Serum uric acid levels predict the severity and morphology of coronary atherosclerosis detected by multidetector computed tomography

Relationship between uric acid to albumin ratio and in-stent restenosis in patients with coronary artery disease undergoing drug-eluting stenting

BACKGROUND

In-stent restenosis (ISR) in patients undergoing percutaneous coronary intervention (PCI) to treat coronary artery disease (CAD) is an urgent issue in clinical practice. Recent studies have highlighted uric acid-albumin ratio (UAR) as a new marker for evaluating inflammation and oxidative stress, capable of predicting cardiovascular ailments. We aimed to examine the correlation between UAR levels and ISR in patients who underwent drug-eluting stent (DES) implantation.

METHODS

We included 503 patients with CAD who underwent initial DES implantation and angiography during the follow-up period. Based on coronary angiographic findings, the patients were categorized into ISR (n = 73) and non-ISR groups (n = 430). Before angiography, laboratory parameters were measured for all enrolled patients. To ascertain the influential factors linked to ISR, multivariate logistic regression analysis was performed. The predictive capability of UAR in determining ISR was assessed using receiver operating characteristic (ROC) curve analysis. Statistical significance was set at P  < 0.05.

RESULTS

Multivariate logistic regression analysis revealed that diabetes mellitus, stent length, UAR, albumin levels, and C-reactive protein levels independently predicted ISR. ROC curve analysis revealed that UAR had an area under the curve of 0.767 (95% CI: 0.709 - 0.826) for predicting ISR and demonstrated that UAR outperformed the individual predictive abilities of uric acid and albumin for ISR.

CONCLUSION

UAR was associated with ISR in patients with CAD undergoing PCI with DES implantation. Moreover, ROC curve analysis demonstrated that UAR exhibited superior predictive accuracy for ISR compared with evaluating uric acid and albumin levels separately.

Association of Serum Uric Acid Level with Risk of Abdominal Aortic Calcification: A Large Cross-Sectional Study

Objective

The association between serum uric acid (sUA) and incident abdominal aortic calcification (AAC), and severe abdominal aortic calcification (SAAC) in the general population of the United States (US) is unclear. Therefore, this research aimed to investigate the association between sUA and the risk of AAC and SAAC.

Methods

Individuals from National Health and Nutrition Examination Survey (NHANES) database were analyzed cross-sectionally between 2013 and 2014. The restricted cubic spline (RCS), multivariable logistic regression model and subgroup analysis were utilized to evaluate the correlation between sUA and incident AAC, and SAAC. In addition, generalized additive models with smooth functions were employed to survey the relationship between sUA and the degree of AAC.

Results

This study included 3016 individuals from the NHANES database. According to the RCS plot, sUA levels were associated with the risk of AAC/SAAC in a U-shaped pattern in the US population. The degree of calcification decreased at first and then increased with the increase in the sUA level.

Conclusion

Close monitoring and adequate control of sUA levels in the US general population may reduce the risk of AAC and SAAC.

Investigation of the association between serum uric acid levels and HEART risk score in patients with acute coronary syndrome

The association between uric acid (UA) and cardio-metabolic conditions has been recognized for a long time. However, recently, a body of evidence has highlighted the independent role of UA in a series of conditions, including renal and cardiovascular diseases. In this light, data regarding the prognostic role of UA in acute coronary syndrome (ACS) is scarce. A total number of 100 patients, 59 males and 41 females, diagnosed with ACS were recruited in this study. At the time of admission to the hospital, the serum level of UA was measured. In addition, the HEART score was calculated based on each patients' profile. Participants were on average 61.37 ± 12.08 years old. The most prevalent risk factors were hypertension (48%), a history of coronary artery disease (40%), and diabetes mellitus (33%). The average serum level of UA was 5.81 ± 1.81 mg/dl, and the calculated HEART score had a median of six (minimum of two and maximum of ten). A positive yet statistically insignificant correlation was found between the measured UA level and the calculated HEART score (R = 0.375, p = 0.090). However, further studies with larger sample size are required to assess the direct association of UA level with major adverse cardiac events in patients with cardiovascular disease.

Effect of Asymptomatic Hyperuricemia on Mortality of Elderly Patients After Elective Percutaneous Coronary Intervention

Purpose

The purpose of this study is to investigate the effect of asymptomatic hyperuricemia on mortality of elderly patients with coronary artery disease (CAD) after elective percutaneous coronary intervention (PCI).

Methods

One thousand two hundred ninety-six patients with coronary heart disease ≥65 years old who had increased uric acid records and without gout history underwent elective PCI from January 2015 to January 2016 were enrolled. The hyperuricemia is defined as serum uric acid level >420 μ mol/l (7 mg/dl) for males and >357 μ mol/l (6 mg/dl) for females. Patients were divided into hyperuricemia group and non-hyperuricemia group. After an average of 519 days follow-up, the differences in mortality between the two groups were compared.

Results

There were 236 patients in hyperuricemia group and 1060 patients in non-hyperuricemia group. In hyperuricemia group, BMI was higher (P = 0.036); the proportions of patients with hypertension (P < 0.001) and myocardial infarction history (P = 0.046) were higher; white blood cells (P = 0.015) and triglyceride levels were higher (P < 0.001); and estimated glomerular filtration rate (P < 0.001) and high-density lipoprotein cholesterol level were lower (P = 0.007). In addition, in hyperuricemia group, during hospitalization, the ratios of patients treated with diuretics (P < 0.001) and the number of PCI lesions were higher (P = 0.030), and the complete revascularization rate was lower (P = 0.017). The mortality rate (2.2 vs. 7.6%, P < 0.001) of hyperuricemia group was significantly higher than that of non-hyperuricemia group. Multivariate Cox regression analysis showed that after adjusting for other factors, hyperuricemia was an independent risk factor for increased mortality after PCI (HR 2.786, 95% CI 1.233–6.297, P = 0.014).

Conclusion

Asymptomatic hyperuricemia is an independent risk factor for increased mortality of elderly patients with coronary heart disease undergoing elective PCI.

Serum uric acid is associated with coronary artery calcification in early chronic kidney disease: a cross-sectional study

Background

Although uric acid (UA) is regarded as a risk factor for cardiovascular disease, whether UA is an independent risk factor contributing to coronary artery calcification in chronic kidney disease (CKD) is not well known. We evaluated whether UA level is associated with coronary artery calcium (CAC) score in a predialysis CKD cohort.

Methods

A total of 1,350 subjects who underwent coronary computed tomography as part of the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease were analysed. We conducted a logistic regression analysis to evaluate the association between UA and the presence of CAC.

Results

CAC was detected in 705 (52.2 %) patients, and the level of UA was significantly higher in CAC > 0 patients. UA showed a positive relationship with CAC > 0 in age- and sex-adjusted logistic regression analysis (Odds ratio (OR) 1.11, 95 % confidence interval (CI) 1.04–1.19, P = 0.003). However, UA showed no association with CAC > 0 in multivariate analysis. Further analysis showed that UA showed a positive association with CAC > 0 only in estimated glomerual filtration rate (eGFR) > 60 ml/min/1.73 m² (OR 1.23, 95 % CI 1.02–1.49, P = 0.036) but not in eGFR 30–59 ml/min/1.73 m² (OR 0.92, 95 % CI 0.78–1.08, P = 0.309) or < 30 ml/min/1.73 m² (OR 0.92, 95 % CI 0.79–1.08, P = 0.426).

Conclusions

UA level was significantly associated with CAC in early CKD, but not in advanced CKD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02463-2.

Asymptomatic hyperuricaemia and coronary artery disease

BACKGROUND

Uric acid has been related to a tendency to precipitate to form crystals, presenting asymptomatically, until the formation of arthritis, tophi or renal lithiasis. Previously, the presence of asymptomatic hyperuricaemia has been associated with the presence of cardiovascular disease.

OBJECTIVES

To determine the association of complex coronary artery disease in patients with asymptomatic hyperuricaemia.

MATERIAL AND METHODS

An observational retrospective, transversal, unicentric study was conducted in a tertiary hospital in Mexico, in the period from June 2017 to March 2019. All patients admitted for coronary angiography were included; patients with gout, use of diuretics and chronic kidney disease were excluded.

RESULTS

During the study period, a total of 300 patients were collected, of which 40% presented hyperuricaemia. The patients with hyperuricaemia were older (59 vs. 63, P = .002). The group of patients with asymptomatic hyperuricaemia had a higher proportion of complex coronary lesions (64 vs. 35%, P ≤ .0001) as well as a higher SYNTAX I score (27 vs. 17, P ≤ .001). There was a higher probability of presenting complex coronary lesions in this group of patients (OR 3.4, P ≤ .0001). In addition, in the group division of uric acid levels, it was related to the presence of complex coronary lesions (Q1 = .5, P = .06), (Q2 = 2, P = .01) and (Q3 = 3, P ≤ .0001).

CONCLUSION

Asymptomatic hyperuricaemia has a higher prevalence and association of presenting complex coronary lesions.

Serum Uric Acid Levels and Risk of Intracranial Atherosclerotic Stenosis: A Cross-Sectional Study

Elevated serum uric acid (SUA) has been reported to be associated with an increased risk of cardiovascular diseases, but the role of SUA in intracranial atherosclerosis remains unclear. To investigate the association between SUA and intracranial atherosclerotic stenosis (ICAS), we evaluated 1522 subjects (305 with ICAS, 1217 without ICAS) with magnetic resonance angiography (MRA). Subjects were classified into ten groups according to the deciles of the SUA level. The rate of ICAS reached a minimum in the seventh decile (6.0-6.3 mg/dL; reference group). After adjusting for confounding factors, multivariate logistic regression analysis demonstrated that both low SUA level (≤ 3.8 mg/dL; OR, 2.34; 95% CI, 1.29-4.39; p = 0.006) and high SUA level (≥ 7.8 mg/dL; OR, 2.10; 95% CI, 1.15-3.92; p = 0.017) conferred greater risk for ICAS. In multivariable analysis with a quadratic model which used SUA as a continuous variable, a U-shaped association between SUA and the rate of ICAS was confirmed (α > 0; p < 0.001). The estimated SUA level associated with the lowest rate of ICAS was 6.2 mg/dL. In conclusion, our findings suggest a U-shaped association between ICAS and SUA.

Serum uric acid and risk of cardiovascular mortality: a systematic review and dose-response meta-analysis of cohort studies of over a million participants

Background

Cardiovascular disease (CVD) is the leading cause of death worldwide. Some studies have suggested anassociation between serum uric acid levels and cardiovascular mortality; however, the results have not been summarized in a meta-analysis.

Methods

A comprehensive search of all related studies until April 2018was performed in MEDLINE/PubMed and Scopus databases DerSimonianand Laird random-effects models were used to combine hazard ratios (HRs) with 95% confidence intervals (CIs). Dose-response analysis was also carried out.

Results

Thirty-two studies containing forty-four arms with 1,134,073 participants reported association between uric acid and risk of CVD mortality were included in our analysis. Pooled results showed a significant positive association between uric acid levels and risk of CVD mortality (HR 1.45, 95% CI 1.33–1.58, I² = 79%). Sub-group analysis showed this relationshipwasstronger in women compared to men. Moreover, there was a significant non-linear association between uric acid levels and the risk of CVD mortality (r = 0.0709, p = 0.001).

Conclusion

Our analysis indicates a positive dose-response association between SUA and CVD mortality risk.

Assessment of PON1 activity and circulating TF levels in relation to BMI, testosterone, HOMA-IR, HDL-C, LDL-C, CHO, SOD activity and TAC in women with PCOS: An observational study

BACKGROUND

Polycystic Ovary Syndrome (PCOS) is the most common female endocrinopathy among premenopausal women associated with hyperandrogenism, obesity, dyslipidemia, insulin resistance and inflammation. Oxidative stress is an important component of cardio-metabolic risk seen in PCOS.

MATERIAL AND METHODS

A total of 95 women with PCOS and 95 healthy controls were included in this observational study. Serum PON1 activity and stress markers were measured by spectrophotometric methods. Circulating TF level was measured by ELISA.

RESULTS

We found decreased PON1 activity and increased TF levels in women with PCOS compared to healthy controls. Fasting insulin, HOMA-IR, testosterone, LDL-C, MDA, PC and SOD activity were significantly increased whereas FGIR, QUICKI, HDLC, CAT and TAC were significantly decreased in PCOS women than controls. We observed a positive association of PON1 activity with FGIR, QUICKI, HDL-C and TAC, and its negative association was observed with LH, testosterone, fasting insulin and HOMA-IR in PCOS women. We further observed a positive association of TF with waist, waist to hip ratio, BMI, glucose 1hr, cholesterol, LDL-C, SGPT, uric acid and SOD activity in PCOS women.

CONCLUSIONS

Decreased PON1 activity and raised circulating TF levels are respective indicators of pro-inflammatory and procoagulant status in PCOS women. The imbalanced oxidant/antioxidant status further supports the evidences that PCOS is an oxidant state. Further, the association of PON1 activity and TF levels with the clinical, laboratory findings and stress marker levels suggest that these factors taken together are involved in aggravating the pro-inflammatory status in PCOS women.

Elevated serum uric acid is associated with peripheral endothelial dysfunction in women

BACKGROUND AND AIMS

Both elevated serum uric acid (SUA) and peripheral endothelial dysfunction (PED) are associated independently with cardiovascular disease (CVD). However, the association between SUA and PED is yet to be established. We hypothesized that high normal range of SUA is associated with PED.

METHODS

We performed a retrospective cross-sectional analysis of patients who were referred to Mayo Clinic between 2006 and 2014 for routine cardiovascular evaluation and who underwent evaluation of Reactive Hyperemia Peripheral Arterial Tonometry (index <2 consistent with PED). A high UA was defined as ≥5 mg/dL, in keeping with previous studies evaluating the link between SUA and CVD outcomes.

RESULTS

One hundred forty patients were included (mean age 50.7 ± 12.9 years, 86 (61.4%) female). Twenty four patients (17.1%) had pre-existing CVD (8 (9.3%) in females). Thirty patients (21.6%) had a Framingham score > 10% (8 (9.4%) in females). Fifty eight (41.4%) had PED and 77 (55.0%) had an elevated SUA. SUA levels were higher in patients with PED compared to those without (5.5 ± 1.4 vs 4.8 ± 1.2 mg/dL; p = 0.004). In an univariate analysis, elevated SUA levels were associated with PED (Odds Ratio (OR): 2.7; 95% confidence interval [CI] 1.33-5.48; p = 0.005). In a multivariate analysis adjusting for age, sex, presence of obstructive CVD and Framingham score>10, elevated SUA levels were associated with PED (OR 2.45; 95% CI 1.08-5.52; p = 0.031). After stratifying by sex, this association persisted in females only.

CONCLUSIONS

High normal SUA levels are associated with PED in women who are otherwise at low risk for CVD. Thus, SUA is a promising circulating biomarker that could be used to assist in risk stratification in female patients with chest pain and/or those undergoing evaluation of CVD risk.

Relation of Elevated Serum Uric Acid Level to Endothelial Dysfunction in Patients with Acute Coronary Syndrome

Aim: Serum uric acid (SUA) level is known to have a prognostic value in patients with acute coronary syndrome (ACS). Endothelial function plays an important role in the development of cardiovascular disease. Although relation between SUA level and endothelial function has been previously studied in various populations, it is partially understood in patients with ACS.

Methods: A total of 55 patients with ACS with measurements of SUA level and reactive hyperemia index (RHI) to evaluate endothelial function were included. They were classified into three groups according to the tertiles of SUA level. The tertiles of SUA level were as follows: low tertile, ≤ 5.2 mg/dl; intermediate tertile, 5.3 to 6.5 mg/dl; and high tertile, ≥ 6.6 mg/dl.

Results: Mean SUA level and RHI were 5.8 ± 1.5 mg/dl and 1.88 ± 0.58. There was a significant negative correlation between SUA level and RHI (r = −0.41, p = 0.002). RHI was stepwisely observed in favor of the higher tertile groups (2.14 ± 0.74 vs. 1.84 ± 0.45 vs. 1.67 ± 0.38, p = 0.04). Multivariate analysis showed elevated SUA level as an independent predictor of reduced RHI.

Conclusion: Elevated SUA level was significantly associated with endothelial dysfunction in patients with ACS, possibly leading to subsequent poor outcomes following ACS.

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 is associated with long-term adverse cardiovascular outcomes in patients with acute coronary syndrome undergoing percutaneous coronary intervention

BACKGROUND AND AIMS

Evidence links uric acid (UA) with the promotion of cardiovascular disease. We assessed the prognostic value of UA on long-term major adverse outcomes (MACE) in patients with acute coronary syndrome (ACS), undergoing percutaneous coronary intervention (PCI).

METHODS

As primary endpoint, we assessed the association of UA (continuous and dichotomized) with MACE, including cardiovascular death, myocardial infarction (MI) and stroke, using Cox regression and propensity matching. As secondary endpoints, the influence of hyperuricemia (defined as UA levels > 6.0 mg/dl in women, and >7.0 mg/dl in men) was analysed separately for cardiovascular death, MI, and stroke. The incremental prognostic value of UA was tested using the net reclassification improvement (NRI), and the integrated discrimination improvement (IDI).

RESULTS

We included 1215 patients. Hyperuricemia was present in 356 (29.3%) patients. Mean follow-up was 5.5 years. UA (HR 1.091 [1.035-1.150]; p = 0.001) and hyperuricemia (HR 1.750 [1.388-2.207]; p < 0.001) were significantly associated with MACE. Results were consistent between Cox regression and propensity matched analysis. Patients with hyperuricemia had a 1.6-fold increased relative risk for cardiovascular death (p = 0.005) and a 1.5-fold increased risk for MI (p = 0.032). For stroke, hyperuricemia only constituted a confounder (HR 1.104; p = 0.970). The prognostic accuracy of an established risk prediction model was significantly increased by adding UA (continuous NRI p = 0.004; categorical NRI p = 0.029; IDI p = 0.002).

CONCLUSIONS

Our data suggest an independent association of elevated UA with long-term MACE in ACS patients undergoing PCI. Whether lowering UA might be beneficial remains to be elucidated in large clinical trials.

Inflammation-regulated mRNA stability and the progression of vascular inflammatory diseases

Cardiovascular disease remains a major medical and socioeconomic burden in developed and developing societies, and will increase with an aging and increasingly sedentary society. Vascular disease and atherosclerotic vascular syndromes are essentially inflammatory disorders, and transcriptional and post-transcriptional processes play essential roles in the ability of resident vascular and inflammatory cells to adapt to environmental stimuli. The regulation of mRNA translocation, stability, and translation are key processes of post-transcriptional regulation that permit these cells to rapidly respond to inflammatory stimuli. For the most part, these processes are controlled by elements in the 3'-UTR of labile, proinflammatory transcripts. Since proinflammatory transcripts almost exclusively contain AU-rich elements (AREs), this represents a tightly regulated and specific mechanism for initiation and maintenance of the proinflammatory phenotype. RNA-binding proteins (RBPs) recognize cis elements in 3'-UTR, and regulate each of these processes, but there is little literature exploring the concept that RBPs themselves can be directly regulated by inflammatory stimuli. Conceptually, inflammation-responsive RBPs represent an attractive target of rational therapies to combat vascular inflammatory syndromes. Herein we briefly describe the cellular and molecular etiology of atherosclerosis, and summarize our current understanding of RBPs and their specific roles in regulation of inflammatory mRNA stability. We also detail RBPs as targets of current anti-inflammatory modalities and how this may translate into better treatment for vascular inflammatory diseases.

NLRP3 inflammasome pathways in atherosclerosis

Atherosclerosis is the major cause of death and disability. Atherosclerotic plaques are characterized by a chronic sterile inflammation in the large blood vessels, where lipid-derived and damage-associated molecular patterns play important roles in inciting immune responses. Following the initial demonstration that NLR family Pyrin domain containing 3 (NLRP3) was important for atherogenesis, a substantial number of studies have emerged addressing the basic mechanisms of inflammasome activation and their relevance to atherosclerosis. In this review, we introduce the basic cellular and molecular mechanisms of NLRP3 inflammasome activation, and discuss the current findings and therapeutic strategies that target NLRP3 inflammasome activation during the development and progression of atherosclerosis.

Effects of febuxostat on platelet-derived microparticles and adiponectin in patients with hyperuricemia

Platelet-derived microparticles (PDMPs) and adiponectin play an important role in the development of atherothrombosis. We investigated the effect of febuxostat on circulating PDMP levels and adiponectin in hyperuricemic patients. Levels of PDMP and biomarkers were measured using an ELISA at baseline and after 2 and 6 months of treatment. Plasma levels of PDMPs and biomarkers were higher, while those of adiponectin were lower in hyperuricemic patients than in normouricemic controls. Uric acid and interleukin (IL)-6 levels decreased significantly in hyperuricemic patients after 2 months of febuxostat treatment. However, PDMP and biomarkers decreased significantly in hyperuricemic patients after only 6 months of febuxostat treatment and adiponectin increased significantly. These results suggest that the effects of febuxostat for PDMPs seen may be the effect on xanthine oxidase but not the decrease of uric acid, and febuxostat may be beneficial for primary prevention of atherothrombosis in hyperuricemic patients.

Association between Serum Uric Acid and Mortality among Chinese Patients with Coronary Artery Disease

OBJECTIVES

Several studies have investigated the association between serum uric acid (SUA) and the risks of coronary artery disease (CAD) but have yielded inconsistent results. The aim of this study was to assess whether there is an independent association of SUA with all-cause and cardiovascular disease (CVD) mortality in Chinese patients with CAD.

METHODS

A prospective cohort study of 1,799 patients was conducted. Cox regression models were used to estimate the association of SUA with the risk of death.

RESULTS

During a median follow-up of 3.9 years, 177 deaths were recorded and 126 of these were due to CVD. Patients in the highest SUA quartile had a 2.43-fold risk of all-cause mortality and a 2.44-fold risk of CVD mortality compared with those in the lowest quartile. In the subpopulation analysis, the association between SUA and mortality remained similar when participants were stratified by age, gender, body mass index and type of CAD. In contrast, we found a significant interaction with estimated glomerular filtration rate (eGFR). There was a stronger association between SUA and the risk of all-cause and CVD mortality among patients with an eGFR ≥60 ml/min/1.73 m2, but no significant association was found in the population with an eGFR <60 ml/min/1.73 m2.

CONCLUSIONS

Elevated SUA levels were positively associated with an increased risk of all-cause and CVD mortality among CAD patients.

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

AIM

Because the prevalence of hyperuricemia is lower in females than in males, the association between hyperuricemia and cardiovascular disease has been frequently reported in females. Increased serum uric acid levels are associated with the presence of cardiovascular risk factors such as hypertension, renal dysfunction, insulin resistance, and metabolic syndrome. However, it is controversial whether hyperuricemia is an independent risk factor for coronary artery disease in both the genders. The purpose of this study was to investigate the relationship between serum uric acid levels and coronary plaque components assessed using integrated backscatter intravascular ultrasound (IB-IVUS) in males and females.

METHODS

In total, 385 patients (298 males and 87 females) who underwent percutaneous coronary intervention using IB-IVUS were divided into three groups in each gender according to their serum uric acid levels. We characterized tissue from coronary plaques in culprit lesions.

RESULTS

Serum uric acid levels significantly correlated with percent lipid volume (r=0.37) and inversely correlated with percent fibrous volume (r=－0.35). Multivariate analysis showed that the uric acid level was independently associated with lipid-rich plaques (odds ratio 2.43, 95%, confidence interval 1.75-3.47). The prevalence of lipid-rich plaques increased with increasing uric acid levels in both genders.

CONCLUSION

Increased serum uric acid levels were associated with larger lipid content plaques in both genders.

Relation of Lipid Content of Coronary Plaque to Level of Serum Uric Acid

Elevated serum uric acid (SUA) level is known to be a prognostic factor in patients with acute coronary syndrome (ACS). However, the pathogenesis of the relation between SUA level and coronary plaque characteristics has not been fully evaluated. The aim of this study was to investigate the relation between SUA level and plaque composition of nonculprit lesions in patients with ACS. A total of 81 patients with ACS who underwent intravascular ultrasound (IVUS)-guided percutaneous coronary intervention were included. They were classified into 3 groups according to tertiles of SUA level. Using integrated backscatter (IB)-IVUS system, tissue components were classified into 4 categories: calcium deposits, dense fibrosis, fibrosis, and lipid. Tertiles of SUA level were as follows: low tertile <5.0 mg/dl; intermediate tertile 5.0 to 6.4 mg/dl; and high tertile >6.4 mg/dl. There was a trend toward greater vessel volume in the high tertile group than in the low and intermediate tertile groups (19.4 ± 3.7 vs 17.4 ± 4.4 vs 16.7 ± 4.1 mm(3)/mm, p = 0.05). There was no significant difference in lumen volume between the 3 groups. Plaque volume was significantly greater in the high than in the low tertile group (8.6 ± 2.4 vs 6.7 ± 2.2 mm(3)/mm, p = 0.01). IB-IVUS analysis demonstrated greater lipid (59.1 ± 9.1% vs 49.7 ± 10.9% vs 51.1 ± 9.3%, p = 0.001) and less fibrous components (36.8 ± 7.8% vs 44.3 ± 7.8% vs 43.2 ± 6.7%, p <0.001) in the high than in the low and intermediate tertile groups. Multivariate analysis showed high SUA as an independent predictor of increasing lipid volume. In conclusion, elevated SUA level is associated with greater lipid content of coronary plaque in patients with ACS than in patients with normal levels.

Danger signaling in atherosclerosis

All aspects of the pathogenesis of atherosclerosis are critically influenced by the inflammatory response in vascular plaques. Research in the field of innate immunity from the past 2 decades has uncovered many novel mechanisms elucidating how immune cells sense microbes, tissue damage, and metabolic derangements. Here, we summarize which triggers of innate immunity appear during atherogenesis and by which pathways they can contribute to inflammation in atherosclerotic plaques. The increased understanding gained from studies assessing how immune activation is associated with the pathogenesis of atherosclerosis has provided many novel targets for potential therapeutic intervention. Excitingly, the concept that inflammation may be the core of cardiovascular disease is currently being clinically evaluated and will probably encourage further studies in this area.

Anti-inflammatory therapies for atherosclerosis

The view of atherosclerosis as an inflammatory disease has emerged from observations of immune activation and inflammatory signalling in human atherosclerotic lesions, from the definition of inflammatory biomarkers as independent risk factors for cardiovascular events, and from evidence of low-density lipoprotein-induced immune activation. Studies in animal models of hyperlipidaemia have also supported the beneficial effects of countering inflammation to delay atherosclerosis progression. Specific inflammatory pathways with relevance to human diseases have been identified, and inhibitors of these pathways are either already in use for the treatment of other diseases, or are under development and evaluation. These include 'classic' drugs (such as allopurinol, colchicine, and methotrexate), biologic therapies (for example tumour necrosis factor inhibitors and IL-1 neutralization), as well as targeting of lipid mediators (such as phospholipase inhibitors and antileukotrienes) or intracellular pathways (inhibition of NADPH oxidase, p38 mitogen-activated protein kinase, or phosphodiesterase). The evidence supporting the use of anti-inflammatory therapies for atherosclerosis is mainly based on either observational or small interventional studies evaluating surrogate markers of disease activity. Nevertheless, these data are crucial to understand the role of inflammation in atherosclerosis, and to design randomized controlled studies to evaluate the effect of specific anti-inflammatory strategies on cardiovascular outcomes.

Association between serum vitamin D levels and subclinical coronary atherosclerosis and plaque burden/composition in young adult population

Evidence suggests that low 25-OH vitamin D 25(OH)D concentrations may increase the risk of several cardiovascular diseases such as hypertension, peripheral vascular disease, diabetes mellitus, obesity, myocardial infarction, heart failure and cardiovascular mortality. Recent studies suggested a possible relationship between vitamin D deficiency and increased carotid intima-media wall thickness and vascular calcification. We hypothesized that low 25(OH)D may be associated with coronary atherosclerosis and coronary plaque burden and composition, and investigated the relationship between serum vitamin D levels and coronary atherosclerosis, plaque burden or structure, in young adult patients by using dual-source 128x2 slice coronary computed tomography angiography (CCTA). We included 98 patients with coronary atherosclerosis and 110, age and gender matched, subjects with normal findings on CCTA examinations. Patients with subclinical atherosclerosis had significantly higher serum total cholesterol, triglycerides, hs-CRP, uric acid, HbA1c and creatinine levels and lower serum 25(OH)D levels in comparison with controls. There was no significant correlation between 25(OH)D and plaque morphology. There was also a positive relationship between 25(OH)D and plaque burden of coronary atherosclerosis. In multivariate analysis, coronary atherosclerosis was associated high hs-CRP (adjusted OR: 2.832), uric acid (adjusted OR: 3.671) and low 25(OH)D (adjusted OR: 0.689). Low levels of 25(OH)D were associated with coronary atherosclerosis and plaque burden, but there was no significant correlation between 25(OH)D and plaque morphology.

A cross-sectional analysis of the relationship between uric acid and coronary atherosclerosis in patients with suspected coronary artery disease in China

Background

Although many studies have examined the relationship between uric acid (UA) and coronary artery disease (CAD), whether UA is an independent risk factor contributing to progression of CAD is still controversial. Whether UA plays a different role in different sexes is also unclear.

Methods

A total of 1116 individuals with suspected CAD were stratified into four groups according to their serum UA quartiles in total (men and women combined), in men, and in women. The association of UA with coronary atherosclerosis was assessed by univariable and multivariable logistic regression.

Results

In total and in women, the prevalence of any plaques and significant/severe stenosis was significantly increased with an increase in quartiles of UA (all P < 0.05). The proportion of triple-vessel disease and left main artery lesion was highest in the fourth quartile (both p < 0.05). Increasing quartiles of UA were significantly associated with a coronary artery calcium score (CACS) >10 (all P < 0.01). As UA levels increased in women, the incidence of double-vessel lesions (p = 0.017) and the proportion of mixed plaques (p = 0.022) were significantly increased. The proportion of a CACS of 0 in total, in men and women was highest in the first quartile (all P < 0.01). UA was the strongest predictor of significant stenosis, multivessel disease, and mixed plaques in women (all p < 0.05). UA was the only risk factor for mixed plaques in total (P = 0.046).

Conclusion

The level of UA was significantly associated with coronary atherosclerosis in women, but not men.

Optimizing current treatment of gout

Gout is the most common inflammatory arthritis worldwide. Although effective treatments exist to eliminate sodium urate crystals and to 'cure' the disease, the management of gout is often suboptimal. This article reviews available treatments, recommended best practice and barriers to effective care, and how these barriers might be overcome. To optimize the management of gout, health professionals need to know not only how to treat acute attacks but also how to up-titrate urate-lowering therapy against a specific target level of serum uric acid that is below the saturation point for crystal formation. Current perspectives are changing towards much earlier use of urate-lowering therapy, even at the time of first diagnosis of gout. Holistic assessment and patient education are essential to address patient-specific risk factors and ensuring adherence to individualized therapy. Shared decision-making between a fully informed patient and practitioner greatly increases the likelihood of curing gout.

Usefulness of preprocedural serum uric acid level to predict restenosis of bare metal stents

Serum uric acid (SUA) level is known as a significant predictor for cardiovascular diseases, partly through increased inflammatory response and smooth muscle cell proliferation. Inflammation and smooth muscle cells play a crucial role in the pathogenesis of in-stent restenosis (ISR). However, the relation between SUA and ISR has not been studied. The aim of the present study was to investigate the predictive value of preprocedural SUA on the development of ISR in patients who undergo coronary bare-metal stent implantation. Clinical, biochemical, and angiographic data from 708 consecutive patients (mean age 60.3 ± 9.3 years, 71% men) who had undergone bare-metal stent implantation and additional control coronary angiography for stable or unstable angina pectoris were analyzed. Patients were divided into tertiles on the basis of preprocedural SUA levels. Stent restenosis was observed in 54 patients (23%) in the lowest tertile, in 79 (34%) in the middle tertile, and in 109 (46%) in the highest tertile (p <0.001). Using multiple logistic regression analysis, diabetes mellitus, smoking, high-density lipoprotein cholesterol, stent length, C-reactive protein level, and preprocedural SUA level emerged as independent predictors of ISR. On receiver-operating characteristics curve analysis, SUA level >5.5 mg/dl had 75% sensitivity and 71% specificity (area under the curve 0.784, p <0.001) in predicting ISR. In conclusion, higher preprocedural SUA is a powerful and independent predictor of bare-metal stent restenosis in patients with stable and unstable angina pectoris.

Actions of "antioxidants" in the protection against atherosclerosis

This review addresses the role of oxidative processes in atherosclerosis and its resulting cardiovascular disease by focusing on the outcome of antioxidant interventions. Although there is unambiguous evidence for the presence of heightened oxidative stress and resulting damage in atherosclerosis, it remains to be established whether this represents a cause or a consequence of the disease. This critical question is complicated further by the increasing realization that oxidative processes, including those related to signaling, are part of normal cell function. Overall, the results from animal interventions suggest that antioxidants provide benefit neither generally nor consistently. Where benefit is observed, it appears to be achieved at least in part via modulation of biological processes such as increase in nitric oxide bioavailability and induction of protective enzymes such as heme oxygenase-1, rather than via inhibition of oxidative processes and lipid oxidation in the arterial wall. Exceptions to this may be situations of multiple/excessive stress, the relevance of which for humans is not clear. This interpretation is consistent with the overall disappointing outcome of antioxidant interventions in humans and can be rationalized by the spatial compartmentalization of cellular oxidative signaling and/or damage, complex roles of oxidant-producing enzymes, and the multifactorial nature of atherosclerosis.

The effects of mammalian target of rapamycin inhibitors on serum uric acid levels in renal transplant patients

BACKGROUNDS/AIMS

Elevated uric acid (UA) levels are frequently observed after renal transplantation. We investigated the consequences of shifting from calcineurin inhibitors (CNI) to mammalian target of rapamycin inhibitors (mTORi) on UA levels and graft functions.

METHODS

Ninety-six patients were enrolled. Main points of interest were changes in UA and glomerular filtration rate (GFR).

RESULTS

Mean age of the whole population was 39 ± 11 years (18-73), and 64.2 % were male. Patients were stratified into two groups according to their CNI type prior to the switch as cyclosporin A (CsA) or tacrolimus (Tac). Patients that were switched from CsA had a mean GFR of 49 ± 18 ml/min and serum UA level of 7.4 ± 1.8 mg/dl at the pre-switch period. Mean GFR increased to 53 ± 22 ml/min (p = 0.03), and UA levels decreased to 6.2 ± 1.6 mg/dl at the final visit (p < 0.001). In the Tac group, pre-switch mean GFR was 59 ± 28 ml/min and serum UA level 6.6 ± 2.6 mg/dl. In this group, mean GFR increased to 63 ± 28 ml/min (p = 0.03) and UA levels decreased to 6.2 ± 2.1 at the last visit (p < 0.001).

CONCLUSION

Switch from CNI to mTORi-based regimen provides better control of UA levels and improves renal functions.

Associations between serum uric acid and markers of subclinical atherosclerosis in young adults. The cardiovascular risk in Young Finns study

BACKGROUND AND METHODS

Serum uric acid (SUA) is a suggested biomarker for established coronary artery disease, but the role of SUA in early phases of atherosclerosis is controversial. The relations of SUA with vascular markers of subclinical atherosclerosis, including carotid artery intima-media thickness (cIMT), carotid plaque, carotid distensibility (Cdist) and brachial flow-mediated dilatation (FMD) were examined in 1985 young adults aged 30-45 years. In addition to ordinary regression, we used Mendelian randomization techniques to infer causal associations.

RESULTS

In women, the independent multivariate correlates of SUA included BMI, creatinine, alcohol use, triglycerides, glucose and adiponectin (inverse association) (Model R(2) = 0.30). In men, the correlates were BMI, creatinine, triglycerides, C-reactive protein, alcohol use, total cholesterol and adiponectin (inverse) (Model R(2) = 0.33). BMI alone explained most of the variation of SUA levels both in women and men (Partial R(2) ∼ 0.2). When SUA was modeled as an explanatory variable for vascular markers, it directly associated with cIMT and inversely with Cdist in age- and sex-adjusted analysis. After further adjustments for BMI or glomerular filtration rate, these relations were reduced to non-significance. No associations were found between SUA and FMD or the presence of a carotid plaque. Mendelian randomization analyses using known genetic variants for BMI and SUA confirmed that BMI is causally linked to SUA and that BMI is a significant confounder in the association between SUA and cIMT.

CONCLUSION

SUA is associated with cardiovascular risk markers in young adults, especially BMI, but we found no evidence that SUA would have an independent role in the pathophysiology of early atherosclerosis.

Uric acid as one of the important factors in multifactorial disorders--facts and controversies

With considering serum concentration of the uric acid in humans we are observing hyperuricemia and possible gout development. Many epidemiological studies have shown the relationship between the uric acid and different disorders such are obesity, metabolic syndrome, hypertension and coronary artery disease. Clinicians and investigators recognized serum uric acid concentration as very important diagnostic and prognostic factor of many multifactorial disorders. This review presented few clinical conditions which are not directly related to uric acid, but the concentrations of uric acid might have a great impact in observing, monitoring, prognosis and therapy of such disorders. Uric acid is recognized as a marker of oxidative stress. Production of the uric acid includes enzyme xanthine oxidase which is involved in producing of radical-oxigen species (ROS). As by-products ROS have a significant role in the increased vascular oxidative stress and might be involved in atherogenesis. Uric acid may inhibit endothelial function by inhibition of nitric oxide-function under conditions of oxidative stress. Down regulation of nitric oxide and induction of endothelial dysfunction might also be involved in pathogenesis of hypertension. The most important and well evidenced is possible predictive role of uric acid in predicting short-term outcome (mortality) in acute myocardial infarction (AMI) patients and stroke. Nephrolithiasis of uric acid origin is significantly more common among patients with the metabolic syndrome and obesity. On contrary to this, uric acid also acts is an “antioxidant”, a free radical scavenger and a chelator of transitional metal ions which are converted to poorly reactive forms.

The role of serum uric acid in cardiovascular disease in type 2 diabetic and non-diabetic subjects: a narrative review

The role of serum uric acid (UA) as a marker or risk factor of cardiovascular disease (CVD) is still controversial. The strong association of serum UA with established risk factors such as hypertension, Type 2 diabetes, dyslipidemia, and chronic kidney disease makes it difficult to establish a direct causal role of serum UA in the development and progression of CVD. The main aims of this review are: 1) to briefly summarize the most relevant studies concerning the association of serum UA with hypertension, chronic kidney disease, CVD events, and death both in patients without diabetes and in those with Type 2 diabetes; and 2) to briefly discuss the putative underlying mechanisms that link serum UA to adverse CVD outcomes. A search was conducted to identify relevant studies in the major electronic databases (MEDLINE and EMBASE, from January 1990 to December 2010) using Medical Subjects Headings and keywords. Collectively, by reviewing the published data in the literature, it emerges that serum UA may exert a number of potentially adverse cardiovascular effects. Nevertheless, the prognostic role of elevated serum UA level as a causal risk factor of adverse CVD outcomes remains still controversial, especially in patients with Type 2 diabetes. At this time, the treatment of asymptomatic hyperuricemia for the primary prevention of CVD is not recommended.