Clinical implications of longitudinally assessed uric acid in heart failure

BACKGROUND AND AIMS

Numerous studies have evaluated the association between baseline uric acid (UA) and heart failure (HF) outcomes. The impact of longitudinal UA on HF survival remains unknown. We aim to investigate the association between different parameterizations of longitudinal UA measurements and survival outcomes in HF patients.

METHODS AND RESULTS

We retrospectively included patients hospitalized for HF with multiple repeated UA measurements. Joint models were fitted to assess the longitudinal association between UA and outcomes of all-cause and cardiovascular (CV) death. The study included 1596 patients (mean age 54 years, 26.9 % women) with 7875 UA measurements. During a median follow-up of 34.7 months, 330 all-cause deaths occurred, among them 280 of CV causes. After adjusting for clinically relevant covariates, every doubling of UA at any time led to a 5.14-fold increase of all-cause death risk (95 % confidence interval [CI] 3.79-8.29) and a 4.56-fold increase of CV death risk (95 % CI 2.96-8.29) for men; for women, the corresponding hazard ratios were 4.47 for all-cause death (95 % CI 3.02-7.40) and 4.93 for CV death (95 % CI 2.78-8.58). The increase in slope and area under the UA trajectory were additionally associated with a higher risk of all-cause and CV death in both genders. All the associations remained consistent after adjusting for repeatedly measured renal function and across the ejection fraction phenotypes.

CONCLUSION

The longitudinally measured UA and its derived parameterizations are strong prognostic factors in hospitalized HF patients, independent of clinically relevant confounders and repeatedly assessed renal function.

Non-traditional risk factors for atrial fibrillation: epidemiology, mechanisms, and strategies

Atrial fibrillation (AF) has become the pre-dominant arrhythmia worldwide and is associated with high morbidity and mortality. Its pathogenesis is intricately linked to the deleterious impact of cardiovascular risk factors, emphasizing the pivotal imperative for early detection and mitigation strategies targeting these factors for the prevention of primary AF. While traditional risk factors are well recognized, an increasing number of novel risk factors have been identified in recent decades. This review explores the emerging non-traditional risk factors for the primary prevention of AF, including unhealthy lifestyle factors in current society (sleep, night shift work, and diet), biomarkers (gut microbiota, hyperuricaemia, and homocysteine), adverse conditions or diseases (depression, epilepsy, clonal haematopoiesis of indeterminate potential, infections, and asthma), and environmental factors (acoustic pollution and other environmental factors). Unlike traditional risk factors, individuals have limited control over many of these non-traditional risk factors, posing challenges to conventional prevention strategies. The purpose of this review is to outline the current evidence on the associations of non-traditional risk factors with new-onset AF and the potential mechanisms related to these risk factors. Furthermore, this review aims to explore potential interventions targeting these risk factors at both the individual and societal levels to mitigate the growing burden of AF, suggesting guideline updates for primary AF prevention.

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.

Incidence, progression, and outcomes of heart failure with improved ejection fraction: The added value of longitudinally assessed ejection fraction

BACKGROUND

The revised universal definition of heart failure (HF) established a standardized definition for HF with improved ejection fraction (HFimpEF) and emphasized the importance of longitudinally assessing left ventricular EF (LVEF). We aim to investigate the incidence, disease progression, and clinical outcomes of HFimpEF in a longitudinal cohort of hospitalized HF patients.

METHODS

We retrospectively included HF patients with baseline LVEF ≤40 % and satisfactory echocardiographic follow-ups. HFimpEF was defined as a ≥ 10-point increase in LVEF to >40 %. Transient HFimpEF was defined as a recurrent LVEF ≤40 % after achieving HFimpEF. Clinical outcomes were all-cause death, cardiovascular death, and HF rehospitalization.

RESULTS

During a median follow-up of 47.9 months, 517 of 923 patients met HFimpEF criteria; 65.0 % HFimpEF cases occurred within 12 months. HFimpEF patients had lower risks of all-cause death (hazard ratio [HR] = 0.16, P < 0.001), cardiovascular death (HR = 0.19, P < 0.001), and HF rehospitalization (HR = 0.39, P < 0.001). However, 160 HFimpEF patients experienced LVEF worsening during follow-up; their risks for adverse events were higher (HR = 1.89 for all-cause death, HR = 2.13 for cardiovascular death, HR = 2.13 for HF rehospitalization, P < 0.05 for all) compared to persistent HFimpEF patients, and their capability of LVEF re-improvement was diminished. An inverted U-shaped LVEF profile for HFimpEF-characterized by a slow, modest increase followed by a decline-portended a higher mortality risk.

CONCLUSIONS

HFimpEF was observed in 56.0 % of HF patients. Longitudinally assessing LVEF helps identify HFimpEF patients and facilitates disease progression monitoring and risk stratification.

High Uric Acid Orchestrates Ferroptosis to Promote Cardiomyopathy Via ROS-GPX4 Signaling

Aims: High uric acid (HUA), as a pro-oxidant, plays a significant role in the pathophysiology of cardiovascular disease. Studies have indicated that elevated uric acid levels can adversely affect cardiovascular health. Nevertheless, the impact of hyperuricemia on cardiomyopathy remains uncertain. Further research is needed to elucidate the relationship between HUA and cardiomyopathy, shedding light on its potential implications for heart health. Results: We demonstrated that uricase knockout (Uox-KO) mice accelerated the development of cardiomyopathy, causing significantly impaired cardiac function and myocardial fibrosis. Meanwhile, the mitochondrial morphology was destroyed, the lipid peroxidation products increased in number and the antioxidant function was weakened. In addition, we evaluated the effects of ferrostatin-1 (Fer-1), the ferroptosis inhibitor. Myocardial damage can be reversed by the Fer-1 treatment caused by HUA combined with doxorubicin (DOX) treatment. Benzbromarone, a uric acid-lowering drug, decreases myocardial fibrosis, and ferroptosis by alleviating hyperuricemia in Uox-KO mice by DOX administration. In vitro, we observed that the activity of cardiomyocytes treated with HUA combined with DOX decreased significantly, and lipid reactive oxygen species (ROS) increased significantly. Afterward, we demonstrated that HUA can promote oxidative stress in DOX, characterized by increased mitochondrial ROS, and downregulate protein levels of glutathione peroxidase 4 (GPX4). N-acetyl-l-cysteine, an antioxidant, inhibits the process by which HUA promotes DOX-induced ferroptosis by increasing the GPX4 expression. Innovation: We verified that HUA can exacerbate myocardial damage. This has clinical implications for the treatment of cardiac damage in patients with hyperuricemia. Conclusions: Our data suggested that HUA promotes the cardiomyopathy. HUA promotes DOX-induced ferroptosis by increasing oxidative stress and downregulating GPX4. Antioxid. Redox Signal. 41, 1134-1149.

Relationship between serum uric acid and sarcopenia in geriatric heart failure patients with preserved ejection fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) presents a serious risk to human health. The increased prevalence of sarcopenia in the HFpEF population has a negative impact on patient prognosis. Uric acid (UA) is the byproduct of purine metabolism and is harmful to the cardiovascular system. This study aims to establish the potential relationship between sarcopenia and serum UA in HFpEF patients.

METHODS

Data were obtained from 180 individuals (aged ≥60 years) with HFpEF admitted to the Geriatric Department of Jiangsu Province Hospital between January 2021 and December 2022. The UA values were grouped into 4 quartiles (Q1-Q4). Logistic generalized linear models and restricted cubic spline (RCS) regression were used to analyze the relationship between sarcopenia and UA. Subgroups based on gender were utilised for further analysis.

RESULTS

After adjusting for covariates, odds ratios (ORs) and 95 % confidence intervals (CIs) for sarcopenia prevalence in the 2nd, 3rd, and 4th quartiles were 2.56 (0.57-12.65), 4.94 (1.10-24.49), and 6.95 (1.30-44.25), respectively, unlike the 1st quartile (P for trend = 0.022). The RCS plot demonstrated a positive linear relationship between serum UA levels and sarcopenia (P for non-linearity = 0.190). A sex-based subgroup analysis revealed a statistically significant relationship between UA and sarcopenia in males (P < 0.05).

CONCLUSIONS

In summary, the prevalence of sarcopenia is positively related to serum UA levels among the elderly diagnosed with HFpEF. Due to the cross-sectional nature of the study design, additional investigations are necessary to validate our findings and identify the optimal range for UA reduction.

J-shaped association of serum uric acid concentrations with all-cause mortality in individuals with osteoarthritis: A prospective cohort study

OBJECTIVE

The purpose of this study was to explore the relationship between serum uric acid (SUA) concentrations and all-cause mortality in individuals with osteoarthritis (OA).

METHODS

All participant data were retrieved from the National Health and Nutrition Examination Survey database. A total of 4671 participants (age range: 20 to 85 years old), including 2988 females and 1683 males, were included in this study. The determination of death outcome was based on the National Death Index (up to December 31, 2019). We explored the nonlinear relationship between SUA concentrations and all-cause mortality in OA patients by establishing a Cox proportional risk model and a two-segment Cox proportional risk model and ran an interaction test to identify the high-risk population for all-cause mortality.

RESULTS

During 30,645 person-years of follow-up, the number of all-cause deaths for females and males was 736 and 516, respectively. After multivariate adjustment, we found a nonlinear relationship between SUA concentrations and all-cause mortality in both females and males with OA. In addition, we found a J-shaped relationship between SUA concentrations and all-cause mortality. The SUA concentration thresholds for all-cause mortality of females and males were stable at 5.6mg/dl and 6.2mg/dl, respectively. Compared with SUA concentrations below the inflection point, the all-cause mortality risk at higher SUA concentrations in females and males with OA increased by 20% (hazard ratio [HR]: 1.2, 95% confidence interval [CI]: 1.1 to 1.2) and 25% (HR: 1.2, 95% CI: 1.12 to 1.39), respectively.

CONCLUSIONS

There is a nonlinear relationship between SUA concentrations and all-cause mortality in the American OA population (J-shaped association). The all-cause mortality thresholds for SUA concentrations in females and males are 5.6mg/dl and 6.2mg/dl, respectively.

Uric Acid Levels, Number of Standard Modifiable Cardiovascular Risk Factors, and Prognosis in Patients With Coronary Artery Disease: A Large Cohort Study in Asia

Background Serum uric acid (UA) is correlated closely with traditional cardiovascular risk factors, which might interfere with the action of UA, in patients with coronary artery disease. We performed this study to evaluate the prognostic effect of UA levels in individuals with different numbers of standard modifiable cardiovascular risk factors (SMuRFs). Methods and Results In this prospective study, we consecutively enrolled 10 486 patients with coronary artery disease. They were stratified into 3 groups according to the tertiles of UA concentrations and, within each UA tertile, further classified into 3 groups by the number of SMuRFs (0-1 versus 2-3 versus 4). The primary end point was major adverse cardiovascular and cerebrovascular events (MACCEs), including death, myocardial infarction, stroke, and unplanned revascularization. Over a median follow-up of 2.4 years, 1233 (11.8%) MACCEs were recorded. Patients with high UA levels developed significantly higher risk of MACCEs than those with low UA levels. In addition, UA levels were positively associated with MACCEs as a continuous variable. More importantly, in patients with 0 to 1 SMuRF, the risks of MACCEs were significantly higher in the high-UA-level group (adjusted hazard ratio [HR], 1.469 [95% CI, 1.197-1.804]) and medium-UA-level group (adjusted HR, 1.478 [95% CI, 1.012-2.160]), compared with the low-UA-level group, whereas no significant association was found between UA levels and the risk of MACCEs in participants with 2 to 3 or 4 SMuRFs. Conclusions In patients with coronary artery disease who received evidence-based secondary prevention therapies, elevated UA levels might affect the prognosis of individuals with 0 to 1 SMuRF but not that of individuals with ≥2 SMuRFs.

Hyperuricaemia Does Not Interfere with Aortopathy in a Murine Model of Marfan Syndrome

Redox stress is involved in the aortic aneurysm pathogenesis in Marfan syndrome (MFS). We recently reported that allopurinol, a xanthine oxidoreductase inhibitor, blocked aortopathy in a MFS mouse model acting as an antioxidant without altering uric acid (UA) plasma levels. Hyperuricaemia is ambiguously associated with cardiovascular injuries as UA, having antioxidant or pro-oxidant properties depending on the concentration and accumulation site. We aimed to evaluate whether hyperuricaemia causes harm or relief in MFS aortopathy pathogenesis. Two-month-old male wild-type (WT) and MFS mice (Fbn1^C1041G/+) were injected intraperitoneally for several weeks with potassium oxonate (PO), an inhibitor of uricase (an enzyme that catabolises UA to allantoin). Plasma UA and allantoin levels were measured via several techniques, aortic root diameter and cardiac parameters by ultrasonography, aortic wall structure by histopathology, and pNRF2 and 3-NT levels by immunofluorescence. PO induced a significant increase in UA in blood plasma both in WT and MFS mice, reaching a peak at three and four months of age but decaying at six months. Hyperuricaemic MFS mice showed no change in the characteristic aortic aneurysm progression or aortic wall disarray evidenced by large elastic laminae ruptures. There were no changes in cardiac parameters or the redox stress-induced nuclear translocation of pNRF2 in the aortic tunica media. Altogether, the results suggest that hyperuricaemia interferes neither with aortopathy nor cardiopathy in MFS mice.

Correlation Analysis and Diagnostic Value of Serum Homocysteine, Cystatin C and Uric Acid Levels with the Severity of Coronary Artery Stenosis in Patients with Coronary Heart Disease

Background

Coronary angiography (CAG) is an invasive examination with high risks and costs and various complications may occur. It is necessary to find a diagnostic method, non-invasiveness, inexpensive with low risk. This study aims to analyze the correlation between the levels of serum homocysteine (Hcy), cystatin C (Cys C) and uric acid (UA) and Gensini score in patients with coronary heart disease (CHD) and assess their diagnostic value for CHD.

Methods

A retrospective analysis was conducted on 1412 patients underwent CAG from October 2019 to December 2021, and we conducted this study from January to July 2022. A total of 765 patients with CHD confirmed by CAG were selected as the research group, while 647 patients revealed as non-obstructive stenosis by CAG as the control group. The serum Hcy, Cys C and UA levels were detected and the correlation between Gensini score and variables was analyzed. The receiver-operating characteristic (ROC) curve was performed to assess the diagnostic value of the Hcy, Cys C and UA for CHD.

Results

The serum Hcy, Cys C and UA levels in the research group were higher as compared with the control group (p<0.05). Spearman correlation and multivariate linear regression analysis showed that there was a significantly positive correlation between Gensini score and serum Hcy, Cys C and UA levels (p<0.05). The ROC curve analysis presented the combined Hcy and Cys C with UA having the highest specificity of diagnostic value for CHD (area under the curve (AUC)=0.768, 95% CI 0.706-0.823, specificity = 72.34%, sensitivity = 67.88%, Youden Index = 0.4022).

Conclusion

The serum Hcy, Cys C and UA levels in patients with CHD were significantly increased, positive correlation with Gensini score. The combined Hcy and Cys C with UA could be used to assess the severity of coronary artery stenosis and provide predictive and early intervention treatment values for CHD and a new way of diagnosing CHD, which is cheap, safe, effective and deserving of clinical application.

The association between serum uric acid and creatine phosphokinase in the general population: NHANES 2015-2018

BACKGROUND

The association between serum creatine phosphokinase (CPK), a standard biochemical measure of acute myocardial infarction, and serum uric acid (sUA) has not been studied. This study aimed to determine the association between sUA and CPK in the general population of the US.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) 2015-2018 were used, including a total of 8,431 subjects aged ≥ 30 years. Weighted multiple regression analysis was used to estimate the independent relationship between sUA and CPK. Fitted smoothing curves and weighted generalized additive models were also performed.

RESULTS

We found a positive relationship between sUA and CPK after adjusting for potential confounders. In subgroup analyses stratified by sex and race/ethnicity, sUA was positively correlated with CPK in each subgroup. The association between sUA and CPK followed an inverted U-shaped curve in females (turning point: sUA = 428.3 μmol/L).

CONCLUSIONS

Our study suggested that sUA level was positively correlated with CPK in the general population of the US. However, CPK increased with sUA until the turning point (sUA = 428.3 μmol/L) in females. Fundamental research and large sample prospective studies are needed to determine the exact mechanism of the association between sUA and CPK.

Atrial Fibrillation Risk and Urate-Lowering Therapy in Patients with Gout: A Cohort Study Using a Clinical Database

Individuals of Asian descent are at higher risk for developing hyperuricemia and gout as compared to Western populations. Urate-lowering therapy (ULT) is an effective treatment for hyperuricemia and gout. It was reported that febuxostat, one of the ULTs, raises the risk of atrial fibrillation (AF) in elderly populations. Nevertheless, this association has not been properly investigated in Asian populations. We aimed to investigate the development of AF after ULT with different drugs in an Asian population. We conducted a retrospective cohort study using the clinical database at Kaohsiung Veterans General Hospital. Patients newly diagnosed with gout between 1 January 2013 and 31 December 2020 and with a documented baseline serum uric acid (sUA) level but no prior diagnosis of AF were identified. Patients were divided into three groups-allopurinol, benzbromarone, and febuxostat users. During the follow-up period, the risks of incident AF following the initiation of ULT with different drugs were assessed. Development of incident AF was noted in 43 (6%) of the 713 eligible patients during the follow-up period (mean, 49.4 ± 26.6 months). Febuxostat-treated patients had a higher prevalence of certain comorbidities (diabetes mellitus, heart failure, and chronic kidney disease) and higher CHA2DS2-VASc scores. Compared with allopurinol, neither febuxostat nor benzbromarone was associated with increased adjusted hazard ratios (HR) for incident AF (HR: 1.20, 95% confidence interval [CI]: 0.43-3.34; HR: 0.68, 95% CI: 0.22-2.08). There was no difference in the risk of incident AF among Asian patients with gout who received febuxostat, allopurinol, or benzbromarone. Further studies are needed to evaluate long-term cardiovascular outcomes in patients receiving different ULT drugs.

Serum urate and heart failure: a bidirectional Mendelian randomization study

AIMS

Observational studies indicate that serum urate level is associated with heart failure (HF). However, whether this association is causal remains controversial, due to confounding factors and reverse causality. We aim to evaluate the causal relationship of genetically predicted serum urate level with HF.

METHODS AND RESULTS

A bidirectional Mendelian randomization (MR) study was performed. Instrumental variables were obtained from the largest genome-wide association studies of serum urate (457 690 individuals) to date. We obtained summary statistics of HF from HERMES consortium (47 309 cases; 930 014 controls), the FinnGen study (13 087 cases; 195 091 controls), and the UK Biobank study (1088 cases; 360 106 controls). Inverse-variance-weighted method was applied to obtain MR estimates and other statistical methods were conducted in the sensitivity analyses. The reverse MR analysis was performed to evaluate the effect of HF on serum urate levels. Genetically determined serum urate level was associated with HF [odds ratio (OR), 1.07; 95% confidence interval (CI), 1.03-1.10; P = 8.6×10-5]. The main results kept robust in the most sensitivity analyses. The association pattern remained for the HF in FinnGen (OR, 1.10; 95% CI, 1.03-1.19; P = 0.008) and the combined results of three data sources (OR, 1.08; 95% CI, 1.04-1.13; P < 0.001). No consistent evidence was found for the causal effect of HF on serum urate levels.

CONCLUSION

We provide consistent evidence for the causal effect of genetically predicted serum urate level on HF, but not the reverse effect of HF. Urate-lowering therapy may be of cardiovascular benefit in the prevention of HF.

Temporal changes in serum uric acid and risk for metabolic syndrome: a longitudinal cohort study

BACKGROUND

Studies suggested elevated serum uric acid (SUA) levels are associated with metabolic syndrome (MetS). However, it remains unclear whether baseline SUA and temporal changes predict MetS. The study aimed to investigate the association of baseline SUA and its temporal longitudinal changes with subsequent risk of MetS.

METHODS

We conducted a retrospective longitudinal cohort study among 44,176 healthy participants aged 18 years and older without MetS at enrollment. The baseline levels and longitudinal changes of SUA were categorized by gender-specific quintiles. Participants were followed to identify newly developed MetS. We employed Cox model to investigate the relationship between SUA and MetS in men and women separately.

RESULTS

During a median follow-up of 2.4 years, 5461 (12.36%) participants developed MetS. After adjustment of demographic, major clinical factors, a higher level of baseline SUA was associated with a significant higher risk of MetS. The corresponding HRs (95% CIs) comparing participants at extreme quintiles were 2.59 (2.32, 2.88) in men and 2.87 (2.41, 3.43) in women. Larger longitudinal absolute increase in SUA was also related to an increases risk of MetS (top vs bottom quintile, 1.70 [1.53, 1.89] in men and 1.94 [1.65, 2.28] in women), regardless the level of baseline SUA. Similarly, the HRs about SUA longitudinal percentage changes were 1.74 (1.56, 1.94) in men and 2.01 (1.69, 2.39) in women, respectively. Moreover, we observed the highest risk of MetS among participants with both higher baseline SUA and larger longitudinal increase in SUA.

CONCLUSION

Higher baseline SUA and larger temporal increase in SUA independently predicted risk of MetS, highlighting the importance of longitudinal SUA monitoring and management for primary prevention of MetS in the general population.

Sex-specific effect of serum urate levels on coronary heart disease and myocardial infarction prevention: A Mendelian randomization study

BACKGROUND AND AIMS

Observational studies have examined serum urate levels in relation to coronary heart disease (CHD) and myocardial infarction (MI). Whether these associations are causal remains controversial, due to confounding factors and reverse causality. We aim to investigate the causality of these associations using Mendelian randomization method.

METHODS AND RESULTS

Instrumental variables were obtained from the largest genome-wide association studies of serum urate (457,690 individuals) to date. Summary statistics were from CARDIoGRAMplusC4D consortium (60,801 CHD cases; 43,676 MI cases), FinnGen (21,012 CHD cases; 12,801 MI cases), UK Biobank (10,157 CHD cases; 7018 MI cases), and Biobank Japan (29,319 CHD cases). Inverse-variance weighted method was applied as the main results. Other statistical methods and reverse MR analysis were conducted in the supplementary analyses. Elevated genetically determined serum urate levels were associated with increased risks of CHD and MI. The association pattern remained for the datasets in FinnGen, the combined results of three independent data sources (CHD: odds ratio (OR), 1.10; 95%CI, 1.06-1.15; p = 4.2 × 10^-6; MI: OR, 1.12; 95%CI, 1.07-1.18; p = 2.7 × 10^-6), and East Asian population. Interestingly, sex-specific subgroup analyses revealed that these associations kept in men only, but not among women in individuals of European ancestry. No consistent evidence was found for the causal effect of CHD or MI on serum urate levels.

CONCLUSION

We provide consistent evidence for the causal effect of genetically predicted serum urate levels on CHD and MI, but not the reverse effect. Urate-lowering therapy may be of cardiovascular benefit in the prevention of CHD and MI, especially for men.

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.

The U-Shaped Association Between Serum Uric Acid and Red Blood Cell Distribution Width in Acute Ischemic Stroke

Objective: The U-shaped association between serum uric acid (SUA) and the functional outcome has been found in acute ischemic stroke (AIS). However, it is unclear if SUA is associated with red blood cell morphology in AIS. This study aimed to determine the relationship between SUA and red blood cell distribution width (RDW) in patients with AIS. Methods: A cross-sectional study including 438 consecutive patients with AIS was conducted. SUA and RDW, biochemical parameters that reflect the heterogeneity of red blood cell volume, were evaluated on admission. We evaluated the association between SUA and RDW through linear curve fitting analyses and two-piecewise regression analyses. Results: The association between SUA levels and RDW followed a U-shape in all patients. In females, the values of RDW significantly decreased with the increment of SUA (per mg/dl: β, -1.45; 95% CI: -2.15 to -0.75; p < 0.001) in patients with SUA <3.86 mg/dl and increased with the increment of SUA (per mg/dl: β, 0.60; 95% CI: 0.22-0.97; p = 0.002) in patients with SUA ≥ 3.86 mg/dl. Similar results were observed in males with the turning point of SUA = 4.82 mg/dl. After adjusting for potential confounders, a U-shaped association between SUA and RDW was maintained in females, but no statistical significance was maintained in patients with SUA ≥ 4.82 mg/dl in males (p = 0.206). Conclusion: In the sample of patients with AIS, we found a U-shaped relationship between SUA levels and RDW, with the turning point of SUA (3.96 mg/dl in females and 4.82 mg/dl in males) by the threshold effect analysis.

Designing a Strategy Trial for the Management of Gout: The Use of a Modified Delphi Panel

OBJECTIVE

Disagreement exists between rheumatology and primary care societies regarding gout management. This paper describes a formal process for gathering input from stakeholders in the planning of a trial to compare gout management strategies.

METHODS

We recruited patients, nurses, physician assistants, primary care clinicians, and rheumatologists to participate in a modified Delphi panel (mDP) to provide input on design of a trial focused on optimal management for primary care patients with gout. The 16 panelists received a plain-language briefing document that discussed the rationale for the trial, key clinical issues in gout, and aspects of trial design. The panelists also received information and considerations on nine voting questions (VQs), judged to be the key design questions. Cognitive interviews with panelists ensured that the VQs were understood by the range of panelists involved in the mDP. Panelists were asked to score all VQs from 1 (definitely no) to 9 (definitely yes). Two voting rounds were conducted-round 1 by email and round 2 by video conference.

RESULTS

The VQs were modified through the cognitive interviews. The round 1 voting resulted in consensus on eight items, with consensus defined as median voting score in the same tercile (1-3, 4-6 or 7-9). Re-voting at the meeting (round 2) reached consensus on the remaining item.

CONCLUSION

An mDP with various stakeholders facilitated consensus on the design of a trial of different management strategies for chronic gout. This method may be useful for designing trials of clinical questions with substantial disagreement across stakeholders.

Uric acid aggravates myocardial ischemia-reperfusion injury via ROS/NLRP3 pyroptosis pathway

BACKGROUND

The NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome activation-mediated pyroptosis pathway has been linked to myocardial ischemia-reperfusion (MI/R) injury. This study explored whether uric acid (UA) aggravates MI/R injury through NLRP3 inflammasome-mediated pyroptosis.

METHODS

In vivo, a mouse MI/R model was established by ligating the left coronary artery, and a mouse hyperuricemia model was created by intraperitoneal injection of potassium oxonate (PO). Then, the myocardial infarction (MI) size; terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) immunofluorescence; and serum levels of lactate dehydrogenase (LDH), creatine kinase isoenzyme (CK-MB), and UA, as well as the expression level of pyroptosis-related protein and caspase-3 in heart tissues, were measured. Separately, primary mouse cardiomyocytes were cultured in vitro to create a hypoxia/reoxygenation (H/R) model. We then compared cardiomyocytes viability, TUNEL immunofluorescence, and the levels of LDH, reactive oxygen species (ROS), and pyroptosis-related protein and caspase-3 in cardiomyocytes.

RESULTS

In vivo, the MI area, levels of CK-MB and LDH, rate of cell death, and pyroptosis-related protein and the expression of caspase-3 were significantly higher in the MI/R group than in the sham group, and high UA levels worsened these changes. In vitro, cardiomyocytes viability was significantly downregulated, and the levels of ROS, LDH, pyroptosis-related protein, caspase-3, and the rate of cardiomyocyte death were significantly higher in the H/R + UA group compared with the HR group. Administration of an NLRP3 inflammasome inhibitor and ROS scavenger reversed these effects.

CONCLUSION

UA aggravates MI/R-induced activation of the NLRP3 inflammatory cascade and pyroptosis by promoting ROS generation, while inflammasome inhibitors and ROS scavengers partly reverse the injury.

Xanthine oxidase inhibition attenuates doxorubicin-induced cardiotoxicity in mice

Accumulating evidence suggests that high serum uric acid (UA) is associated with left ventricular (LV) dysfunction. Although xanthine oxidase (XO) activation is a critical regulatory mechanism of the terminal step in ATP and purine degradation, the pathophysiological role of cardiac tissue XO in LV dysfunction remains unclear. We herein investigated the role and functional significance of tissue XO activity in doxorubicin-induced cardiotoxicity. Either doxorubicin (10 mg/kg) or vehicle was intraperitonially administered in a single injection to mice. Mice were treated with or without oral XO-inhibitors (febuxostat 3 mg/kg/day or topiroxostat 5 mg/kg/day) for 8 days starting 24 h before doxorubicin injection. Cardiac tissue XO activity measured by a highly sensitive assay with liquid chromatography/mass spectrometry and cardiac UA content were significantly increased in doxorubicin-treated mice at day 7 and dramatically reduced by XO-inhibitors. Accordingly, XO-inhibitors substantially improved LV ejection fraction (assessed by echocardiography) and LV developed pressure (assessed by ex vivo Langendorff heart perfusion) impaired by doxorubicin administration. This was associated with an increase in XO-derived hydrogen peroxide production with concomitant upregulation of apoptotic and ferroptotic pathways, all of which were reduced by XO-inhibitors. Furthermore, metabolome analyses revealed enhanced purine metabolism in doxorubicin-treated hearts, and XO-inhibitors suppressed the serial metabolic reaction of hypoxanthine-xanthine-UA, the paths of ATP and purine degradation. In summary, doxorubicin administration induces cardiac tissue XO activation associated with impaired LV function. XO-inhibitors attenuate doxorubicin-induced cardiotoxicity through inhibition of XO-derived oxidative stress and cell death signals as well as the maintenance of cardiac energy metabolism associated with modulation of the purine metabolic pathway.

Metformin alleviates hyperuricaemia-induced serum FFA elevation and insulin resistance by inhibiting adipocyte hypertrophy and reversing suppressed white adipose tissue beiging

Hyperuricaemia (HUA) significantly increases the risk of metabolic syndrome and is strongly associated with the increased prevalence of high serum free fatty acids (FFAs) and insulin resistance. However, the underlying mechanisms are not well established, especially the effect of uric acid (UA) on adipose tissue, a vital organ in regulating whole-body energy and FFA homeostasis. In the present study, we noticed that adipocytes from the white adipose tissue of patients with HUA were hypertrophied and had decreased UCP1 expression. To test the effects of UA on adipose tissue, we built both in vitro and in vivo HUA models and elucidated that a high level of UA could induce hypertrophy of adipocytes, inhibit their hyperplasia and reduce their beige-like characteristics. According to mRNA-sequencing analysis, UA significantly decreased the expression of leptin in adipocytes, which was closely related to fatty acid metabolism and the AMPK signalling pathway, as indicated by KEGG pathway analysis. Moreover, lowering UA using benzbromarone (a uricosuric agent) or metformin-induced activation of AMPK expression significantly attenuated UA-induced FFA metabolism impairment and adipose beiging suppression, which subsequently alleviated serum FFA elevation and insulin resistance in HUA mice. Taken together, these observations confirm that UA is involved in the aetiology of metabolic abnormalities in adipose tissue by regulating leptin-AMPK pathway, and metformin could lessen HUA-induced serum FFA elevation and insulin resistance by improving adipose tissue function via AMPK activation. Therefore, metformin could represent a novel treatment strategy for HUA-related metabolic disorders.