Uric acid is an independent predictor of cardiovascular events in post-menopausal women

Uric acid and metabolic syndrome: Importance of hyperuricemia cut-off

BACKGROUND

The relationship between HyperUricemia (HU) and Metabolic Sindrome (MS) and if Uric Acid (UA) should be inserted into MS definitions is a matter of debate. Aim of our study was to evaluate the correlation between UA and HU with Insulin Resistance (IR) and MS in a population of hypertensive patients. HU was defined with two cut-offs (the classic one of ≥6 mg/dL for women and ≥ 7 for men; the newly proposed URRAH one with ≥5.6 mg/dL for both sexes).

METHODS

We enrolled 473 Hypertensive patients followed by the Hypertension Unit of San Gerardo Hospital (Monza, Italy). IR was defined through TG/HDL ratio and NCEP-ATP-III criteria were used for MS diagnosis.

RESULTS

MS was found in 33.6 % while HU affected 14.8 % of subjects according to the traditional cut-off and 35.9 % with the URRAH cut-off. 9.7 % (traditional cut-off) and 17.3 % (URRAH's threshold) of the subjects had both HU and MS. UA level was significantly higher in MS group (5.7 vs 4.9 mg/dL, p < 0.0001) as well as for HU (29.0 vs 7.6 % and 51.6 vs 28.0 %, for classic and URRAH cut-off respectively, p < 0.0001 for both comparison). Logistic multivariable regression models showed that UA is related to MS diagnosis (OR = 1.608 for each 1 mg/dL), as well as HU with both cut-off (OR = 5.532 and OR = 3.379, p < 0.0001 for all comparison, for the classic cut-off and the URRAH one respectively).

CONCLUSIONS

The main finding of our study is that UA and HU significantly relate to IR and MS. The higher the values of UA and the higher the cut-off used, the higher the strength of the relationship.

Prognostic role of serum albumin levels in patients with chronic heart failure

BACKGROUND

Hypoalbuminemia is common in heart failure (HF) patients; however, there are no data regarding the possible long-term prognostic role of serum albumin (SA) in the younger population with chronic HF without malnutrition. The aim of this study was to examine the long-term prognostic role of SA levels in predicting major adverse cardiac events (MACE) in middle-aged outpatients with chronic HF.

METHODS

In the present retrospective analysis, 378 subjects with HF were enrolled. MACE (non-fatal ischemic stroke, non-fatal myocardial infarction, cardiac revascularization or coronary bypass surgery, and cardiovascular death), total mortality, and HF hospitalizations (hHF) occurrence were evaluated during a median follow-up of 6.1 years.

RESULTS

In all population, 152 patients had a SA value < 3.5 g/dL and 226 had a SA value ≥ 3.5 g/dL. In patients with SA ≥ 3.5 g/dL, the observed MACE were 2.1 events/100 patient-year; while in the group with a worse SA levels, there were 7.0 events/100 patient-year (p < 0.001). The multivariate analysis model confirmed that low levels of SA increase the risk of MACE by a factor of 3.1. In addition, the presence of ischemic heart disease, serum uric acid levels > 6.0 mg/dL, chronic kidney disease, and a 10-year age rise, increased the risk of MACE in study participants. Finally, patients with SA < 3.5 g/dl had a higher incidence of hHF (p < 0.001) and total mortality (p < 0.001) than patients with SA ≥ 3.5 g/dl.

CONCLUSIONS

Patients with chronic HF that exhibits low SA levels show a higher risk of MACE, hHF and total mortality.

Sex-related differences for uric acid in the prediction of cardiovascular events in essential hypertension. A population prospective study

BACKGROUND

Uric acid (UA) is an independent prognostic factor for cardiovascular events, but there are no data demonstrating a different risk profile between women and men. Thus, we tested whether UA is associated with a possible sex-related difference in fatal and non-fatal cardiovascular events.

METHODS

In this prospective population-based study we enrolled 1,650 never-treated Caucasian hypertensive outpatients referred to Catanzaro University Hospital (Italy). Inclusion criteria were newly diagnosed hypertensive patients, aged 20 years or more. Exclusion criteria were secondary form of hypertension, previous cardiovascular events, rheumatic and non-rheumatic valvular heart disease, prosthetic valves, cardiomyopathies, type-2 diabetes, chronic kidney disease, malignant diseases, gout arthritis and secondary forms of hyperuricemia, liver diseases, peripheral vascular diseases, and heart failure. Anthropometric, clinical, and biochemical parameters were measured. UA prognostic role was investigated by Cox regression analyses. Receiver-operating characteristic curve analyses and area under the curve were used to determine the predictive validity and the optimal cut-off point of UA. We investigated following endpoints: coronary events (fatal and nonfatal myocardial infarction, unstable angina, coronary revascularization procedures, coronary death); fatal and nonfatal stroke; all-cause mortality and major adverse cardiovascular events (MACE).

RESULTS

We enrolled 830 males and 820 females aged 52.2 ± 11.3 years. During 9.5 ± 3.1 years follow-up, there were 424 new clinical events (2.71%): 250 coronary (1.59%), 118 (0.75%) cerebrovascular, and 56 (0.40%) deaths. Comparison between groups demonstrated a higher and significant difference in incidence rate in females for MACE (3.08 vs 2.33%, P = 0.001), coronary (1.82 vs 1.36%, P = 0.014) and cerebrovascular events (0.93 vs 0.57%, P = 0.006). UA at multiple Cox regression analysis resulted a strong and significant predictor of coronary events (HR = 1.493;95% CI 1.375-1.621), cerebrovascular events (HR = 1.256;95% CI 1.109-1.423), MACE (HR = 1.415;95% CI 1.328- 53 1.508), and all-cause mortality (HR = 1.469;95% CI 1.237-1.745) in the whole population and in both groups with a HR higher in females. The best estimated cut-off values of uric acid for males and females predicted these endpoints equally well, but it was always lower in females than males.

CONCLUSIONS

We demonstrate, that UA operates with a sex-related impact and best cut-off value in predicting cardiovascular outcomes and all-cause mortality, reflecting a possible sex difference in disease pathophysiology.

Uric acid level in climacteric women and its association with clinical and metabolic parameters

Climacteric women often experience unfavorable metabolic changes. Consequently, identifying markers that may contribute to such undesirable changes is imperative. This study aimed to evaluate serum uric acid (UA) concentration and its association with metabolic and clinical parameters in climacteric women. We selected 672 women between 40 and 65 years and performed interviews, biochemical analyses, blood pressure, and anthropometric measurements. UA levels were determined using the enzymatic-colorimetric method. We compared variables according to the quartiles of UA using the Kruskal-Wallis test. The mean UA level was 4.9 ± 1.5 mg/dl, ranging from 2.0 to 11.6 mg/dl. We found that UA levels greater than 4.8 mg/dl were associated with adverse metabolic parameters in climacteric women. For all anthropometric and biochemical variables, we observed significantly better results in women who had lower UA levels (p < 0.05). Similarly, we observed a significant increase in blood pressure, frequency of metabolic syndrome, and cardiovascular risk as UA levels increased (p < 0.05). Our findings showed that climacteric women with high levels of UA were more likely to have adverse metabolic and clinical parameters than those with lower UA levels. Further studies may determine the causal relationship between UA and metabolic changes in climacteric women.

Association of uric acid levels with cardiac syndrome X: A meta-analysis

Objective: The pathogenesis of elevated uric acid (UA) levels in patients with cardiac syndrome X (CSX) is unclear, and the results presented in recent papers on UA levels in patients with CSX are controversial. Therefore, we conducted a meta- analysis to assess the relationship between UA levels and CSX.

Methods: Three databases, including the Web of Science, EMBASE and PubMed, were systematically searched until January 2022. Fixed-effect and random-effects models were used to analyze the relationship between UA levels and CSX. Subgroup analysis and sensitivity analysis were also performed.

Results: Six studies involving 406 CSX patients and 267 non-CSX were included. Our results showed a significant relationship between UA levels and CSX, with a pooled SMD of 0.68 (95% CI 0.37 to 1.00; p < 0.0001). We also found a close relationship between UA levels and CSX for patients ≥ 55 years old (SMD:0.70, 95% CI: 0.41 to 0.99, p < 0.00001), for patients < 55 years old (SMD: 0.68, 95% CI: 0.25 to 1.12, p =0 .002), for women ≥ 60% (SMD: 0.77, 95% CI: 0.33 to 1.14, p =0 .0004), for women < 60% (SMD: 0.61, 95% CI:0.23 to 0.98, p =0 .001), for BMI ≥ 28 Kg/m² (SMD :0.61, 95% CI: 0.23 to 0.98, p =0 .001), for BMI < 28 Kg/m² (SMD:0.75, 95% CI: 0.31 to 1.19, p =0 .0009), for publication years ≥ 2012 (SMD :0.69, 95% CI: 0.23 to 1.15, p = 0.003), for publication years < 2012 (SMD:0.73, 95% CI:0.41 to 1.05, p < 0.00001), and for Turkey (SMD:0.75, 95% CI:0.38 to 1.11, p <.0001). Sensitivity analysis showed that the pooled results remained consistent after removing any one study or converting the random-effects model to fixed-effects model.

Conclusion: Our results indicated a strong association between high UA levels and CSX. However, more well-designed studies are needed to investigate whether early treatment of hyperuricemia can reduce the incidence of CSX.

Cardiovascular events in hyperuricemia population and a cardiovascular benefit-risk assessment of urate-lowering therapies: a systematic review and meta-analysis

BACKGROUND

Hyperuricemia and gout have become public health concerns; many important guidelines have recommended xanthine oxidase inhibitors (XOIs) as the first-line urate-lowering therapies (ULTs) to treat chronic gout with hyperuricemia. However, whether treating hyperuricemia and gout with ULTs modifies cardiovascular risks remains controversial. The aim of this study was to assess the incident risk of cardiovascular (CV) events (CVE) in hyperuricemia population, assess the cardiovascular benefit-risk of ULTs in hyperuricemia patients with or without gout in diverse cardiovascular risk sub-groups, and specify the safety of different ULTs.

METHODS

We searched PubMed, Embase, the Cochrane Library, Wanfang, Chongqing VIP (CQVIP, en.cqvip.com), and China National Knowledge Infrastructure Database for prospective cohort studies and randomized controlled trials (RCTs) in English and Chinese. Potential medications included XOIs, and uricosurics. RCTs were divided into sub-groups analysis based on blinding status and patients' history of CV diseases. Risk ratios (RRs) were calculated and were reported with corresponding 95% confidence intervals (CIs) by fixed-effects or random-effects model.

RESULTS

Seven prospective cohort studies and 17 RCT studies were included. The risks of both major adverse cardiovascular events (MACE) (RR = 1.72, 95% CI 1.28-2.33) and CVE (RR = 1.35, 95% CI 1.12-1.62) were higher in the hyperuricemia population than non-hyperuricemia one. In seven RCT studies where XOIs were compared with no-treatment or placebo, the results of five low CV risk studies showed that XOIs lowered the risks of both MACE (RR = 0.35, 95% CI 0.20-0.62) and CVE (RR = 0.61, 95% CI 0.44-0.85); whereas two high CV risk studies showed that XOIs lowered the risk of CVE (RR = 0.69, 95% CI 0.54-0.88) rather than MACE (RR = 0.62, 95% CI 0.29-1.35). In nine RCT studies where the cardiovascular safety between febuxostat and allopurinol were compared, no statistical difference was found in the risk of MACE or CVE.

CONCLUSIONS

The hyperuricemia population does have a higher incidence of CVE, and the results suggested that XOIs might reduce the incidence of MACE and total CVE. In addition, from the perspective of cardiovascular safety, febuxostat equaled allopurinol in our meta-analysis.

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

For 40 years many studies have been conducted to verify the connection between serum uric acid concentration and cardiovascular diseases, such as myocardial infarction. Unfortunately, it remains unclear which form of uric acid - prooxidant or antioxidant - could be a predictive marker of cardiovascular disease, especially in patients after myocardial infarction. It is well-known that uric acid is an organic compound and the water-soluble final product of purine catabolism, which is catalysed by xanthine oxidoreductase and excreted by kidneys. An increased concentration of UA in human plasma leads to diseases like tumours, renal disorders, atherosclerosis, hypertension, diabetes, metabolic syndrome, polycythaemia vera, haemolytic anaemias, ischemia, oxidative stress, and rare genetic disorders connected with UA degradation. Epidemiological studies have shown that UA might be a marker of oxidative stress, progression of inflammation, or renal disease. A fortiori, it is possible that could also be a predictor for short/long-term survival of patients with CVD. Evidence provided by multiple studies is controversial and mutually exclusive. Among 71 studies the most of them found an independent association between SUA and CVD risk. Some of those studies confirm that CVD risk is higher in women who had elevated SUA levels. On the other hand, many studies reached the opposite conclusion and did not find any relationship between SUA and CVD mortality and morbidity.

Serum Uric Acid is Associated with Renal Prognosis of Lupus Nephritis in Women but not in Men

Lupus nephritis (LN) is a major complication of systemic lupus erythematosus. Early intervention in lupus nephritis improves prognosis. There is an association between hyperuricemia and lupus nephritis; nevertheless, the sex-specific role of uric acid in lupus nephritis remains unclear. We retrospectively analyzed 578 patients diagnosed with LN by renal biopsy. We determine the relationship of serum uric acid to progression of LN using Kaplan–Meier survival analyses and Cox proportional hazards models. The primary end point was LN progression defined as the initiation of dialysis or kidney transplantation. Men had higher mean serum uric acid levels than did women. Every 1 mg/dL increase in baseline uric acid level increased the risk of LN progression by 15.1%. The serum uric acid level was an independent risk factor for LN progression in women (hazard ratio [HR], 1.158; confidence interval [CI], 1.018–1.317; p = 0.028) but not in men (HR, 1.499; CI, 0.964–2.331; p = 0.072). Sensitivity analysis involving serum uric acid terciles generated consistent and robust results. Serum uric acid level was an independent risk factor for LN progression in women but not in men.

Predictive Value of Uric Acid Regarding Cardiometabolic Disease in a Community-Dwelling Older Population in Shanghai: A Cohort Study

Aim: This study aimed to test the predictive power of serum uric acid (UA) levels on new-onset cardiometabolic risk in the Chinese population.

Methods: Older people who visited a community health center for a yearly health check (N = 5,000; men: 47%, women: 53%) were enrolled. Participants were followed for 4 years from baseline (median: 48 months), with the endpoints being development of heart failure, atrial fibrillation, diabetes, hypertension, metabolic syndrome, or kidney disease.

Results: During follow-up, 342 men (7.4%) and 360 women (8.6%) developed hypertension; 98 men (2.48%) and 135 women (3.06%) developed diabetes; and 175 men (5.04%) and 214 women (4.51%) developed metabolic syndrome. Incident diabetes, hypertension, and metabolic syndrome increased with increased UA levels at baseline (P < 0.001). A multivariate Cox proportional hazards analysis revealed a significant, independent association between the baseline UA level and the onset and future hypertension and/or diabetes in both men and women. However, UA is associated with the development of metabolic syndrome in men, but not in women.

Conclusion: UA is an independent predictor of new-onset diabetes and hypertension in both women and men and a predictor of new-onset metabolic syndrome only in men.

The Effects of Hyperuricemia on the Prognosis of IgA Nephropathy are More Potent in Females

Hyperuricemia is a potential risk factor for immunoglobulin A nephropathy (IgAN) progression but its sex-specific effects on IgAN progression remain unclear. This study aimed to determine the effect of serum uric acid on IgAN progression and whether its effect varied according to sex. A total of 4339 patients who diagnosed with IgAN by renal biopsy were retrospectively analyzed. We assessed the association of serum uric acid on IgAN progression using Kaplan–Meier survival analyses and Cox proportional hazards models. The study’s primary end point was IgAN progression that was defined as a 50% decline in the estimated glomerular filtration rate or the initiation of dialysis. On average, the serum uric acid levels were higher in the men than in the women. In the fully adjusted Cox proportional hazards model that considered all subjects, the risk of IgAN progression increased by about 25.6% for every 1 mg/dL increase in the baseline uric acid level. The serum uric acid level was an independent risk factor for IgAN progression in both sexes but its effect was more pronounced in the women (hazard ratio [HR], 1.383; confidence interval [CI],1.263 to 1.514; p < 0.001) than in the men (HR, 1.181; CI, 1.097 to 1.272; p < 0.001) (p_interaction < 0.001). A sensitivity analysis involving serum uric acid quartiles generated consistent and robust results. In conclusion, the serum uric acid level was an independent risk factor for IgAN progression and its effect was more pronounced among the women compared with that among the men.

Serum Uric Acid and Triglycerides in Chinese Patients with Newly Diagnosed Moyamoya Disease: A Cross-Sectional Study

Background

Evidence regarding the relationship between serum uric acid and triglycerides is limited. Therefore, the specific objective of this study was to investigate whether serum uric acid was independently related to triglycerides in Chinese patients with newly diagnosed moyamoya disease after adjusting for other covariates.

Methods

The present study was a cross-sectional study. A total of 261 Chinese patients with newly diagnosed moyamoya disease were recruited from a hospital in China from 24 March 2013 to 24 December 2018. The independent variable and the dependent variable were serum uric acid measured at baseline and triglycerides, respectively. The covariates involved in this study included age, sex, body mass index, smoking status, and alcohol consumption.

Results

The average age of the 227 selected participants was 47.5 ± 12.6 years old, and approximately 48.5% of them were male. The results of the fully adjusted linear regression showed that serum uric acid (10 μmol/L) was positively associated with triglycerides (mmol/L) after adjusting for confounders (β 0.048, 95% CI 0.032, 0.064).

Conclusions

In patients with moyamoya disease, there seemed to be a positive association between serum uric acid and triglycerides.

Association between Serum Urate and Risk of Hypertension in Menopausal Women with XDH Gene

Elevated serum urate (sUA) concentrations have been associated with an increased risk of hypertension. We aimed to examine the association of sUA concentration on the risk of hypertension in pre- and post-menopausal women and investigated the association between the polymorphism of the xanthine dehydrogenase gene and the risk of hypertension. Among 7294 women, 1415 premenopausal and 5879 postmenopausal women were recruited. Anthropometric parameters as risk factors of hypertension were identify by logistic regression models. In addition, we investigated an association between xanthine dehydrogenase gene and sUA and their combined associations on the risk of hypertension. Body mass index (BMI) and waist circumference (WC) were significantly increased in accordance to the increase of sUA levels (p < 0.001). Multivariate logistic regression analysis showed postmenopausal women with a high sUA and high BMI were 3.18 times more likely to have hypertension than in those with normal and lower sUA (Odds ratio: 3.18, 95% confidence interval: 2.54–3.96). Postmenopausal women with a high WC were 1.62 times more likely to have hypertension than in those with normal and lower sUA. Subjects with the AG genotype of rs206860 was found to be at lower risk of hypertension (odd ratio: 0.287, 95% confidence interval: 0.091–0.905, p = 0.033). This cross-sectional study indicated a high sUA is associated with a higher risk of hypertension in postmenopausal women. Further well-designed prospective studies in other populations are warranted to validate our results.

Association of uric acid with stenosis of intracranial and extracranial arteries in elderly patients with cerebral infarction

BACKGROUND

To determine whether uric acid (UA) and intracranial and extracranial atherosclerosis stenosis of elderly patients suffering from ischaemic stroke are inter-related.

METHODS

Elderly patients with ischaemic stroke underwent computed tomography angiography (CTA) were enrolled between October 2015 and December 2017. We collected clinical assessment, image data, and laboratory tests, and divided patients into four groups: (1) intracranial stenosis atherosclerosis (ICAS) group, (2) combined intracranial and extracranial atherosclerosis stenosis (COAS) group, (3) extracranial carotid stenosis atherosclerosis (ECAS) group, and (4) non-cerebral stenosis atherosclerosis (NCAS) group. We used univariate and multiple logistic regression analyses to explore potential predictors.

RESULTS

We included 408 patients in this study, then divided them into elder group (n = 196) and young- and middle-aged group (n = 212). In old stroke patients, 72 cases (36.73%) were classified as the ICAS group, 45 cases (22.96%) as the COAS group, 21 cases (10.71%) as the ECAS group, and 58 cases (29.59%) as the NCAS group. The level of UA was comparatively higher (p = 0.033) in ICAS than in NCAS. Compared with the group which had only one stenosis artery, UA was substantially increased in patients with more than one stenosis intracranial artery (p < 0.001). With a multivariable analysis, UA was an independent predictor for intracranial stenosis of elderly patients (OR = 1.003, p = 0.042), but the relationship between extracranial artery stenosis and uric acid was negative.

CONCLUSIONS

Hyperuricaemia is a risk factor of intracranial artery stenosis rather than of ECAS in elderly patients with cerebral infarction.

One-Hour Postload Hyperglycemia: Implications for Prediction and Prevention of Type 2 Diabetes

CONTEXT

Recently, a value of 1-hour postload glucose concentration (1-h-PG) ≥155 mg/dL (8.6 mmol/L) in individuals with normal glucose tolerance (NGT) has been found to be associated with an increased risk for future type 2 diabetes mellitus (T2DM). In this review, we analyze the implication of 1-h-PG determination in prediction of T2DM and cardiovascular disease.

DESIGN

A literature search was performed using MEDLINE. We included all English studies published up to February 2018 in peer-reviewed journals that examined the relationship between 1-h-PG and diabetes, cardiometabolic alterations, organ damage, and cardiovascular disease.

RESULTS

Several longitudinal studies have consistently shown that 1-h-PG ≥155 mg/dL can recognize individuals at increased risk for future T2DM among subjects with NGT. Additionally, we describe the pathophysiological abnormalities associated with 1-h-PG ≥155 mg/dL including impaired insulin sensitivity, β-cell dysfunction, and increased glucose intestinal absorption, which are known to be involved in T2DM pathogenesis. Importantly, numerous studies have demonstrated that a value of 1-h-PG ≥155 mg/dL in individuals with NGT is not only linked to an increased risk for future T2DM, but also able to identify those having a worse cardiovascular phenotype and an increased risk of adverse cardiovascular outcomes.

CONCLUSIONS

Although 1-h-PG determination is not currently recommended by the American Diabetes Association for identifying high-risk individuals, the available evidence indicates that a value of 1-h-PG ≥155 mg/dL may be a useful tool to recognize, among subjects with NGT, those at increased risk of T2DM and cardiovascular disease.

The polymorphism rs35767 at IGF1 locus is associated with serum urate levels

Previous studies suggested that the IGF-1/IGF-1 receptor signaling pathway may contribute to regulate uric acid levels. To confirm this hypothesis, we assessed the effects of the IGF-1-raising genetic variant rs35767 on urate levels in serum and urine, and we investigated IGF-1 ability to modulate the expression of transporters involved in reabsorption and secretion of uric acid in the kidney. The study population included 2794 adult Whites. 24-hour urinary uric acid concentration was available for 229 subjects. rs35767 polymorphism was screened using TaqMan genotyping assays. HEK293 (human embryonic kidney-293) cell line was treated with IGF-1 (1, 5, 10, 50 nM) for 24-hours, and differences in the expression of urate transporters were evaluated via Western Blot and real time rtPCR. Individuals carrying the IGF-1-raising allele (rs35767 T) exhibited significantly lower levels of serum urate according to both additive and recessive models, after correction for gender, age, BMI, glucose tolerance, glomerular filtration rate, and anti-hypertensive treatment. TT genotype carriers displayed higher uricosuria than C allele carriers did, after adjusting for confounders. Exposure of HEK293 cells to IGF-1 resulted in a dose-dependent increase of uric acid transporters deputed to uric acid excretion (MRP4, NPT1 and BCRP), and reduction of GLUT9 expression, the major mediator of uric acid reabsorption, both at mRNA and protein level. We observed a significant association between the functional polymorphism rs35767 near IGF1 with serum urate concentrations and we provide a mechanistic explanation supporting a causal role for IGF-1 in the regulation of uric acid homeostasis.

Uric Acid Impairs Insulin Signaling by Promoting Enpp1 Binding to Insulin Receptor in Human Umbilical Vein Endothelial Cells

High levels of uric acid (UA) are associated with type-2 diabetes and cardiovascular disease. Recent pieces of evidence attributed to UA a causative role in the appearance of diabetes and vascular damage. However, the molecular mechanisms by which UA induces these alterations have not been completely elucidated so far. Among the mechanisms underlying insulin resistance, it was reported the role of a transmembrane glycoprotein, named either ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) or plasma cell antigen 1, which is able to inhibit the function of insulin receptor (I_R) and it is overexpressed in insulin-resistant subjects. In keeping with this, we stimulated human umbilical vein endothelial cells (HUVECs) with insulin and UA to investigate the effects of UA on insulin signaling pathway, testing the hypothesis that UA can interfere with insulin signaling by the activation of ENPP1. Cultures of HUVECs were stimulated with insulin, UA and the urate transporter SLC22A12 (URAT1) inhibitor probenecid. Akt and endothelial nitric oxide synthase (eNOS) phosphorylation levels were investigated by immunoblotting. ENPP1 binding to I_R and its tyrosine phosphorylation levels were tested by immunoprecipitation and immunoblotting. UA inhibited insulin-induced Akt/eNOS axis. Moreover, UA induced ENPP1 binding to I_R that resulted in an impairment of insulin signaling cascade. Probenecid reverted UA effects, suggesting that UA intracellular uptake is required for its action. In endothelial cells, UA directly interferes with insulin signaling pathway at receptor level, through ENPP1 recruitment. This evidence suggests a new molecular model of UA-induced insulin resistance and vascular damage.

Uric Acid Is Associated With Inflammatory Biomarkers and Induces Inflammation Via Activating the NF-κB Signaling Pathway in HepG2 Cells

Objective—

Serum uric acid (UA) has been associated with increased risk of cardiovascular and metabolic diseases. However, the causal mechanisms linking elevated UA levels to cardio-metabolic diseases are still unsettled. One potential explanation for how UA might contribute to cardio-metabolic disease might be its ability to induce systemic inflammation.

Approach and Results—

Herein, we report a positive relationship between serum UA and acute-phase reactants, such as high-sensitivity C-reactive protein, fibrinogen, ferritin, complement C3, and erythrocyte sedimentation rate, in a cohort of 2731 nondiabetic adults. The relationship remains significant after adjustment for several confounders, including age, sex, adiposity, anti-hypertensive treatments or diuretics use. To confirm the existence of a causal relationship, we examined the effect of UA on the expression of inflammatory biomarkers in human hepatoma HepG2 cells and characterized the signaling pathway by which UA acts. We show that UA stimulates the expression of C-reactive protein, fibrinogen, ferritin, and complement C3 in a dose-dependent fashion. The proinflammatory effects of UA were abrogated by benzbromarone, a specific inhibitor of UA transporters. Exposure of cells to UA resulted in activation of the IκB kinase/IκBα/NF-κB signaling pathway that was attenuated by benzbromarone. The effect of UA was completely blocked by the antioxidant N -acetylcysteine.

Conclusions—

These in vivo and in vitro data suggest that hyperuricemia might induce the expression of hepatic inflammatory molecules by activating the proinflammatory NF-κB signaling cascade. Because inflammation has an important pathogenetic role in metabolic and cardiovascular disease, our study may help understanding the mechanism by which hyperuricemia may contribute to organ damage.

Serum uric acid levels are associated with obesity but not cardio-cerebrovascular events in Chinese inpatients with type 2 diabetes

We aim to explore the associations between serum uric acid (SUA) and obesity and cardio-cerebrovascular events (CCEs) in Chinese inpatients with type 2 diabetes mellitus (T2DM). 2 962 inpatients with T2DM were stratified into quartile based on SUA concentrations. There were significant increases in the prevalence of both obesity (32.6%, 41.9%, 50.1%, and 62.8%, respectively, p < 0.001 for trend) and severe obesity (0.4%, 0.6%, 0.8%, and 1.3%, respectively, p < 0.001 for trend) across the SUA quartiles. A fully adjusted multiple logistic regression analysis revealed that SUA quartiles were independently associated with the presence of obesity (p < 0.001). The prevalence of CCEs was significantly higher in the obese diabetics than in the nonobese diabetics (16.8% vs. 13.2%, p = 0.027). After controlling for multiple confounding factors, BMI levels were also significantly correlated with the presence of CCEs (p = 0.020). However, there was no significant association of SUA quartiles/SUA levels with the presence of CCEs in T2DM. This study suggested that SUA levels were independently associated with obesity but not with CCEs in patients with T2DM. In selected populations such as subjects with T2DM, the role of uric acid in cardiovascular complications might be attributable to other cardiovascular risk factors, such as obesity.

Uric Acid Is Associated With Inflammation, Coronary Microvascular Dysfunction, and Adverse Outcomes in Postmenopausal Women

Uric acid is a risk factor for coronary artery disease in postmenopausal women, but the association with inflammation and coronary endothelial dysfunction (CED) is not well defined. The aim of this study was to determine the relationship of serum uric acid (SUA), inflammatory markers, and CED. In this prospective cohort study, SUA, high-sensitivity C-reactive protein levels, and neutrophil count were measured in 229 postmenopausal women who underwent diagnostic catheterization, were found to have no obstructive coronary artery disease, and underwent coronary microvascular function testing, to measure coronary blood flow response to intracoronary acetylcholine. The average age was 58 years (interquartile range, 52-66 years). Hypertension was present in 48%, type 2 diabetes mellitus in 5.6%, and hyperlipidemia in 61.8%. CED was diagnosed in 59% of postmenopausal women. Mean uric acid level was 4.7±1.3 mg/dL. Postmenopausal women with CED had significantly higher SUA compared with patients without CED (4.9±1.3 versus 4.4±1.3 mg/dL; P=0.02). There was a significant correlation between SUA and percent change in coronary blood flow to acetylcholine (P=0.009), and this correlation persisted in multivariable analysis. SUA levels were significantly associated with increased neutrophil count (P=0.02) and high-sensitivity C-reactive protein levels (P=0.006) among patients with CED, but not among those without CED. SUA is associated with CED in postmenopausal women and may be related to inflammation. These findings link SUA levels to early coronary atherosclerosis in postmenopausal women.

Sex-specific association between serum uric acid and prolonged corrected QT interval: Result from a general rural Chinese population

Recently, it has been found that high level of serum uric acid (SUA) is causally related to sudden cardiac death (SCD). We examined the sex-specific associations of SUA with prolonged heart rate-corrected QT (QTc) interval in a general Chinese population.A large sample of 11,206 Chinese research participants aged 35 years and older was recruited from rural areas of Liaoning Province during 2012 to 2013. SUA were divided into quartiles separated for males and females. Prolonged QTc interval, assessed by the Bazett formula, was defined as cut points of 460 ms or longer in females and 450 ms or longer in males. Mean (+/- standard deviation) QTc intervals were 422.1 ± 24.2 ms among 5104 males and 436.1 ± 23.5 ms among 6102 females, respectively. In both sexes, SUA showed significant correlations with QTc interval (both P < 0.001). Among male participants, the highest quartile of SUA (>379 μmol/L) was related to an increased risk for prolonged QTc interval (odds ratios: 1.402, 95% confidence interval: 1.073-1.831) compared to the lowest quartile (≤276 μmol/L) after fully adjustment. However, there were no significant relationships between SUA and prolonged QTc interval among females in all the models.Males with high SUA are prone to a higher risk for prolonged QTc interval. This study provides novel explanation for population-based findings on SUA and SCD, as well as important implications for management strategies for hyperuricemic patients in clinical practice.

Hyperuricemia as a risk factor for cardiovascular disease: clinical review

Cardiovascular diseases are one of the most important causes of morbidity and mortality worldwide. Several risk factors have been associated with the development of these pathologies. However, there is controversy about whether hyperuricemia is an independent risk factor for developing cardiovascular disease. To answer this question, we performed a recent literature review of relevant published material to assess the association of hyperuricemia with four major cardiovascular diseases: hypertension, coronary heart disease, heart failure and atrial fibrillation.

Serum Uric Acid Level Predicts Progression of IgA Nephropathy in Females but Not in Males

Background

Immunoglobulin A nephropathy (IgAN) is one of most common forms of glomerulonephritis. At this point, the clinical impact of hyperuricemia on IgAN is not clear. The aim of the present study was to explore the clinical impact of hyperuricemia on the progression of IgAN.

Study Design

Multicenter retrospective cohort study.

Setting & Participants

935 IgAN patients who were diagnosed by kidney biopsy at Osaka University Hospital, Osaka General Hospital, and Osaka Rosai Hospital. were included in this study.

Predictor

Uric acid levels at renal biopsy.

Outcomes

The outcome of interest was the time from the kidney biopsy to the time when a 50% increase in the baseline serum creatinine level was observed, which was defined as "progression".

Measurements

The baseline characteristics according to the kidney biopsy at the time of diagnosis were collected from the medical records, and included age, gender, body mass index, hypertension, diabetes (use of antidiabetic drugs), serum levels of creatinine, urinary protein, smoking status, RAAS blockers and steroid therapy.

Results

An elevated serum uric acid level was an independent risk factor for progression in female patients (per 1.0 mg/dL, multivariate-adjusted incident rate ratio 1.33 [95% confidence interval 1.07, 1.64], P = 0.008) but not in male patients (1.02 [0.81, 1.29], P = 0.855). To control a confounding effect of renal function on an association between serum uric acid level and progression in female patients, age- and serum creatinine-matched and propensity score-matched analyses were performed, and these results also supported the effect by uric acid on kidney disease progression independent of basal kidney function.

Limitations

A cohort analyzed retorospectively.

Conclusions

This study revealed that an elevated uric acid level was an independent risk factor for ESKD in female IgAN patients. Therefore, uric acid might be a treatable target in female IgAN patients.

One-hour post-load hyperglycemia combined with HbA1c identifies pre-diabetic individuals with a higher cardio-metabolic risk burden

BACKGROUND AND AIMS

Evidence suggests that combining 1-hour plasma glucose ≥155 mg/dl during an oral glucose tolerance test (OGTT) with glycosylated hemoglobin (HbA1c) significantly increases their predictive power for incident diabetes, while their individual and joint associations with cardio-metabolic risk factors remain undefined. Herein, we evaluated whether 1-hour post-load plasma glucose ≥155 mg/dl combined with HbA1c may identify pre-diabetic individuals with a higher cardio-metabolic risk.

METHODS

Anthropometric and metabolic characteristics, insulin sensitivity and insulin secretion assessed by OGTT-derived indexes, carotid intima-media thickness (IMT), pulse pressure, and rate pressure product were evaluated in 1495 individuals.

RESULTS

As compared with subjects with 1-hour post-load glucose <155 mg/dl, individuals with 1-hour post-load glucose ≥155 mg/dl exhibited a significantly worse cardio metabolic profile, both in the group with HbA1c <5.7%, and in the group with prediabetes (HbA1c 5.7-6.4%). Specifically, in both groups, subjects with 1-hour post-load glucose ≥155 mg/dl had higher fasting and 2-h post-load glucose (p < 0.0001 for all in both groups), higher HOMA-IR (p < 0.0001 in both groups), and carotid IMT (p = 0.05 in the group with HbA1c <5.7% and p = 0.03 in the group HbA1c 5.7-6.4%), as well as lower Matsuda index, insulinogenic index and disposition index (p < 0.0001 in both groups), and lower insulin-stimulated glucose disposal (p < 0.0001 in the group with HbA1c <5.7% and p = 0.03 in the group HbA1c 5.7-6.4%).

CONCLUSIONS

Hyperglycemia at 1-hour during an OGTT may be a useful tool to identify a subset of individuals within HbA1c-defined glycemic categories at higher risk of developing type 2 diabetes and cardiovascular disease.