoarginine levels and global arginine bioavailability ratio were statistically significantly lower. Conclusion: There may be an association between gout, methylarginine levels and hyperuricemia and increased risk of cardiovascular disease.

A flavonoid-rich fraction of Monolluma quadrangula inhibits xanthine oxidase and ameliorates potassium oxonate-induced hyperuricemia in rats

Hyperuricemia represents a risk factor for the progression of chronic kidney disease. Oxidative stress and inflammation are implicated in the mechanisms underlying hyperuricemia-mediated kidney injury. Monolluma quadrangula possesses several beneficial effects; however, its effect on hyperuricemia has not been investigated. This study evaluated the renoprotective and xanthine oxidase (XO) inhibitory activity of M. quadrangula in hyperuricemic rats. Phytochemical investigation revealed the presence of six known flavonoid isolated for the first time from this species. The rats received M. quadrangula extract (MQE) and potassium oxonate (PO) for 7 days. In vitro assays showed the radical scavenging and XO inhibitory activities of MQE, and in silico molecular docking revealed the inhibitory activity of the isolated flavonoids towards XO. Hyperuricemic rats showed elevated serum uric acid, creatinine, urea, and XO activity, and renal pro-inflammatory cytokines, MDA and NO, and decreased GSH, SOD, and catalase. MQE ameliorated serum uric acid, urea, creatinine, and XO activity, and renal pro-inflammatory cytokines. In addition, MQE attenuated renal oxidative stress, enhanced antioxidants, downregulated URAT-1, and GLUT-9 and upregulated OAT-1 in PO-induced rats. In conclusion, M. quadrangula attenuated hyperuricemia and kidney impairment by suppressing XO activity, oxidative stress and inflammation, and modulating urate transporters.

Traditional Chinese herbs and natural products in hyperuricemia-induced chronic kidney disease

Hyperuricemia is a common biochemical disorder, which resulted from both excessive uric acid (UA) production and/or absolute or relative impairment of urinary UA excretion. Growing evidence has indicated that hyperuricemia is an independent risk factor for the development and progression of chronic kidney disease (CKD), causing hyperuricemia-induced CKD (hyperuricemic nephropathy, HN). The therapeutic strategy of HN is managing hyperuricemia and protecting kidney function. Adverse effects of commercial drugs make persistent treatment of HN challenging. Traditional Chinese medicine (TCM) has exact efficacy in lowering serum UA without serious adverse effects. In addition, TCM is widely applied for the treatment of CKD. This review aimed to provide an overview of efficacy and mechanisms of traditional Chinese herbs and natural products in hyperuricemia-induced CKD.

Effect of Physical Exertion on the effect of physical exertion on the concentration of copper and blood pressure in athletesn the Concentration of Copper and Blood Pressure in Athletes

Background and Study Aim. Several mineral elements are necessary for the athlete's body, which significantly impact the development of sports achievements because of their active role in bringing internal balance to the athlete's body. The study aims to determine the concentration of copper in the blood before and after the implementation of physical exertion at a level of 180 pulse/min on middle-distance runners. Material and Methods. Twelve athletes who are team members at Egyptian clubs were chosen deliberately as a research sample. The study participants were at the end of their special preparation. The experiment was conducted between July 12, 2021, and July 14, 2021, on the research sample, resting after exerting physical effort by running on a treadmill at a speed of 10 km / h. The runner continued at this speed for 3 minutes, after which the device's speed increased by 2 km / h every minute until reaching a heart rate of 180 pulse/ min. Results. The mineral differences in the copper element are attributed to the immediate induced by physical exertion by increasing the copper element in the blood within the normal level. This causes many changes and responses within the body cells. The copper element plays a significant role in oxidation and reduction processes via enzymes that require the copper element to produce energy in the cells and tissues due to the body's exposure to physical exertion. Athletes' exposure to physical exertion causes copper-dependent enzymes to produce energy in cells and tissues due to the element's requirement. Conclusions. Copper affected the physical effort of middle-distance runners at a heart rate of 180 pulse/min. In addition,  Middle-distance runners' blood pressure (systolic and diastolic) was affected by the physical exertion at a heart rate of 180 rpm.

The relationship between uric acid and brain health from observational studies

This study conducts a systematic literature review and meta-analysis regarding the potential influence of serum uric acid levels on cerebral small vessel diseases and the cognitive status in the prodromal stages of dementia. We identified four different cerebral small vessel diseases and three specific domains of cognitive performance to be considered in the literature search. The analysis contained 14 studies (13 cross-sectional design and one longitudinal design) with 11,502 participants measuring the relationship between uric acid and cerebral small vessel disease. In both continuous and categorical analyses, significant associations were found between hyperuricemia and cerebral small vessel diseases (continuous data: pooled OR: 1.00, 95%CI: 1.00-1.01 and categorical data: pooled OR: 1.42, 95%CI: 1.15-1.75). For the relationship between uric acid and cognitive performance, 19 studies with 49,901 participants were considered, including eight cohort studies, and 11 cross-sectional studies. The cross-sectional data showed that a marginal relationship existed between uric acid and global cognition (β: 0.00, 95%CI: -0.01-0.00). The pooled analysis of cohort studies indicated that higher uric acid had a deleterious effect on attention and executive function (continuous data: β: -0.02, 95%CI: -0.04-0.00 and categorical data: β: -0.03, 95%CI: -0.07-0.00). Conclusion: Our study indicated that a higher level of uric acid had an adverse effect on brain health. Furthermore, a high level of uric acid is related to cognitive decline in attention and executive function, which may exist a long time before the diagnosis of dementia.

Sodium glucose co-transport 2 inhibitors for gout treatment

Hyperuricemia remains the most prevalent cause of gout. Gout patients present with joint inflammation and uric acid crystals deposition manifesting as tophi. The association of gout with increased risk of insulin resistance, diabetes, metabolic disorders, increased cardiometabolic risk, and kidney disease is well established. These factors influence the treatment plan, and current treatment options have limited cardiovascular risk reduction. So the need for novel treatments with a broad range of coverage for the complications is warranted. Sodium-glucose co-transporter 2 inhibitors are novel drugs approved for treating type-2 diabetes. They prevent glucose reabsorption and lower serum uric acid levels. Recently few studies have studied their association with reducing the risk of gout. They may help address the gout related complications through their recorded benefit with weight loss, improved insulin resistance, and cardiovascular benefits in recent studies. . SGLT2-Is may be useful to reduce the risk of gout in individuals with type 2 diabetes. Limited literature is available on the safety and efficacy of these novel antidiabetic drugs in patients with gout. This review is aimed to summarize the current knowledge on the role and effectiveness of novel antidiabetic medication as an early therapeutic option in gout patients.

Synergistic Impacts of Alpinia oxyphylla Seed Extract and Allopurinol against Experimental Hyperuricemia

In traditional medicine, Alpinia oxyphylla Miquel seed has been used to treat gout and hyperuricemia-related symptoms by enhancing kidney functions. Allopurinol is the most commonly used drug to treat hyperuricemia; however, the drug has many adverse effects. Combining allopurinol with another compound could reduce the need for high doses and result in improved safety. We investigated the possible synergistic effects of Alpinia oxyphylla seed extract (AE) and allopurinol in decreasing urate concentrations in rats with potassium oxonate-induced hyperuricemia. This study evaluated the effects of allopurinol combined with AE on levels of serum urate, blood urea nitrogen (BUN), and creatinine in a hyperuricemic rat model. The effects of allopurinol plus AE on xanthine oxidase (XOD) activity and urate uptake were measured. The concomitant administration of allopurinol and AE normalized serum urate and reduced BUN and creatinine. The attenuation of hyperuricemia-induced impaired kidney function was related to downregulation of renal urate transporter 1 and upregulation of renal organic anion transporter 1, with inhibition of serum and hepatic XOD activities. The antihyperuricemic effects of allopurinol were enhanced when combined with AE. These results suggested that the combined use of allopurinol and AE may have clinical efficacy in treating hyperuricemia.

Systematically Exploring the Chemical Ingredients and Absorbed Constituents of Polygonum capitatum in Hyperuricemia Rat Plasma Using UHPLC-Q-Orbitrap HRMS

Polygonum capitatum as an ethnic medicine has been used to treat urinary tract infections, pyelonephritis and urinary calculi. In our previous study, P. capitatum was found to have anti-hyperuricemia effects. Nevertheless, the active constituents of P. capitatum for treating hyperuricemia were still unclear. In this study, an ultra-high-performance liquid chromatography coupled to quadrupole/orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) was used to comprehensively detect the chemical ingredients of P. capitatum and its absorbed constituents in the plasma of hyperuricemia rats for the first time. Xcalibur 3.0 and Compound Discoverer 2.0 software coupled to mzCloud and ChemSpider databases were utilized for qualitative analysis. A total of 114 chemical components including phenolics, flavonoids, tannins, phenylpropanoids, amino acids, amides and others were identified or tentatively characterized based on the exact mass, retention time and structural information. Compared to the previous P. capitatum study, an additional 66 different components were detected. Moreover, 68 related xenobiotics including 16 prototype components and 52 metabolites were found in the plasma of hyperuricemia rats. The metabolic pathways included ring fission, hydrolysis, decarboxylation, dehydroxylation, methylation, glucuronidation and sulfation. This work may provide important information for further investigation on the active constituents of P. capitatum and their action mechanisms for anti-hyperuricemia effects.

Hyperuricemia and Its Association with Osteoporosis in a Large Asian Cohort

In this paper, we aimed to examine the protective role of hyperuricemia in the prevalence of osteoporosis in a large Asian cohort. A total of 119,037 participants from 29 recruitment centers in Taiwan were enrolled onto our study. Participants with serum uric acid greater than 7.0 mg/dL in men and 6.0 mg/dL in women were classified as the hyperuricemia group whereas the others were the control group. The mean age of all participants was 50; there were 23,114 subjects (19%) with hyperuricemia. Osteoporosis was observed in 8243 (9%) and 1871 (8%) participants in the control and hyperuricemia groups, respectively. After adjusting for confounders, a lower risk of osteoporosis was found in the hyperuricemia group compared with the control group (odds ratio, 0.916; 95% confidence interval, 0.864 to 0.970). A subgroup analysis showed that hyperuricemia was associated with a lower risk of osteoporosis in females, but not in males. Women with serum uric acid greater than 8.0 mg/dL were not associated with a greater risk of osteoporosis. Our study suggests that hyperuricemia decreases the risk of osteoporosis in females, but not in males. The protective role was no longer apparent when the serum uric acid level was greater than 8 mg/dL.

Hyperuricemia and the small intestine: Transport mechanisms and co-morbidities

There is a global increase in cases of hyperuricemia over the last 10 years. A critical component of serum uric acid control is the transport of uric acid to the intestinal lumen, which accounts for 30% of the uric acid eliminated from the serum. This mini review looks at two important aspects of elevated uric acid: the dynamics of intestinal uric acid transport and hyperuricemia co-morbidities. Elevated serum uric acid can lead to gout and it can also impact other diseases such as diabetes, cardiovascular diseases and nervous system diseases. The level of uric acid in the intestine could be related to the potential for uric acid to impact other morbidities. We review the evidence for this and what it would mean for persons with elevated serum uric acid.

Carvacrol Alleviates Hyperuricemia-Induced Oxidative Stress and Inflammation by Modulating the NLRP3/NF-κB Pathwayt

Purpose

Gouty arthritis is generally induced by the accumulation of monosodium urate (MSU) crystals in the joints due to elevated serum uric acid levels, potentially leading to serious pathological disorders such as nephrolithiasis, renal failure, and acute gouty arthritis. In this study, we aimed to validate the anti-gout effects of carvacrol, a phenolic monoterpene.

Materials and Methods

Male Sprague–Dawley rats were divided into normal saline, disease group by injecting potassium mono-oxonate (PO) at a dose of 250 mg/kg, and three treatment groups, either with carvacrol 20 mg/kg or 50 mg/kg and 10 mg/kg allopurinol. The blood and tissue samples were subsequently collected and analyzed using different biochemical and histopathological techniques.

Results

Our results revealed a significant increase in the serum levels of oxidative stress-related markers, namely, uric acid and C-reactive protein (CRP), and NLRP3 inflammasome-dependent inflammatory mediators, including nuclear factor kappa B (NF-κB) and tumor necrosis factor-alpha (TNF-α). Carvacrol administration for seven consecutive days exhibited significant anti-hyperuricemic and anti-inflammatory effects in a dose-dependent manner. Notably, the 50 mg/kg carvacrol treatment was observed to produce results similar to the allopurinol treatment. Furthermore, the renal safety of carvacrol was confirmed by the renal function test.

Conclusion

Carvacrol potentially alleviates hyperuricemia-induced oxidative stress and inflammation by regulating the ROS/NRLP3/NF-κB pathway, thereby exerting protective effects against joint degeneration.

Uricaemia and associated health determinants in a paediatric population in Mexico

BACKGROUND AND AIM

Uric acid (UA) is a product of the catabolism of purines, and its increase in blood may be related to the development of cardiometabolic diseases. Whether UA is the result or causal determinant of the appearance of risk factors for cardiometabolic disease is not yet known. UA levels among the young student population in San Luis Potosi have increased in recent years, which may be indicative of a serious future public health concern. Therefore, the objective of this study was to evaluate the association of sociodemographic, lifestyle and cardiometabolic determinants with UA levels in children and adolescents in San Luis Potosí.

METHODS AND RESULTS

A total of 730 students (54.1% female and 45.9% male, 6-19 years old) participated in the study. The subjects attended one of five public schools located in San Luis Potosí. Venous blood samples were collected, blood serum was separated by centrifugation, and UA concentrations were measured with an automated analytical platform. UA was associated with most of the independent variables studied. It presented a positive correlation with body mass index (r = 0.363, p < 0.01). Male sex, socioeconomic status, total screen time, exercise, adequate sleep, systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol explained 23%-39% (p < 0.001) of the variability of plasma concentrations of UA in children and adolescents.

CONCLUSION

Early detection of these determinants will prevent future diseases. Moreover, it will help with the implementation of preventive strategies that could improve the health of this population.

Comparison of Benzbromarone and Allopurinol on Primary Prevention of the First Gout Flare in Asymptomatic Hyperuricemia

Objectives. Whether uric acid-lowering agent use in asymptomatic hyperuricemia can reduce the development of the first gout flare remains unsettled. The goal of the present research was to test the efficacy of benzbromarone and allopurinol on primary prevention of the first gout flare in persons with asymptomatic hyperuricemia in Taiwan. Methods. One observational cohort study was constructed to examine the 2001−2015 dataset adapted from the National Health Insurance Program of Taiwan containing the claims data of 2 million beneficiaries. Asymptomatic hyperuricemia was considered as individuals on uric acid-lowering therapy who did not have gout flares. Individuals aged 20−84 without gout flares who had the use of benzbromarone alone were assigned into a benzbromarone group. Individuals ages 20−84 without gout flares who had the use of allopurinol alone were assigned into an allopurinol group. The final study included 6111 pairs of 1:1 propensity score-matched individuals from both benzbromarone and allopurinol groups. The end point was assigned as individuals who were newly diagnosed with their first gout flare. The incidence rate of the first gout flare was estimated between the benzbromarone and allopurinol groups. A Cox proportional hazards regression model was applied to explore the hazard ratio and 95% confidence interval of the first gout flare related to benzbromarone use and allopurinol use. Results. The incidence rate of the first gout flare was lower in the benzbromarone group compared with an allopurinol group (3.29 versus 5.46 per 1000 person-months, incidence rate ratio = 0.60 and 95% confidence interval = 0.56−0.64). After adjustment for co-variables, the adjusted hazard ratio of the first gout flare was 0.63 (95% confidence interval = 0.59−0.68, p < 0.001) for the benzbromarone group when compared with the allopurinol group. Conclusion. People with asymptomatic hyperuricemia taking benzbromarone have a lower hazard of developing their first gout flare when compared with those taking allopurinol. Based on the medication safety, the therapeutic effects and the low price, with oral administration once daily, we suggest that benzbromarone should be the first drug of choice if clinicians are treating asymptomatic hyperuricemia.

Prevalence of hyperuricemia and the relationship between serum uric acid concentrations and lipid parameters among King Abdulaziz University Hospital patients

Background

Several studies have associated uric acid with dyslipidemia. However, no previous studies have examined patients without chronic illness.

Aim

: The aim of this study is to assess the relationship between serum uric acid concentration and lipid profile parameters and to estimate the prevalence of hyperuricemia in the city of Jeddah.

Patients and Methods

A retrospective study was conducted on 1206 patients who undergone laboratory blood testing over a 3-year period (2018-2020) at King Abdulaziz University Hospital, which was ethically approved. We used a predesigned checklist to collect data from electronic hospital records using Google Forms. Bivariate analysis, tables, and graphs were used to represent and identify the relationships between variables. A P value of <0.05 was considered significant.

Results

Our study revealed a prevalence of 12% for hyperuricemia in the study population. Males were more frequently affected than females (8.13% vs. 3.73%, respectively). There was no association between serum uric acid concentration and lipid profile parameters, including total cholesterol (P = 0.92), triglyceride (P = 0.42), high-density lipoprotein (P = 0.47), and low-density lipoprotein (P = 0.66). There was a strong association between serum uric acid concentration and high body mass index (P < 0.001), older age (P = 0.002), male sex (P < 0.001), and nationality (P < 0.001). Furthermore, there was an association between sex and mean erythrocyte sedimentation rate (P = 0.02) and mean triglyceride concentration (P = 0.02).

Conclusion

We observed a low prevalence of hyperuricemia, and our results indicate no association between serum uric acid concentration and lipid profile parameters.

Polyethylene Glycol-Like Brush Polymer Conjugate of a Protein Drug Does Not Induce an Antipolymer Immune Response and Has Enhanced Pharmacokinetics than Its Polyethylene Glycol Counterpart

Protein therapeutics, except for antibodies, have a short plasma half-life and poor stability in circulation. Covalent coupling of polyethylene glycol (PEG) to protein drugs addresses this limitation. However, unlike previously thought, PEG is immunogenic. In addition to induced PEG antibodies, ≈70% of the US population has pre-existing anti-PEG antibodies. Both induced and preexisting anti-PEG antibodies result in accelerated drug clearance, reduced clinical efficacy, and severe hypersensitivity reactions that have limited the clinical utility of uricase, an enzyme drug for treatment for refractory gout that is decorated with a PEG corona. Here, the authors synthesize a poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) conjugate of uricase that decorates the protein with multiple polymer chains to create a corona to solve these problems. The resulting uricase-POEGMA is well-defined, has high bioactivity, and outperforms its PEG counterparts in its pharmacokinetics (PK). Furthermore, the conjugate does not induce anti-POEGMA antibodies and is not recognized by anti-PEG antibodies. These findings suggest that POEGMA conjugation may provide a solution to the immunogenicity and antigenicity limitations of PEG while improving upon its PK benefits. These results transcend uricase and can be applied to other PEGylated therapeutics and the broader class of biologics with suboptimal PK.

Association between Dietary Fiber Intake and Hyperuricemia among Chinese Adults: Analysis of the China Adult Chronic Disease and Nutrition Surveillance (2015)

This study aimed to assess the association of dietary fiber intake with serum uric acid (SUA) levels and risk of hyperuricemia (HUA) among Chinese adults using the latest nationally representative data. A total of 66,427 Chinese adults aged 18 years and over from the China Adult Chronic Disease and Nutrition Surveillance in 2015 were included in this study. Dietary intakes were measured with a 3-day 24 h dietary recall and the household condiment weighing method. Mixed-effect linear and logistic regression models were used to evaluate the associations of dietary fiber intake with SUA levels and risk of HUA, respectively. Compared to the lowest intake group, the coefficient and 95% confidence in the highest intake group of total fiber were −0.06 (−0.08, −0.04) (p-trend < 0.001), −0.18 (−0.2, −0.16) (p-trend < 0.001) for cereal fiber, 0.03 (0.01, 0.04) (p-trend = 0.051) for legume fiber, 0 (−0.01, 0.02) (p-trend = 0.869) for vegetable fiber and 0.01 (−0.001, 0.04) (p-trend = 0.296) for fruit fiber. The odds ratio (OR) and 95% confidence interval (CI) of HUA for the highest vs. lowest intake group of total fiber were 0.88 (0.84, 0.91) (p-trend = 0.001), 0.67 (0.63, 0.71) (p-trend < 0.001) for cereal fiber, 1.05 (1, 1.09) (p-trend = 0.248) for legume fiber, 1.01 (0.97, 1.05) (p-trend = 0.982) for vegetable fiber and 1.06 (1, 1.12) (p-trend = 0.264) for fruit fiber. Our findings suggest that consumption of total fiber and cereal fiber were significantly inversely associated with SUA levels and HUA risk among the Chinese adult population. Developing and implementing effective public education programs are urgently needed to increase the intake of dietary fiber, especially cereal fiber among Chinese adults.

Inhibitory activities of grape bioactive compounds against enzymes linked with human diseases

A quest for identification of novel, safe and efficient natural compounds, as additives in the modern food and cosmetic industries, has been prompted by concerns about toxicity and side effects of synthetic products. Plant phenolic compounds are one of the most documented natural products due to their multifarious biological applications. Grape (Vitis vinifera) is an important source of phenolic compounds such as phenolic acids, tannins, quinones, coumarins and, most importantly, flavonoids/flavones. This review crisply encapsulates enzyme inhibitory activities of various grape polyphenols towards different key human-ailment-associated enzymes: xanthine oxidase (gout), tyrosinase (hyperpigmentation), α-amylase and α-glucosidase (diabetes mellitus), pancreatic lipase (obesity), cholinesterase (Alzheimer's disease), angiotensin i-converting enzymes (hypertension), α-synuclein (Parkinson's disease) and histone deacetylase (various diseases). The review also depicts the enzyme inhibitory mechanism of various grape polyphenols and briefly discusses their stature as potential therapeutic and drug development candidates. KEY POINTS: • Nineteen major bioactive polyphenols from the grape/grape products and their disease targets are presented • Sixty-two important polyphenols as enzyme inhibitors from grape/grape products are presented • A thorough description and graphical presentation of biological significance of polyphenols against various diseases.

Eurycomanol alleviates hyperuricemia by promoting uric acid excretion and reducing purine synthesis

BACKGROUND

An elevated level of blood uric acid (UA) leads to serious damages to human health. In clinic, xanthine oxidase inhibitor is commonly used to reduce uric acid production. However, UA excretion promotion drug is rare. Our previous study demonstrated that the 70% ethanolic extract of stem of Eurycoma longifolia could effectively increase UA excretion and decrease blood level of UA in hyperuricemia animal model. In this paper, we tried to find active substance on UA regulation from E. longifolia.

METHODS

The constituents of stem from E. longifolia were isolated and analyzed by chemical and spectral methods. Ultra Performance Liquid Chromatography was applied to measure the concentrations of UA in serum and urine. H&E staining was used to characterize renal histopathological changes. The protein and mRNA expressions of UA transporters were measured by western blot and quantitative real-time PCR analysis.

RESULTS

Ten kinds of quassinoids were isolated from stem of E. longifolia, and the structures were identified. Pharmacological research revealed the major component, eurycomanol (5-20 mg/kg, p.o.) significantly decreased serum UA level and increased 24 h clearance of uric acid in potassium oxonate and adenine induced hyperuricemic mice. Eurycomanol ameliorated UA induced kidney histological injury, inhibited hepatic purine synthesis through decreasing phosphoribosyl pyrophosphate synthetase, promoted UA excretion by modulation of renal and intestinal urate transporters, such as GLUT9, ABCG2, OAT1, and NPT1.

CONCLUSION

The results showed eurycomanol from E. longifolia can promote UA excretion through kidney and intestine, decrease hepatic purine synthesis and further keep UA homeostasis, suggesting that eurycomanol has the potential to be developed into a novel drug for the treatment of under-excretion type hyperuricemia.

Febuxostat and its Major Acyl Glucuronide Metabolite are Potent Inhibitors of Organic Anion Transporter 3: Implications for Drug-Drug Interactions with Rivaroxaban

Febuxostat is a second-line xanthine oxidase inhibitor that undergoes extensive hepatic metabolism to yield its major acyl-β-D-glucuronide metabolite (febuxostat AG). It was recently reported that febuxostat inhibited organic anion transporter 3 (OAT3)-mediated uptake of enalaprilat. Here, we investigated the inhibition of febuxostat and febuxostat AG on organic anion transporter 3 (OAT3) in transfected human embryonic kidney 293 cells. Our transporter inhibition assays confirmed the potent noncompetitive and competitive inhibition of OAT3-mediated estrone-3-sulfate transport by febuxostat and febuxostat AG with corresponding apparent K_i values of 0.55 μM and 6.11 μM respectively. After accounting for probe substrate-dependency and protein binding effects, mechanistic static modelling with the direct factor Xa anticoagulant rivaroxaban estimated a 1.47-fold increase in its systemic exposure when co-administered with febuxostat based on OAT3 interaction which in turn exacerbates the bleeding risk from baseline for patients with atrial fibrillation by 1.51-fold. Taken together, our results suggested that the concomitant usage of febuxostat with rivaroxaban may potentially culminate in a clinically-significant drug-drug interaction and result in an increased risk of bleeding as a result of its OAT3 inhibition. This article is protected by copyright. All rights reserved.

Genetic assessment of hyperuricemia and gout in Asian, Native Hawaiian, and Pacific Islander subgroups of pregnant women: biospecimens repository cross-sectional study

Background

Gout, an inflammatory condition, is characterized by the precipitation of monosodium urate crystals (MSU) in or around distal joints. The latter is caused by chronic hyperuricemia (HU)—high urate levels in the blood. Genetic variations in urate transporters play a significant role in determining urate levels within the human body, rendering some racial and ethnic groups more or less susceptible to developing either HU or gout. This study aims to estimate the frequencies of HU and gout risk alleles in Asian, Native Hawaiian, and Pacific Islander subgroups, using biorepository DNA samples.

Methods

The biospecimens repository at the University of Hawai’i provided DNA samples of consented post-partum women of Japanese, Filipino, Korean, Native Hawaiian, Samoan, and Marshallese descent. The DNA was previously extracted from maternal blood and genotyped at the Genomics and Bioinformatics Shared Resource, Cancer Center (Honolulu, HI). Nine urate genes: ABCG2, SLC2A9, SLC16A9, GCKR, SLC22A11, SLC22A12, LRR16A, PDZK1, and SLC17A1, were selected due to their significant association with HU and gout risk. Hardy–Weinberg Equilibrium (HWE) for genotype frequencies was assessed, using the Chi-Square test with p < 0.006 for statistical significance. Allele frequencies in our study were then compared to EUR from the 1000 Genomes Project Database Phase III, using Chi-square or Fisher's exact test, when appropriate. Bonferroni correction for multiple comparisons was used, with p < 0.006 for statistical significance.

Results

Our study involved 1059 post-partum women 18-year-old or older who self-reported their respective race and ethnicity, including Asian, Native Hawaiian, and Pacific Islander ancestry. The Asian subgroups included Japanese, Filipino, and Korean. The Pacific Islander subgroups included Marshallese and Samoan. None of the study participants had a history of gout. We excluded the PDZK1 gene from the final analysis due to its deviation from HWE (p < 0.006) across all the population subgroups, with eight loci remaining for cross-subgroup comparisons. Compared to EUR, the genetic polymorphism frequencies were significantly different-8/8 in Japanese, 6/8 in Korean, 6/8 in Filipino, 8/8 in Samoan, 6/8 in Native Hawaiian, and 6/8 in Marshallese. HU and gout risk alleles indices were 8, 6, 5, 5, 4, and 4 in Japanese, Filipino, Korean, Samoan, Marshallese, and Native Hawaiian, respectively. The percentage of cumulative risk alleles was 100% in both Japanese and Filipino, followed by 83.5% in Korean.

Conclusions

Compared to EUR, Asian subgroups, particularly Japanese, Filipino, and Korean, had the highest percentage of the cumulative uric acid risk alleles. These results could partly explain the increased risk of developing gout among some Asian ancestral subgroups compared to EUR.

Microporous carbon in the selective electro-oxidation of molecular biomarkers: uric acid, ascorbic acid, and dopamine

Herein, we demonstrate the superior electrocatalytic activities of microporous carbon in the oxidation of three molecular biomarkers, ascorbic acid (AA), dopamine (DA), and uric acid (UA), which are co-present in biological fluids.

Acute Oral Toxicity Assessment and Anti-hyperuricemic Activity of Alocasia longiloba Extracts on Sprague-Dawley Rats

Hyperuricemia is defined as a metabolic abnormality that occurs when serum uric acid (UA) level is abnormally high in the body. We previously reported that A. longiloba possesses various important phytochemicals and in vitro xanthine oxidase activity. Despite A. longiloba ethnomedicinal benefits, its toxicity and anti-hyperuricemic effects have not been reported. The present study was carried out to ensure the safety and investigate the anti-hyperuricemic effects of A. longiloba fruit and petiole ethanolic extracts on rats. In the acute toxicity study, extracts were orally administered at a dose of 2000 mg/kg bodyweight and closely monitored for 2-week for any toxicity effects. The rats were then sacrificed and samples were collected and analyzed for hematological, biochemical, and histopathological parameters. The anti-hyperuricemic effect of A. longiloba fruit or petiole extract was investigated through determination of UA levels on potassium oxonate (PO)-induced hyperuricemic rats. Extracts or standard drug treatments were orally administrated 1-h after PO administration for 14-day. Animals were euthanized and samples were collected for further experiments. The toxicity results show, no significant changes were observed in behavioral, bodyweight changes in experimental groups compared to the control. Moreover, there were no significant changes in hematological, biochemical, and histological parameters between extracts treated and control group. In the anti-hyperuricemia study, the fruit and petiole extracts treatments significantly reduced the level of UA in serum compared to the hyperuricemic model group. This study demonstrated that the extracts of A. longiloba have anti-hyperuricemic activity and was found to be non-toxic to rats in acute toxicity test.

Incident hyperuricemia in relation to antihypertensive therapy with the irbesartan/hydrochlorothiazide combination

OBJECTIVE

We investigated serum uric acid changes and incident hyperuricemia in relation to the achieved blood pressure (BP) after 12 weeks of antihypertensive therapy with the irbesartan/hydrochlorothiazide combination.

METHODS

The study participants were 449 patients who completed the study. Analysis of covariance and multiple logistic regression analyses were performed to calculate the least square mean changes (± standard error) from baseline in serum uric acid and odds ratios (ORs) for incident hyperuricemia according to the achieved levels of BP.

RESULTS

Adjusted analyses showed that serum uric acid changes differed according to the achieved SBP/DBP (P = 0.002), with a smaller mean (± standard error) increase in the range of 130-139/<90 mm Hg (n = 132, 19.8 ± 5.7 µmol/L) than that of ≥140/90 (n = 129, 32.4 ± 7.3 µmol/L) or <130/90 mm Hg (n = 188, 39.5 ± 5.1 µmol/L). Adjusted analyses showed similar results for the incident hyperuricemia (n = 95, 24.0%) in those patients with normal serum uric acid at baseline (n = 396). The risk of incident hyperuricemia was lower (OR, 0.45; 95% confidence interval 0.25-0.83; P = 0.04) in patients with an achieved SBP/DBP of 130-139/<90 mm Hg (n = 117, incidence rate, 17.1%) than those with an achieved SBP/DBP of ≥140/90 (n = 118, 31.4%) or <130/90 mm Hg (n = 161, 23.6%).

CONCLUSIONS

Thiazide-induced changes in serum uric acid or incident hyperuricemia were associated with the achieved SBP/DBP, being lower at the level of 130-139/<90 mm Hg.

Guidelines for purine extraction and determination in foods

With the improvement of living standards over the years, the demand for “delicious food” has been increasing rapidly. Accordingly, the hidden risks associated with these kinds of food have gradually been attracting attention and purines have especially become of great interest. Food‐derived purines are one of the important sources of purine in the body. Eventually, it is metabolized by the body to produce uric acid, which may lead to hyperuricemia and gout. Thus, detecting the purine content in foods could be a significant guidance for dietary intake. Here, this article reviews purine pretreatment and detection methods as well as the purine content of common foods. Perchloric acid hydrolysis and high‐performance liquid chromatography were found to be the most commonly used pretreatment and quantification methods in purine detection. In addition, total purine content was in the order of plant foods < fungus and algae foods < animal foods < aquatic products. This reenforces the suggestion that, for individuals with hyperuricemia and gout, fewer or none intake of aquatic products and animal foods and increase intake of plant and fungal and algae foods may be a healthier option.