The differential role of uric acid - The purpose or cause of cardiovascular diseases?

Serum uric acid: an independent risk factor for cardiovascular disease in Pakistani Punjabi patients

BACKGROUND

It is well-known that serum uric acid (SUA) can increase the risk of hypertension, diabetes, obesity and dyslipidemia. However, its independent association with the risk of cardiovascular diseases (CVD) is controversial particularly in different populations. Hence, this study was aimed to assess an independent association of SUA with CVD risk in a Punjabi Pakistani cohort.

METHODS

This is a retrospective observational study in which 502 human subjects having CVD, hypertension and/or diabetes were grouped based on SUA levels as normouricemia (n = 266) and hyperuricemia (n = 236). Role of SUA was assessed in increasing the risk of CVD independent of other key confounding factors (i.e. age, gender, dyslipidemia, hypertension, diabetes, dietary and life-style habits). All clinical and biochemical data were analyzed in SPSS (ver. 20).

RESULTS

Subjects aged 55 ± 13 years were of both genders (males: 52%). SUA levels were significantly different among clinical subtypes of CVD [i.e. acute coronary syndrome (ACS), myocardial infarction (MI) and heart failure (HF)]. Spearman correlation showed a significantly positive association between CVD and SUA (rho = 0.149, p < 0.001). Multivariate logistic regression of SUA quartiles showed that hyperuricemia is associated with CVD [3rd quartile: OR: 1.78 (CI: 1.28-2.48), p = 0.001 and 4th quartile: OR: 2.37 (CI: 1.72-3.27), p < 0.001]. Moreover, this association remained significant even after adjusting for confounding factors.

CONCLUSION

This study showed that SUA is positively associated with CVD, thus it can act as an independent risk factor for CVD.

The association of perioperative serum uric acid variation with in-hospital adverse outcomes in coronary artery bypass grafting patients

Background

Previous studies proposed the predictive value of baseline serum uric acid (SUA) in the prognosis of coronary artery bypass grafting (CABG) patients. The association of perioperative SUA variation with in-hospital adverse outcomes in CABG patients is unknown.

Methods

A total of 2,453 patients were included in the study and were divided into four groups (G1-G4) according to perioperative SUA variation (ΔSUA) (G1, ΔSUA ≤ -90 μmol/L; G2, -90 μmol/L < ΔSUA < 0; G3, 0 ≤ ΔSUA < 30 μmol/L; G4, 30 μmol/L ≤ ΔSUA.) The basic characteristics and incidence of adverse outcomes were compared between the groups in the overall population and the subgroups. Multivariate logistic regression was performed to explore the association between perioperative SUA increases and adverse outcomes, and receiver operating characteristic analysis was used to obtain the cutoff value of SUA increases.

Results

The patients had a mean age of 60.9 years and the majority were males (76.7%). In the group with the most significant increase in SUA (G4), incidences of in-hospital all-cause death and fatal arrhythmia were higher than in other groups in the overall population and the subgroups. Multivariate logistic regression showed that an increase in the SUA level of ≥30 µmol/L was significantly associated with in-hospital all-cause death and fatal arrhythmia, independent of the baseline SUA level and renal function. This association was significant in most subgroups for in-hospital fatal arrhythmia and in the ≥60 years, myocardial infarction, and female subgroups for in-hospital all-cause death. The cutoff values of SUA increases in the overall population were 54.5 µmol/L for in-hospital all-cause death and 42.6 µmol/L for in-hospital fatal arrhythmia.

Conclusions

The perioperative SUA increase significantly correlated with a higher incidence of in-hospital all-cause death and fatal arrhythmia in CABG patients, independent of the baseline SUA level and renal function. Perioperative SUA variation may provide complementary information in the identification of patients potentially at risk.

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

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

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

Bio-inspired nanoparticles mediated from plant extract biomolecules and their therapeutic application in cardiovascular diseases: A review

Nanoparticles (NPs) have gained recognition for diagnosis, drug delivery, and therapy in fatal diseases. This review focuses on the benefits of green synthesis of bioinspired NPs using various plant extract (containing various biomolecules such as sugars, proteins, and other phytochemical compounds) and their therapeutic application in cardiovascular diseases (CVDs). Multiple factors including inflammation, mitochondrial and cardiomyocyte mutations, endothelial cell apoptosis, and administration of non-cardiac drugs, can trigger the cause of cardiac disorders. Furthermore, the interruption of reactive oxygen species (ROS) synchronization from mitochondria causes oxidative stress in the cardiac system, leading to chronic diseases such as atherosclerosis and myocardial infarction. NPs can decrease the interaction with biomolecules and prevent the incitement of ROS. Understanding this mechanism can pave the way for using green synthesized elemental NPs to reduce the risk of CVD. This review delivers information on the different methods, classifications, mechanisms and benefits of using NPs, as well as the formation and progression of CVDs and their effects on the body.

LC-MS-based metabolomics reveals metabolic changes in short- and long-term administration of Compound Danshen Dripping Pills against acute myocardial infarction in rats

BACKGROUND

Mild and systematically improving multiple metabolic disorders was a focused view for Compound Danshen Dripping Pills playing synergistic effects through multiple components and multiple targets. The difference in overall therapeutic effects and endogenous metabolic regulation between short- and long-term administration was still unclear.

PURPOSE

This study aimed to explore the difference in endogenous metabolic regulation between short- and long-term Compound Danshen Dripping Pills (CDDP) administration against acute myocardial infarction (AMI).

METHODS

The model of AMI was induced by ligating the left anterior descending coronary artery. The cardiac protection effects of CDDP were investigated by echocardiography, 1- or 2-week were defined as short- and long-term based on desirable efficacy variability. The entire metabolic changes between short- and long-term administration of CDDP were profiled by UPLC-Q-TOF-MS. In addition, the metabolic regulatory network of CDDP administration against myocardial infarction rats was also compared with those of a typical chemical drug isosorbide 5-mononitrate (ISMN).

RESULTS

After 1- or 2-week continuous oral administration, CDDP could significantly alleviate AMI-induced cardiac dysfunction. By using LC-MS-based metabolomics analyses, we systematically investigated the metabolic profiles of plasma and heart tissue samples at fixed exposure time-points (2 h, 24 h) from AMI rats with CDDP treatment. Most interestingly, global endogenous metabolic changes were observed in cardiac samples collected at different stages post consecutive CDDP administration, fluctuating at 2 and 24 h after 1 week but stabilizing after 2 weeks. The disrupted metabolic pathways such as glycerophospholipid, amino acids, fatty acids, and arachidonic acid metabolism were reconstructed after both short- and long-term CDDP treatment, while taurine and hypotaurine metabolism and purine metabolism contributed to the whole efficacy after long-term CDDP administration.

CONCLUSION

Long-term CDDP treatment plays prolonged and stable efficacy against AMI compared with short-term treatment by specifically regulating purine and taurine and hypotaurine metabolism and systematically redressing metabolic disorders.

Uric Acid Expression in Carotid Atherosclerotic Plaque and Serum Uric Acid Are Associated With Cerebrovascular Events

BACKGROUND

Uric acid (UA) concentration within carotid plaque and its association with cerebrovascular events have not been detected or quantified. Systemically, serum UA is a marker of inflammation and risk factor for atherosclerosis. However, its association with carotid plaque instability and stroke pathogenesis remains unclear. In patients undergoing carotid endarterectomy, we aimed to determine whether UA is present differentially in symptomatic versus asymptomatic carotid plaques and whether serum UA is associated with cerebrovascular symptoms (stroke, transient ischemic attack, or amaurosis fugax).

METHODS

Carotid atherosclerotic plaques were collected during carotid endarterectomy. The presence of UA was assessed using Gomori methenamine silver staining as well as anti-UA immunohistochemical staining and its quantity measured using an enzymatic colorimetric assay. Clinical information was obtained through a retrospective review of data.

RESULTS

UA was more commonly detected in symptomatic (n=23) compared with asymptomatic (n=9) carotid plaques by Gomori methenamine silver (20 [86.9%] versus 2 [22.2%]; P=0.001) and anti-UA immunohistochemistry (16 [69.5%] versus 1 [11.1%]; P=0.004). UA concentration was higher in symptomatic rather than asymptomatic plaques (25.1 [9.5] versus 17.9 [3.8] µg/g; P=0.021). Before carotid endarterectomy, serum UA levels were higher in symptomatic (n=341) compared with asymptomatic (n=146) patients (5.9 [interquartile range, 4.6-6.9] mg/dL versus 5.2 [interquartile range, 4.6-6.2] mg/dL; P=0.009).

CONCLUSIONS

The current study supports a potential role of UA as a potential tissue participant and a systemic biomarker in the pathogenesis of carotid atherosclerosis. UA may provide a mechanistic explanation for plaque instability and subsequent ischemic cerebrovascular events.

A novel electronic tongue using electropolymerized molecularly imprinted polymers for the simultaneous determination of active pharmaceutical ingredients

The combination of chemometrics and electrochemical sensors modified with molecularly imprinted polymers (MIPs) towards the development of MIP-based electronic tongues (ETs) was explored herein. To demonstrate the potential of such an approach, the simultaneous determination of paracetamol, ascorbic acid and uric acid mixtures in pharmaceutical samples was evaluated. To this aim, MIP-based sensors for the different compounds were prepared by in situ electropolymerization of pyrrole in the presence of p-toluenesulfonate anion (pTS^-), which acted as functional doping ion of the polypyrrole (PPy) MIP backbone. Morphological characterization of the MIPs was done by scanning electron microscopy (SEM), while functionalization of the electrodes was monitored electrochemically. Under the optimized measuring conditions, the developed sensors showed a good performance, with good linearity at the μM level (R² > 0.992, limits of detection between 1 and 24 μM) as well as good repeatability (intra- and inter-day RSD values between 3 and 6% over 30 consecutive measurements). Finally, the quantification of the individual substances in different pharmaceutical samples was achieved by an artificial neural networks (ANNs) model, showing satisfactory agreement between expected and obtained values (R² > 0.987).

A multiethnic association analysis of hyperuricaemia with cardiovascular risk in rural and urban areas in Chinese adults

Comprehensive research on rural-urban disparities in the association of hyperuricaemia (HUA) with cardiovascular disease (CVD) in China, especially among minority groups, is limited. We explored the HUA-CVD relationship between rural and urban areas within ethnic Chinese groups. We included Dong, Miao, and Bouyei adults in Southwest China from the China Multi-Ethnic Cohort Study. Multivariable logistic regression models were used to assess the relationship between HUA and CVD in both residences. We performed stratified analyses by sex and age. The study population included 16,618 people (37.48% Dong, 30.00% Miao, and 32.52% Bouyei) without a reduced estimated glomerular filtration rate. We identified 476 (188 Dong, 119 Miao, and 169 Bouyei) and 175 (62 Dong, 77 Miao, and 36 Bouyei) CVD cases in rural and urban areas. Compared to urban residents, an at least 49% increased CVD risk (adjusted OR 1.49, 95%CI 1.06-2.08 for the Dong ethnic group; 1.55, 1.07-2.25 for the Bouyei ethnic group) and a 1.65-fold elevated coronary heart disease risk (1.65, 1.03-2.64) related to HUA was present in rural residents. Moreover, HUA was positively associated with increased risk of CVD and coronary heart disease in rural women (2.05, 1.26-3.31; 2.11, 1.19-3.75) and rural older adults (1.83, 1.22-2.75; 2.32, 1.39-3.87) among the Bouyei ethnic group, respectively. We found rural elderly individuals with HUA among the Dong ethnic group had a 52% elevated risk of CVD (1.52, 1.05-2.21); furthermore, an at least 79% increased risk of stroke related to HUA was observed in women (2.24, 1.09-4.62) and elderly people (1.79, 1.02-3.13) in rural areas among the Dong ethnic group. But a positive association was not found among the Miao ethnic group. Screening early-onset HUA patients may be helpful for the control and prevention of CVD in rural residents, especially for women and older adults living in a rural community, among the Dong and Bouyei ethnic groups in China.

The Association of Serum Uric Acid with Beta-Cell Function and Insulin Resistance in Nondiabetic Individuals: A Cross-Sectional Study

PURPOSE

Higher serum levels of uric acid (SUA) are associated with an increased risk of developing type 2 diabetes. Meanwhile, insulin resistance and beta-cell dysfunction are critical factors that mediate the progression from normal glucose tolerance to impaired fasting glucose (IFG) and type 2 diabetes. We aimed to investigate the association between SUA levels and insulin resistance and beta-cell dysfunction in individuals without diabetes, thus explicating the role of uric acid in the early stage of the natural history of type 2 diabetes.

PATIENTS AND METHODS

We used cross-sectional data from the China Health and Nutrition Survey to examine the association. Insulin resistance and beta-cell dysfunction were estimated using the homeostasis model assessment of insulin resistance (HOMA-IR) index and homeostasis model assessment of beta-cell function (HOMA-beta) index, respectively. The associations were analyzed by using partial correlation analysis and multivariate logistic regressionl analysis.

RESULTS

SUA levels were positively associated with fasting glucose, fasting insulin, HOMA-IR in the total population. After adjustment for age, drinking, smoking, living area, daily dietary nutrient intake, body mass index (BMI), estimated glomerular filtration rate (eGFR), hypertension, and dyslipidemia, compared with participants in the lowest quartile of SUA, the adjusted odds ratios for the fourth quartiles were 1.56(1.09-2.24) for IFG, 1.51(1.27-1.78) for insulin resistance, and 1.06(0.88-1.27) for beta-cell dysfunction. In the subgroup analysis, no interactions were found between serum uric acid and age, drinking status, smoking status, BMI, hypertension, or dyslipidemia (all p for interaction>0.05).

CONCLUSION

In nondiabetic individuals, SUA levels are independently associated with IFG and insulin resistance, while no significant association exists between SUA and beta-cell dysfunction.

Influence of uric acid on the correlation between waist circumference and triglyceride glucose index: an analysis from CHARLS

Background

Waist circumference (WC) and uric acid (UA) are significantly related. Still, their temporal sequence and how the sequence works on future risk of triglyceride glucose (TyG) are unknown, especially in the Chinese population.

Methods

Cross-lagged panel model was used to analyze the reciprocal, longitudinal relationships among a set of interrelated variables. The mediation model was constructed to test the effect of the relationship between WC and UA on TyG.

Results

A total of 5727 subjects were enrolled in our study population, of which 53.5% were women, and the mean age was 59.0 (standard deviation, 8.62) years. After adjusting for traditional confounding factors, the results showed that a higher level of baseline WC was significantly associated with a higher level of follow-up UA (β = 0.003, P = 0.031) and follow-up TyG (β = 0.003, P < 0.001);. Simultaneously, there was no statistical association between the level of baseline UA and the level of follow-up WC (β = − 0.009, P = 0.951). The mediation effects of UA on WC-TyG were estimated to be 18.1% in adults, and 36.2% in women.

Conclusions

The current study demonstrated that higher baseline level of WC probably preceded UA’ level in general population. In addition, UA mediated the relationship of WC to TyG, especially in females. And the possible mechanism would require further clarification.

Why Does Hyperuricemia Not Necessarily Induce Gout?

Hyperuricemia is a risk factor for gout. It has been well observed that a large proportion of individuals with hyperuricemia have never had a gout flare(s), while some patients with gout can have a normuricemia. This raises a puzzle of the real role of serum uric acid (SUA) in the occurrence of gout flares. As the molecule of uric acid has its dual effects in vivo with antioxidant properties as well as being an inflammatory promoter, it has been placed in a delicate position in balancing metabolisms. Gout seems to be a multifactorial metabolic disease and its pathogenesis should not rely solely on hyperuricemia or monosodium urate (MSU) crystals. This critical review aims to unfold the mechanisms of the SUA role participating in gout development. It also discusses some key elements which are prerequisites for the formation of gout in association with the current therapeutic regime. The compilation should be helpful in precisely fighting for a cure of gout clinically and pharmaceutically.

Meta-analysis of the correlation between serum uric acid level and carotid intima-media thickness

Objective

Recently, increasing epidemiological evidence has shown that there is a correlation between serum uric acid level (SUA) and carotid intima-media thickness (CIMT). This paper explored the relationship between them through meta-analysis.

Methods

PubMed, Cochrane Library, EMBASE, Web of Science and Google Scholar were searched to obtain literature. The keywords used to retrieve the literature were carotid intima thickness, intima-media thickness, carotid atherosclerosis, carotid stenosis, carotid artery, uric acid, blood uric acid, and hyperuricaemia. The retrieval time was from the establishment of the database through July 2020. Stata15.0 and RevMan5.3 software were used for statistical analysis. The standardized mean difference (SMD) and 95% confidence interval (95% CI) were calculated by a random effect model to estimate the correlation. Publication bias was assessed using the Begg and Egger tests. The stability of these results was evaluated using sensitivity analyses.

Results

Fifteen studies were included with a total sample size of 11382, including 7597 participants in the high uric acid group and 3785 in the control group, on the basis of the inclusion and exclusion criteria. According to the evaluation of the JBI scale, the literature was of high quality. The average age ranged from 42 to 74. Meta-analysis showed that CIMT in the high uric acid group was significantly higher than that in the control group (SMD = 0.53, 95% CI: [0.38, 0.68]), and the difference was significant (z = 6.98, P < 0.00001). The heterogeneity among the 15 articles was obvious (I² = 89%, P < 0.00001). Subgroup analysis by disease status illustrated a positive relationship between SUA and CIMT in healthy people and people with diseases. SUA was shown to be positively correlated with CIMT in people aged 45–60 years and ≥60 years by subgroup analysis by age. SUA was also found to be positively correlated with CIMT in a population with BMI>24 kg/m² by subgroup analysis by BMI. In addition, subgroup analysis of other risk factors for CIMT, including TC, SBP, DBP, triglycerides, and LDL-C, all showed a positive correlation between SUA and CIMT.

Conclusions

There is a significant correlation between serum uric acid level and carotid intima-media thickness, and a high concentration of serum uric acid is related to carotid artery intima-media thickness.