Uric acid as a danger signal in gout and its comorbidities. Nat Rev Rheumatol. 2013;9:13-23. [PMID: 22945591 DOI: 10.1038/nrrheum.2012.143]

Disparity of serum uric acid threshold for CKD among hypertensive and non-hypertensive individuals

INTRODUCTION

Hypertension and rising serum uric acid (sUA) played a pivotal role in the development of Chronic Kidney Disease (CKD). This study investigates the interactive effect of sUA and hypertension on CKD and identifies the optimal threshold of sUA among individuals with and without hypertension in the Chinese community population.

MATERIALS AND METHODS

The study included 4180 individuals aged 45-85 years, derived from the China Health and Retirement Longitudinal Study (CHARLS) between 2011 and 2015. Additionally, a hospital-based study enrolled subjects in the Department of Nephrology at Zhongshan Hospital, China from January 1, 2019, to December 31, 2021. The interaction effect analysis were used to assess the impact of sUA and hypertension on CKD. We also compared the distribution of sUA and the CKD risk in community populations, distinguishing between those with and without hypertension. For the hospital-based population, kidney injury was marked by a KIM-1 positive area.

RESULTS

Our results indicate a higher prevalence of CKD in the community population with hypertension (10.2% vs. 3.9%, p < .001). A significant additive synergistic effects of the sUA and hypertension on the CKD risk were found. When the sUA level was < 4.55 mg/dL in the hypertensive population and < 5.58 mg/dL in the non-hypertensive population, the risk of CKD was comparable (p = .809). In the propensity score matched (PSM) population, the result remained roughly constant.

CONCLUSION

Therefore, even moderate levels of sUA was associated with a higher risk of CKD in middle-aged hypertensive patients, who warrant stricter sUA control.

Risk factors for cardio-cerebrovascular events among patients undergoing continuous ambulatory peritoneal dialysis and their association with serum magnesium

Serum magnesium levels exceeding 0.9 mmol/L are associated with increased survival rates in patients with CKD. This retrospective study aimed to identify risk factors for cardio-cerebrovascular events among patients receiving continuous ambulatory peritoneal dialysis (CAPD) and to examine their correlations with serum magnesium levels. Sociodemographic data, clinical physiological and biochemical indexes, and cardio-cerebrovascular event data were collected from 189 patients undergoing CAPD. Risk factors associated with cardio-cerebrovascular events were identified by univariate binary logistic regression analysis. Correlations between the risk factors and serum magnesium levels were determined by correlation analysis. Univariate regression analysis identified age, C-reactive protein (CRP), red cell volume distribution width standard deviation, red cell volume distribution width corpuscular volume, serum albumin, serum potassium, serum sodium, serum chlorine, serum magnesium, and serum uric acid as risk factors for cardio-cerebrovascular events. Among them, serum magnesium ≤0.8 mmol/L had the highest odds ratio (3.996). Multivariate regression analysis revealed that serum magnesium was an independent risk factor, while serum UA (<440 μmol/L) was an independent protective factor for cardio-cerebrovascular events. The incidence of cardio-cerebrovascular events differed significantly among patients with different grades of serum magnesium (χ2 = 12.023, p = 0.002), with the highest incidence observed in patients with a serum magnesium concentration <0.8 mmol/L. High serum magnesium levels were correlated with high levels of serum albumin (r = 0.399, p < 0.001), serum potassium (r = 0.423, p < 0.001), and serum uric acid (r = 0.411, p < 0.001), and low levels of CRP (r = -0.279, p < 0.001). In conclusion, low serum magnesium may predict cardio-cerebrovascular events in patients receiving CAPD.

Glucoconjugated monoterpene indole alkaloids with xanthine oxidase inhibitory activity from Ophiorrhiza japonica

Continued interest in the bioactive alkaloids led to the isolation of five undescribed alkaloids (1-5), ophiorglucidines A-E, and seven known analogues (6-12) from the water-soluble fraction of Ophiorrhiza japonica. The structures were elucidated based on spectroscopic data and quantum calculations as well as X-ray crystallographic analysis. The structure of 1 was characterized as a hexacyclic skeleton including a double bridge linking the indole and the monoterpene moieties, which is the first report of a single crystal with this type of structure. Moreover, the inhibitory effect of zwitterionic indole alkaloid glycosides on xanthine oxidase was found for the first time. The alkaloids 2 and 3, both of which have a pentacyclic zwitterionic system, were more active than the reference inhibitor, allopurinol (IC50 = 11.1 μM) with IC50 values of 1.0 μM, and 2.5 μM, respectively. Structure-activity relationships analyses confirmed that the carbonyl group at C-14 was a key functional group responsible for the inhibitory effects of these alkaloids.

Advancements in the study of IL-6 and its receptors in the pathogenesis of gout

Gout is an autoinflammatory disease characterized by the deposition of monosodium urate crystals in or around the joints, primarily manifesting as inflammatory arthritis that recurs and resolves spontaneously. Interleukin-6 (IL-6) is a versatile cytokine with both anti-inflammatory and pro-inflammatory capabilities, linked to a variety of inflammatory diseases such as gouty arthritis, rheumatoid arthritis, inflammatory bowel disease, vasculitis, and several types of cancer. The rapid production of IL-6 during infections and tissue damage aids in host defense. However, excessive synthesis of IL-6 and dysregulation of its receptor signaling (IL-6R) might contribute to the pathology of diseases. Recent advancements in clinical and basic research, along with developments in animal models, have established the significant role of IL-6 and its receptors in the pathogenesis of gout, although the precise mechanisms remain to be fully elucidated. This review discusses the role of IL-6 and its receptors in gout progression and examines contemporary research on modulating IL-6 and its signaling pathways for treatment. It aims to provide insights into the pathogenesis of gout and to advance the development of targeted therapies for gout-related inflammation.

Unveiling overlooked pathways: The uric acid catabolism genes in the human genome

In hominids, including Homo sapiens, uric acid is the end product of purine catabolism. In contrast, other placental mammals further degrade uric acid to (S)-allantoin by enzymes such as urate oxidase (uricase), HIU hydrolase (HIUase), and OHCU decarboxylase. Some organisms, such as frogs and fish, hydrolyze (S)-allantoin to allantoate and eventually to (S)-ureidoglycolate and urea, while marine invertebrates convert urea to ammonium. In H. sapiens, mutations in the uricase gene led to a reduction in the selective pressure for maintaining the integrity of the genes encoding the other enzymes of the purine catabolism pathway, resulting in an accumulation of uric acid. The hyperuricemia resulting from this accumulation is associated with gout, cardiovascular disease, diabetes, and preeclampsia. Many commonly used drugs, such as aspirin, can also increase uric acid levels. Despite the apparent absence of these enzymes in H. sapiens, there appears to be production of transcripts for uricase (UOX), HIUase (URAHP), OHCU decarboxylase (URAD), and allantoicase (ALLC). While some URAHP transcripts are classified as long non-coding RNAs (lncRNAs), URAD and ALLC produce protein-coding transcripts. Given the presence of these transcripts in various tissues, we hypothesized that they may play a role in the regulation of purine catabolism and the pathogenesis of diseases associated with hyperuricemia. Here, we specifically investigate the unique aspects of purine catabolism in H. sapiens, the effects mutations of the uricase gene, and the potential regulatory role of the corresponding transcripts. These findings open new avenues for research and therapeutic approaches for the treatment of hyperuricemia and related diseases.

Anti-hyperuricemia bioactive peptides: a review on obtaining, activity, and mechanism of action

Hyperuricemia, a disorder of uric acid metabolism, serves as a significant risk factor for conditions such as hypertension, diabetes mellitus, renal failure, and various metabolic syndromes. The main contributors to hyperuricemia include overproduction of uric acid in the liver or impaired excretion in the kidneys. Despite traditional clinical drugs being employed for its treatment, significant health concerns persist. Recently, there has been growing interest in utilizing protein peptides sourced from diverse food origins to mitigate hyperuricemia. This article provides a comprehensive review of bioactive peptides with anti-hyperuricemia properties derived from animals, plants, and their products. We specifically outline the methods for preparing these peptides from food proteins and elucidate their efficacy and mechanisms in combating hyperuricemia, supported by in vitro and in vivo evidence. Uric acid-lowering peptides offer promising prospects due to their safer profile, enhanced efficacy, and improved bioavailability. Therefore, this review underscores significant advancements and contributions in identifying peptides capable of metabolizing purine and/or uric acid, thereby alleviating hyperuricemia. Moreover, it offers a theoretical foundation for the development of functional foods incorporating uric acid-lowering peptides.

Adjunctive administration of parabiotic Lactobacillus sakei CVL-001 ameliorates drug-induced toxicity and pulmonary inflammation during antibiotic treatment for tuberculosis

Tuberculosis (TB) treatment requires a long therapeutic duration and induces adverse effects such as hepatotoxicity, causing discontinuation of treatment. Reduced adherence to TB medications elevates the risk of recurrence and the development of drug resistance. Additionally, severe cavitary TB with a high burden of Mycobacterium tuberculosis (Mtb) and inflammation-mediated tissue damage may need an extended treatment duration, resulting in a higher tendency of drug-induced toxicity. We previously reported that the administration of Lactobacillus sakei CVL-001 (L. sakei CVL-001) regulates inflammation and improves mucosal barrier function in a murine colitis model. Since accumulating evidence has reported the functional roles of probiotics in drug-induced liver injury and pulmonary inflammation, we employed a parabiotic form of the L. sakei CVL-001 to investigate whether this supplement may provide beneficial effects on the reduction in drug-induced liver damage and pulmonary inflammation during chemotherapy. Intriguingly, L. sakei CVL-001 administration slightly reduced Mtb burden without affecting lung inflammation and weight loss in both Mtb-resistant and -susceptible mice. Moreover, L. sakei CVL-001 decreased T cell-mediated inflammatory responses and increased regulatory T cells along with an elevated antigen-specific IL-10 production, suggesting that this parabiotic may restrain excessive inflammation during antibiotic treatment. Furthermore, the parabiotic intervention significantly reduced levels of alanine aminotransferase, an indicator of hepatotoxicity, and cell death in liver tissues. Collectively, our data suggest that L. sakei CVL-001 administration has the potential to be an adjunctive therapy by reducing pulmonary inflammation and liver damage during anti-TB drug treatment and may benefit adherence to TB medication in lengthy treatment.

Large-scale cross-ancestry genome-wide meta-analysis of serum urate

Hyperuricemia is an essential causal risk factor for gout and is associated with cardiometabolic diseases. Given the limited contribution of East Asian ancestry to genome-wide association studies of serum urate, the genetic architecture of serum urate requires exploration. A large-scale cross-ancestry genome-wide association meta-analysis of 1,029,323 individuals and ancestry-specific meta-analysis identifies a total of 351 loci, including 17 previously unreported loci. The genetic architecture of serum urate control is similar between European and East Asian populations. A transcriptome-wide association study, enrichment analysis, and colocalization analysis in relevant tissues identify candidate serum urate-associated genes, including CTBP1, SKIV2L, and WWP2. A phenome-wide association study using polygenic risk scores identifies serum urate-correlated diseases including heart failure and hypertension. Mendelian randomization and mediation analyses show that serum urate-associated genes might have a causal relationship with serum urate-correlated diseases via mediation effects. This study elucidates our understanding of the genetic architecture of serum urate control.

Arthroscopic surgery for ankle gouty arthritis: a retrospective analysis of clinical outcomes at six month follow-up based on a novel classification system

PURPOSE

This study aimed to evaluate the clinical outcomes, patient-reported outcomes, and recurrence rate of patients diagnosed with ankle gouty arthritis who underwent arthroscopic surgery based on the new classification.

METHODS

A total of 51 patients diagnosed with ankle gouty arthritis were included in this retrospective study. A new classification was proposed based on the location and extent of MSU crystal deposition under an arthroscopy view. Patients are classified into different types and underwent arthroscopic surgery accordingly. The primary outcome measure was the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score. The secondary outcomes included the visual analog pain scale (VAS), serum uric acid levels, and the recurrence rate of ankle gouty arthritis at one year postoperatively.

RESULTS

Based on the new classification, five patients were Type I, 24 patients were Type II, five were Type III A, six were Type III B, and 11 were Type IV. The average follow-up time was 23.5 ± 10.9 months. The AOFAS hindfoot-ankle score improved significantly from 70.3 ± 15.9 to 85.6 ± 13.0 (p < 0.01). The mean serum uric acid level was significantly decreased from 442.0 ± 109.2 to 540.5 ± 132.4 (p < 0.01). The average VAS scale decreased from 3.8 ± 1.9 to 1.4 ± 1.7 (p < 0.01). The median of recurrences in one year postoperatively was significantly decreased from 1.5 (1, 3.75) to 0 (0, 0.75) (p < 0.01).

CONCLUSION

A new classification strategy for ankle gouty arthritis based on arthroscopic view was proposed. Patients with ankle gouty arthritis showed significant improvement in ankle function and pain relief after undergoing arthroscopic surgery driven by the new classification.

Assessing the causal relationships of gut microbial genera with hyperuricemia and gout using two-sample Mendelian randomization

BACKGROUND AND AIMS

The causal relationship between gut microbiota and gout and hyperuricemia (HUA) has not been clarified. The objective of this research was to evaluate the potential causal effects of gut microbiota on HUA and gout using a two-sample Mendelian randomization (MR) approach.

METHODS AND RESULTS

Genetic instruments were selected using summary statistics from genome-wide association studies (GWASs) comprising a substantial number of individuals, including 18,473 participants for gut microbiome, 288,649 for serum urate (SU), and 763,813 for gout. Two-sample MR analyses were performed to determine the possible causal associations of gut microbial genera with the risk of HUA and gout using the inverse-variance weighted (IVW) method, and robustness of the results was confirmed by several sensitivity analyses. A reverse MR analysis was conducted on the bacterial taxa that were identified in forward MR analysis. Based on the results of MR analyses, Escherichia-Shigella (OR = 1.05; 95% CI, 1.01-1.08; P = 0.009) exhibited a positive association with SU levels, while Lachnospiraceae NC2004 group (OR = 0.95; 95% CI, 0.92-0.98; P = 0.001) and Family XIII AD3011 group (OR = 0.94; 95% CI, 0.90-0.99; P = 0.015) were associated with a reduced HUA risk. Moreover, Coprococcus 3 (OR = 1.17, 95% CI: 1.01-1.34, P = 0.031) was causally associated with a higher gout risk. In reverse MR analysis, no causal relationships were identified between these bacterial genera and HUA or gout.

CONCLUSION

This study provides evidence for a causal association between gut microbial genera and HUA or gout, and further investigations of the underlying mechanism are warranted.

Polyvinylpyrrolidone-Coated Cubic Hollow Nanocages of PdPt3 and PdIr3 as Highly Efficient Self-Cascade Uricase/Peroxidase Mimics

Uricase-catalyzed uric acid (UA) degradation has been applied for hyperuricemia therapy, but this medication is limited by H2O2 accumulation, which can cause oxidative stress of cells, resulting in many other health issues. Herein, we report a robust cubic hollow nanocage (HNC) system based on polyvinylpyrrolidone-coated PdPt3 and PdIr3 to serve as highly efficient self-cascade uricase/peroxidase mimics to achieve the desired dual catalysis for both UA degradation and H2O2 elimination. These HNCs have hollow cubic shape with average wall thickness of 1.5 nm, providing desired synergy to enhance catalyst's activity and stability. Density functional theory calculations suggest the PdIr3 HNC surface tend to promote OH*/O* desorption for better peroxidase-like catalysis, while the PdPt3 HNC surface accelerates the UA oxidation by facilitating O2-to-H2O2 conversion. The dual catalysis power demonstrated by these HNCs in cell studies suggests their great potential as a new type of nanozyme for treating hyperuricemia.

The non-causative role of abnormal serum uric acid in intervertebral disc degeneration: A Mendelian randomization study

Background

Intervertebral disc degeneration (IDD) is a common musculoskeletal disorder that contributes significantly to disability and healthcare costs. Serum urate concentration has been implicated in the development of various musculoskeletal conditions. While previous observational studies have suggested an association between the two conditions, it might confound the effect of serum urate concentrations on IDD. This Mendelian randomization (MR) study aimed to investigate the causal relationship between serum urate concentration and IDD.

Methods

We performed a two-sample MR analysis using summary-level data from genome-wide association studies (GWAS) of serum urate concentration (n = 13 585 994 European ancestry) and IDD (n = 16 380 337 European ancestry). Single nucleotide polymorphisms (SNPs) significantly associated with serum urate concentration (p < 5 × 10-8) were selected as instrumental variables. The associations between genetically predicted serum urate concentration and IDD were estimated using the inverse-variance weighted (IVW) method, with sensitivity analyses employing the weighted median, MR-Egger, and MR-PRESSO approaches to assess the robustness of the findings.

Results

In the primary IVW analysis, genetically predicted serum urate concentration was unrelated associated with IDD (odds ratio [OR] = 1.00, 95% confidence interval (CI): 1.00-1.00, p = 0.17)). The results remained consistent across the sensitivity analyses, and no significant directional pleiotropy was detected (MR-Egger intercept: p = 0.15).

Conclusions

This MR study provides evidence that there is no causal relationship between serum urate concentration and IDD. It suggests previous observational associations may be confounded. Serum urate levels are unlikely to be an important contributor to IDD.

Modulation of Performance, Plasma Constituents, Small Intestinal Morphology, and Cecum Microbiota in Growing Geese by Dietary Citric Acid Supplementation

To investigate the efficiency and optimum inclusion level of CA in growing geese diets on performance, plasma constituents, and intestinal health, 240 healthy female geese at the age of 28d were randomly allotted six treatment diets incorporated with 0, 0.8, 1.6, 2.4, 3.2, and 4% CA. Each treatment group consisted of five replicates and eight birds per replicate. The findings demonstrated that 3.2% CA supplementation resulted in improved growth performance (ADG, ADFI, and FBW) (p = 0.001), and geese who received CA also showed lower body fat contents (p < 0.05) than the control group. Moreover, geese from the 2.4% and 3.2% CA group had the highest plasma glutathione peroxidase and insulin-like growth factor 1 levels compared to the other groups (p < 0.05). A microbial diversity analysis of the cecum conducted by 16S rDNA sequencing revealed that 3.2% CA supplementation showed a significantly higher abundance of beneficial bacteria (Muribaculaceae, CHKCI001, Erysipelotricha-ceae_UCG_003, and UCG_009) (p < 0.05) and a lower abundance of harmful bacteria (Atopobiaceae, Streptococcus, Acinetobacter, Pseudomonas, and Alistipes) (p < 0.10). Collectively, our results revealed that dietary supplementation with 3.2% CA had several benefits on the performance and physiological health of growing geese by promoting nutrients metabolism, improving antioxidant capacity, and modulating cecum microbiota.

Sonoelectrochemical exfoliation of defective black phosphorus nanosheet with black phosphorus quantum dots as a uric acid sensor

To maintain human health, the development of rapid uric acid (UA) sensing is crucial. In this study, defective black phosphorus nanosheets with black phosphorus quantum dots (dBPN/BPQDs) were successfully and rapidly prepared by sonoelectrochemical exfoliation. In this process, the intercalation of phosphate ions into the black phosphorus working electrode was improved by coupling ultrasonic radiation with a high intercalating potential (8 V vs. Ag/AgCl/3M). The dBPN/BPQDs with various vacancies (5-9 defects, 5-7-7-5 defects, and 5-8-5 defect vacancies) exhibited a remarkable mass activity (jm, 1.22 × 10-3 mA μg-1) for uric acid oxidation, which was 5.92 times greater than that of reduced graphene oxide (rGO) (2.06 × 10-4 mA μg-1). In addition, the sensitivity of the dBPN/BPQD UA sensor was 474.2 μA mM-1 cm-2 in the linear analysis range of 0.1-1.3 mM. The sensitivity of the sensor was apparently higher than 67.7 μA mM-1cm-2 for rGO. The data from real sample experiments using serum showed that the dBPN/BPQD catalyst had high recoveries (97.3 %-100.2 %) and low related standard deviation (0.44 %-1.52 %). The dBPN/BPQDs exhibited the potential as an amperometric sensor to detect UA without needing enzymes.

Bisphenol A and its alternatives bisphenol S and F exposure with serum uric acid levels, hyperuricemia, and gout prevalence among US adults: a nationally representative cross-sectional study

BACKGROUND

Recent studies suggested inconclusive associations between bisphenols exposure and hyperuricemia risk. Our objective was to assess the potential association of bisphenol A (BPA) and its substitutes bisphenol S and F (BPS and BPF) exposure with serum uric acid (SUA) levels, hyperuricemia, and gout prevalence among US adults within the NHANES 2013-2016 datasets.

METHODS

Multivariable linear and logistic regression models were used to explore the associations of urinary bisphenols concentrations with SUA levels, hyperuricemia, and gout prevalence, in total population and different sex groups. The restricted cubic spline (RCS) model was used to explore the dose-response relationship.

RESULTS

In total population, doubling of urinary BPS and ∑BPs concentrations showed associations with an increase of 2.64 μmol/L (95% CI: 0.54, 4.74) and 3.29 μmol/L (95% CI: 0.59, 5.99) in SUA levels, respectively. The RCS model indicated a significantly "J"-shaped dose-response relationship between BPS exposure and SUA levels. Compared to the reference group of urinary BPS, males in the highest quartile displayed a 13.06 μmol/L (95% CI: 0.75, 25.37) rise in SUA levels. For females, doubling of urinary BPS concentrations was associated with a 3.30 μmol/L (95% CI: 0.53, 6.07) increase in SUA levels, with a significant linear dose-response relationship. In total population, doubling of urinary BPA concentrations showed a 1.05-fold (95% CI: 0.97, 1.14) adjusted risk of having hyperuricemia, with an inverted "U" curve. Doubling of urinary ∑BPs concentrations was associated with a 1.05-fold (95% CI: 0.96, 1.14) adjusted risk of hyperuricemia in total population, with a significant monotonic dose-response relationship. In females, doubling of urinary BPS concentrations was associated with a 1.45-fold (95% CI: 1.01, 2.08) adjusted increased risk of having gout, with a "J" shaped relationship.

CONCLUSIONS

BPA and BPS exposure to some extent were associated with elevated SUA levels and increased risk of hyperuricemia, with different dose-response relationships and sex differences.

Two horizontally acquired bacterial genes steer the exceptionally efficient and flexible nitrogenous waste cycling in whiteflies

Nitrogen is an essential element for all life on earth. Nitrogen metabolism, including excretion, is essential for growth, development, and survival of plants and animals alike. Several nitrogen metabolic processes have been described, but the underlying molecular mechanisms are unclear. Here, we reveal a unique process of nitrogen metabolism in the whitefly Bemisia tabaci, a global pest. We show that it has acquired two bacterial uricolytic enzyme genes, B. tabaci urea carboxylase (BtUCA) and B. tabaci allophanate hydrolase (BtAtzF), through horizontal gene transfer. These genes operate in conjunction to not only coordinate an efficient way of metabolizing nitrogenous waste but also control B. tabaci's exceptionally flexible nitrogen recycling capacity. Its efficient nitrogen processing explains how this important pest can feed on a vast spectrum of plants. This finding provides insight into how the hijacking of microbial genes has allowed whiteflies to develop a highly economic and stable nitrogen metabolism network and offers clues for pest management strategies.

Effects of evodiamine on ROS/TXNIP/NLRP3 pathway against gouty arthritis

Evodiamine (EVO) was tested on acute gouty arthritis rats to investigate its anti-inflammatory effect. Seventy-two male Sprague-Dawley (SD) rats were randomly assigned into the control, model, high, medium, and low dose of EVO groups and colchicine group. The ankle swelling degrees were measured at 2 h, 6 h, and 24 h following sodium urate injection into ankle joint. Histopathological examination was performed 24 h after injection. Reactive oxygen species (ROS) content in the ankle joint was detected using chemical fluorescence. Serum interleukin-1β (IL-1β), interleukin-18 (IL-18), and tumor necrosis factor-α (TNF-α) content were determined by ELISA. Serum xanthine oxidase (XOD), superoxide dismutase (SOD), and malondialdehyde (MDA) were determined by spectrophotometry. The expressions of thioredoxin-interacting protein (TXNIP), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), pro-caspase-1, caspase-1, and apoptosis-related spot like protein (ASC) in synovium were detected by Western blot. Evodiamine alleviated the ankle swelling of the affected foot in gouty arthritis rats and reduced inflammatory cell infiltration in joint synovial tissue. Evodiamine also decreased the content of serum inflammatory factors including IL-1β, IL-18, and TNF-α, and increased serum SOD activity, while it decreased serum XOD, MDA activity, and ROS level. Moreover, evodiamine downregulated the protein expression levels of TXNIP, NLRP3, pro-caspase-1, cleaved caspae-1, and ASC. The mechanism of EVO in treating gouty arthritis is associated with the inhibition of NLRP3 inflammasome by regulating the ROS/TXNIP/NLRP3 signaling pathway.

Impact of gout on cardiovascular disease mortality: a meta-analysis

BACKGROUND

Several epidemiological studies have suggested that gout patients have a higher risk of cardiovascular disease mortality than healthy people. In contrast, the association between gout and cardiovascular disease (CVD) mortality was not obvious in other studies. In the present study, we aimed to investigate the relative risk for CVD mortality in gout patients in comparison to healthy controls.

METHODS

Literature published before March 2023 was searched in Google Scholar, PubMed, and the Web of Science. We summarized the impact of gout on CVD mortality with a meta-analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) regarding the impact of gout on CVD mortality were summarized with STATA 12.0 software.

RESULTS

Compared to individuals without gout, those with gout had higher mortality risks for CVD during follow-up, with a random effects model showing a risk of 1.30 (95% CI 1.15 to 1.48, p < 0.001; p-value for Cochran Q test < 0.001, I2 = 95.9%). Similarly, subjects with gout had a mortality risk of 1.28 (95% CI 1.12 to 1.46, p < 0.001; p-value for Cochran Q test = 0.050, I2 = 50.2%) for coronary heart disease (CHD) mortality during follow-up using the same statistical model. Furthermore, using a fixed effects model, individuals with gout had a mortality risk of 1.13 (95% CI 1.00 to 1.27, p = 0.049; p-value for Cochran Q test = 0.494, I2 = 0.0%) for myocardial infarction (MI) mortality during follow-up.

CONCLUSION

In conclusion, this meta-analysis provides evidence supporting a markedly increased mortality risk from CVD and CHD as well as MI in patients with gout relative to reference subjects without gout.

Polystyrene microplastics induce size-dependent multi-organ damage in mice: Insights into gut microbiota and fecal metabolites

Particle size is one of the most important factors in determining the biological toxicity of microplastics (MPs). In this study, we attempted to examine the systemic toxicity of polystyrene MPs of different sizes (0.5 µm MP1 and 5 µm MP2) in C57BL/6 J mice. After the mice were given oral gavage of MPs for 8 consecutive weeks, histopathology and molecular biology assays, 16 S rRNA sequencing of the gut microbiota, and untargeted metabolomics were performed. The results showed that MPs were distributed in the organs in a size-dependent manner, with smaller particles demonstrating greater biodistribution. Further analysis indicated that exposure to MPs caused multi-organ damage through distinct toxicity pathways. Specifically, exposure to 0.5 µm MP1 led to excessive accumulation and induced more serious inflammation and mechanical damage in the spleen, kidney, heart, lung, and liver. However, 5 µm MP2 led to more severe intestinal barrier dysfunction, as well as gut dysbiosis and metabolic disorder in association with neuroinflammation. These results are helpful in expanding our knowledge of the toxicity of MPs of different sizes in mammalian models.

Oral-gut axis as a novel biological mechanism linking periodontal disease and systemic diseases: A review

Substantial evidence suggests that periodontal disease increases the risk of developing and progressing extraoral manifestations such as diabetes, atherosclerosis, rheumatoid arthritis, and inflammatory bowel disease. The most probable causative mechanism behind this is the influx of bacteria and/or bacterial products (endotoxin) and inflammatory cytokines into the systemic circulation originating from inflamed periodontal tissues. However, recent studies have revealed that oral bacteria, especially periodontopathic bacteria, play a role in inducing dysbiosis of the gut microbiota resulting induction of gut dysbiosis-related pathology associated with systemic diseases. Conversely, the disruption of gut microbiota has been shown to have a negative impact on the pathogenesis of periodontal disease. Based on our study findings and the available literature, this review presents an overview of the relationship between periodontal disease and systemic health, highlighting the mouth-gut connection.

Agents for the Treatment of Gout: Current Advances and Future Perspectives

Gout is characterized by hyperuricemia and the deposition of monosodium urate (MSU) crystals around joints. Despite the availability of several drugs on the market, its treatment remains challenging owing to the notable side effects, such as hepatorenal toxicity and cardiovascular complications, that are associated with most existing agents. This perspective aims to summarize the current research progress in the development of antigout agents, particularly focusing on xanthine oxidase (XO) and urate anion transporter 1 (URAT1) inhibitors from a medicinal chemistry viewpoint and their preliminary structure-activity relationships (SARs). This perspective provides valuable insights and theoretical guidance to medicinal chemists for the discovery of antigout agents with novel chemical structures, better efficiency, and lower toxicity.

Elevated triglyceride-glucose index predisposes to the initial episode of peritonitis in chronic peritoneal dialysis patients

OBJECTIVE

The serum triglyceride-glucose (TyG) index is a marker of inflammation. However, the relationship between TyG index and peritoneal dialysis-related peritonitis (PDRP) is unclear. This study aimed to investigate the potential relationship between the baseline TyG index and the initial episode of PDRP.

METHODS

A total of 208 peritoneal dialysis (PD) patients were enrolled from January 1, 2012, to December 31, 2019 and followed up until December 31, 2022. They were divided into 2 groups according to the median TyG. The primary outcome was the occurrence of the initial episode of PDRP while on PD therapy. Kaplan-Meier curves and Cox regression analyses were used to examine the association between them.

RESULTS

Eighty-five initial episodes of PDRP were identified. The risk of PDRP was higher in the high-TyG index group (p = 0.030). Multivariate Cox regression analysis showed a higher risk of PDRP in patients with a high TyG index (HR = 1.800, 95% CI 1.511-2.815, p = 0.010).

CONCLUSION

The baseline serum TyG index was an independent risk factor for the initial episode of PDRP in chronic PD patients.

Causality of occupational exposure on rheumatoid arthritis and ankylosing spondylitis: a two-sample mendelian randomization study

Objective

This study aimed to explore the potential causal link between three specific types of occupational exposure on rheumatoid arthritis (RA) and ankylosing spondylitis (AS).

Method

A Two-sample Mendelian randomization (TSMR) analysis, comprising univariate MR (UVMR) and multivariate MR (MVMR) analyses, was performed to investigate the potential causal association between three types of occupational exposures, jobs involving mainly walking or standing (JWS), jobs involving heavy manual or physical work (JMP), and jobs involving shift work(JSW) on RA and AS. Genetic variants for genome-wide association studies (GWAS) of occupational exposure and AS were obtained from the UK Biobank. GWAS summary data for RA were obtained from FinnGen Biobank analysis. For UVMR, six methods of Inverse Variance Weighted (IVW), MR-Egger, Weighted Mode, Weighted Median, Simple Mode, MR pleiotropy residual sum, and outlier (MR-PRESSO) were used for the analysis. The MVMR was analyzed using the IVW model as well as the MR-Egger model.

Results

The UVMR suggested no causal relationship between the three occupational exposure and RA [IVW: P=0.59,0.21,0.63] or AS [IVW: P=0.43,0.57,0.04], as did the bidirectional MR [IVW: P=0.73,0.70,0.16], [IVW: P=0.65,0.68,0.74]. Although unadjusted MVMR suggested a causal relationship between JMP and AS [IVW: OR = 1.01, 95% CI = 1.00- 1.02, p = 0.02], the adjusted MVMR denied this relationship and concluded that there was no causal relationship between the other occupational exposure and either RA or AS.

Conclusion

Our MR analysis did not establish a direct causal relationship between certain occupational exposures and either RA or AS.

Role of inflammasomes and cytokines in immune dysfunction of liver cirrhosis

Liver cirrhosis develops as a result of persistent inflammation and liver injury. The prolonged inflammation triggers the buildup of fibrous tissue and regenerative nodules within the liver, leading to the distortion of the hepatic vascular structure and impaired liver function. Cirrhosis disrupts the ability of liver function to maintain homeostasis and hepatic immunosurveillance which causes immunological dysfunction in the body. In pathological conditions, the production of cytokines in the liver is carefully regulated by various cells in response to tissue stimulation. Cytokines and inflammasomes are the key regulators and systematically contribute to the development of cirrhosis which involves an inflammatory response. However, the crosstalk role of different cytokines in the cirrhosis progression is poorly understood. Tumour necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), and interferon-gamma (IFN-γ), among others, are proinflammatory cytokines that contribute to liver cell necrosis, which in turn causes the development of fibrosis. While IL-10 exhibits a potent anti-inflammatory effect on the liver by inhibiting immune cell activation and neutralizing pro-inflammatory cytokine activity. Inflammasomes have also been implicated in the profibrotic processes of liver cirrhosis, as well as the production of chemokines such as CCL2/MCP-1. It is evident that inflammasomes have a role in the proinflammatory response seen in chronic liver illnesses. In conclusion, cirrhosis significantly impacts the immune system, leading to immunological dysfunction and alterations in both innate and acquired immunity. Proinflammatory cytokines like TNF-α, IL-1β, IL-6, and IFNγ are upregulated in cirrhosis, contributing to liver cell necrosis and fibrosis development. Managing cytokine-mediated inflammation and fibrosis is a key therapeutic approach to alleviate portal hypertension and its associated liver complications. This review attempted to focus largely on the role of immune dysfunction mediated by different cytokines and inflammasomes involved in the progression, regulation and development of liver cirrhosis.

Gout therapeutics and drug delivery

Gout is a common inflammatory arthritis caused by persistently elevated uric acid levels. With the improvement of people's living standards, the consumption of processed food and the widespread use of drugs that induce elevated uric acid, gout rates are increasing, seriously affecting the human quality of life, and becoming a burden to health systems worldwide. Since the pathological mechanism of gout has been elucidated, there are relatively effective drug treatments in clinical practice. However, due to (bio)pharmaceutical shortcomings of these drugs, such as poor chemical stability and limited ability to target the pathophysiological pathways, traditional drug treatment strategies show low efficacy and safety. In this scenario, drug delivery systems (DDS) design that overcome these drawbacks is urgently called for. In this review, we initially describe the pathological features, the therapeutic targets, and the drugs currently in clinical use and under investigation to treat gout. We also comprehensively summarize recent research efforts utilizing lipid, polymeric and inorganic carriers to develop advanced DDS for improved gout management and therapy.

The association between BMI and serum uric acid is partially mediated by gut microbiota

Obesity is a risk factor for the development of hyperuricemia, both of which were related to gut microbiota. However, whether alterations in the gut microbiota lie in the pathways mediating obesity's effects on hyperuricemia is less clear. Body mass index (BMI) and serum uric acid (SUA) were separately important indicators of obesity and hyperuricemia. Our study aims to investigate whether BMI-related gut microbiota characteristics would mediate the association between BMI and SUA levels. A total of 6,280 participants from Guangdong Gut Microbiome Project were included in this study. Stool samples were collected for 16S rRNA gene sequencing. The results revealed that BMI was significantly and positively associated with SUA. Meanwhile, BMI was significantly associated with the abundance of 102 gut microbial genera, 16 of which were also significantly associated with SUA. The mediation analysis revealed that the association between BMI and SUA was partially mediated by the abundance of Proteobacteria (proportion mediated: 0.94%, P < 0.05). At the genus level, 25 bacterial genera, including Ralstonia, Oscillospira, Faecalibacterium, etc., could also partially mediate the association of BMI with SUA (the highest proportion is mediated by Ralstonia, proportion mediated: 2.76%, P < 0.05). This study provided evidence for the associations among BMI, gut microbiota, and SUA, and the mediation analysis suggested that the association of BMI with SUA was partially mediated by the gut microbiota. IMPORTANCE Using 16S rRNA sequencing analysis, local interpretable machine learning technique analysis and mediation analysis were used to explore the association between BMI with SUA, and the mediating effects of gut microbial dysbiosis in the association were investigated.

Clec12a inhibits MSU-induced immune activation through lipid raft expulsion

Monosodium uric acid (MSU) crystal, the etiological agent of gout, has been shown to trigger innate immune responses via multiple pathways. It is known that MSU-induced lipid sorting on plasma membrane promotes the phosphorylation of Syk and eventually leads to the activation of phagocytes. However, whether this membrane lipid-centric mechanism is regulated by other processes is unclear. Previous studies showed that Clec12a, a member of the C-type lectin receptor family, is reported to recognize MSU and suppresses this crystalline structure-induced immune activation. How this scenario is integrated into the lipid sorting-mediated inflammatory responses by MSU, and particularly, how Clec12a intercepts lipid raft-originated signaling cascade remains to be elucidated. Here, we found that the ITIM motif of Clec12a is dispensable for its inhibition of MSU-mediated signaling; instead, the transmembrane domain of Clec12a disrupts MSU-induced lipid raft recruitment and thus attenuates downstream signals. Single amino acid mutagenesis study showed the critical role of phenylalanine in the transmembrane region for the interactions between C-type lectin receptors and lipid rafts, which is critical for the regulation of MSU-mediated lipid sorting and phagocyte activation. Overall, our study provides new insights for the molecular mechanisms of solid particle-induced immune activation and may lead to new strategies in inflammation control.

Potential clinical value of serum interleukin-41 levels in patients with acute gout

BACKGROUND

Gout is a common metabolic rheumatic disease, and there have been no reports on the serum levels of interleukin (IL)-41 in gout patients. The purpose of this study was to therefore determine the expression of IL-41 in the serum of gout patients.

METHODS

Eighty-one participants were enrolled in this study, including 34 patients with acute gout, 27 gout patients in remission, and 20 healthy controls (HCs). Baseline data were obtained through interviews and laboratory parameters were acquired via blood sample testing. We measured serum IL-41 concentrations with an enzyme-linked immunosorbent assay, and executed Spearman's correlation analysis to investigate the correlation between IL-41 and other parameters, and the diagnostic value for IL-41 was demonstrated using a receiver operating characteristic curve. Multivariate analysis was conducted by adopting logistic regression.

RESULTS

Serum IL-41 concentrations in acute-gout patients were higher than those in HCs and there was no significant difference in serum IL-41 levels between remission gout patients and HCs. In addition, IL-41 was positively correlated with white blood cell count, erythrocyte sedimentation rate, and C-reactive protein and serum amyloid A concentrations, while it was negatively correlated with triglyceride levels. IL-41 showed good diagnostic value for gout, and the combination of IL-41 and uric acid produced a superior diagnostic value. We also noted that IL-41 was an independent risk factor for acute gout.

CONCLUSIONS

This study revealed that serum IL-41 was elevated in patients with acute gout, and suggests that IL-41 may constitute a novel diagnostic marker for acute gout.

Associations between blood essential metal mixture and serum uric acid: a cross-sectional study

Introduction

Although several studies have explored the associations between single essential metals and serum uric acid (SUA), the study about the essential metal mixture and the interactions of metals for hyperuricemia remains unclear.

Methods

We performed a cross-sectional study to explore the association of the SUA levels with the blood essential metal mixture, including magnesium (Mg), calcium (Ca), iron (Fe), copper (Cu), zinc (Zn), manganese (Mn) in Chinese community-dwelling adults (n=1039). The multivariable linear regression, the weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were conducted to estimate the associations of blood essential metals with SUA levels and the BKMR model was also conducted to estimate the interactions of the essential metals on SUA.

Results

In the multivariable linear regression, the association of blood Mg, Mn, and Cu with SUA was statistically significant, both in considering multiple metals and a single metal. In WQS regression [β=13.59 (95%CI: 5.57, 21.60)] and BKMR models, a positive association was found between the mixture of essential metals in blood and SUA. Specifically, blood Mg and Cu showed a positive association with SUA, while blood Mn showed a negative association. Additionally, no interactions between individual metals on SUA were observed.

Discussion

In conclusion, further attention should be paid to the relationship between the mixture of essential metals in blood and SUA. However, more studies are needed to confirm these findings.

Association between serum uric acid and triglyceride-glucose index in children and adolescents with short stature

The aim of this study was to explore the relationship between serum uric acid (SUA) and the triglyceride-glucose (TyG) index, which is a more effective indicator of insulin resistance. The study participants included 1700 children and adolescents with short stature who were recruited at the Affiliated Hospital of Jining Medical University in China between March 2013 and April 2021. A positive association between SUA levels and the TyG index was detected by univariate analysis (p < 0.001). Furthermore, a nonlinear relationship was detected between SUA and the TyG index, whose point was 6.55 mg/dL. There was a positive association between SUA and the TyG index when the SUA level was greater than 6.55 mg/dL (β 0.17, 95% CI: 0.07, 0.27; P < 0.001). However, we did not observe a significant relationship between SUA and the TyG index when the SUA level was less than 6.55 mg/dL (β 0.02, 95% CI: - 0.01, 0.05; P = 0.091). In addition, a stratified analysis was performed to appraise changes in this relationship for different sexes. The relationship between SUA and the TyG index in males and females is consistent with that in the general population, showing a nonlinear relationship. However, the inflection points of SUA level were significantly higher in males than in females, and the inflection points were approximately 6.72 and 5.88 mg/dL, respectively. This study revealed a nonlinear relationship between SUA and the TyG index in children with short stature. The nonlinear relationship remained in gender stratification analysis, but the inflection point of SUA level was higher in men. Further studies are needed to establish a causal relationship between SUA levels and the TyG index in children with short stature.

A microfluidic approach for the detection of uric acid through electrical measurement using an atomically thin MoS2 field-effect transistor

There is a demand for biosensors working under in vivo conditions, which requires significant device size and endurance miniaturization in solution environments. We demonstrated the detection of uric acid (UA) molecules, a marker of diseases like gout, whose continuous monitoring is required in medical diagnosis. We used a field effect transistor (FET) composed of an atomically thin transition metal dichalcogenide (TMD) channel. The sensor detection was carried out in a solution environment, for which we protected the electrodes of the source and drain from the solution. A microfluidic channel controls the solution flow that can realize evaporation-free conditions and provide an accurate concentration and precise measurement. We detected a systematic change of the drain current with the concentration of the UA in isopropyl alcohol (IPA) solvent with a detection limit of 60 nM. The sensor behavior is reversible, and the drain current returns to its original value when the channel is washed with pure solvent. The results demonstrate the feasibility of applying the MoS2-FET device to UA detection in solution, suggesting its possible use in the solution environment.

SERUM URIC ACID TO HDL CHOLESTEROL RATIO IS ASSOCIATED WITH DIABETIC CONTROL IN NEW ONSET TYPE 2 DIABETIC POPULATION

Since uric acid to HDL cholesterol ratio (UHR) is proposed as a novel predictor of metabolic and inflammatory disorders, we aimed to study UHR levels in patients with new onset type 2 diabetes mellitus (T2DM) and compare them to those in healthy controls. Patients with new onset T2DM were enrolled and control subjects were volunteers to participate without any established diseases. Laboratory data including UHR, fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) were compared. The mean UHR of the T2DM and control groups was 16±8% and 10±3%, respectively (p<0.001). Moreover, UHR was significantly and positively correlated with HbA1c (r=0.75, p<0.001), FBG (r=0.64, p<0.001), waist circumference (r=0.35, p<0.001), body mass index (r=0.20, p=0.002) and inversely correlated with glomerular filtration rate (r=-0.24, p<0.001). High levels of UHR might be associated with increased mean blood glucose levels for a long time, since UHR was correlated with both FBG and HbA1c in patients with new onset T2DM.

Hyperuricemia promotes the progression of atherosclerosis by activating endothelial cell pyroptosis via the ROS/NLRP3 pathway

Hyperuricemia closely correlates with the development of atherosclerosis, but little is known of the mechanism by which atherosclerosis progression occurs in hyperuricemia. Atherosclerosis appears to involve pyroptosis, an emerging mechanism of proinflammatory regulated cell death. This study tested the hypothesis that pyroptosis underlies the relationship between hyperuricemia and atherosclerosis, using ApoE-/- mice (a model of atherosclerosis), human umbilical vein endothelial cells (HUVECs), and human atherosclerotic arterial samples. We found that hyperuricemia can aggravate the aortic atherosclerotic plaque-load in ApoE-/- mice and promote endothelial cell pyroptosis. Additionally, hyperuricemia can increase the levels of serum inflammatory factors (including IL-1β and IL-18). Exposure to lipopolysaccharide plus a high concentration of soluble uric acid (≥12 mg/dL) induced cell pyroptosis in HUVECs, as evidenced by increased expression of pyroptosis-related proteins and elevated release of lactate dehydrogenase (a marker of tissue damage). Further, MCC950, a selective nucleotide-binding oligomerization domain (NOD)-like receptor 3 (NLRP3) inflammasome inhibitor, and N-acetyl- l-cysteine, an antioxidant, attenuated HUVEC pyroptosis by inhibiting activation of the NLRP3 inflammasome and production of intracellular reactive oxygen species (ROS). Finally, we detected significantly higher expression of pyroptosis-associated proteins in carotid specimens from patients with hyperuricemia. Collectively, our findings suggest that hyperuricemia can aggravate endothelial cell pyroptosis in aortic atherosclerotic plaques, promoting the development of atherosclerosis. Additionally, a high concentration of soluble uric acid can trigger the activation stage of the NLRP3 inflammasome, mediating endothelial cell pyroptosis, and this process is regulated by the cellular ROS level.

Myeloid Src-family kinases are critical for neutrophil-mediated autoinflammation in gout and motheaten models

Autoinflammatory diseases include a number of monogenic systemic inflammatory diseases, as well as acquired autoinflammatory diseases such as gout. Here, we show that the myeloid Src-family kinases Hck, Fgr, and Lyn are critical for experimental models of gout, as well as for genetically determined systemic inflammation in the Ptpn6me-v/me-v (motheaten viable) mouse model. The Hck-/-Fgr-/-Lyn-/- mutation abrogated various monosodium urate (MSU) crystal-induced pro-inflammatory responses of neutrophils, and protected mice from the development of gouty arthritis. The Src-family inhibitor dasatinib abrogated MSU crystal-induced responses of human neutrophils and reduced experimental gouty arthritis in mice. The Hck-/-Fgr-/-Lyn-/- mutation also abrogated spontaneous inflammation and prolonged the survival of the Ptpn6me-v/me-v mice. Spontaneous adhesion and superoxide release of Ptpn6me-v/me-v neutrophils were also abolished by the Hck-/-Fgr-/-Lyn-/- mutation. Excessive activation of tyrosine phosphorylation pathways in myeloid cells may characterize a subset of autoinflammatory diseases.

Association between decreases in serum uric acid levels and unfavorable outcomes after ischemic stroke: A multicenter hospital-based observational study

BACKGROUND

The association between clinical outcomes in ischemic stroke patients and decreases in serum uric acid levels, which often occur during the acute phase, remains unknown. Herein, we aimed to investigate the association using a large-scale, multicenter stroke registry.

METHODS

We analyzed 4,621 acute ischemic stroke patients enrolled in the Fukuoka Stroke Registry between June 2007 and September 2019 whose uric acid levels were measured at least twice during hospitalization (including on admission). The study outcomes were poor functional outcome (modified Rankin Scale score ≥3) and functional dependence (modified Rankin Scale score 3-5) at 3 months after stroke onset. Changes in uric acid levels after admission were evaluated using a decrease rate that was classified into 4 sex-specific grades ranging from G1 (no change/increase after admission) to G4 (most decreased). Multivariable logistic regression analyses were used to assess the associations between decreases in uric acid levels and the outcomes.

RESULTS

The frequencies of the poor functional outcome and functional dependence were lowest in G1 and highest in G4. The odds ratios (95% confidence intervals) of G4 were significantly higher for poor functional outcome (2.66 [2.05-3.44]) and functional dependence (2.61 [2.00-3.42]) when compared with G1 after adjusting for confounding factors. We observed no heterogeneity in results for subgroups categorized according to age, sex, stroke subtype, neurological severity, chronic kidney disease, or uric acid level on admission.

CONCLUSIONS

Decreases in serum uric acid levels were independently associated with unfavorable outcomes after acute ischemic stroke.

Critical role for uricase and xanthine dehydrogenase in soybean nitrogen fixation and nodule development

De novo purine biosynthesis is required for the incorporation of fixed nitrogen in ureide exporting nodules, as formed on soybean [Glycine max (L.) Merr.] roots. However, in many cases, the enzymes involved in this pathway have been deduced strictly from genome annotations with little direct genetic evidence, such as mutant studies, to confirm their biochemical function or importance to nodule development. While efforts to develop large mutant collections of soybean are underway, research on this plant is still hampered by the inability to obtain mutations in any specific gene of interest. Using a forward genetic approach, as well as CRISPR/Cas9 gene editing via Agrobacterium rhizogenes-mediated hairy root transformation, we identified and characterized the role of GmUOX (Uricase) and GmXDH (Xanthine Dehydrogenase) in nitrogen fixation and nodule development in soybean. The gmuox knockout soybean mutants displayed nitrogen deficiency chlorosis and early nodule senescence, as exemplified by the reduced nitrogenase (acetylene reduction) activity in nodules, the internal greenish-white internal appearance of nodules, and diminished leghemoglobin production. In addition, gmuox1 nodules showed collapsed infected cells with degraded cytoplasm, aggregated bacteroids with no discernable symbiosome membranes, and increased formation of poly-β-hydroxybutyrate granules. Similarly, knockout gmxdh mutant nodules, generated with the CRISPR/Cas9 system, also exhibited early nodule senescence. These genetic studies confirm the critical role of the de novo purine metabolisms pathway not only in the incorporation of fixed nitrogen but also in the successful development of a functional, nitrogen-fixing nodule. Furthermore, these studies demonstrate the great utility of the CRISPR/Cas9 system for studying root-associated gene traits when coupled with hairy root transformation.

Uremic Toxin Indoxyl Sulfate Promotes Macrophage-Associated Low-Grade Inflammation and Epithelial Cell Senescence

In this study, we investigated the impact of the uremic toxin indoxyl sulfate on macrophages and tubular epithelial cells and its role in modulating the response to lipopolysaccharide (LPS). Indoxyl sulfate accumulates in the blood of patients with chronic kidney disease (CKD) and is a predictor of overall and cardiovascular morbidity/mortality. To simulate the uremic condition, primary macrophages and tubular epithelial cells were incubated with indoxyl sulfate at low concentrations as well as concentrations found in uremic patients, both alone and upon LPS challenge. The results showed that indoxyl sulfate alone induced the release of reactive oxygen species and low-grade inflammation in macrophages. Moreover, combined with LPS (proinflammatory conditions), indoxyl sulfate significantly increased TNF-α, CCL2, and IL-10 release but did not significantly affect the polarization of macrophages. Pre-treatment with indoxyl sulfate following LPS challenge induced the expression of aryl hydrocarbon receptor (Ahr) and NADPH oxidase 4 (Nox4) which generate reactive oxygen species (ROS). Further, experiments with tubular epithelial cells revealed that indoxyl sulfate might induce senescence in parenchymal cells and therefore participate in the progression of inflammaging. In conclusion, this study provides evidence that indoxyl sulfate provokes low-grade inflammation, modulates macrophage function, and enhances the inflammatory response associated with LPS. Finally, indoxyl sulfate signaling contributes to the senescence of tubular epithelial cells during injury.

The Role of Interleukin-17A and NLRP3 Inflammasome in the Pathogenesis of Graves' Ophthalmopathy

The development of Graves' ophthalmopathy (GO) is associated with autoimmune dysfunction. Recent studies have indicated that IL-17A, inflammasomes, and related cytokines may be involved in the etiology of GO. We sought to investigate the pathogenic role of IL-17A and NLRP3 inflammasomes in GO. Orbital fat specimens were collected from 30 patients with GO and 30 non-GO controls. Immunohistochemical staining and orbital fibroblast cultures were conducted for both groups. IL-17A was added to the cell cultures, and cytokine expression, signaling pathways, and inflammasome mechanisms were investigated using reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assay, Western blotting, and small interfering RNA (siRNA) methods. Immunohistochemical staining showed higher NLRP3 expression in GO orbital tissue than in non-GO controls. IL-17A upregulated pro-IL-1β mRNA levels and IL-1β protein levels in the GO group. Furthermore, IL-17A was confirmed to enhance caspase-1 and NLRP3 protein expression in orbital fibroblasts, suggesting NLRP3 inflammasome activation. Inhibiting caspase-1 activity could also decrease IL-1β secretion. In siRNA-transfected orbital fibroblasts, significantly decreased NLRP3 expression was observed, and IL-17A-mediated pro-IL-1β mRNA release was also downregulated. Our observations illustrate that IL-17A promotes IL-1β production from orbital fibroblasts via the NLRP3 inflammasome in GO, and cytokines subsequently released may induce more inflammation and autoimmunity.

Fructose potentiates the protective efficiency of live Edwardsiella tarda cell vaccine

Vaccination is an effective measure to prevent infection by pathogens. Live vaccines have higher protective efficacy than inactivated vaccines. However, how live vaccines interact with the host from a metabolic perspective is unknown. The present study aimed to explore whether a live Edwardsiella tarda vaccine regulates host metabolism and whether this regulation is related to the protective efficacy of the vaccine. Therefore, a gas chromatography mass spectrometry (GC-MS)-based metabolomics approach was used to investigate the metabolomic profile of mice serum after vaccination with live E. tarda vaccine. Fructose was identified as a key biomarker that contributes to the immune protection induced by the live vaccine. Moreover, co-administration of exogenous fructose and the live vaccine synergistically promoted survival of mice and fish after bacterial challenge. These results indicate that metabolites, especially fructose, can potentiate the live E. tarda vaccine to increase its protective efficiency.

CARD-only proteins regulate in vivo inflammasome responses and ameliorate gout

Inflammatory responses are crucial for controlling infections and initiating tissue repair. However, excessive and uncontrolled inflammation causes inflammatory disease. Processing and release of the pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18 depend on caspase-1 activation within inflammasomes. Assembly of inflammasomes is initiated upon activation of cytosolic pattern recognition receptors (PRRs), followed by sequential polymerization of pyrin domain (PYD)-containing and caspase recruitment domain (CARD)-containing proteins mediated by homotypic PYD and CARD interactions. Small PYD- or CARD-only proteins (POPs and COPs, respectively) evolved in higher primates to target these crucial interactions to limit inflammation. Here, we show the ability of COPs to regulate inflammasome activation by modulating homotypic CARD-CARD interactions in vitro and in vivo. CARD16, CARD17, and CARD18 displace crucial CARD interactions between caspase-1 proteins through competitive binding and ameliorate uric acid crystal-mediated NLRP3 inflammasome activation and inflammatory disease. COPs therefore represent an important family of inflammasome regulators and ameliorate inflammatory disease.

Highly Sensitive Electrochemical Non-Enzymatic Uric Acid Sensor Based on Cobalt Oxide Puffy Balls-like Nanostructure

Early-stage uric acid (UA) abnormality detection is crucial for a healthy human. With the evolution of nanoscience, metal oxide nanostructure-based sensors have become a potential candidate for health monitoring due to their low-cost, easy-to-handle, and portability. Herein, we demonstrate the synthesis of puffy balls-like cobalt oxide nanostructure using a hydrothermal method and utilize them to modify the working electrode for non-enzymatic electrochemical sensor fabrication. The non-enzymatic electrochemical sensor was utilized for UA determination using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The puffy balls-shaped cobalt oxide nanostructure-modified glassy carbon (GC) electrode exhibited excellent electro-catalytic activity during UA detection. Interestingly, when we compared the sensitivity of non-enzymatic electrochemical UA sensors, the DPV technique resulted in high sensitivity (2158 µA/mM.cm²) compared to the CV technique (sensitivity = 307 µA/mM.cm²). The developed non-enzymatic electrochemical UA sensor showed good selectivity, stability, reproducibility, and applicability in the human serum. Moreover, this study indicates that the puffy balls-shaped cobalt oxide nanostructure can be utilized as electrode material for designing (bio)sensors to detect a specific analyte.

Trends in serum uric acid levels among Korean children and adolescents between 2016 and 2020: a nationwide study

The aim of this study was to examine trends in serum uric acid (SUA) levels over a recent 5-year period according to age, sex, obesity, and abdominal obesity among Korean children and adolescents. We conducted a serial cross-sectional analysis using nationally representative data from the Korea National Health and Nutritional Examination Survey from 2016 to 2020. The study outcome was trends in SUA levels. SUA trends were analyzed by survey-weighted linear regression analysis considering the survey year as a continuous variable. SUA trends were also analyzed for subgroups based on age, sex, abdominal obesity, or obesity. This study included 3,554 children and adolescents aged 10-18 years. SUA increased significantly over the study period in boys (p for trend = 0.043), but not in girls (p for trend = 0.300). In age-specific analyses, SUA increased significantly in the 10-12 years group (p for trend = 0.029). After adjusting for age, SUA increased significantly in the obese group of both boys (p for trend = 0.026) and girls (p for trend = 0.023), but not in the overweight, normal, or under-weight groups of either sex. After adjusting for age, SUA increased significantly in the abdominal obesity group of boys (p for trend = 0.017) and girls (p for trend = 0.014), but not in the non-abdominal obesity group of either sex.   Conclusion: In the current study, SUA levels significantly increased in both boys and girls with obesity or abdominal obesity. Further studies of the effect of SUA on health outcomes in boys and girls with obesity or abdominal obesity are needed. What is Known: • High serum uric acid (SUA) is a risk factor for various metabolic diseases, including gout, hypertension, and type 2 diabetes. What is New: • SUA levels increased in boys and the 10-12 years group of Korean children and adolescents. • SUA levels increased significantly in Korean children and adolescents with obesity or central obesity.

Multiplexed cell-based diagnostic devices for detection of renal biomarkers

The number of synthetic biology-based solutions employed in the medical industry is growing every year. The whole cell biosensors being one of them, have been proven valuable tools for developing low-cost, portable, personalized medicine alternatives to conventional techniques. Based on this concept, we targeted one of the major health problems in the world, Chronic Kidney Disease (CKD). To do so, we developed two novel biosensors for the detection of two important renal biomarkers: urea and uric acid. Using advanced gene expression control strategies, we improved the operational range and the response profiles of each biosensor to meet clinical specifications. We further engineered these systems to enable multiplexed detection as well as an AND-logic gate operating system. Finally, we tested the applicability of these systems and optimized their working dynamics inside complex medium human blood serum. This study could help the efforts to transition from labor-intensive and expensive laboratory techniques to widely available, portable, low-cost diagnostic options.

Association between serum uric acid levels and long-term mortality of metabolic dysfunction-associated fatty liver disease: a nationwide cohort study

BACKGROUND

The association between hyperuricemia and metabolic dysfunction-associated fatty liver disease (MAFLD) remains undetermined. This study aimed to examine the association of serum uric acid (SUA) levels with prevalence and long-term mortality of MAFLD in a nationally representative sample of US adults.

METHODS

This analysis included 11,177 participants from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994) with matched mortality data until 2019. We used logistic regression models to estimate the adjusted odd ratios (ORs) for factors associated with risk of MAFLD, and applied restricted cubic spline (RCS) regression to assess the non-linear associations of SUA levels with all-cause and cause-specific mortality of MAFLD. We also used Cox proportional hazards regression analysis to estimate hazard ratios (HRs) for the mortality.

RESULTS

A higher SUA level contributed to a significant increased risk of MAFLD. every 1 mg/dL increment of SUA level was related to 17% (95% CI 9-24%) increased risk of MAFLD. Furthermore, a U-shaped association for males and a J-shaped association for females was discovered between SUA levels and all-cause mortality in participants with MAFLD. Specifically, among males, when SUA > 6.7 mg/dL, the higher SUA showed increased risk of cardio-cerebrovascular disease (CVD) mortality [HR (95% CI): 1.29 (1.05-1.58)]. As for females, only when SUA > 5.5 mg/dL, it showed a significantly positive association with risk of CVD and cancer mortality [HR (95% CI) 1.62 (1.24-2.13) and 1.95 (1.41-2.68)].

CONCLUSIONS

Elevated SUA level is significantly associated with an increased risk of MAFLD. Besides, SUA level is also a predictor of long-term mortality of MAFLD.

Transient receptor potential melastatin 2 regulates neutrophil extracellular traps formation and delays resolution of neutrophil-driven sterile inflammation

The formation of neutrophil extracellular traps (NETs) is a process releasing into the extracellular space networks of chromatin fibers decorated with granular proteins. It is implicated in infection-related as well as sterile inflammation. Monosodium urate (MSU) crystals serve as damage-associated molecular pattern (DAMP) in various conditions of disease. Formation of NETs or aggregated NETs (aggNETs) orchestrates initiation and resolution of MSU crystals-triggered inflammation, respectively. Elevated intracellular calcium levels and the generation of reactive oxygen species (ROS) are crucial for the formation of MSU crystal-induced NETs. However, the exact signaling pathways involved are still elusive. Herein, we demonstrate that the ROS-sensing, non-selective calcium-permeable channel transient receptor potential cation channel subfamily M member 2 (TRPM2) is required for a full-blown MSU crystal-induced NET formation. Primary neutrophils from TRPM2^-/- mice showed reduced calcium influx and ROS production and, consequently a reduced formation of MSU crystal-induced NETs and aggNETs. Furthermore, in TRPM2^-/- mice the infiltration of inflammatory cells into infected tissues and their production of inflammatory mediators was suppressed. Taken together these results describe an inflammatory role of TRPM2 for neutrophil-driven inflammation and identify TRPM2 as potential target for therapeutic intervention.

Xanthine oxidoreductase mediates genotoxic drug-induced autophagy and apoptosis resistance by uric acid accumulation and TGF-β-activated kinase 1 (TAK1) activation

Autophagy is a highly conserved cellular process that profoundly impacts the efficacy of genotoxic chemotherapeutic drugs. TGF-β-activated kinase 1 (TAK1) is a serine/threonine kinase that activates several signaling pathways involved in inducing autophagy and suppressing cell death. Xanthine oxidoreductase (XOR) is a rate-limiting enzyme that converts hypoxanthine to xanthine, and xanthine to uric acid and hydrogen peroxide in the purine catabolism pathway. Recent studies showed that uric acid can bind to TAK1 and prolong its activation. We hypothesized that genotoxic drugs may induce autophagy and apoptosis resistance by activating TAK1 through XOR-generated uric acid. Here, we report that gemcitabine and 5-fluorouracil (5-FU), two genotoxic drugs, induced autophagy in HeLa and HT-29 cells by activating TAK1 and its two downstream kinases, AMP-activated kinase (AMPK) and c-Jun terminal kinase (JNK). XOR knockdown and the XOR inhibitor allopurinol blocked gemcitabine-induced TAK1, JNK, AMPK, and Unc51-like kinase 1 (ULK1)^S555 phosphorylation and gemcitabine-induced autophagy. Inhibition of the ATM-Chk pathway, which inhibits genotoxic drug-induced uric acid production, blocked gemcitabine-induced autophagy by inhibiting TAK1 activation. Exogenous uric acid in its salt form, monosodium urate (MSU), induced autophagy by activating TAK1 and its downstream kinases JNK and AMPK. Gene knockdown or the inhibitors of these kinases blocked gemcitabine- and MSU-induced autophagy. Inhibition of autophagy by allopurinol, chloroquine, and 5Z-7-oxozeaenol (5Z), a TAK1-specific inhibitor, enhanced gemcitabine-induced apoptosis. Our study uncovers a previously unrecognized role of XOR in regulating genotoxic drug-induced autophagy and apoptosis and has implications for designing novel therapeutic strategies for cancer treatment.

Association between smoking behavior and serum uric acid among the adults: Findings from a national cross-sectional study

BACKGROUND

Gout incidence is increasing worldwide; appropriate management of serum uric acid levels and a healthy lifestyle may help its prevention. The popularity of electronic cigarettes and the resultant emergence of dual smokers is increasing. Despite many studies on the effects of various health behaviors on serum uric acid levels, the association between smoking and serum uric acid levels remains controversial. This study aimed to investigate the association between smoking and serum uric acid levels.

METHODS

In this study, total sample of 27,013 participants (11,924 men and 15,089 women) were analyzed. This study used data from the Korea National Health and Nutrition Examination Survey (2016-2020) and grouped adults into dual smokers, single smokers, ex-smokers, and non-smokers. Multiple logistic regression analyses were performed to investigate the association between smoking behavior and serum uric acid levels.

RESULTS

Compared to male non-smokers, male dual smokers had significantly higher serum uric acid level (odds ratio [OR], 1.43; 95% confidence interval [CI], 1.08-1.88). In female, serum uric acid level was higher among single smokers than non-smokers (OR, 1.68; 95% CI, 1.25-2.25). Higher serum uric acid levels were more likely to be present in male dual smokers with a > 20 pack-year smoking habit (OR, 1.84; 95% CI, 1.06-3.18).

CONCLUSION

Dual smoking may contribute to high serum uric acid levels in adults. Thus, serum uric acid levels should be properly managed through smoking cessation.

Whole transcriptome expression profiles in kidney samples from rats with hyperuricaemic nephropathy

Hyperuricaemic nephropathy (HN) is a common clinical complication of hyperuricaemia (HUA) and poses a huge threat to human health. Hence, we aimed to prospectively investigate the dysregulated genes, pathways and networks involved in HN by performing whole transcriptome sequencing using RNA sequencing. Six kidney samples from HN group (n = 3) and a control group (n = 3) were obtained to conduct RNA sequencing. To disclose the relevant signalling pathways, we conducted the analysis of differentially expressed genes (DEGs), Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. A competitive endogenous RNA (ceRNA) network was established to reveal the interactions between lncRNAs, circRNAs, mRNAs and miRNAs and investigate the potential mechanisms of HN. Ultimately, 2250 mRNAs, 306 lncRNAs, 5 circRNAs, and 70 miRNAs were determined to be significantly differentially expressed in the HN group relative to the control group. We further authenticated 8 differentially expressed (DE)-ncRNAs by quantitative real-time polymerase chain reaction, and these findings were in accordance with the sequencing results. The analysis results evidently showed that these DE-ncRNAs were significantly enriched in pathways related to inflammatory reaction. In conclusion, HUA may generate abnormal gene expression changes and regulate signalling pathways in kidney samples. Potentially related genes and pathways involved in HN were identified.

Association of Elevated Serum Uric Acid with Nerve Conduction Function and Peripheral Neuropathy Stratified by Gender and Age in Type 2 Diabetes Patients

Background: The relationship between serum uric acid (SUA) level and diabetic peripheral neuropathy (DPN) remains controversial. We aimed to investigate the association between SUA level and DPN and evaluate the effects of SUA level on nerve conduction function via electromyography in patients with type 2 diabetes (T2DM), stratified by gender and age. Methods: This cross-sectional study included 647 inpatients with T2DM from the First Affiliated Hospital of Wenzhou Medical University between February 2017 and October 2020. The diagnosis of DPN was confirmed according to the Toronto Expert Consensus. Clinical data, SUA level, and nerve conduction parameters were obtained from electronic medical records. Results: A total of 647 patients with T2DM were included, and 471 patients were diagnosed with DPN. The level of SUA was higher in the DPN group than in the Non-DPN group (330.58 ± 99.67 vs. 309.16 ± 87.04, p < 0.05). After adjustment, a higher SUA level was associated with the presence of DPN [odds ratio (OR) 1.003, 95% confidence interval (CI), 1.001−1.005; p = 0.017]. The area under the curve for the prediction of DPN was 0.558 (95% CI, 0.509−0.608; p = 0.022), and the optimized cut-off of SUA level was 297.5 µmol/L. The SUA > 297.5 µmol/L level was independently associated with DPN in the male subgroup (OR 2.507, 95% CI, 1.405−4.473; p = 0.002) rather than in the female subgroup. Besides, SUA > 297.5 µmol/L was independently associated with DPN in the younger subgroup (age < 65 years) (OR 2.070, 95% CI, 1.278−3.352; p = 0.003) rather than in the older subgroup. In multiple linear regression analysis, SUA was significantly correlated with certain nerve conduction study parameters in the all patients group, and was also observed in the male and younger subgroups. Conclusions: Elevated SUA was independently associated with poorer nerve conduction functions, and hyperuricemia was also significantly associated with a higher risk of developing DPN in T2DM patients, especially in male and younger patients.