Impact of Serum Uric Acid Levels on Coronary Plaque Stability Evaluated Using Integrated Backscatter Intravascular Ultrasound in Patients with Coronary Artery Disease

The uric acid/HDL-C ratio may predict significant coronary stenosis in moderate left main coronary artery lesions: an intravascular ultrasonography study

BACKGROUND

There may be severe difficulties in determining the severity of LMCA (left main coronary artery) lesions. The use of intravascular ultrasound (IVUS) facilitates decisions about lesion severity in these patients. The aim of this study was to investigate the relationship between the UHR (uric acid to HDL-C ratio) and lesion severity in patients who underwent LMCA IVUS.

METHODS

This study included 205 patients with ICS (intermediate coronary stenosis) in the LMCA who underwent IVUS. In the IVUS measurements of these patients, the plaque burden (PB) and the minimal lumen area (MLA) showing lesion severity were measured.

RESULTS

The patients were separated into two groups according to plaque burden (< 65% and ≥ 65%). The UHR was significantly greater in the high plaque burden group (479.5 vs. 428.6, P = 0.001). When the patients were separated into two groups according to the MLA (< 6mm2 and ≥ 6mm2), the UHR was determined to be significantly greater in the group with low MLA (476.8 vs. 414.9, P < 0.001). In the ROC analysis performed according to the MLA and plaque burden values, the UHR cutoff value of 450 was found to have similar sensitivity and the same specificity for both parameters.

CONCLUSIONS

The results of this study suggested that there is a relationship between UHR and MLA < 6mm2 and plaque burden ≥ 65%, which are independently evaluated as critical in IVUS, and this could predict anatomically significant lesions in patients with a moderate degree of LMCA stricture.

Insulin resistance surrogate markers and risk of hyperuricemia among patients with and without coronary artery disease: a cross-sectional study

Background

Although emerging evidence emphasizes the associations between both insulin resistance and hyperuricemia with coronary artery disease (CAD) risk, no definite relationship has yet been established. In this respect, time-efficient and affordable methods to estimate insulin resistance (IR) status, and to predict risk of hyperuricemia, are needed. Thus, the goal of this investigation was to examine the associations between IR, as assessed by novel surrogate markers [triglyceride-glucose (TyG) and TyG-body mass index (TyG-BMI)], and risk of hyperuricemia in patients with and without diagnosed CAD.

Methods

This cross-sectional study used data from the medical records of 1,170 patients who were referred to the cardiology outpatient clinic. Medical records, anthropometrics, and serum analytes were determined at the initial visit. Hyperuricemia was defined as serum uric acid ≥ 5.6 mg/dL. IR was estimated through surrogate markers (TyG and TyG-BMI). Multiple regression analysis was performed to assess the relationship between these indices and odds of hyperuricemia among patients with and without CAD.

Results

Overall, 814 angiographically-confirmed CAD cases (mean age (SD) = 52 (8)yrs) were compared with 356 patients without CAD (mean age (SD) = 48 (8)yr). There were positive associations between TyG and TyG-BMI indices and odds of hyperuricemia in CAD patients after controlling for confounders (adjusted odds ratio (aOR) = 1.60; 95%CI: 1.02-2.51; p-value = 0.036; and aOR = 1.83; 95%CI: 1.24-2.70; p-value = 0.002, third tertiles for TYG and TYG-BMI, respectively).

Conclusion

The present findings suggest that higher levels of the IR surrogate markers, TyG and TyG-BMI, are associated with higher odds of hyperuricemia in patients with CAD. However, given the cross-sectional design of this study, the sensitivity and specificity of these novel markers could not be determined for confirming the diagnosis of IR and hyperuricemia, further studies are needed to determine such outcomes and to confirm the current findings.

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.

A Randomized Trial on Resveratrol Supplement Affecting Lipid Profile and Other Metabolic Markers in Subjects with Dyslipidemia

Resveratrol is a polyphenol with a well-established beneficial effect on dyslipidemia and hyperuricemia in preclinical experiments. Nonetheless, its efficacy and dose-response relationship in clinical trials remains unclear. This study examined whether resveratrol supplement improves the serum lipid profile and other metabolic markers in a dose-response manner in individuals with dyslipidemia. A total of 168 subjects were randomly assigned to placebo (n = 43) and resveratrol treatment groups of 100 mg/d (n = 41), 300 mg/d (n = 43), and 600 mg/d (n = 41). Anthropometric and biochemical parameters were analyzed at baseline and 4 and 8 weeks. Resveratrol supplementation for 8 weeks did not significantly change the lipid profile compared with the placebo. However, a significant decrease of serum uric acid was observed at 8 weeks in 300 mg/d (-23.60 ± 61.53 μmol/L, p < 0.05) and 600 mg/d resveratrol groups (-24.37 ± 64.24 μmol/L, p < 0.01) compared to placebo (8.19 ± 44.60 μmol/L). Furthermore, xanthine oxidase (XO) activity decreased significantly in the 600 mg/d resveratrol group (-0.09 ± 0.29 U/mL, p < 0.05) compared with placebo (0.03 ± 0.20 U/mL) after 8 weeks. The reduction of uric acid and XO activity exhibited a dose-response relationship (p for trend, <0.05). Furthermore, a marked correlation was found between the changes in uric acid and XO activity in the resveratrol groups (r = 0.254, p < 0.01). Resveratrol (10 μmol/L) treatment to HepG2 cells significantly reduced the uric acid levels and intracellular XO activity. Nevertheless, we failed to detect significant differences in glucose, insulin, or oxidative stress biomarkers between the resveratrol groups and placebo. In conclusion, resveratrol supplementation for 8 weeks had no significant effect on lipid profile but decreased uric acid in a dose-response manner, possibly due to XO inhibition in subjects with dyslipidemia. The trial was registered on ClinicalTrials.gov (NCT04886297).

Association between serum uric acid levels and atrial fibrillation in different fasting glucose patterns: A case-control study

BACKGROUND

Previous studies have shown both dysglycaemia and hyperuricemia are associated with an increased risk of atrial fibrillation (AF), while the relationship between serum uric acid (SUA) levels and AF in different fasting glucose patterns (FBG) is unclear. Therefore, this study aimed to determine the association between SUA and AF in different FBG patterns.

METHODS

A total of 1840 patients in this case-control study were enrolled, including 920 AF patients and 920 controls. Patients were divided into three groups according to the different FBG patterns: normoglycemic, impaired fasting glucose (IFG), and diabetes mellitus (DM). Multivariate logistic regression models were performed to evaluate the relationship between SUA and AF in different FBG patterns. Pearson correlation analysis was used to explore the correlation between SUA and metabolic factors. Receiver operating characteristic (ROC) curve models indicated the diagnostic efficiency of SUA for diagnosing AF.

RESULTS

SUA was independently associated with AF after adjusting for all confounding factors in different FBG patterns(normoglycemic: OR=1.313, 95% CI:1.120-1.539; IFG: OR=1.386, 95% CI:1.011-1.898; DM: OR=1.505, 95% CI:1.150-1.970). Pearson's correlation analysis suggested that SUA in AF patients was correlated with several different metabolic factors in different FBG patterns (p<0.05). ROC curve analysis showed that SUA in the normoglycemic group combined with CHD and APOB [AUC: 0.906 (95% CI: 0.888-0.923)], in the IFG group combined with CHD and Scr [AUC: 0.863 (95% CI: 0.820-0.907)], in the DM group combined with CHD and SBP [AUC: 0.858 (95% CI: 0.818-0.898)] had the highest AUC for predicting AF.

CONCLUSION

Findings implied a significant association between SUA and AF in different FBG patterns and provide specific models combined with other factors (CHD, APOB, SCr, SBP), which might contribute to the diagnosis of AF.

Predictors and morphological properties of culprit healed plaques in patients with angina pectoris

BACKGROUND

Plaque healing may serve a vital function in the natural progression of atherosclerotic disease. This study sought to investigate predictors and morphological characteristics of healed plaque (HP) among angina pectoris (AP) patients.

METHODS

Patients who presented with AP and received preintervention optical coherence tomography (OCT) imaging were consecutively selected for this single-center retrospective observational study. Patient's demographic and clinical information was collected from the hospital's electronic medical records. Coronary angiograms and OCT images were compared via offline software.

RESULTS

A total of 390 patients were chosen as the final study population. HP was identified in 186 patients (47.7%) and was relatively less in cases of unstable angina pectoris (UAP) than in stable angina pectoris (SAP) (89/233 [38.2%] vs. 97/157[61.8%]). The HP group had greater prevalence rates of previous myocardial infarction and SAP and higher levels of triglycerides and uremia (median, 1.67 vs. 1.31 mmol/L [p = .01] and 364.22 ± 91.80 vs. 341.53 ± 77.64 µmol/L [p = .01], respectively). Using multivariate analysis, SAP and long lesion length were shown to be stand-alone indicators of HP. HP presented with more severe stenosis as well as a longer lesion length and had more vulnerable and more complex features. In HP lesions, UAP patients had more plaque ruptures and thrombosis, whereas SAP patients had lower uric acid levels and more multiple HPs(≥3 HPs).

CONCLUSION

Clinical presentation of SAP and long lesion length were strong predictors for HP in patients with AP. Patients with HP presented with more severe stenosis, longer lesion lengths, greater inflammation, and vulnerability.

Systemic Endothelial Function, Plasma Xanthine Oxidoreductase Activity, and Blood Pressure Variability in Patients with Stable Coronary Artery Disease

Background and Objectives: Although previous studies showed that an activity of xanthine oxidoreductase (XOR), a rate-limiting enzyme in purine metabolism, beyond the serum uric acid level, was associated with the development of coronary artery disease (CAD), the underlying mechanisms are unclear. Because endothelial dysfunction and a greater blood pressure (BP) variability may play a role, we investigated the relations among the endothelial function, XOR, and BP variability. Materials and Methods: This was a post-hoc study using pooled data of patients with a stable CAD from two prospective investigations, in which the systemic endothelial function was assessed with the reactive hyperemia index (RHI) and the XOR activity was measured. The BP variability was evaluated using BP measurements during the three- and four-day hospitalization. Results: A total of 106 patients with a stable CAD undergoing a percutaneous coronary intervention were included. Of the 106 patients, 46 (43.4%) had a systemic endothelial dysfunction (RHI < 1.67). The multivariable analysis identified a higher body mass index (BMI), female gender, and diabetes as factors associated with an endothelial dysfunction. A higher BMI was also related to an elevated XOR activity, in addition to current smoking. No significant correlation was observed between the RHI and XOR activity. Similarly, the in-hospital BP variability was associated with neither the endothelial function nor XOR. Conclusions: Among patients with a stable CAD, several factors were identified as being associated with a systemic endothelial dysfunction or an elevated XOR activity. However, no direct relations between the endothelial function, XOR, and BP variability were found.

Correlation Between Serum Uric Acid Levels and Coronary Plaque Characteristics on Optical Coherence Tomography

Elevated serum uric acid (sUA) is associated with increasing risk of coronary heart disease (CHD). However, existing research is limited by potential confounders. Herein, our study aims to probe the association between sUA levels and the morphological characteristics of coronary plaque by a propensity score matching (PSM) analysis.All 420 patients with CHD who had undergone optical coherence tomography of culprit lesions were included. Eligible patients were assigned into 2 groups according to sUA level: high-sUA group (sUA ≥ 6.0 mg/dL) and low-sUA group (sUA < 6.0 mg/dL). PSM was applied to control the balance of baseline characteristics.After PSM, a total of 112 patients were included in our study (56 in each group). The high-sUA group showed a higher prevalence of TCFA (35.7% versus 16.1%, P = 0.03) and macrophage infiltration (33.9% versus 14.3%, P = 0.026) compared with the low-sUA group. Plaques in the high-sUA group had a wider maximum lipid arc (166.51° (115.77°, 224.14°) versus 142.29° (93.95°, 169.06°), P = 0.048), longer calcification length (6.77 (3.90, 20.55) mm versus 4.20 (1.95, 7.45) mm, P = 0.040), and thinner minimum fibrous cap thickness (43.81 (28.17, 62.26) μm versus 92.57 (46.25, 135.37) μm, P = 0.003). Correlation analysis indicated that the sUA value was inversely associated with the minimum fibrous cap thickness (r = -0.332, P = 0.015) and positively associated with the maximum lipid arc (r = 0.399, P = 0.003), average lipid arc (r = 0.347, P = 0.011), and calcification length (r = 0.386, P = 0.006).The relationship between high-sUA levels and typical vulnerable features of plaques persisted after balancing the traditional risk factors.

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.

Serum uric acid is an independent risk factor of worse mid- and long-term outcomes in patients with non-ST-segment elevation acute coronary syndromes

BACKGROUND

The data on the association between serum uric acid (sUA) concentration and outcomes in patients with an ACS are inconsistent and do not focus on patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS). The aim of this study was to analyze an association of sUA concentration on admission and outcomes in those patients.

METHODS

Data from the prospective, single-center registry of patients hospitalized due to NSTE-ACS from January 2006 to December 2016 were analyzed retrospectively. The population was divided into quartiles according to the baseline sUA. The primary outcome was the incidence of all-cause death, non-fatal myocardial infarction, stroke and ACS-driven revascularization at 36 months.

RESULTS

Total of 2,824 patients with sUA measured on admission were included in this analysis with a median sUA of 352 µmol/L (5.92 mg/dL). Patients with higher sUA were older and more burdened with cardiovascular risk factors and history of coronary events. The prevalence of multivessel coronary artery disease and left main stenosis was significantly higher in patients with higher sUA. Elevated sUA concentration was associated with significantly worse short-, mid- and long-term outcomes. All-cause mortality was significantly higher in each analyzed period. In the multivariable analysis, sUA elevation was identified as an independent predictor of all-cause mortality at 12-month and 36-month follow-up.

CONCLUSIONS

Elevated baseline sUA concentration was independently associated with worse mid- and long-term outcomes in patients with NSTE-ACS. Baseline sUA concentration could identify patients with NSTE-ACS at higher risk of more dismal prognosis.

Gender Differences in the Impact of Plasma Xanthine Oxidoreductase Activity on Coronary Artery Spasm

Xanthine oxidoreductase (XOR) is the rate-limiting enzyme in uric acid (UA) production that plays a pivotal role in generating oxidative stress. Gender differences in the impact of plasma XOR activity on coronary artery spasm (CAS) remain unclear. We investigated plasma XOR activity in 132 patients suspected of having CAS (male, n = 78; female, n = 54) and who underwent an intracoronary acetylcholine provocation test. Plasma XOR activity was significantly lower in female patients compared with male patients. CAS was provoked in 36 male patients and 17 female patients, and both had significantly higher plasma XOR activity than those without. Multivariate logistic regression analysis showed that this activity was independently associated with the incidence of CAS in both sexes after adjusting for confounding factors. The optimal cut-off values for predicting CAS were lower in female patients than in male patients. Multivariate analysis demonstrated that female patients with high XOR activity exhibited a higher incidence of CAS than male patients. Plasma XOR activity was an independent predictor of the incidence of CAS in both sexes. The impact of plasma XOR activity on CAS was stronger in female patients than in male patients.

Correlation between serum uric acid levels and carotid plaque neovascularisation assessed by contrast-enhanced ultrasound

AIM

To investigate the potential impact of serum uric acid (SUA) levels on the grade of intraplaque neovascularisation (IPN) at contrast-enhanced ultrasound (CEUS).

MATERIAL AND METHODS

The study screened 212 patients with carotid atherosclerotic plaques using conventional ultrasound, and the patients then underwent CEUS. Based on the distribution of contrast medium microbubbles in the plaque, patients were split into three groups: 60 patients regarded as grade 0-1 (group A), 81 patients as grade 2 (group B), and 71 patients as grade 3 (group C), and SUA levels were measured on the second day after CEUS.

RESULTS

The frequencies of stroke were statistically different between the three groups (p<0.05). In grades 0, 1, 2, and 3, SUA levels ranged from 236.92 ± 72.75, 276.46 ± 67.31, 283.93 ± 53.85, and 384.49 ± 79.80 μmol/l, respectively. Spearman's analysis showed that the visual grade of IPN at CEUS correlated linearly with the SUA level (r=0.551, p<0.01). The difference in SUA levels between different sexes was statistically significant (p<0.05), and the differences in plaque echogenicity and diastolic blood pressure (DBP) between the three groups were also statistically significant (all p<0.05).

CONCLUSIONS

SUA levels correlate positively with the visual grade of IPN at CEUS, which may promote plaque vulnerability. The present results may further help to optimise therapy for vulnerable plaque and improve stroke risk stratification strategies.

Carotid Plaques From Symptomatic Patients Are Characterized by Local Increase in Xanthine Oxidase Expression

[Figure: see text].

Uric acid and cardiovascular disease: A clinical review

Uric acid, the end-product of purine metabolism in humans, is not only a cause of gout, but also may play roles in developing cardiovascular diseases such as hypertension, atrial fibrillation, chronic kidney disease, heart failure, coronary artery disease, and cardiovascular death. Several clinical investigations have reported serum uric acid as a predictive marker for cardiovascular outcomes. Although the causal relationship of hyperuricemia to cardiovascular diseases remains controversial, there has been a growing interest in uric acid because of the increased prevalence of hyperuricemia worldwide. This review article summarizes current evidence concerning the relation between hyperuricemia and cardiovascular diseases.

Greater coronary lipid core plaque assessed by near-infrared spectroscopy intravascular ultrasound in patients with elevated xanthine oxidoreductase: a mechanistic insight

Elevated serum uric acid level was reportedly associated with greater coronary lipid plaque. Xanthine oxidoreductase (XOR) is a rate-limiting enzyme in purine metabolism and believed to play an important role in coronary atherosclerosis. However, the relation of XOR to coronary lipid plaque and its mechanism are unclear. Patients with stable coronary artery disease undergoing elective percutaneous coronary intervention under near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) guidance were prospectively enrolled. They were divided into three groups according to serum XOR activities: low, normal, and high. Coronary lipid core plaques in non-target vessels were evaluated by NIRS-IVUS with lipid core burden index (LCBI) and a maximum LCBI in 4 mm (maxLCBI_4mm). Systemic endothelial function and inflammation were assessed with reactive hyperemia index (RHI) and high-sensitivity C-reactive protein, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio. Of 68 patients, 26, 31, and 11 were classified as low, normal, and high XOR activity groups. LCBI (474.4 ± 171.6 vs. 347.4 ± 181.6 vs. 294.0 ± 155.9, p = 0.04) and maxLCBI_4mm (102.1 ± 56.5 vs. 65.6 ± 48.5 vs. 55.6 ± 37.8, p = 0.04) were significantly higher in high XOR group than in normal and low XOR groups. Although RHI was significantly correlated with body mass index, diabetes, current smoking, and high-density lipoprotein cholesterol, no relation was found between XOR activity and RHI. There were also no relations between XOR activity and C-reactive protein, neutrophil-to-lymphocyte ratio, or platelet-to-lymphocyte ratio. In conclusion, elevated XOR activity was associated with greater coronary lipid core plaque in patients with stable coronary artery disease, without significant relations to systemic endothelial function and inflammation.

Relation of Plasma Xanthine Oxidoreductase Activity to Coronary Lipid Core Plaques Assessed by Near-Infrared Spectroscopy Intravascular Ultrasound in Patients With Stable Coronary Artery Disease

Previous studies reported that elevated serum uric acid level was associated with greater coronary lipid plaque. Xanthine oxidoreductase (XOR) is a rate-limiting enzyme in purine metabolism and is believed to play important roles in coronary atherosclerosis. However, the relation between XOR and coronary lipid plaque is unclear. Patients with stable coronary artery disease who underwent elective percutaneous coronary intervention under near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) guidance were prospectively included. They were divided into 3 groups according to plasma XOR activities based on a previous report: low, normal, and high. Quantitative coronary angiography and gray-scale IVUS were analyzed. The primary end point was coronary lipid plaques in a nontarget vessel assessed by NIRS-IVUS with lipid core burden index (LCBI) and maximum LCBI in 4 mm (maxLCBI_4mm). Out of 68 patients, 26, 31, and 11 patients were classified as low, normal, and high XOR activity groups. Quantitative coronary angiography demonstrated that the high XOR activity group had longer lesion length, smaller minimum lumen diameter, and higher percentage of diameter stenosis in a nontarget vessel among the 3 groups. Gray-scale IVUS analysis also showed smaller lumen area in the high XOR activity group than the others. LCBI (102.1 ± 56.5 vs 65.6 ± 48.5 vs 55.6 ± 37.8, p = 0.04) and maxLCBI_4mm (474.4 ± 171.6 vs 347.4 ± 181.6, 294.0 ± 155.9, p = 0.04) in a nontarget vessel were significantly higher in the high XOR group than in the normal and low groups. In conclusion, elevated XOR activity was associated with coronary lipid-rich plaque in a nontarget vessel in patients with stable coronary artery disease.

Converging Relationships of Obesity and Hyperuricemia with Special Reference to Metabolic Disorders and Plausible Therapeutic Implications

BACKGROUND

Obesity and hyperuricemia mutually influence metabolic syndrome. This study discusses the metabolic relationships between obesity and hyperuricemia in terms of pathophysiology, complications, and treatments.

METHODS

We searched for preclinical or clinical studies on the pathophysiology, complications, and therapy of obesity and hyperuricemia on the PubMed database.

RESULTS

In this systemic review, we summarized our searching results on topics of pathophysiology, complications and therapeutic strategy. In pathophysiology, we firstly introduce genetic variations for obesity, hyperuricemia and their relationships by genetic studies. Secondly, we talk about the epigenetic influences on obesity and hyperuricemia. Thirdly, we describe the central metabolic regulation and the role of hyperuricemia. Then, we refer to the character of adipose tissue inflammation and oxidative stress in the obesity and hyperuricemia. In the last part of this topic, we reviewed the critical links of gut microbiota in the obesity and hyperuricemia. In the following part, we review the pathophysiology of major complications in obesity and hyperuricemia including insulin resistance and type 2 diabetes mellitus, chronic kidney disease, cardiovascular diseases, and cancers. Finally, we recapitulate the therapeutic strategies especially the novel pharmaceutic interventions for obesity and hyperuricemia, which concurrently show the mutual metabolic influences between two diseases.

CONCLUSION

The data reviewed here delineate the metabolic relationships between obesity and hyperuricemia, and provide a comprehensive overview of the therapeutic targets for the management of metabolic syndromes.

Impact of Elevated Serum Uric Acid Level on Target Lesion Revascularization After Percutaneous Coronary Intervention for Chronic Total Occlusion

Elevated serum uric acid (SUA) level is reportedly associated with subsequent cardiovascular events including revascularization in patients with coronary artery disease. However, the impact of SUA level on revascularization in patients with chronic total occlusion (CTO), one of the highest risk subsets in coronary artery disease, is unclear. The aim of this study was to evaluate the impact of SUA level on target lesion revascularization (TLR) in contemporary percutaneous coronary intervention (PCI) for CTO. A total of 165 patients who underwent successful PCI with new-generation drug-eluting stent for CTO under intravascular ultrasound guidance were included. Patients were classified into 3 groups according to the tertiles of SUA level at baseline. Coronary angiography was qualitatively and quantitatively assessed, and gray-scale intravascular ultrasound was also analyzed. The primary end point was TLR. The tertiles of SUA level were as follows: low tertile, ≤5.2 mg/dl; intermediate tertile, 5.3 to 6.4 mg/dl; and high tertile, ≥6.5 mg/dl. During a median follow-up of 34 months, TLR was observed in 5 patients (8.8%) in the low tertile, in 5 (9.4%) in the intermediate tertile, and in 14 (25.5%) in the high tertile (p = 0.02). Kaplan-Meier analysis demonstrated a significantly higher incidence of TLR in patients with high tertile than the low and intermediate groups. Multivariable analysis showed SUA ≥6.5 mg/dl, diabetes mellitus, and longer CTO length as independent predictors of TLR. In conclusion, in patients who underwent PCI with drug-eluting stent, elevated SUA level was associated with TLR after successful recanalization of CTO.

[Hyperuricemia, gout and high cardiovascular risk - how to manage them in clinical practice]

In recent years, the relationship of hyperuricemia and gout with a high risk of cardiovascular disease has been widely discussed. Therefore, it is important to systematically examine patients in order to diagnose comorbidities, among which cardiovascular disease and its complications occupy a leading place and consider mandatory treatment of patients with hyperuricemia and gout with high cardiovascular risk with lowering drugs, which fully reflects the provisions of the latest European recommendations for the management and treatment of patients with gout.

[Comorbidity in gout and hyperuricemia: prevalence, causes, prospects of urate lowering therapy]

Nowadays, there is increased interest in the connection of gout and asymptomatic hyperuricemia with comorbid conditions such as diabetes mellitus, cardiovascular diseases, hypertension, chronic kidney disease and other. Studies conducted over the past few decades suggest that not only gout, but also asymptomatic hyperuricemia can significantly worsen the prognosis in patients with cardiovascular diseases, as the deposition of urate crystals can be both an immediate cause and a factor in the progression of renal failure. In that way, the timely appointment of urate - lowering therapy and achieving the target serum uric acid level can not only affect joint damage, but also can significantly slow the progression of life - threatening comorbid conditions.

Impact of Accumulated Serum Uric Acid on Coronary Culprit Lesion Morphology Determined by Optical Coherence Tomography and Cardiac Outcomes in Patients with Acute Coronary Syndrome

Objectives: We aimed to examine the relations of very high levels of serum uric acid (sUA) with features of culprit lesion plaque morphology determined by optical coherence tomography (OCT) and adverse clinical outcomes in patients with acute coronary syndrome (ACS). Methods: We retrospectively compared ACS patients according to sUA levels of > 8.0 mg/dL (n = 169), 7.1–8.0 mg/dL (n = 163), 6.1–7.0 mg/dL (n = 259), and ≤6.0 mg/dL (n = 717). Angiography and OCT findings were analyzed in patients with preintervention OCT and the 4 sUA groups (> 8.0 mg/dL, n = 61; 7.1–8.0 mg/dL, n = 72; 6.1–7.0 mg/dL, n = 131; and ≤6.0 mg/dL, n = 348) were compared. Results: Cardiogenic shock was more prevalent in ACS patients with sUA > 8.0 mg/dL (22% vs. 19% vs. 10% vs. 6%, p < 0.001). Plaque rupture was observed more prevalently by OCT in patients with sUA > 8.0 mg/dL (67% vs. 47% vs. 56% vs. 45%, p = 0.027). At the 2-year follow-up, Kaplan-Meier estimates showed higher cardiac mortality in patients with sUA > 8.0 mg/dL (25% vs. 12% vs. 5% vs. 5%, p < 0.001). After adjusting for traditional cardiovascular risk factors and creatinine levels, patients with sUA > 8.0 mg/dL showed a 4.5-fold increased risk in 2-year cardiac death by multivariate Cox proportional hazard analysis (hazard ratio 4.54, 95% confidence interval 2.98–6.91; p < 0.001). Conclusions: Very high sUA levels like > 8.0 mg/dL are the primary predictor of 2-year cardiac mortality and could partly be caused by adverse effects of accumulated sUA on plaque morphology in patients with ACS.

Serum Uric Acid Is Highly Associated with Epilepsy Secondary to Cerebral Infarction

In this study, we examined the association between serum uric acid levels and epilepsy secondary to cerebral infarction. Clinical data including age, gender, epileptic seizure type, imaging, and serum uric acid levels before and after seizures in patients with cerebral infarction that were collected and analyzed. One hundred patients with cerebral infarction but without epilepsy, 147 patients with epilepsy secondary to cerebral infarction, and 55 patients with status epilepticus secondary to cerebral infarction were recruited. Interestingly, epilepsy secondary to cerebral infarction was associated with both reduced uric acid (adjusted OR 2.09; 95% CI 1.07-4.08) and increased uric acid (adjusted OR 4.05; 95% CI 1.99-8.25); however, status epilepsy secondary to cerebral infarction was only associated with increased uric acid (adjusted OR 2.60; 95% CI 1.05-6.45). A U-shaped association between uric acid levels and seizures was observed by using a multivariable logistic regression model with restricted cubic spline. Serum uric acid levels are associated with both epilepsy secondary to cerebral infarction and status epilepticus secondary to cerebral infarction in patients with cerebral infarction. The appropriate intervention of serum uric acid level might be a therapeutic strategy to reduce epileptic seizures or inhibit the development of status epilepticus.

Relation of Coronary Culprit Lesion Morphology Determined by Optical Coherence Tomography and Cardiac Outcomes to Serum Uric Acid Levels in Patients With Acute Coronary Syndrome

The aims of the present study were to elucidate features of culprit lesion plaque morphology using optical coherence tomography (OCT) in relation to elevated serum uric acid (sUA) levels and to clarify the impact of sUA levels on adverse clinical outcomes in patients with acute coronary syndrome (ACS). Clinical data and outcomes were compared between ACS patients with sUA ≥6 mg/dl (high-sUA; n = 506) and sUA <6.0 mg/dl (low-sUA; n = 608). Angiography and OCT findings were analyzed in patients with preintervention OCT and compared between groups of high-sUA (n = 206) and low-sUA (n = 273). Patients with high-sUA were more frequently male (88% vs 74%, p <0.001), younger (median 65 years vs 67 years, p = 0.017), more obese (median body mass index; 24.3 kg/m² vs 23.2 kg/m², p <0.001), and had a more frequent history of hypertension (72% vs 62%, p <0.001). ACS with lung congestion or cardiogenic shock was more prevalent in patients with high-sUA (30% vs 13%, p <0.001). Plaque rupture (54% vs 42%, p = 0.021) and red thrombi (55% vs 41%, p = 0.010) were more prevalently observed by OCT in patients with high-sUA. Kaplan-Meier estimate survival curves showed that the 2-year cardiac mortality was higher in patients with high-sUA (12.1% vs 4.2%, p <0.001). The multivariate Cox proportional hazard analysis showed that sUA values independently and significantly predicted cardiac death within 2 years (hazard ratio 1.41 [95% confidence interval 1.26 to 1.57], p <0.001). In conclusion, sUA levels are associated with culprit lesion coronary plaque morphology and raised sUA levels affect cardiovascular mortality after adjusting for several cardiovascular risk factors.

Correlation of Serum Uric Acid Levels with Nonculprit Plaque Instability in Patients with Acute Coronary Syndromes: A 3-Vessel Optical Coherence Tomography Study

Elevated serum uric acid (SUA) level is known to be a prognostic factor in patients with acute coronary syndrome (ACS). However, the correlation between SUA level and coronary plaque instability has not been fully evaluated. The aim of this study was to investigate the association between SUA level and plaque instability of nonculprit lesions in patients with ACS using optical coherence tomography. A total of 150 patients with ACS who underwent 3-vessel optical coherence tomography were selected. Patients were classified into 3 groups according to tertiles of SUA level. There was a trend towards a thinner fibrous cap (0.15 ± 0.06 versus 0.07 ± 0.01 versus 0.04 ± 0.01 mm², p < 0.001) and a wider mean lipid arc (169.41 ± 33.16 versus 177.22 ± 37.76 versus 222.43 ± 47.65°, p < 0.001) with increasing SUA tertile. The plaques of the high and intermediate tertile groups had a smaller minimum lumen area than the low tertile group (6.02 ± 1.11 versus 5.38 ± 1.28 mm², p < 0.001). In addition, thin-cap fibroatheromas, microvessels, macrophages, and cholesterol crystals were more frequent in the high tertile group than the low and intermediate groups. Multivariate analysis showed SUA level to be a predictor of plaque instability.

Uric acid in the pathogenesis of metabolic, renal, and cardiovascular diseases: A review

The association between uric acid (UA) on one side and systemic hypertension (Htn), dyslipidemia, glucose intolerance, overweight, fatty liver, renal disease and cardiovascular disease (CVD) on the other side is well recognized. However, the causal relationship between UA and these different clinical problems is still debatable. The recent years have witnessed hundreds of experimental and clinical trials that favored the opinion that UA is a probable player in the pathogenesis of these disease entities. These studies disclosed the strong association between hyperuricemia and metabolic syndrome (MS), obesity, Htn, type 2 diabetes mellitus (DM), non-alcoholic fatty liver disease, hypertriglyceridemia, acute kidney injury, chronic kidney disease (CKD), coronary heart disease (CHD), heart failure and increased mortality among cardiac and CKD patients. The association between UA and nephrolithiasis or preeclampsia is a non-debatable association. Recent experimental trials have disclosed different changes in enzyme activities induced by UA. Nitric oxide (NO) synthase, adenosine monophosphate kinase (AMPK), adenosine monophosphate dehydrogenase (AMPD), and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase are affected by UA. These changes in enzymatic activities can lead to the observed biochemical and pathological changes associated with UA. The recent experimental, clinical, interventional, and epidemiologic trials favor the concept of a causative role of UA in the pathogenesis of MS, renal, and CVDs.

Impact of comorbidities on gout and hyperuricaemia: an update on prevalence and treatment options

Gout, the most prevalent inflammatory arthritis worldwide, is associated with cardiovascular and renal diseases, and is an independent predictor of premature death. The frequencies of obesity, chronic kidney disease (CKD), hypertension, type 2 diabetes, dyslipidaemias, cardiac diseases (including coronary heart disease, heart failure and atrial fibrillation), stroke and peripheral arterial disease have been repeatedly shown to be increased in gout. Therefore, the screening and care of these comorbidities as well as of cardiovascular risk factors are of outmost importance in patients with gout. Comorbidities, especially CKD, and drugs prescribed for their treatment, also impact gout management. Numerous epidemiological studies have shown the association of asymptomatic hyperuricaemia with the above-mentioned diseases and cardiovascular risk factors. Animal studies have also produced a mechanistic approach to the vascular toxicity of soluble urate. However, causality remains uncertain because confounders, reverse causality or common etiological factors might explain the epidemiological results. Additionally, these uncertainties remain unsolved despite recent studies using Mendelian randomisation or therapeutic approaches. Thus, large randomised placebo-controlled trials are still needed to assess the benefits of treating asymptomatic hyperuricaemia.

Serum uric acid on admission predicts in-hospital mortality in patients with acute coronary syndrome

BACKGROUND

Despite the association between uric acid and cardiovascular disease has been known for decades, the prognostic value of serum uric acid (UA) in all clinical manifestations of acute coronary syndrome (ACS), namely ST-elevation myocardial infarction (STEMI), NSTEMI and unstable angina, has not been definitively assessed.

METHODS

This retrospective analysis included patients from previous SPAI and FAMI studies with the aim to investigate the association between serum uric acid and major adverse cardiovascular events at 180days from hospital admission.

RESULTS

1548 patients were considered and divided in four groups, according UA concentration. Uricemia was significantly associated with gender, BMI, arterial hypertension, HDL-cholesterol, triglycerides, metabolic syndrome and glomerular filtration rate in univariate analysis. Multivariate logistic regression indicated that UA >6.0mg/dL on admission increased the risk of in-hospital mortality in overall population (OR 2.9, 95%CI 1.4-6.1; p=0.0057) and in patients with de novo ACS (OR 3.2, 95%CI 1.5-6.8; p=0.0033). Comparable results were also obtained after adjusting the model for age, gender, body mass index, glomerular filtration rate, metabolic syndrome, acute revascularization and ethnicity. A positive correlation was observed between UA and C reactive protein concentrations in in-hospital deaths only (rho 0.41, p=0.027).

CONCLUSION

In patients with acute coronary syndrome, uricemia levels above the current international reference limit (6.0mg/dl) were associated with in-hospital mortality, independently from ethnicity and renal function.

Association of Serum Uric Acid Levels with Leg Ischemia in Patients with Peripheral Arterial Disease after Treatment

Aim: We investigated the relationships of serum uric acid levels with the progression of atherosclerosis in patients with peripheral arterial disease (PAD) after treatment.

Methods: Subjects were male patients diagnosed with PAD. Atherosclerosis at the common carotid artery was evaluated based on its intima-media thickness (IMT). Leg arterial flow was evaluated by measuring ankle-brachial index (ABI) and exercise-induced decrease in ABI.

Results: Among various risk factors including age, blood pressure, adiposity, estimated glomerular filtration rate, and blood lipid, blood glucose, uric acid, fibrinogen and C-reactive protein levels, only uric acid levels showed significant correlations with ABI [Pearson's correlation coefficient, −0.292 (p < 0.01)] and leg exercise-induced decrease in ABI [Pearson's correlation coefficient, 0.236 (p < 0.05)]. However, there was no significant correlation between uric acid levels and maximum or mean IMT. Odds ratios of subjects with the 3rd tertile versus subjects with the 1st tertile for uric acid levels were significantly higher than the reference level of 1.00 for low ABI [4.44 (95% confidence interval, 1.45–13.65, p < 0.01)] and for high % decrease in ABI after exercise [4.31 (95% confidence interval, 1.34–13.82, p < 0.05)]. The associations of uric acid levels with the indicators of leg ischemia were also found after adjustment for age, history of revascularization therapy, diabetes, smoking, alcohol consumption, body mass index, triglyceride levels, and renal function.

Conclusion: Uric acid levels are associated with the degree of leg ischemia in patients with PAD. Further interventional studies are needed to determine whether the correction of uric acid levels is effective in preventing the progression of PAD.