Uric acid induces oxidative stress via an activation of the renin-angiotensin system in 3T3-L1 adipocytes

Serum amino acid alterations in hyperuricemia: potential targets for renal disease prevention

Observational studies have linked uric acid (UA) levels and kidney disease to amino acid homeostasis, but the causal relationship is unclear. This study aims to determine if elevated UA affects amino acid levels and whether amino acids mediate this relationship, focusing on the causal links between UA, circulating amino acids, and kidney disease.

METHODS

This study utilized Uox-KO mice as a hyperuricemia model, assessed renal injury through blood biochemistry and pathology, analyzed serum amino acid changes via targeted amino acidomics, and employed Mendelian randomization to investigate the causal links between uric acid, amino acids, and renal disease.

RESULTS

Hyperuricemia Uox-KO mice have significantly higher serum UA and renal impairment markers, with histopathological analysis showing extensive renal tissue damage. Changes in amino acid balance were found in the mice's serum, with key metabolites like alanine, isoleucine, leucine, aspartic acid, cysteine, glutamate, and glycine potentially influencing UA pathophysiology. Genetically predicted UA was positively correlated with chronic renal failure (CRF) and blood urea nitrogen(BUN) levels and negatively with serum cystatin C (eGFRcys) and serum creatinine (eGFRcrea). Alanine (Ala) mediated the effect of UA on elevated CRF and BUN risk, accounting for 4.5% of the UA-CRF relationship and 14.4% of the UA-BUN association.

CONCLUSION

In hyperuricemia mice, serum amino acids undergo metabolic changes. Genetically predicted UA levels are positively linked to CRF and BUN, but negatively linked to eGFRcys and eGFRcrea. Ala mediates UA's effect on CRF and BUN risk, indicating Ala could be a target for preventing renal diseases caused by hyperuricemia.

Hyperuricemia and its related diseases: mechanisms and advances in therapy

Hyperuricemia, characterized by elevated levels of serum uric acid (SUA), is linked to a spectrum of commodities such as gout, cardiovascular diseases, renal disorders, metabolic syndrome, and diabetes, etc. Significantly impairing the quality of life for those affected, the prevalence of hyperuricemia is an upward trend globally, especially in most developed countries. UA possesses a multifaceted role, such as antioxidant, pro-oxidative, pro-inflammatory, nitric oxide modulating, anti-aging, and immune effects, which are significant in both physiological and pathological contexts. The equilibrium of circulating urate levels hinges on the interplay between production and excretion, a delicate balance orchestrated by urate transporter functions across various epithelial tissues and cell types. While existing research has identified hyperuricemia involvement in numerous biological processes and signaling pathways, the precise mechanisms connecting elevated UA levels to disease etiology remain to be fully elucidated. In addition, the influence of genetic susceptibilities and environmental determinants on hyperuricemia calls for a detailed and nuanced examination. This review compiles data from global epidemiological studies and clinical practices, exploring the physiological processes and the genetic foundations of urate transporters in depth. Furthermore, we uncover the complex mechanisms by which the UA induced inflammation influences metabolic processes in individuals with hyperuricemia and the association with its relative disease, offering a foundation for innovative therapeutic approaches and advanced pharmacological strategies.

The Combination of Hyperuricemia and Elevated High-Sensitivity C-Reactive Protein Increased the Risk of Cardiac Conduction Block

Objective

This study aimed to explore the impact of a combination of hyperuricemia (HUA) and excessive high-sensitivity C-reactive protein (hs-CRP) levels on the likelihood of developing cardiac conduction block (CCB). Additionally, it sought to assess whether the influence of uric acid (UA) on CCB is mediated by hs-CRP.

Methods

A prospective study was executed utilizing data from the Kailuan cohort, including 81,896 individuals initially free from CCB. The participants were categorized into four groups depending on the existence of HUA and low-grade inflammation (hs-CRP>3 mg/L). Cox regression analysis was employed to ascertain hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of incident CCB. A mediation analysis was performed to determine if hs-CRP functioned as a mediator in the connection between UA levels and the incidence of CCB.

Results

During a median observation period of 11.8 years, we identified 3160 cases of newly occurring CCB. Compared with the low UA/low CRP group, the combination of HUA and low-grade inflammation elevated the CCB risks (HR:1.56, 95% CI:1.22-1.99), atrioventricular block (AVB) (HR:1.88, 95% CI:1.27-2.77), and right bundle branch block (HR:1.47, 95% CI:1.02-2.12), respectively. Mediation analysis revealed that in the HUA group, compared with the non-HUA group, the risk of CCB elevated by 14.0%, with 10.3% of the increase mediated through hs-CRP.

Conclusion

HUA combined with elevated hs-CRP increased the risk of CCB, especially AVB. The connection between UA and the CCB risk was partly mediated by hs-CRP.

Assessing brain microstructural changes in chronic kidney disease: a diffusion imaging study using multiple models

Objectives

To explore the effectiveness of diffusion quantitative parameters derived from advanced diffusion models in detecting brain microstructural changes in patients with chronic kidney disease (CKD).

Methods

The study comprised 44 CKD patients (eGFR<59 mL/min/1.73 m2) and 35 age-and sex-matched healthy controls. All patients underwent diffusion spectrum imaging (DSI) and conventional magnetic resonance imaging. Reconstructed to obtain diffusion MRI models, including diffusion tensor imaging (DTI), neurite orientation dispersion and density imaging (NODDI) and Mean Apparent Propagator (MAP)-MRI, were processed to obtain multi-parameter maps. The Tract-Based Spatial Statistics (TBSS) analysis was utilized for detecting microstructural differences and Pearson correlation analysis assessed the relationship between renal metabolism markers and diffusion parameters in the brain regions of CKD patients. Receiver operating characteristic (ROC) curve analysis assessed the diagnostic performance of diffusion models, with AUC comparisons made using DeLong's method.

Results

Significant differences were noted in DTI, NODDI, and MAP-MRI parameters between CKD patients and controls (p < 0.05). DTI indicated a decrease in Fractional Anisotropy(FA) and an increase in Mean and Radial Diffusivity (MD and RD) in CKD patients. NODDI indicated decreased Intracellular and increased Extracellular Volume Fractions (ICVF and ECVF). MAP-MRI identified extensive microstructural changes, with elevated Mean Squared Displacement (MSD) and Q-space Inverse Variance (QIV) values, and reduced Non-Gaussianity (NG), Axial Non-Gaussianity (NGAx), Radial Non-Gaussianity (NGRad), Return-to-Origin Probability (RTOP), Return-to-Axis Probability (RTAP), and Return-to-Plane Probability (RTPP). There was a moderate correlation between serum uric acid (SUA) and diffusion parameters in six brain regions (p < 0.05). ROC analysis showed the AUC values of DTI_FA ranged from 0.70 to 0.793. MAP_NGAx in the Retrolenticular part of the internal capsule R reported a high AUC value of 0.843 (p < 0.05), which was not significantly different from other diffusion parameters (p > 0.05).

Conclusion

The advanced diffusion models (DTI, NODDI, and MAP-MRI) are promising for detecting brain microstructural changes in CKD patients, offering significant insights into CKD-affected brain areas.

Impact of Hyperuricemia and Urate-Lowering Agents on Cardiovascular Diseases

The association between hyperuricemia and cardiovascular diseases has been studied for many years. Research has shown a link between high uric acid levels and increased risk of including coronary artery disease hypertension and other cardiovascular conditions. Urate-lowering therapy, particularly with xanthine oxidase inhibitors like allopurinol, has shown promising results in reducing blood pressure in individuals with hyperuricemia and hypertension. Clinical trials and studies have demonstrated significant reductions in both systolic and diastolic blood pressure with urate-lowering treatment. Urate-lowering treatment has shown a favorable effect on reducing systolic blood pressure and major adverse cardiovascular events in patients with previous cardiovascular disease. In terms of cardiovascular safety, clinical trials have indicated that xanthine oxidase inhibitors such as febuxostat are non-inferior to allopurinol and do not increase the risk of death or serious adverse events. Overall, these findings highlight the importance of managing hyperuricemia and utilizing urate-lowering therapy to mitigate the adverse cardiovascular effects associated with elevated uric acid levels.

A Cohort Study on the Correlation Between Serum Uric Acid Trajectory and New-Onset Hypertension Based on Longitudinal Health Examination Data in Henan Area

Objective

To explore the correlation between serum uric acid (SUA) trajectories and new-onset hypertension, to provide scientific basis for the prevention and treatment of hypertension.

Methods

The study cohort was composed of 4372 subjects who met the inclusion criteria in the cohort study of Henan physical examination population. According to the SUA values of the subjects' physical examination from 2017 to 2019, three different SUA trajectory groups were determined by R LCTM tools, namely low stability group, medium stability group and high stability group. The incidence of hypertension during physical examination in 2020 was followed up, the cumulative incidence rate in each group was calculated by product limit method, and the correlation between different SUA trajectories and new-onset hypertension was analyzed by Cox proportional hazards regression model.

Results

The incidence rate of hypertension increased with the increase of SUA locus, which was 4.65%, 9.18% and 12.43% respectively, and the difference was statistically significant (P<0.001). After adjusting multiple confounding factors, such as gender, waist circumference (WC), blood pressure, body mass index (BMI), fasting plasma glucose (FPG) and blood lipid by Cox proportional hazards regression model, the risk of hypertension in SUA medium stability and high stability group was still 1.476 times (95% CI: 1.089~2.000) and 1.692 times (95% CI: 1.152~2.484) of low-stable SUA group (P<0.05).

Conclusion

The risk of hypertension increases with the increase of SUA level in the long-term normal range. It is necessary to carry out the intervention for hypertension with long-term normal high value to avoid the progress of hypertension disease, to achieve the purpose of early prevention of hypertension.

Ethnic disparities in bidirectional causal effects between serum uric acid concentrations and kidney function: Trans-ethnic Mendelian randomization study

Introduction

Researchers have investigated the causal effect between serum uric acid (SUA) concentrations and kidney function for decades, but studies produced inconsistent results. This study aimed to clarify the bidirectional causal effects between SUA concentrations and kidney function and to explore the potential ethnic disparities by conducting a trans-ethnic Mendelian randomization study in European, African, and Asian ancestries.

Materials and methods

The summary-level data for this study were obtained from the Global Urate Genetics Consortium, CKDGen Consortium, UK Biobank, and Japan Biobank for different outcomes and exposures, respectively. The traits of kidney function were estimated glomerular filtration rate from serum creatinine (eGFRcr), estimated glomerular filtration rate from cystatin C (eGFRcys), and blood urea nitrogen (BUN). Using the multiplicative random-effects inverse variance weighting mode, our primary analysis produced robust results despite heterogeneity. Additionally, we performed the Mendelian randomization pleiotropy residual sum and outlier test to eliminate the horizontal pleiotropy and obtain accurate results.

Results

Our findings revealed that elevated SUA concentrations had causal effects on declined eGFRcys, BUN, and a diagnosis of chronic kidney disease in European ancestries and eGFRcr in Asian ancestries. Additionally, the causal effects of declined eGFRcr and elevated BUN concentrations on elevated SUA concentrations were observed in both European and Asian ancestries. However, no bidirectional causal effect was found between SUA concentrations and eGFRcr among African ancestries.

Conclusions

This trans-ethnic Mendelian randomization study confirmed the bidirectional causal effects between SUA concentrations and kidney function and highlighted the importance of considering ethnic disparities in clinical treatments.

Genetic and Epigenetic Regulation of the Innate Immune Response to Gout

Gout is a disease caused by uric acid (UA) accumulation in the joints, causing inflammation. Two UA forms - monosodium urate (MSU) and soluble uric acid (sUA) have been shown to interact physically with inflammasomes, especially with the nod-like receptor (NLR) family pyrin domain containing 3 (NLRP3), albeit the role of the immune response to UA is poorly understood, given that asymptomatic hyperuricemia does also exist. Macrophage phagocytosis of UA activate NLRP3, lead to cytokines release, and ultimately, lead to chemoattract neutrophils and lymphocytes to the gout flare joint spot. Genetic variants of inflammasome genes and of genes encoding their molecular partners may influence hyperuricemia and gout susceptibility, while also influencing other comorbidities such as metabolic syndrome and cardiovascular diseases. In this review, we summarize the inflammatory responses in acute and chronic gout, specifically focusing on innate immune cell mechanisms and genetic and epigenetic characteristics of participating molecules. Unprecedently, a novel UA binding protein - the neuronal apoptosis inhibitor protein (NAIP) - is suggested as responsible for the asymptomatic hyperuricemia paradox.Abbreviation: β2-integrins: leukocyte-specific adhesion molecules; ABCG2: ATP-binding cassete family/breast cancer-resistant protein; ACR: American college of rheumatology; AIM2: absent in melanoma 2, type of pattern recognition receptor; ALPK1: alpha-protein kinase 1; ANGPTL2: angiopoietin-like protein 2; ASC: apoptosis-associated speck-like protein; BIR: baculovirus inhibitor of apoptosis protein repeat; BIRC1: baculovirus IAP repeat-containing protein 1; BIRC2: baculoviral IAP repeat-containing protein 2; C5a: complement anaphylatoxin; cAMP: cyclic adenosine monophosphate; CARD: caspase activation and recruitment domains; CARD8: caspase recruitment domain-containing protein 8; CASP1: caspase 1; CCL3: chemokine (C-C motif) ligand 3; CD14: cluster of differentiation 14; CD44: cluster of differentiation 44; Cg05102552: DNA-methylation site, usually cytosine followed by guanine nucleotides; contains arbitrary identification code; CIDEC: cell death-inducing DNA fragmentation factor-like effector family; CKD: chronic kidney disease; CNV: copy number variation; CPT1A: carnitine palmitoyl transferase - type 1a; CXCL1: chemokine (CXC motif) ligand 1; DAMPs: damage associated molecular patterns; DC: dendritic cells; DNMT(1): maintenance DNA methyltransferase; eQTL: expression quantitative trait loci; ERK1: extracellular signal-regulated kinase 1; ERK2: extracellular signal-regulated kinase 2; EULAR: European league against rheumatism; GMCSF: granulocyte-macrophage colony-stimulating factor; GWAS: global wide association studies; H3K27me3: tri-methylation at the 27th lysine residue of the histone h3 protein; H3K4me1: mono-methylation at the 4th lysine residue of the histone h3 protein; H3K4me3: tri-methylation at the 4th lysine residue of the histone h3 protein; HOTAIR: human gene located between hoxc11 and hoxc12 on chromosome 12; IκBα: cytoplasmatic protein/Nf-κb transcription inhibitor; IAP: inhibitory apoptosis protein; IFNγ: interferon gamma; IL-1β: interleukin 1 beta; IL-12: interleukin 12; IL-17: interleukin 17; IL18: interleukin 18; IL1R1: interleukin-1 receptor; IL-1Ra: interleukin-1 receptor antagonist; IL-22: interleukin 22; IL-23: interleukin 23; IL23R: interleukin 23 receptor; IL-33: interleukin 33; IL-6: interleukin 6; IMP: inosine monophosphate; INSIG1: insulin-induced gene 1; JNK1: c-jun n-terminal kinase 1; lncRNA: long non-coding ribonucleic acid; LRR: leucine-rich repeats; miR: mature non-coding microRNAs measuring from 20 to 24 nucleotides, animal origin; miR-1: miR followed by arbitrary identification code; miR-145: miR followed by arbitrary identification code; miR-146a: miR followed by arbitrary identification code, "a" stands for mir family; "a" family presents similar mir sequence to "b" family, but different precursors; miR-20b: miR followed by arbitrary identification code; "b" stands for mir family; "b" family presents similar mir sequence to "a" family, but different precursors; miR-221: miR - followed by arbitrary identification code; miR-221-5p: miR followed by arbitrary identification code; "5p" indicates different mature miRNAs generated from the 5' arm of the pre-miRNA hairpin; miR-223: miR followed by arbitrary identification code; miR-223-3p: mir followed by arbitrary identification code; "3p" indicates different mature miRNAs generated from the 3' arm of the pre-miRNA hairpin; miR-22-3p: miR followed by arbitrary identification code, "3p" indicates different mature miRNAs generated from the 3' arm of the pre-miRNA hairpin; MLKL: mixed lineage kinase domain-like pseudo kinase; MM2P: inductor of m2-macrophage polarization; MSU: monosodium urate; mTOR: mammalian target of rapamycin; MyD88: myeloid differentiation primary response 88; n-3-PUFAs: n-3-polyunsaturated fatty-acids; NACHT: acronym for NAIP (neuronal apoptosis inhibitor protein), C2TA (MHC class 2 transcription activator), HET-E (incompatibility locus protein from podospora anserina) and TP1 (telomerase-associated protein); NAIP: neuronal apoptosis inhibitory protein (human); Naip1: neuronal apoptosis inhibitory protein type 1 (murine); Naip5: neuronal apoptosis inhibitory protein type 5 (murine); Naip6: neuronal apoptosis inhibitory protein type 6 (murine); NBD: nucleotide-binding domain; Nek7: smallest NIMA-related kinase; NET: neutrophil extracellular traps; Nf-κB: nuclear factor kappa-light-chain-enhancer of activated b cells; NFIL3: nuclear-factor, interleukin 3 regulated protein; NIIMA: network of immunity in infection, malignancy, and autoimmunity; NLR: nod-like receptor; NLRA: nod-like receptor NLRA containing acidic domain; NLRB: nod-like receptor NLRA containing BIR domain; NLRC: nod-like receptor NLRA containing CARD domain; NLRC4: nod-like receptor family CARD domain containing 4; NLRP: nod-like receptor NLRA containing PYD domain; NLRP1: nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 1; NLRP12: nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 12; NLRP3: nod-like receptor family pyrin domain containing 3; NOD2: nucleotide-binding oligomerization domain; NRBP1: nuclear receptor-binding protein; Nrf2: nuclear factor erythroid 2-related factor 2; OR: odds ratio; P2X: group of membrane ion channels activated by the binding of extracellular; P2X7: p2x purinoceptor 7 gene; p38: member of the mitogen-activated protein kinase family; PAMPs: pathogen associated molecular patters; PBMC: peripheral blood mononuclear cells; PGGT1B: geranylgeranyl transferase type-1 subunit beta; PHGDH: phosphoglycerate dehydrogenase; PI3-K: phospho-inositol; PPARγ: peroxisome proliferator-activated receptor gamma; PPARGC1B: peroxisome proliferative activated receptor, gamma, coactivator 1 beta; PR3: proteinase 3 antigen; Pro-CASP1: inactive precursor of caspase 1; Pro-IL1β: inactive precursor of interleukin 1 beta; PRR: pattern recognition receptors; PYD: pyrin domain; RAPTOR: regulatory associated protein of mTOR complex 1; RAS: renin-angiotensin system; REDD1: regulated in DNA damage and development 1; ROS: reactive oxygen species; rs000*G: single nuclear polymorphism, "*G" is related to snp where replaced nucleotide is guanine, usually preceded by an id number; SLC2A9: solute carrier family 2, member 9; SLC7A11: solute carrier family 7, member 11; SMA: smooth muscular atrophy; Smac: second mitochondrial-derived activator of caspases; SNP: single nuclear polymorphism; Sp3: specificity protein 3; ST2: serum stimulation-2; STK11: serine/threonine kinase 11; sUA: soluble uric acid; Syk: spleen tyrosine kinase; TAK1: transforming growth factor beta activated kinase; Th1: type 1 helper T cells; Th17: type 17 helper T cells; Th2: type 2 helper T cells; Th22: type 22 helper T cells; TLR: tool-like receptor; TLR2: toll-like receptor 2; TLR4: toll-like receptor 4; TNFα: tumor necrosis factor alpha; TNFR1: tumor necrosis factor receptor 1; TNFR2: tumor necrosis factor receptor 2; UA: uric acid; UBAP1: ubiquitin associated protein; ULT: urate-lowering therapy; URAT1: urate transporter 1; VDAC1: voltage-dependent anion-selective channel 1.

Association of serum uric acid with benefits of intensive blood pressure control

INTRODUCTION AND OBJECTIVES

Intensive systolic blood pressure (SBP) control improved outcomes in the Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients (STEP) trial. Whether the serum uric acid concentration at baseline alters the benefits of intensive SBP control is unknown.

METHODS

The STEP trial was a randomized controlled trial that compared the effects of intensive (SBP target of 110 to<130mmHg) and standard (SBP target of 130 to <150mmHg) SBP control in Chinese patients aged 60 to 80 years with hypertension. The primary outcome was a composite of cardiovascular disease events. This post hoc analysis was performed to examine whether the effects of intensive SBP intervention differed by the baseline uric acid concentration using 2 models: restricted cubic spline curves and subgroup analyses, both based on the Fine-Gray subdistribution hazard model in the analysis of the primary outcome and secondary outcomes (excluding all-cause death). In the analysis of all-cause death, the Cox regression model was used. We also examined the change in the follow-up uric acid concentrations.

RESULTS

Overall, the risk of the primary outcome rose as the cumulative uric acid concentration increased in both the intensive and standard treatment groups. Patients with intensive treatment had a lower multivariable-adjusted subdistribution hazard ratio for the primary outcome, but with a wide overlap of 95%CI. Next, we stratified patients according to their baseline uric acid concentration (tertile 1 [T1], <303.0μmol/L; tertile 2 [T2], 303.0 to <375.8μmol/L; and tertile 3 [T3], ≥375.8μmol/L). Subgroup analyses using tertiles provided HRs and 95%CI in T1 (HR, 0.55; 95%CI, 0.36-0.86; P=.008), T2 (HR, 0.80; 95%CI, 0.56-1.14; P=.22) and T3 (HR, 0.86; 95%CI, 0.60-1.21; P=.39), with an interaction P value of .29. The results for most of the secondary outcomes followed the same trends.

CONCLUSIONS

There was no evidence that the benefit of the intensive SBP control differed by baseline uric acid concentrations. This trial was registered at ClinicalTrial.gov (Identifier: NCT03015311).

Overnutrition-induced gout: An immune response to NLRP3 inflammasome dysregulation by XOD activity increased in quail

Background

Gout is a progressive metabolic disease closely related to hyperuricemia and urate deposition, with an increasing prevalence and incidence across the globe. Recent studies have shown that the pathological process of gout includes two stages: asymptomatic hyperuricemia and MSU crystal deposition. However, the immune response during the development of hyperuricemia to gouty arthritis is not fully elucidated.

Methods

Thus, an overnutrition-induced whole-course gout model was established to clarify the immune response and pathological changes in the development from hyperuricemia to gouty arthritis. The quails without urate oxidase were used as experimental animals. And we confirmed that uric acid metabolic targets were changed when quails were in the asymptomatic hyperuricemia stage.

Results

When the quail showed gout symptoms, the NLRP3 inflammasome was activated, and the expressions of IL-1β, TNF-α, IL-6, IL-8, and IL-18 were significantly increased. The relationship between the uric acid metabolism target and the NLRP3 inflammasome may be the critical immune response between hyperuricemia and gouty arthritis. Our data showed that, in the process of gout disease, the expression of xanthine oxidase (XOD) has been increasing, which increases the level of uric acid, disrupts the balance of oxidative stress, generates a large amount of ROS, activates the NLRP3 inflammasome, and release IL-1β. Treatment with the XOD inhibitor can reduce uric acid, restore the body's degree of peroxidative damage and antioxidant capacity, and inhibit NLRP3 inflammasome and IL-1β. In vitro, we extracted and identified primary fibroblast-like synoviocytes (FLS) from quail for the first time. Stimulating FLS with uric acid also caused ROS release and NLRP3 inflammasome activation. However, treatment with an XOD inhibitor prevented all these responses in FLS.

Conclusion

Our results indicate that the immune response between the uric acid metabolism target XOD and NLRP3 inflammasomes plays a crucial role in developing hyperuricemia to gouty arthritis, and inhibition of both XOD and NLRP3 inflammasomes may be an effective treatment for avoiding the development of asymptomatic hyperuricemia to MSU crystal deposition. Meanwhile, this study also provides an advantageous animal model for pathological mechanisms and research and development drugs for gout.

Association between Serum Uric Acid and Hypertension in a Large Cross-Section Study in a Chinese Population

Background: The association of serum uric acid (SUA) with hypertension has been well established in Caucasian populations. However, its association with hypertension in Chinese remained to be clarified. Methods: Consecutive patients, homogeneous in Chinese Han ethnicity, aged ≥18 years, abstracted from the database, admitted from 1 January 2010 to 31 December 2013, were included for potential analysis. The patients were grouped according to the presence or absence of hypertension. Unconditional logistic regression was performed to estimate the association between SUA and hypertension. Its possible interactions with risk factors on hypertension were also explored. Results: A total of 9587 patients were finally analyzed in the current study, where 5692 were with hypertension and 3895 were without hypertension. Per 100 μmol/L higher SUA concentration was associated with multivariable-adjusted odds ratios (95% CI) of 1.25 (1.08−1.22) in males, 1.10 (1.01−1.20) in females, and 1.19 (1.13−1.24) in total. On a categorical scale, when compared with the first quintile, the multivariable-adjusted odds ratios (95% CI) were 1.40 (1.20−1.64) for the 2nd quintile, 1.48 (1.27−1.74) for the 3rd quintile, 1.55 (1.32−1.82) for the 4th quintile, and 1.92 (1.63−2.26) for the 5th quintile, with a p for trend < 0.01. Conclusions: SUA is associated with hypertension in a dose-response manner among the Chinese hospitalized population. Management of SUA could help to the prevention and control of hypertension.

Cardiovascular protection by SGLT2 inhibitors - Do anti-inflammatory mechanisms play a role?

BACKGROUND

Metabolic syndrome and related metabolic disturbances represent a state of low-grade inflammation, which accelerates insulin resistance, type 2 diabetes (T2D) and cardiovascular disease (CVD) progression. Among antidiabetic medications, sodium glucose co-transporter (SGLT) 2 inhibitors are the only agents which showed remarkable reductions in heart failure (HF) hospitalizations and major cardiovascular endpoints (MACE) as well as renal endpoints regardless of diabetes status in large randomized clinical outcome trials (RCTs). Although the exact mechanisms underlying these benefits are yet to be established, growing evidence suggests that modulating inflammation by SGLT2 inhibitors may play a key role.

SCOPE OF REVIEW

In this manuscript, we summarize the current knowledge on anti-inflammatory effects of SGLT2 inhibitors as one of the mechanisms potentially mediating their cardiovascular (CV) benefits. We introduce the different metabolic and systemic actions mediated by these agents which could mitigate inflammation, and further present the signalling pathways potentially responsible for their proposed direct anti-inflammatory effects. We also discuss controversies surrounding some of these mechanisms.

MAJOR CONCLUSIONS

SGLT2 inhibitors are promising anti-inflammatory agents by acting either indirectly via improving metabolism and reducing stress conditions or via direct modulation of inflammatory signalling pathways. These effects were achieved, to a great extent, in a glucose-independent manner which established their clinical use in HF patients with and without diabetes.

A retrospective observational study of serum uric acid and in-hospital mortality in acute type A aortic dissection

There is currently insufficient evidence of correlation between on-admission serum uric acid and in-hospital mortality of patients with acute type A aortic dissection. Thus, this study analysed the relation between serum uric acid and in-hospital deaths in patients with acute type A aortic dissection. A total of 1048 patients with acute type A aortic dissection participated in this study between January 2010 and December 2018. The independent variable was on-admission serum uric acid, whilst the dependent variable was in-hospital deaths. The covariates of the study included patient age, gender, body mass index, smoking status, hypertension, diabetes, Marfan syndrome, bicuspid aortic valve, chronic renal insufficiency, stroke, atherosclerosis, time to presentation, systolic blood pressure, diastolic blood pressure, aortic diameter, aortic regurgitation, abdominal vessel involvement, arch vessel involvement, ejection fraction value, laboratory parameters, symptom, coronary malperfusion, mesenteric malperfusion, cerebral malperfusion, hypotension/shock, cardiac tamponade and operation status. The mean age of the sample was 50.17 ± 11.47 years, with approximately 24.24% of the participants being female. After analysis, it was found that the admission serum uric acid of patients with acute type A aortic dissection was positively correlated with in-hospital death (OR = 1.04, 95% CI 1.02–1.06). Subsequently, a non-linear relationship was determined between admission serum uric acid (point 260 µmol/L) and in-hospital mortality for patients with acute type A aortic dissection. The effect sizes and confidence intervals of the right (serum uric acid > 260 µmol/L) and left (serum uric acid ≤ 260 µmol/L) aspects of the inflection point were 1.04 (1.02–1.05) and 1.00 (0.99–1.02), respectively. Furthermore, subgroup analysis indicated a stable relationship between serum uric acid and in-hospital mortality, whilst an insignificant difference was found for the interactions between different subgroups. Overall, a non-linear correlation was determined between admission serum uric acid and in-hospital mortality of patients with acute type A aortic dissection. When serum uric acid > 260 µmol/L, it showed a positive correlation with in-hospital mortality.

Association of Uric Acid-Lowering Therapy With Incident Chronic Kidney Disease

IMPORTANCE

Uric acid is a waste metabolite produced from the breakdown of purines, and elevated serum uric acid levels are associated with higher risk of hypertension, cardiovascular disease, and mortality and progression of chronic kidney disease (CKD). Treatment of hyperuricemia in patients with preexisting CKD has not been shown to improve kidney outcomes, but the associations of uric acid-lowering therapies with the development of new-onset kidney disease in patients with estimated glomerular filtration rate (eGFR) within reference range and no albuminuria is unclear.

OBJECTIVE

To examine the association of initiating uric acid-lowering therapy with the incidence of CKD.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included patients with eGFR of 60 mL/min/1.73 m2 or greater and no albuminuria treated at US Department of Veterans Affairs health care facilities from 2004 to 2019. Clinical trial emulation methods, including propensity score weighting, were used to minimize confounding. Data were analyzed from 2020 to 2022.

EXPOSURE

Newly started uric acid-lowering therapy.

MAIN OUTCOMES AND MEASURES

The main outcomes were incidences of eGFR less than 60 mL/min/1.73 m2, new-onset albuminuria, and end-stage kidney disease.

RESULTS

A total of 269 651 patients were assessed (mean [SD] age, 57.4 [12.5] years; 252 171 [94%] men). Among these, 29 501 patients (10.9%) started uric acid-lowering therapy, and 240 150 patients (89.1%) did not. Baseline characteristics, including serum uric acid level, were similar among treated and untreated patients after propensity score weighting. In the overall cohort, uric acid-lowering therapy was associated with higher risk of both incident eGFR less than 60 mL/min/1.73 m2 (weighted subhazard ratio [SHR], 1.15 [95% CI, 1.10-1.20; P < .001) and incident albuminuria (SHR, 1.05 [95% CI, 1.01-1.09; P < .001) but was not associated with the risk of end-stage kidney disease (SHR, 0.96 [95% CI, 0.62-1.50]; P = .87). In subgroup analyses, the association of uric acid-lowering therapy with worse kidney outcomes was limited to patients with baseline serum uric acid levels of 8 mg/dL or less.

CONCLUSIONS AND RELEVANCE

These findings suggest that in patients with kidney function within reference range, uric acid-lowering therapy was not associated with beneficial kidney outcomes and may be associated with potential harm in patients with less severely elevated serum uric acid levels.

Research progress on related mechanisms of uric acid activating NLRP3 inflammasome in chronic kidney disease

Hyperuricemia is an independent risk factor for the progression of chronic kidney disease. High levels of uric acid can lead to a series of pathological conditions, such as gout, urinary stones, inflammation, and uric acid nephropathy. There is a close relationship between uric acid and the NLRP3 inflammasome. NLRP3 inflammasome activation can cause cell damage and even death through endoplasmic reticulum stress, lysosome destruction, mitochondrial dysfunction, and the interaction between the Golgi apparatus and extracellular vesicles. In addition, the NLRP3 inflammasome acts as a molecular platform, triggering the activation of caspase-1 and the lysis of IL-1β, IL-18 and Gasdermin D (GSDMD) through different molecular mechanisms. Cleaved NT-GSDMD forms pores in the cell membrane and triggers pyrophosphorylation, thereby inducing cell death and releasing many intracellular proinflammatory molecules. In recent years, studies have found that hyperuricemia or uric acid crystals can activate NLRP3 inflammasomes, and the activation of NLRP3 inflammasomes plays an important role in kidney disease. This article reviews the possible pathophysiological mechanisms by which uric acid activates inflammasomes and induces kidney damage at the cellular and molecular levels.

Pathophysiological Mechanisms of Hypertension Development Induced by Fructose Consumption

During the past several decades, there has been a dramatic increase in fructose consumption worldwide in parallel with epidemics of metabolic diseases. Accumulating evidence has suggested that excessive fructose consumption...

Hyperuricemia Increases the Risk of Atrial Fibrillation: A Systematic Review and Meta-Analysis

Association between hyperuricemia (HUA) and atrial fibrillation (AF) remains unclear. We reviewed clinical evidence and aimed to determine whether hyperuricemia leads to a high risk of atrial fibrillation. Most studies were identified through databases online. Keywords used in literature search were hyperuricemia, atrial fibrillation, metabolic disorder, endocrine disorder, or uric acid. Three studies were provided by the authors. Literature search was performed without any data or language restriction. Observational studies, including cohort studies and cross-sectional studies, were used. Study type should be clearly defined. Cross-sectional studies should clearly introduce the sources of epidemiological data. Studies were excluded if with too many complications unrelated to AF enrolled. Data were independently extracted by three individuals. Data synthesis was conducted by R version 4.1.2. Prevalence of atrial fibrillation was the main outcome. Results of meta-analysis were presented as risk ratio (RR) for different prevalence of AF between individuals with and without HUA. All data included were obtained after follow-up work is completed. Data from 608,810 participants showed that patients with hyperuricemia were easier to suffer from atrial fibrillation (RR, 2.42; 95% CI, 1.24-3.03). And the meta-regressions suggested growth of linear proportion between the ratio of current drinkers and hyperuricemia (QM = 41.0069, P < 0.001). Subgroup analyses demonstrated consistent results in different countries. And design of the observational studies brought heterogeneity, but no uncertainties. Patients with hyperuricemia were easier to suffer from atrial fibrillation. Treatment of hyperuricemia or gout may bring potential benefits for AF patients.

CTRP3 protects against uric acid-induced endothelial injury by inhibiting inflammation and oxidase stress in rats

Hyperuricemia, which contributes to vascular endothelial damage, plays a key role in multiple cardiovascular diseases. This study was designed to investigate whether C1q/tumor necrosis factor (TNF)-related protein 3 (CTRP3) has a protective effect on endothelial damage induced by uric acid and its underlying mechanisms. Animal models of hyperuricemia were established in Sprague-Dawley (SD) rats through the consumption of 10% fructose water for 12 weeks. Then, the rats were given a single injection of Ad-CTRP3 or Ad-GFP. The animal experiments were ended two weeks later. In vitro, human umbilical vein endothelial cells (HUVECs) were first infected with Ad-CTRP3 or Ad-GFP. Then, the cells were stimulated with 10 mg/dL uric acid for 48 h after pretreatment with or without a Toll-like receptor 4 (TLR4)-specific inhibitor. Hyperuricemic rats showed disorganized intimal structures, increased endothelial apoptosis rates, increased inflammatory responses and oxidative stress, which were accompanied by reduced CTRP3 and elevated TLR4 protein levels in the thoracic aorta. In contrast, CTRP3 overexpression decreased TLR4 protein levels and ameliorated inflammatory responses and oxidative stress, thereby improving the morphology and apoptosis of the aortic endothelium in rats with hyperuricemia. Similarly, CTRP3 overexpression decreased TLR4-mediated inflammation, reduced oxidative stress, and rescued endothelial damage induced by uric acid in HUVECs. In conclusion, CTRP3 ameliorates uric acid-induced inflammation and oxidative stress, which in turn protects against endothelial injury, possibly by inhibiting TLR4-mediated inflammation and downregulating oxidative stress.

Therapeutic enzymes as non-conventional targets in cardiovascular impairments:A Comprehensive Review

Over the last few decades, substantial progress has been made towards the understanding of cardiovascular diseases (CVDs). In-depth mechanistic insights have also provided opportunities to explore novel therapeutic targets and treatment regimens to be discovered. Therapeutic enzymes are an example of such opportunities. The balanced functioning of such enzymes protects against a variety of CVDs while on the other hand, even a small shift in the normal functioning of these enzymes may lead to deleterious outcomes. Owing to the great versatility of these enzymes, inhibition and activation are key regulatory approaches to counter the onset and progression of several cardiovascular impairments. While cardiovascular remedies are already available in excess and of course they are efficacious, a comprehensive description of novel therapeutic enzymes to combat CVDs is the need of the hour. In light of this, the regulation of the functional activity of these enzymes also opens a new avenue for the treatment approaches to be employed. This review describes the importance of non-conventional enzymes as potential candidates in several cardiovascular disorders while highlighting some of the recently targeted therapeutic enzymes in CVDs.

Role of asymptomatic hyperuricemia in the progression of chronic kidney disease and cardiovascular disease

Previous research has investigated whether hyperuricemia serves as an independent risk factor for cardiovascular and renal diseases. Hyperuricemia is defined as an abnormally high level of uric acid (UA; i.e., serum urate level > 6.8 mg/dL). Hyperuricemia has been considered a complication of chronic kidney disease (CKD). However, it seems to play a pathogenic role in the progression of renal diseases. There has been increasing focus on the link between hyperuricemia and CKD. The results of randomized controlled trials have implied independent associations between hyperuricemia and the progression of cardiovascular and renal morbidities. These associations may be mediated by renin-angiotensin system activation, nitric oxide synthase inhibition, and macrovascular/microvascular disease development. There remains controversy regarding the use of serum UA level as an indirect index of renal vascular disease. This literature review focuses on the role of asymptomatic hyperuricemia in the progression of CKD, as well as the association between hyperuricemia and cardiovascular disease. It also provides a general overview of the physiological metabolism of UA.

Network Pharmacology Study on Morus alba L. Leaves: Pivotal Functions of Bioactives on RAS Signaling Pathway and Its Associated Target Proteins against Gout

M. alba L. is a valuable nutraceutical plant rich in potential bioactive compounds with promising anti-gouty arthritis. Here, we have explored bioactives, signaling pathways, and key proteins underlying the anti-gout activity of M. alba L. leaves for the first-time utilizing network pharmacology. Bioactives in M. alba L. leaves were detected through GC-MS (Gas Chromatography-Mass Spectrum) analysis and filtered by Lipinski's rule. Target proteins connected to the filtered compounds and gout were selected from public databases. The overlapping target proteins between bioactives-interacted target proteins and gout-targeted proteins were identified using a Venn diagram. Bioactives-Proteins interactive networking for gout was analyzed to identify potential ligand-target and visualized the rich factor on the R package via the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway on STRING. Finally, a molecular docking test (MDT) between bioactives and target proteins was analyzed via AutoDock Vina. Gene Set Enrichment Analysis (GSEA) demonstrated that mechanisms of M. alba L. leaves against gout were connected to 17 signaling pathways on 26 compounds. AKT1 (AKT Serine/Threonine Kinase 1), γ-Tocopherol, and RAS signaling pathway were selected as a hub target, a key bioactive, and a hub signaling pathway, respectively. Furthermore, three main compounds (γ-Tocopherol, 4-Dehydroxy-N-(4,5-methylenedioxy-2-nitrobenzylidene) tyramine, and Lanosterol acetate) and three key target proteins-AKT1, PRKCA, and PLA2G2A associated with the RAS signaling pathway were noted for their highest affinity on MDT. The identified three key bioactives in M. alba L. leaves might contribute to recovering gouty condition by inactivating the RAS signaling pathway.

Association of hyperuricemia and hypertension phenotypes in hypertensive patients without uric acid lowering treatment

BACKGROUND

Current study was to evaluate the association of hypertensive and hypertension phenotypes in hypertensive populations.

METHODS

Patients with primary hypertension and without any uric acid (UA)-lowering treatment were enrolled. Baseline characteristics including office blood pressure (OBP), 24 h ambulatory blood pressure (ABP), and serum UA (SUA) were measured. According to SUA, patients were divided into normal SUA and hyperuricemia groups. Based on OBP and 24 h-ABP, hypertension phenotypes were classified as controlled hypertension (CH), white-coat uncontrolled hypertension (WCUH), masked uncontrolled hypertension (MUCH), and sustained uncontrolled hypertension (SUCH).

RESULTS

Compared to patients with normal SUA (n = 336), patients with hyperuricemia (n = 284) were older and more likely to be men, obese, physically inactive, and have a higher prevalence of diabetes. C-reactive protein (CRP) level was higher in patients with hyperuricemia. The prevalence of CH, WCUH, and MUCH was similar between these two groups. However, the prevalence of SUCH was higher in patients with hyperuricemia than patients with normal SUA. Linear regression analysis indicated that increased SUA was significantly associated with 24 h-systolic BP and daytime-systolic BP. Normal SUA was served as the reference group, and presence of hyperuricemia was associated with higher odds of SUCH (odds ratio 1.46 and 95% confidence interval 1.27-1.93) after adjusted for potential covariates including age, male gender, obesity, diabetes, CRP, and antihypertensive drugs.

CONCLUSION

In hypertensive patients without UA-lowering treatment, presence of hyperuricemia was associated with higher odds of SUCH. Future studies are needed to evaluate whether lowering SUA can help to improve 24 h-ABP control.

High uric acid induces liver fat accumulation via ROS/JNK/AP-1 signaling

Uric acid is the end metabolite derived from the oxidation of purine compounds. Overwhelming evidence shows the vital interrelationship between hyperuricemia (HUA) and nonalcoholic fatty liver disease (NAFLD). However, the mechanisms for this association remain unclear. In this study, we established a urate oxidase-knockout (Uox-KO) mouse model by clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 technology. To study the correlation between HUA and NAFLD, human HepG2 hepatoma cells were treated in culture medium with high level of uric acid. In vivo, the Uox-KO mice spontaneously developed hyperuricemia and aberrant lipid-metabolism, concomitant with abnormal hepatic fat accumulation. HUA activated c-Jun N-terminal kinase (JNK) in vivo and in vitro. Furthermore, inhibiting JNK activation by a JNK-specific inhibitor, SP600125, decreased fat accumulation and lipogenic gene expression induced by HUA. Overexpression of the lipogenic enzymes fatty acid synthase and acetyl-CoA carboxylase 1 was via activation of JNK, which was blocked by the JNK inhibitor SP600125. HUA activated AP-1 to upregulate lipogenic gene expression via JNK activation. In addition, HUA caused mitochondrial dysfunction and reactive oxygen species production. Pretreatment with the antioxidant N-acetyl-l-cysteine could ameliorate HUA-activated JNK and hepatic steatosis. These data suggest that ROS/JNK/AP-1 signaling plays an important role in HUA-mediated fat accumulation in liver.NEW & NOTEWORTHY Hyperuricemia and nonalcoholic fatty liver disease are global public health problems, which are strongly associated with metabolic syndrome. In this study, we demonstrate that uric acid induces hepatic fat accumulation via the ROS/JNK/AP-1 pathway. This study identifies a new mechanism of NAFLD pathogenesis and new potential therapeutic strategies for HUA-induced NAFLD.

Relationship between uric acid and lipid accumulation product index by gender in Korean adults: The 2016 Korean National Health and Nutrition Examination Survey

AIMS

The present study assesses the relationship between uric acid (UA) and lipid accumulation product index (LAP) by gender among Korean adults.

METHODS

Data from 5670 subjects (2463 men and 3207 women) in the Korean National Health and Nutrition Examination Survey (KNHANES VII-1) 2016 were analyzed. LAP was divided into four quartiles (Q1-Q4).

RESULTS

There were several key findings. Compared with Q1, in the overall population, the odds ratios (ORs) of hyperuricemia (UA ≥ 7.0 mg/dL in men or UA ≥ 6.0 mg/dL in women) were significantly higher in Q2 [1.847 (95% confidence interval [CI], 1.325-2.575)], Q3 [3.050 (95% CI, 2.216-4.198)], and Q4 of LAP [6.367 (95% CI, 4.658-8.704)]. In men, the ORs of hyperuricemia were significantly higher in Q2 [1.658 (95% CI, 1.162-2.367)], Q3 [2.341 (95% CI, 1.656-3.308)], and Q4 [4.633 (95% CI, 3.290-6.525)] than Q1. In women, the ORs of hyperuricemia were significantly higher in Q2 [2.254 (95% CI, 1.085-4.680)], Q3 [5.402 (95% CI, 2.735-10.668)], and Q4 [11.025 (95% CI, 5.620-21.628)] than Q1. In addition, UA levels were positively associated with LAP level in men (r = 0.218; p < 0.001), women (r = 0.261; p < 0.001), and the overall population (r = 0.260; p < 0.001).

CONCLUSIONS

Hyperuricemia was positively associated with LAP in Korean men and women.

Associations of Obesity Measurements with Serum Metabolomic Profile: A Chinese Twin Study

The objective of this study was to investigate how different obesity measures link to circulating metabolites, and whether the connections are due to genetic or environmental factors. A cross-sectional analysis was performed on follow-up survey data at the Chinese National Twin Registry (CNTR), which was conducted in four areas of China (Shandong, Jiangsu, Zhejiang and Sichuan) in 2013. The survey collected detailed questionnaire information and conducted physical examinations, fasting blood sampling and untargeted metabolomic measurements among 439 adult twins. Linear regression models and bioinformatics analysis were used to examine the relation of obesity measures, including body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) with serum metabolite levels and related pathways. A co-twin control study was additionally conducted among 15 obesity-discordant monozygotic (MZ) pairs (intrapair BMI difference >3 kg/m2) to examine any differences in metabolites controlling for genetic factors. Eleven metabolites were associated with BMI, WC and WHR after controlling for genetic and shared environmental factors. Pathway analysis identified pathways such as phenylalanine metabolism, purine metabolism, valine, leucine and isoleucine biosynthesis that were associated with obesity. A wide range of unfavorable alterations in the serum metabolome was associated with obesity. Obesity-discordant twin analysis suggests that these associations are independent of genetic liability.

Elevated serum uric acid is associated with incident hypertension in the health according to various contemporary blood pressure guidelines

BACKGROUND AND AIMS

Elevated serum uric acid (SUA) is associated with hypertension according to its traditional definition. We investigated the association between SUA and incident hypertension according to the European Society of Cardiology (ESC) and American Society of Cardiology (ACC) guidelines.

METHODS AND RESULTS

In this retrospective cohort study, we enrolled 10,537 healthy individuals ≥30 years old who underwent a routine annual health examination with office blood pressure recorded at our hospital in 2016; of the participants, 7349 repeated the exam in 2017. According to the ESC and ACC guidelines, hypertension was defined as office BP ≥ 140/90 mmHg or ≥130/80 mmHg. Hyperuricemia (HUA) was defined as SUA ≥7 mg/dL in men and ≥6 mg/dL in women. The hypertension incidence was 5.8% among 6378 individuals in the ESC cohort and 19% among 4330 individuals in the ACC cohort. Incident hypertension was significantly more common in the hyperuricemic group than in the normouricemic group (ESC: 8.6% vs. 4.7%, P < 0.001; ACC: 25.5% vs. 16.9%, P < 0.001). In the fully adjusted multivariate logistic regression analyses, each increase in SUA was associated with an increase in incident hypertension risk (ESC: adjusted OR: 1.167, 95% CI: 1.061-1.284, P = 0.001; ACC: adjusted OR: 1.125, 95% CI: 1.044-1.213, P = 0.002). The association can be explained by a significant correlation of baseline SUA with the BP in the following year (r = 0.24, P < 0.001 for baseline SUA and SBP in the following year; r = 0.239, P < 0.001 for baseline SUA and DBP in the following year).

CONCLUSION

Elevated SUA was associated with incident hypertension in healthy individuals according to various contemporary BP guidelines (ClinicalTrials.gov: NCT03473951).

CLINICAL TRIALS

ClinicalTrials.gov with the identification number of NCT03473951.

Inhibition of xanthine oxidase in the acute phase of myocardial infarction prevents skeletal muscle abnormalities and exercise intolerance

AIMS

Exercise intolerance in patients with heart failure (HF) is partly attributed to skeletal muscle abnormalities. We have shown that reactive oxygen species (ROS) play a crucial role in skeletal muscle abnormalities, but the pathogenic mechanism remains unclear. Xanthine oxidase (XO) is reported to be an important mediator of ROS overproduction in ischaemic tissue. Here, we tested the hypothesis that skeletal muscle abnormalities in HF are initially caused by XO-derived ROS and are prevented by the inhibition of their production.

METHODS AND RESULTS

Myocardial infarction (MI) was induced in male C57BL/6J mice, which eventually led to HF, and a sham operation was performed in control mice. The time course of XO-derived ROS production in mouse skeletal muscle post-MI was first analysed. XO-derived ROS production was significantly increased in MI mice from Days 1 to 3 post-surgery (acute phase), whereas it did not differ between the MI and sham groups from 7 to 28 days (chronic phase). Second, mice were divided into three groups: sham + vehicle (Sham + Veh), MI + vehicle (MI + Veh), and MI + febuxostat (an XO inhibitor, 5 mg/kg body weight/day; MI + Feb). Febuxostat or vehicle was administered at 1 and 24 h before surgery, and once-daily on Days 1-7 post-surgery. On Day 28 post-surgery, exercise capacity and mitochondrial respiration in skeletal muscle fibres were significantly decreased in MI + Veh compared with Sham + Veh mice. An increase in damaged mitochondria in MI + Veh compared with Sham + Veh mice was also observed. The wet weight and cross-sectional area of slow muscle fibres (higher XO-derived ROS) was reduced via the down-regulation of protein synthesis-associated mTOR-p70S6K signalling in MI + Veh compared with Sham + Veh mice. These impairments were ameliorated in MI + Feb mice, in association with a reduction of XO-derived ROS production, without affecting cardiac function.

CONCLUSION

XO inhibition during the acute phase post-MI can prevent skeletal muscle abnormalities and exercise intolerance in mice with HF.

Hyperuricemia precedes non-alcoholic fatty liver disease with abdominal obesity moderating this unidirectional relationship: Three longitudinal analyses

BACKGROUND AND AIMS

The temporal relationship between hyperuricemia and non-alcoholic fatty liver disease (NAFLD) is debatable. This study aimed to explore whether there exists a bidirectional or temporal relationship between them.

METHODS

A total of 11,585 participants were recruited from the Beijing Health Management Cohort during the period 2012-2016. We evaluated whether hyperuricemia was associated with NAFLD development (part I) and whether NAFLD was associated with hyperuricemia incidence (part II) using a logistic regression model. Further, the cross-lagged panel analysis model was used to simultaneously examine the bidirectional relationship between hepatic steatosis and serum uric acid (SUA) (part III). Subgroup and interaction analyses were also performed to assess whether other variables moderated those relationships.

RESULTS

In part I, multiple logistic regression indicated that baseline hyperuricemia was associated with the development of NAFLD (OR = 1.5970, p < 0.0001). In part II, multiple logistic regression showed that baseline NAFLD was not correlated with hyperuricemia incidence (OR = 0.8600, p = 0.1976). In part III, cross-lagged panel analyses indicated that the standard regression coefficient of baseline SUA to follow-up hepatic steatosis (0.1516) was significantly greater than the coefficient from the baseline hepatic steatosis to follow-up SUA (-0.0044) with p < 0.0001 for the difference. This indicated a unidirectional relationship from baseline SUA to follow-up hepatic steatosis, suggesting hyperuricemia may precede NAFLD; and this relationship was not affected by age, sex, dyslipidemia, metabolism syndrome, diabetes but was moderated by abdominal obesity.

CONCLUSIONS

This study demonstrated a unidirectional relationship from hyperuricemia to NAFLD incidence, and suggested that lowering SUA levels in hyperuricemia patients may prevent subsequent NAFLD.

Serum uric acid is independently associated with aortic arch calcification in a cross-sectional study of middle-aged and elderly women

BACKGROUND AND AIMS

The increased serum uric acid (SUA) level is associated with the prevalence of cardiovascular disease (CVD) risks. Aortic arch calcification (AAC) reflects subclinical coronary atherosclerosis and is linked to subsequent cardiovascular morbidity and mortality risks closely. To better understand the role of SUA on arteriosclerosis and CVD, we aim to determine the association between SUA and the presence of AAC.

METHODS AND RESULTS

A total of 5920 individuals aged >45 years old without prior CVD disease were included. The prevalence rate of AAC was 14.4% in all participants and a significantly increasing trend for AAC prevalence rate was found across the SUA tertiles (p < 0.001 for trend). Subsequent subgroup analyses revealed that this positive association trend was only significant in female subjects. After adjusting for confounders, SUA is an independent predictor for the presence of AAC in overall participants and in women.

CONCLUSION

SUA is independently associated with AAC in middle-aged and elderly population, especially in the women. More research needs to determine whether lower thresholds for CVD risk screening for those middle-aged and elderly women with higher SUA tertile even without hyperuricemia are warranted.

The association of urinary uric acid excretion with ambulatory blood pressure values in patients with chronic kidney disease

BACKGROUND

To analyze the association between hypertension and urinary uric acid excretion in patients with chronic kidney disease (CKD).

METHODS

We screened 87 patients who had been admitted at the Dept of Nephrology, Huadong hospital between April 2017 to April 2019 who had completed 24-h ambulatory blood pressure monitoring and retained 24-h urine biochemical test specimens, thirty adult patients (age ≤ 65 years) with CKD 1-2 stages were recruited in the study. Pearson's correlation analysis and multiple linear regression analysis were used to study the correlation of urinary uric acid excretion with ambulatory blood pressure values and the association of morning mean diastolic pressure (mMDP), night mean diastolic pressure (nMDP) and CV of dMSP (coefficient of variation of day mean systolic pressure) with fractional excretion of uric acid (FEua) and uric acid clearance rate (Cur). Independent T test was used to compare the differences of blood pressure values in FEua1 (FEua< 6.0%) and FEua2 (FEua≥6.0%) or Cur1 (Cur < 6.2 ml/min/1.73 m2) and Cur2 (Cur ≥ 6.2 ml/min/1.73m2) groups according to the median of FEua or Cur, respectively.

RESULTS

After adjusting for confounding factors, multiple linear regression analysis showed that FEua was positively associated with the mMDP and nMDP, Cur was positively associated with CV of dMSP. Levels of mMDP and nMDP in FEua1 group was lower than that in FEua2 group (both P < 0.05), level of CV of dMSP in Cur2 group were higher than that in Cur1 group (P < 0.01).

CONCLUSIONS

We demonstrated that there is a positive correlation of FEua with morning and night mean diastolic pressure separately and Cur is positively related to CV of dMSP in CKD population. Monitoring the trend of urinary uric acid, may have a role in the early detection for hypertension or relative risks in the population of CKD.

Central Macular Thickness in Diabetic Macular Edema

Context

Retinal microvascular dysfunction differs in macular edema lesions in the two eyes of the same patient with diabetic retinopathy.

Objective

To evaluate the relationship between central macular thickness (CMT) and metabolic/systemic factors including anthropometric and laboratory findings, in patients with regressed diabetic retinopathy and a history of pars plana vitrectomy (PPV) combined with internal limiting membrane peeling in one eye.

Subjects and Methods

Forty-two eyes with PPV and the same patients' fellow 42 eyes (without PPV) included this study. Fasting blood samples of these 42 diabetics were collected to study adiponectin levels and other routine parameters.

Results

The average hemoglobinA1c value was 7.3±1.3%. CMT of the vitrectomized eyes were significantly correlated with atherogenic index of plasma, total cholesterol, low density lipoprotein cholesterol and uric acid (UA). On the other hand, CMT of the nonvitrectomized fellow eyes significantly correlated with glucose levels and diabetes duration. Adiponectin, adiponectin/body mass index, adiponectin/fibrinogen were found significantly higher in the subgroup with CMT≥300μm in the vitrectomized eyes (P<0.05). UA levels were higher in the subgroup with CMT≥300μm in the fellow (nonvitrectomized) eyes (P<0.05).

Conclusions

Although there was no relationship between CMT and hemoglobinA1c values, CMT seemed to be affected by atherogenicity, prooxidant chemical alterations in the course of inflammation, so determination of adiponectin and UA levels may be suggested before surgery to predict the atherosclerotic damage and the postoperative CMT value. Vitrectomy performed at the proper time may be helpful in metabolic remodeling process of the retinal tissue along with life style changes, well control of diabetes, and intraocular treatments.

Protective Effects of α-Lipoic Acid on Vascular Oxidative Stress in Rats with Hyperuricemia

The aim of the present study was to observe the protective effects of α-lipoic acid (ALA) on vascular injury in rats with hyperuricemia (HUA). The ALA treatment groups (10, 30 and 90 mg/kg, respectively) were administered with ALA via gavage for 2 weeks. Subsequently, the levels of blood urea nitrogen (BUN), creatinine (CREA), uric acid (UA), total cholesterol (TC), high density lipoprotein-C (HDL-C) and low density lipoprotein-C (LDL-C) were measured; the activities of glutathione peroxidase (GSH-Px), catalase (CAT), malonaldehyde (MDA), superoxide dismutase (SOD) and xanthine oxidase (XOD) were also determined. The thoracic aorta of rats in each experimental group was observed under a light microscope; ultrastructural analysis was performed. SOD and CAT protein contents were investigated by Western blotting. The results revealed that: i) Compared with the model group, the levels of UA were decreased in the ALA groups and the levels of BUN, CREA, TC, and LDL-C decreased in the 30 and 90 mg/kg ALA groups (P<0.05); ii) compared with the model group, the activities of GSH-Px, SOD and XOD were increased and the levels of MDA were reduced in the 90 mg/kg ALA group (P&lt;0.05); and iii) in the model and 10 mg/kg ALA groups, edema and shedding were observed in endothelial cells. Compared with the model and 10 mg/kg ALA groups, the 30 and 90 mg/kg ALA groups exhibited fewer swollen endothelial cells. In summary, the results of the present study indicated that HUA resulted in vascular oxidative stress injury and decreased the activity of antioxidative enzymes, which leads to endothelial cell damage and vascular lesions. ALA may serve as a therapeutic agent for the treatment of HUA-induced endothelial dysfunction.

Elevated Uric Acid Levels Promote Vascular Smooth Muscle Cells (VSMC) Proliferation via an Nod-Like Receptor Protein 3 (NLRP3)-Inflammasome-Dependent Mechanism

BACKGROUND Hyperuricemia has a pathogenic role in the development of hypertension and other cardiovascular diseases (CVD). Uric acid has been reported to activate Nod-like receptor protein 3 (NLRP3)-inflammasome and alter vascular smooth muscle cells (VSMC). However, the potential mechanisms underlying this association are still not understood. The aim of this study was to investigate the role and potential mechanisms of uric acid in proliferation of VSMC. MATERIAL AND METHODS Cell Counting Kit-8 (CCK-8) proliferation assay and colony formation assay were performed to determine the proliferative ability of VSMC under uric acid stimulation. Immunofluorescence microscopy was carried out to determine the expression of Alpha-smooth muscle actin (alpha-SMA). In addition, real-time PCR and Western blot were used to detect the expression of NLRP3-inflammasome, and ELISA was performed to measure the levels of IL-18 and IL-1ß. RESULTS The results showed that uric acid increases the proliferation of VSMC and induces alpha-SMA accumulation. We also found that uric acid increases the level of NLRP3 and induces NLRP3-inflammasome activation. The expressions of uric acid-induced inflammatory markers IL-1ß and IL-18 were decreased by the inhibitor MCC950. CONCLUSIONS Our findings revealed that uric acid induces inflammation through NLRP3-inflammasome-mediated VSMC proliferation. NLRP3 may be a new therapeutic target for hypertension.

Hyperuricemia Inhibition Protects SD Rats Against Fructose-Induced Obesity Hypertension Via Modulation of Inflammation and Renin-Angiotensin System in Adipose Tissue

OBJECTIVE

The present study was aimed to reveal the relationship between uric acid and fructose-induced obesity hypertension and its mechanisms.

METHODS

A rat model with obesity hypertension was induced by a high-fructose diet. In the experiment I, the rats were fed with fructose for 8 wks along with allopurinol or benzbromarone at the beginning. In the experiment II, the rats were fed with fructose for 8 wks firstly. And then, these rats were treated with allopurinol or benzbromarone for additional 6 wks.

RESULTS

Fructose-fed rats showed hyperuricemia, abdominal obesity hypertension and an activation in adipose renin-angiotensin system (RAS). Also, fructose-fed rats had higher levels of proinflammatory cytokines and more macrophages infiltrating in adipose tissue. In the experiment I, allopurinol and benzbromarone significantly reduced serum uric acid at 8 wk. Adipose RAS overactivation, adipose inflammatory responses and the development of obesity hypertension were all effectively prevented by hyperuricemia inhibition. In the experiment II, 6-wk treatment with allopurinol and benzbromarone significantly decreased serum uric acid, downregulated adipose RAS, abolished adipose inflammation and improved obesity hypertension.

CONCLUSION

In conclusion, urate-lowering therapy protects rats against fructose-induced obesity hypertension. The mechanisms appear to be via downregulated adipose RAS and reduced inflammation in adipose tissue.

Beyond adiponectin and leptin: adipose tissue-derived mediators of inter-organ communication

The breakthrough discoveries of leptin and adiponectin more than two decades ago led to a widespread recognition of adipose tissue as an endocrine organ. Many more adipose tissue-secreted signaling mediators (adipokines) have been identified since then, and much has been learned about how adipose tissue communicates with other organs of the body to maintain systemic homeostasis. Beyond proteins, additional factors, such as lipids, metabolites, noncoding RNAs, and extracellular vesicles (EVs), released by adipose tissue participate in this process. Here, we review the diverse signaling mediators and mechanisms adipose tissue utilizes to relay information to other organs. We discuss recently identified adipokines (proteins, lipids, and metabolites) and briefly outline the contributions of noncoding RNAs and EVs to the ever-increasing complexities of adipose tissue inter-organ communication. We conclude by reflecting on central aspects of adipokine biology, namely, the contribution of distinct adipose tissue depots and cell types to adipokine secretion, the phenomenon of adipokine resistance, and the capacity of adipose tissue to act both as a source and sink of signaling mediators.

Sex-Specific Association Between Serum Uric Acid and Elevated Alanine Aminotransferase in a Military Cohort: The CHIEF Study

AIM

The study was conducted in order to examine the sex-specific association of serum uric acid (SUA) levels with elevated serum alanine aminotransferase (ALT) in a Taiwanese military cohort.

METHODS

We made a cross-sectional examination of the sex-specific relationship using 6728 men and 766 women, aged 18-50 years from a large military cohort in Taiwan. SUA levels within the reference range (<7.0 mg/dL for men and <5.7 mg/dL for women respectively) were divided into quartiles and SUA levels greater than the upper reference limits were defined as hyperuricemia. Elevated ALT levels were defined as ≥40 U/L. Multivariate logistic regression analysis was performed to determine the association between each SUA category and elevated ALT levels in men and women, respectively.

RESULTS

The prevalence of hyperuricemia and elevated ALT in men were 18.7% and 12.7%, respectively, and in women were 3.3% and 2.1%, respectively. As compared with the lowest SUA quartile, hyperuricemia was associated with elevated ALT in men (odds ratios (OR): 1.62, 95% confidence intervals (CI): 1.19-2.20) after controlling for age, service specialty, body mass index, metabolic syndrome components, current cigarette smoking, alcohol intake status, and weekly exercise times, but the associations for the other SUA quartiles were null. By contrast, the associations of hyperuricemia (OR: 0.81, 95% CI: 0.10-6.64) and the other SUA quartiles with elevated ALT were null in women.

CONCLUSION

Our findings suggest that the relationship between each SUA level and elevated ALT may differ by sex among military young adults. The mechanism for the sex difference requires further investigations.

TLR2 and TLR4 mediate an activation of adipose tissue renin-angiotensin system induced by uric acid

Both hyperuricemia and adipose tissue renin-angiotensin system (RAS) are closely associated with multiple metabolic and cardiovascular diseases. We previously reported that uric acid could upregulate tissue RAS in adipocytes. In the present study, we aimed to reveal the involvement of toll-like receptors (TLRs) in uric acid-induced RAS activation in adipose tissue. A hyperuricemia rat model fed with a high-fructose diet and rat primary adipocytes were used in this study. Here, we inhibited TLR2 and TLR4 expression in adipose tissue and cultured adipocytes using small interfering RNA (siRNA). We found that high fructose-fed rats had hyperuricemia, higher body weight and greater adipose tissue content. We also found that hyperuricemia rats had raising blood pressure, higher expression levels of inflammatory cytokines and RAS components in adipose tissue, which could be prevented by TLR2/4-siRNA infection. In vitro study, uric acid caused a dose- and time-dependent increase in the mRNA expression of TLR2 and TLR4 in rat adipocytes. Uric acid could increase inflammatory cytokines and upregulate tissue RAS in rat adipocytes, which were both blocked with TLR2/4-siRNA infection. TNF-α and IL-6 could also result in an activation of tissue RAS expression in adipocytes. In conclusion, TLR2/4 mediated adipose inflammation plays a key role in RAS activation induced by uric acid in adipose tissue.

Identification of the metabolic fingerprints in women with polycystic ovary syndrome using the multiplatform metabolomics technique

In addition to chronic anovulation and clinical signs of hyperandrogenism women with polycystic ovary syndrome (PCOS) are insulin resistant and therefore, develop central obesity with its long term consequences such as dyslipidaemia, hypertension, atherosclerosis and type 2 diabetes mellitus (T2DM), which all lead to the development of cardiovascular disease (CVD). Due to the polysymptomatic nature of this syndrome and lack of consensus on its diagnostic criteria there is a strong need of finding a reliable biochemical or molecular marker, which would facilitate making the accurate diagnosis of PCOS. Therefore, the aim of our study was to perform a metabolomics analysis with the use of two complementary techniques: gas chromatography and liquid chromatography coupled with mass spectrometry, of the serum samples from women with PCOS (n = 30) and to compare them with healthy age and BMI matched controls (n = 30). Obtained results were subjected to one-dimensional statistical analysis (student's t-test or its non-parametric equivalent U Mann-Whitney test) and multivariate statistical analysis (the principal component analysis [PCA], variable importance into projection [VIP] and selectivity ratio [SR]). The results of our study showed that women with PCOS are characterised by metabolic disorders of the amino acids, carbohydrates, steroid hormones, lipids and purines. Compared to control subjects, women with PCOS had increased serum levels of phospholipids, aromatic amino acids, organic acids, hormones and sphinganine and decreased total cholesterol. Among the identified compounds, total cholesterol, phenylalanine and dehydroepiandrosterone sulfate, uric and lactic acid were the compounds with the strongest discriminating power.

Apelin-13 reduces oxidative stress induced by uric acid via downregulation of renin-angiotensin system in adipose tissue

Apelin-13, a novel adipocytokine, is found to be a powerful antioxidant. Our previous work reported that uric acid could induce oxidative stress via an activation of renin-angiotensin system (RAS) in 3T3-L1 adipocytes. In the present study, we tried to observe the effect of apelin-13 on uric acid-induced oxidative stress. We also tried to reveal the potential mechanisms. In vivo, the rats were fed with 60% fructose diet for 8 weeks to produce hyperuricemia. Then, the hyperuricemia rats were intraperitoneally injected with apelin-13 for 2 weeks or 12 weeks. In vitro, 3T3-L1 adipocytes were treated with apelin-13 in the presence of 600 μmol/L uric acid for 48 h. When injected with apelin-13 for 12 weeks, the hyperuricemia rats had ameliorated oxidative stress, downregulated RAS components and upregulated angiotensin type 1 receptor related protein (APJ) expression in adipose tissue. Serum uric acid levels were also decreased after treatment. However, 2-week apelin-13 treatment had no obvious effect on the rats with hyperuricemia. Consistent with the findings in vivo, in vitro study, apelin-13 could ameliorate oxidative stress, decrease tissue RAS components, and increase APJ expression in 3T3-L1 adipocytes stimulated by uric acid. In conclusion, apelin-13 reduces uric acid-induced oxidative stress in adipose tissue, maybe through the inhibition of adipose RAS expression.

Fetal programming and the angiotensin-(1-7) axis: a review of the experimental and clinical data

Hypertension is the primary risk factor for cardiovascular disease that constitutes a serious worldwide health concern and a significant healthcare burden. As the majority of hypertension has an unknown etiology, considerable research efforts in both experimental models and human cohorts has focused on the premise that alterations in the fetal and perinatal environment are key factors in the development of hypertension in children and adults. The exact mechanisms of how fetal programming events increase the risk of hypertension and cardiovascular disease are not fully elaborated; however, the focus on alterations in the biochemical components and functional aspects of the renin-angiotensin (Ang) system (RAS) has predominated, particularly activation of the Ang-converting enzyme (ACE)-Ang II-Ang type 1 receptor (AT1R) axis. The emerging view of alternative pathways within the RAS that may functionally antagonize the Ang II axis raise the possibility that programming events also target the non-classical components of the RAS as an additional mechanism contributing to the development and progression of hypertension. In the current review, we evaluate the potential role of the ACE2-Ang-(1-7)-Mas receptor (MasR) axis of the RAS in fetal programming events and cardiovascular and renal dysfunction. Specifically, the review examines the impact of fetal programming on the Ang-(1-7) axis within the circulation, kidney, and brain such that the loss of Ang-(1-7) expression or tone, contributes to the chronic dysregulation of blood pressure (BP) and cardiometabolic disease in the offspring, as well as the influence of sex on potential programming of this pathway.

Pharmacological inhibition of autophagy by 3-MA attenuates hyperuricemic nephropathy

Autophagy has been identified as a cellular process of bulk degradation of cytoplasmic components and its persistent activation is critically involved in the renal damage induced by ureteral obstruction. However, the role and underlying mechanisms of autophagy in hyperuricemic nephropathy (HN) remain unknown. In the present study, we observed that inhibition of autophagy by 3-methyladenine (3-MA) abolished uric acid-induced differentiation of renal fibroblasts to myofibroblasts and activation of transforming growth factor-β1 (TGF-β1), epidermal growth factor receptor (EGFR), and Wnt signaling pathways in cultured renal interstitial fibroblasts. Treatment with 3-MA also abrogated the development of HN in vivo as evidenced by improving renal function, preserving renal tissue architecture, reducing the number of autophagic vacuoles, and decreasing microalbuminuria. Moreover, 3-MA was effective in attenuating renal deposition of extracellular matrix (ECM) proteins and expression of α-smooth muscle actin (α-SMA) and reducing renal epithelial cells arrested at the G₂/M phase of cell cycle. Injury to the kidney resulted in increased expression of TGF-β1 and TGFβ receptor I, phosphorylation of Smad3 and TGF-β-activated kinase 1 (TAK1), and activation of multiple cell signaling pathways associated with renal fibrogenesis, including Wnt, Notch, EGFR, and nuclear factor-κB (NF-κB). 3-MA treatment remarkably inhibited all these responses. In addition, 3-MA effectively suppressed infiltration of macrophages and lymphocytes as well as release of multiple profibrogenic cytokines/chemokines in the injured kidney. Collectively, these findings indicate that hyperuricemia-induced autophagy is critically involved in the activation of renal fibroblasts and development of renal fibrosis and suggest that inhibition of autophagy may represent a potential therapeutic strategy for HN.

High serum uric acid is associated with oxidation of nucleosides in patients with type 2 diabetes

Uric acid presents different roles in an organism, since it can act as an antioxidant or a pro-oxidant molecule. High serum uric acid levels may cause damage to several structures, including nucleic acids and its components. Therefore, in this study the association between increased serum uric acid concentrations and oxidation of nucleosides was investigated by assessment of urinary 8-hydroxydeoxyguanosine (8-OHdG) in patients with type 2 diabetes (T2D) and in healthy individuals. Urinary 8-OHdG and biochemical parameters were assessed in 61 patients who were initially grouped into 2 groups based on the median serum uric acid levels (<5.3 mg/dL and ≥5.3 mg/dL). Urinary 8-OHdG was higher in patients with T2D and serum uric acid levels ≥5.3 mg/dL, when compared with the patients with serum uric acid levels <5.3 mg/dL; however, co-occurrence of high serum uric acid with high urinary 8-OHdG was not observed in healthy individuals. A significant positive correlation between 8-OHdG and uric acid (r = 0.40, P < 0.01) was observed in patients with T2D. High serum uric acid levels were associated with high urinary 8-OHdG levels in patients with T2D, and this association was independent of gender, hypertension, body mass index, and serum creatinine.

Decreased Serum Bilirubin Levels and Increased Uric Acid Levels are Associated with Ulcerative Colitis

Background

In recent years, emerging evidence has suggested that ulcerative colitis occurs as a consequence of an imbalance between oxidative stress and antioxidant capacity. The objective of this study was to investigate whether serum total bilirubin and serum uric acid levels were associated with ulcerative colitis.

Material/Methods

We conducted a retrospective case-control study which included 170 patients with ulcerative colitis and 200 healthy individuals. Concentrations of serum total bilirubin and serum uric acid were obtained from biochemical information and segregated into quartiles. Logistic regression analysis was adopted to explore the correlations between levels of the 2 biochemical markers and the risk of ulcerative colitis.

Results

Compared with healthy controls, patients with ulcerative colitis exhibited lower levels of serum bilirubin (9.30 umol/L versus 12.49 umol/L respectively, P<0.001). Multivariate logistic regression showed that the lowest quartile of total serum bilirubin was independently associated with the occurrence of ulcerative colitis (OR=2.56, 95%CI: 1.54–4.25, P<0.001). Similarly, ulcerative colitis patients exhibited higher concentrations of serum uric acid (338 umol/L versus 300 umol/L respectively, P=0.041). Multivariate logistic regression showed that the highest quartile of serum uric acid was independently associated with ulcerative colitis risk (OR=1.20, 95%CI: 1.05–1.77, P=0.045). Furthermore, a negative association was observed between serum total bilirubin and serum uric acid in patients with ulcerative colitis.

Conclusion

Lower levels of serum total bilirubin and higher levels of serum uric acid are associated with ulcerative colitis patients compared to healthy controls.

Baseline and changes in serum uric acid independently predict 11-year incidence of metabolic syndrome among community-dwelling women

INTRODUCTION

Metabolic syndrome (MetS) is associated with an increased risk of major cardiovascular events. In women, increased serum uric acid (SUA) levels are associated with MetS and its components. However, whether baseline and changes in SUA predict incidence of MetS and its components remains unclear.

METHODS

The subjects comprised 407 women aged 71 ± 8 years from a rural village. We have identified participants who underwent a similar examination 11 years ago, and examined the relationship between baseline and changes in SUA, and MetS based on the modified criteria of the National Cholesterol Education Program's Adult Treatment Panel (NCEP-ATP) III report.

RESULTS

Of these subjects, 83 (20.4%) women at baseline and 190 (46.7%) women at follow-up had MetS. Multiple linear regression analysis was performed to evaluate the contribution of each confounding factor for MetS; both baseline and changes in SUA as well as history of cardiovascular disease, low-density lipoprotein cholesterol, and estimated glomerular filtration ratio (eGFR) were independently and significantly associated with the number of MetS components during an 11-year follow-up. The adjusted odds ratios (ORs) (95% confidence interval) for incident MetS across tertiles of baseline SUA and changes in SUA were 1.00, 1.47 (0.82-2.65), and 3.11 (1.66-5.83), and 1.00, 1.88 (1.03-3.40), and 2.49 (1.38-4.47), respectively. In addition, the combined effect between increased baseline and changes in SUA was also a significant and independent determinant for the accumulation of MetS components (F = 20.29, p < 0.001). The ORs for incident MetS were significant only in subjects with age ≥ 55 years, decline in eGFR, and no baseline MetS.

CONCLUSIONS

These results suggested that combined assessment of baseline and changes in SUA levels provides increased information for incident MetS, independent of other confounding factors in community-dwelling women.

Gout and the risk of age-related macular degeneration in the elderly

Objective

To assess whether gout is associated with incident age-related macular degeneration (AMD)

Methods

We used the 5% Medicare claims data from 2006–12 for all beneficiaries who were enrolled in Medicare fee-for-service (Parts A, B) and not enrolled in a Medicare Advantage Plan, and resided in the U.S. People were censored at the occurrence of new diagnosis of AMD, death or the end of study (12/31/2012), whichever occurred first. We used multivariable-adjusted Cox regression analyses to assess the association of gout with incident AMD, adjusted for demographics, comorbidity, and use of medications for cardiovascular disease and gout. Hazard ratios and 95% confidence intervals were calculated.

Results

In this observational cohort study, of the 1,684,314 eligible people, 116,097 developed incident AMD (6.9%). Incidence rates of AMD per 1,000 person-years were 20.1 for people with gout and 11.7 for people without gout. In multivariable-adjusted analyses, a diagnosis of gout was significantly associated with a higher risk of incident AMD with a hazard ratio of 1.39 (95% CI, 1.35, 1.43). This association was confirmed in sensitivity analyses that substituted Charlson-Romano comorbidity index continuous score with either a categorical Charlson-Romano comorbidity index score or individual Charlson-Romano index comorbidities plus hypertension, hyperlipidemia and coronary artery disease. Other covariates significantly associated with higher hazards of incident AMD were older age, female gender, White race/ethnicity, and higher Charlson-Romano comorbidity index score.

Conclusions

We noted a novel association of gout with AMD in the elderly. Future studies should investigate the pathways that mediate this association.

Ubidecarenone-Loaded Nanostructured Lipid Carrier (UB-NLC): Percutaneous Penetration and Protective Effects Against Hydrogen Peroxide-Induced Oxidative Stress on HaCaT Cells

The objective of the investigation was to evaluate the percutaneous penetration of a ubidecarenone-loaded nanostructured lipid carrier (UB-NLC) and to illuminate the protective effects of UB-NLC for amelioration of hydrogen peroxide-induced oxidative damage on HaCaT cells. Ubidecarenone (UB) was encapsulated in a nanostructured lipid carrier (NLC), which was manufactured by homogenization. The morphological and dimensional properties of the prepared UB-NLC were studied by freeze-fracture transmission electron microscopy (FF-TEM) and photon correlation spectroscopy (PCS). Percutaneous penetration of UB-NLC was carried out by the Franz diffusion cells method. The change of cellular morphology was identified through a non-invasive time-lapse imaging system. The assessment was achieved via the evaluation of the levels of oxidative stress markers: reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and malondialdehyde (MDA). Percutaneous penetration of UB loaded in NLC formulation was enhanced in comparison to free UB. Preincubation of HaCaT cells with UB-NLC attenuated the level of intracellular generation of ROS. Lipid peroxidation was diminished by UB-NLC via inhibition of MDA formation. Pretreatment of cells with UB-NLC reestablished the activity of cellular antioxidant enzymes (SOD and GSH-PX). On the basis of the investigation conducted, results suggest that formulating UB as NLC is advantageous for topical delivery and treatment of oxidative stress-induced human diseases.

What is the role of angiotensin receptor blockers in treatment of hyperuricemia coexisting with arterial hypertension?

Angiotensin receptor blockers or sartans are used to treat arterial hypertension. Hyperuricemia and arterial hypertension often coexist in patients with metabolic syndrome. Also hyperuricemia is correlated with an increased risk of cardiovascular disease and death. There are data suggesting that lowering serum urate may assist in control of arterial hypertension and use of certain drugs for arterial hypertension may reduce the serum uric acid level. The Polish Society of Arterial Hypertension recommends losartan for treatment of arterial hypertension in patients with coexisting hyperuricemia. The aim of the present review was to find evidence supporting the concept of use and explain the role of sartans in treatment of hyperuricemia. Thirty-five original and review articles about hyperuricemia and arterial hypertension focusing on the use of sartans in both these medical conditions were analyzed. In conclusion, sartans should be recommended for treatment of hyperuricemia coexisting with arterial hypertension in patients without bilateral renal artery stenosis and with exclusion of pregnant women.

Interaction between gender and uric acid on hemoglobin A1c in community-dwelling persons

INTRODUCTION

Higher glycated hemoglobin (Hb) (HbA1c) is significantly associated with an increased risk of cardiovascular disease (CVD). Serum uric acid (SUA) levels are associated with glucose intolerance and type 2 diabetes. Whether gender-specific differences regarding the relationship between SUA levels and HbA1c exist is unknown.

AIM

We recruited 1636 (men, 696 aged of 70 ± 10 years; women, 940 aged of 70 ± 9 years) participants and enrolled in the study during their annual health examination from a single community. We investigated the association between SUA levels and HbA1c within each gender.

RESULTS

Multiple linear regression analysis showed that in men, SUA (β = -0.091, p = 0.014) with prevalence of antidiabetic medication (β = 0.428, p < 0.001) and eGFR (β = 0.112, p = 0.016) were significantly and negatively associated with HbA1c, and in women, SUA (β = 0.101, p = 0.002) with prevalence of antidiabetic medication (β = 0.458, p < 0.001) were significantly and positively associated with HbA1c. Moreover, the interaction between gender and SUA (β = 0.445, p < 0.001) as well as gender (β = -0.465, p < 0.001), prevalence of antidiabetic medication (β = 0.444, p < 0.001), eGFR_CKDEPI (β = 0.074, p = 0.014), and SUA (β = -0.356, p < 0.001) was a significant and independent determinant of HbA1c. A significant interactive effect of gender and SUA on determinants of HbA1c was noted in patients not on antidiabetic medications, regardless of age, HbA1c, and renal function.

CONCLUSIONS

The interaction between gender and SUA was associated with HbA1c independent of other metabolic factors in community-dwelling persons.

Uric acid and blood pressure: exploring the role of uric acid production in The Maastricht Study

OBJECTIVE

Accumulation of reactive oxygen species by increased uric acid production has been suggested as a possible underlying mechanism for the association between uric acid and high blood pressure (BP). We, therefore, investigated the association between serum uric acid concentration and 24-h urinary uric acid excretion, as proxy for uric acid production, with ambulatory 24-h blood pressure and hypertension.

METHODS

Cross-sectional analyses were conducted among 2555 individuals [52% men, mean age 60.0 ± 8.2 years; 27% type 2 diabetes (by design)] from The Maastricht Study. Multivariable regression analyses were performed to investigate the association of serum uric acid and 24-h urinary uric acid excretion with 24-h pulse pressure, 24-h mean arterial pressure (MAP), and hypertension.

RESULTS

After adjustment for traditional hypertension risk factors, serum uric acid concentration (per SD of 81 μmol/l) was associated with higher 24-h MAP [β 0.63 mmHg; confidence interval (CI) 0.27-1.00] and positively associated with hypertension (odds ratio 1.43; CI 1.27-1.61). Urinary uric acid excretion (per SD of 140 mg/day/1.73 m) was associated with higher 24-h MAP (β 0.79 mmHg; CI 0.46-1.12) and with hypertension (odds ratio 1.13; CI 1.02-1.25). There was no significant association between serum and 24-h urinary uric acid excretion with 24-h pulse pressure. There was no interaction with sex or age for the aforementioned associations.

CONCLUSION

Higher serum and urinary uric acid concentrations were associated with higher 24-h MAP and hypertension. These results suggest that serum and 24-urinary uric acid concentrations, the latter as proxy for uric acid production are, independent of each other, associated with BP and hypertension.