Uric acid-induced C-reactive protein expression: implication on cell proliferation and nitric oxide production of human vascular cells

Hyperuricemia and Hypertension: Links and Risks

Hyperuricemia has long been recognized to be associated with increased cardiovascular risk, including risk of developing hypertension. Epidemiological findings suggest that the link with hypertension is stronger in children and adolescents. Uric acid acts as a strong antioxidant compound in the extracellular environment but has pro-inflammatory effects within the intracellular setting. A chronic phase of microvascular injury is known to occur after prolonged periods of hyperuricemia. This is proposed to contribute to afferent arteriolopathy and elevation of blood pressure that may become unresponsive to uric acid-lowering therapies over time. Studies have struggled to infer direct causality of hyperuricemia due to a vast number of confounders including body mass index. The aim of this review is to present the available data and highlight the need for large scale prospective randomized controlled trials in this area. At present, there is limited evidence to support a role for uric acid-lowering therapies in helping mitigate the risk of hypertension.

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.

Study of association of serum uric acid with albuminuria and carotid atherosclerosis in type 2 diabetes mellitus patients

Introduction:

Type 2 diabetes mellitus is a heterogeneous group of metabolic disorders of disturbance of carbohydrate, fat, and protein metabolism causing macrovascular (like coronary artery disease) and microvascular (kidney damage) complications. Microalbuminuria is the first manifestation of injury to glomerular filtration barrier and carotid intima-media thickness (IMT) of common carotid artery serves as an excellent marker for early lesion of atherosclerosis.

Method:

A cross-sectional observational study was carried out over a period of 1.5 years in PGIMER, DR. RML Hospital, New Delhi. Patients with type 2 diabetes mellitus, aged between 35 and 60 years, were investigated for uric acid (UA), urine albumin levels, and common carotid IMT during this period. Patients on drugs that affect serum UA level, patients with acute illness, patients with serum creatinine >1.5 mg/dL, or with coronary artery disease were excluded from study.

Result:

Prevalence of hyperuricemia was found to be high (46%) in type 2 diabetic patients. It was also higher in females (73.7%) than males (25.8%). There was positive correlation between serum UA concentrations with logarithm of urine albumin excretion (P < 0.023) and carotid intima-media thickness (IMT) (P < 0.027). Plaque index also showed a positive correlation with UA (P < 0.019). However, there was no positive correlation with UA and other variable such as age, duration of diabetes, systolic blood pressure, diastolic blood pressure, HbA1c, lipid profiles, urea, and creatinine.

Conclusion:

Serum UA concentration thus serves as an early marker of renal dysfunction and cardiovascular diseases in type 2 diabetic patients.

Risk of Acute Myocardial Infarction Among New Users of Allopurinol According to Serum Urate Level: A Nested Case-Control Study

Objectives: To test the hypothesis that allopurinol reduces the risk of acute myocardial infarction (AMI) in hyperuricemic patients and to assess whether the effect is dependent on dose, duration and serum uric acid (SUA) level attained after treatment. Methods: Nested case-control study over the period 2002–2015. From a cohort of patients aged 40–99 years old, we identified incident AMI cases and randomly selected five controls per case, matched for exact age, sex and index date. Adjusted odds ratios (AOR) and 95% CI were computed through unconditional logistic regression. Only new users of allopurinol were considered. Results: A total of 4697 AMI cases and 18,919 controls were included. Allopurinol use was associated with a reduced risk of AMI mainly driven by duration of treatment (AOR ≥180 days = 0.71; 95% CI: 0.60–0.84). Among long-term users (≥180 days), the reduced risk was only observed when the SUA level attained was below 7 mg/dL (AOR_{<6 mg/dL} = 0.64; 95% CI: 0.49–0.82; AOR_6–7mg/dL = 0.64; 95%CI:0.48-0.84); AOR_>7mg/dL = 1.04; 95% CI: 0.75–1.46; p for trend = 0.001). A dose-effect was observed but faded out once adjusted for the SUA level attained. The reduced risk of AMI occurred in both patients with gout and patients with asymptomatic hyperuricemia. Conclusions: The results confirm a cardioprotective effect of allopurinol which is strongly dependent on duration and SUA level attained after treatment.

Severity of Hypertension Mediates the Association of Hyperuricemia With Stroke in the REGARDS Case Cohort Study

Previous studies do not widely support hyperuricemia as a risk factor for stroke and other cardiovascular diseases. We assessed the relationship between hyperuricemia and ischemic stroke (≈900 cases) using a large data set from the REGARDS study (Reasons for Geographic and Racial Differences in Stroke). We employed a case-cohort design (incident stroke cases and randomly selected cohort participants) and weighted Cox-proportional hazard models to estimate the association of serum urate level ≥6.8 mg/dL (ie, hyperuricemia) and 6.0 to <6.8 mg/dL versus <6.0 mg/dL (reference) with incident stroke. Analyses were stratified by race, gender, and age. Mediation of cardiovascular disease comorbidities on the serum urate-stroke association was tested. Hyperuricemia was associated with stroke (hazard ratio, 1.40 [95% CI, 1.10-1.78]) after adjustment for demographic variables and systolic and diastolic blood pressure. This association was substantially attenuated (hazard ratio, 1.17 [95% CI, 0.90-1.51]) by additional covariate adjustment. In particular, apparent treatment-resistant hypertension (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg on 3 antihypertensive medications or use of ≥4 antihypertensive medications) and the count of antihypertensive medication classes significantly reduced the effect of hyperuricemia on ischemic stroke. Specifically, apparent treatment-resistant hypertension and number of antihypertensive, respectively, mediate 45% and 43% of the association. There was no effect modification in the association between hyperuricemia and stroke by age, race, or gender. We conclude that hyperuricemia may be a risk factor for stroke. The substantial attenuation of this association by apparent treatment-resistant hypertension and number of antihypertensive suggests that severe hypertension may be a mediator.

The long-term rapid increase in incidence of adenocarcinoma of the kidney in the USA, especially among younger ages

BACKGROUND

We previously observed a rapid increase in the incidence of renal cell carcinoma (RCC) in men and women between 1935 and 1989 in the USA, using data from the Connecticut Tumor Registry. This increase appeared to be largely explained by a positive cohort effect, but no population-based study has been conducted to comprehensively examine age-period-cohort effects by histologic types for the past decade.

METHODS

We calculated age-adjusted and age-specific incidence rates of the two major kidney-cancer subtypes RCC and renal urothelial carcinoma, and conducted an age-period-cohort analysis of 114 138 incident cases of kidney cancer reported between 1992 and 2014 to the Surveillance, Epidemiology, and End Results programme.

RESULTS

The age-adjusted incidence rates of RCC have been increasing consistently in the USA among both men and women (from 12.18/100 000 in 1992-1994 to 18.35/100 000 in 2010-2014 among men; from 5.77/100 000 in 1992-1994 to 8.63/100 000 in 2010-2014 among women). Incidence rates generally increased in successive birth cohorts, with a continuing increase in rates among the younger age groups (ages 0-54 years) in both men and women and among both Whites and Blacks. These observations were confirmed by age-period-cohort modelling, which suggested an increasing birth-cohort trend for RCC beginning with 1955 birth cohorts, regardless of the assumed value for the period effect for both men and women and for Whites and Blacks.

CONCLUSIONS

Known risk factors for kidney cancer may not fully account for the observed increasing rates or the birth-cohort pattern for RCC, prompting the need for additional etiologic hypotheses (such as environmental exposures) to investigate these descriptive patterns.

Does obesity modify the epidemiological association between hyperuricemia and the prevalence of hypertension among Northern Chinese community-dwelling people? A Chinese population-based study

OBJECTIVES

Hyperuricemia and obesity both play a role in the development of hypertension. However, limited evidence is available for the combined effect of hyperuricemia and obesity on the prevalence of hypertension in the Chinese population. We aimed to assess the separate and combined effects of these two risk factors on the risk of hypertension.

METHODS

We conducted a cross-sectional study in an area of Dalian city, Liaoning Province, China, from September 2015 to November 2016; 8700 adult residents were invited to participate in this study. Hyperuricemia was defined as serum uric acid ≥ 416 μmol/L in men and ≥ 357 μmol/L in women according to the guidelines. Individuals were categorised into four groups: the control group (body mass index (BMI) §amp;lt; 25 without hyperuricemia, the reference group), the obesity group (BMI ≥ 25 without hyperuricemia), the hyperuricemia group (BMI §amp;lt; 25 with hyperuricemia) and the obese-hyperuricemia group (BMI ≥ 25 with hyperuricemia). A multivariable logistic model was used to investigate individual and combined effects of hyperuricemia and obesity on the risk of hypertension.

RESULTS

Of the 8331 individuals included, 44.3% were obese, 13.6% suffered from hyperuricemia, and 7.8% were both obese and hyperuricemic. The hypertension prevalence was the highest in the obese-hyperuricemia group (55.5% (95% CI 51.6% to 59.2%)), followed by that in the obesity (44.3% (42.6% to 46.1%)) and that in the hyperuricemia groups (33.5% (29.5% to 37.9%)). After adjusting for confounders, the obese-hyperuricemia group had a nearly threefold increased risk of hypertension compared with their healthy counterparts (OR 2.98 (2.48 to 3.57)). This pattern was also observed in the obesity group with a higher risk of hypertension (OR 2.18 (1.96 to 2.42)) compared with the control group, whereas the risk of hypertension was not elevated significantly in the hyperuricemia group (OR 1.14 (0.92 to 1.42)).

CONCLUSION

Our study provided the first evidence that obese Chinese individuals with hyperuricemia had a significantly increased risk of hypertension compared with their healthy counterparts. This combined effect on the risk of hypertension is much stronger than the individual effect of either factor.

Possible role of l-carnitine in improvement of metabolic and hepatic changes in hyperuricemic and hyperuricemic-Fructose-supplemented rats

Hyperuricemia was linked to diabetes mellitus, metabolic syndrome, and oxidative stress, and could be induced by higher fructose consumption through altering energy status in liver. l-Carnitine is an antioxidant, affecting mitochondria and cellular energetics; however, little is known about its effects in hyperuricemic states. This study investigated metabolic and hepatic effects of hyperuricemia and fructose feeding, and demonstrated the role of l-Carnitine in such states. Fifty adult male Wistar rats were randomly divided into control, untreated hyperuricemic, fructose-supplemented hyperuricemic, l-Carnitine-treated hyperuricemic, and l-Carnitine-treated fructose-supplemented hyperuricemic groups. The separated plasma was used for determination of the glycemic control, lipid profile, liver function tests, uric acid level, and oxidative stress markers. Atherogenic index, HOMA-IR, and body mass index (BMI) were calculated. Left liver lobe and left kidney specimen from all groups were used for histopathological studies. Hyperuricemic rats exhibited significantly hypoalbuminemia, dyslipidemia, insulin resistance, and oxidative stress compared to the controls. Fructose-supplemented hyperuricemic group showed obesity and more deleterious effects, as well as, steatosis, and renal tubular damage compared to the hyperuricemic rats. Concomitant l-Carnitine treatment with hyperuricemia improved such effects, despite causing adiposity. While combined l-Carnitine treatment and fructose supplementation in hyperuricemia limited the aggressive hyperuricemic picture of fructose supplementation. It is concluded that hyperuricemia has detrimental metabolic and hepatic effects. Artificial fructose supplementation worsened such effects, while l-Carnitine was efficient in ameliorating these hyperuricemia and/or excess fructose-induced hyperuricemia effects, through its anti-inflammatory, antisteatotic, and antioxidant properties.

Effects of Uric Acid on Diabetes Mellitus and Its Chronic Complications

With the deepening of the researches on uric acid, especially in the study of metabolic diseases, uric acid has been found to be closely related to obesity, metabolic syndrome, nonalcoholic fatty liver disease, diabetes, and other metabolic diseases. Uric acid causes a series of pathophysiological changes through inflammation, oxidative stress, vascular endothelial injury, and so on and thus subsequently promotes the occurrence and development of diseases. This review confirmed the positive correlation between uric acid and diabetes mellitus and its chronic complications through the pathogenesis and clinical studies aspects.

Uric acid within the "normal" range predict 9-year cardiovascular mortality in older individuals. The InCHIANTI study

BACKGROUND AND AIMS

Increased uric acid levels correlate with cardiovascular disease and cardiovascular/overall mortality. To identify a uric acid threshold above which cardiovascular mortality rises, we studied the relationship between uric acid concentration and overall/cardiovascular mortality.

METHODS AND RESULTS

We analyzed data from the InCHIANTI study, a cohort study of Italian community-dwelling people with 9 years of follow-up. We selected a sample of 947 individuals over 64 years of age, free from cardio-cerebrovascular disease and with available uric acid measurement at baseline. The sample was divided according to plasma uric acid tertiles. The Hazard ratio (HR) for mortality was calculated by multivariate Cox proportional hazard model. Mean age of participants was 75.3 ± 7.3 years; the mean value of uric acid was 5.1 ± 1.4 mg/dl. Over 9-years of follow-up, 342 (36.1%) participants died, 143 deaths (15.1%) were due to cardiovascular disease. Subjects with higher uric acid concentrations presented a higher cardiovascular mortality [II (4.6-5.5 mg/dl) vs I (1.8-4.5 mg/dl) tertile HR: 1.98, 95%C.I. 1.22-3.23; III (≥5.6 mg/dl) vs I tertile HR: 1.87, 95%C.I. 1.13-3.09]. We found a non-linear association between uric acid concentrations and cardiovascular mortality with the lowest mortality for values of about 4.1 mg/dl and a significant risk increment for values above 4.3 mg/dl.

CONCLUSION

In community-dwelling older individuals free from cardio-cerebrovascular events, the lowest 9-year cardiovascular mortality was observed for uric acid values far below current target values. If confirmed, these data might represent the background for investigating the efficacy of uric acid levels reduction in similar populations.

Uric acid induced the phenotype transition of vascular endothelial cells via induction of oxidative stress and glycocalyx shedding

Recent data suggested a causative role of uric acid (UA) in the development of renal disease, in which endothelial dysfunction is regarded as the key mechanism. Endothelial-to-mesenchymal transition (EndoMT) and shedding of the glycocalyx are early changes of endothelial dysfunction. We investigated whether UA induced EndoMT in HUVECs and an animal model of hyperuricemia fed with 2% oxonic acid for 4 wk. UA induced EndoMT in HUVECs with a generation of reactive oxygen species via the activation of membranous NADPH oxidase (from 15 min) and mitochondria (from 6 h) along with glycocalyx shedding (from 6 h), which were blocked by probenecid. GM6001, an inhibitor of matrix metalloproteinase, alleviated UA-induced glycocalyx shedding and EndoMT. Antioxidants including N-acetyl cysteine, apocynin, and mitotempo ameliorated EndoMT; however, they did not change glycocalyx shedding in HUVECs. In the kidney of hyperuricemic rats, endothelial staining in peritubular capillaries (PTCs) was substantially decreased with a de novo expression of α-smooth muscle actin in PTCs. Plasma level of syndecan-1 was increased in hyperuricemic rats, which was ameliorated by allopurinol. UA caused a phenotypic transition of endothelial cells via induction of oxidative stress with glycocalyx shedding, which could be one of the mechanisms of UA-induced endothelial dysfunction and kidney disease.-Ko, J., Kang, H.-J., Kim, D.-A., Kim, M.-J., Ryu, E.-S., Lee, S., Ryu, J.-H., Roncal, C., Johnson, R. J., Kang, D.-H. Uric acid induced the phenotype transition of vascular endothelial cells via induction of oxidative stress and glycocalyx shedding.

Relationship Between Serum Uric Acid Levels and Nonalcoholic Fatty Liver Disease in Non-Obese Patients

Background and objectives: Nonalcoholic fatty liver disease (NAFLD) is associated with multiple factors such as hypertension, diabetes, dyslipidemia, obesity, and hyperuricemia. We aim to investigate the relationship between uric acid and NAFLD in a non-obese and young population. Materials and Methods: This study was performed in January 2010–2019 with a group of 367 (225 patients in the NAFLD group and 142 in the control group) patients with liver biopsy-proven NAFLD or no NAFLD. Patients with NAFLD were classified according to the percentage of steatosis as follows, group I had 1–20% and group II >20%. Demographic, clinical, and laboratory (biochemical parameters) features were collected retrospectively. Results: The mean body mass index (BMI) and age of the patients were 26.41 ± 3.42 and 32.27 ± 8.85, respectively. The BMI, homeostatic model of assessment (HOMA-IR), and uric acid (UA) values of the NAFLD group were found to be significantly higher than those of the controls. A positive correlation was found between the NAFLD stage and UA. The following factors were independently associated with NAFLD: BMI, HOMA-IR, and UA. In addition, the cut-off value of UA was 4.75 mg/dl with a sensitivity of 45.8% and a specificity of 80.3%. Conclusions: UA is a simple, non-invasive, cheap, and useful marker that may be used to predict steatosis in patients with NAFLD.

J-shaped association between serum uric acid and acute coronary syndrome in patients with essential hypertension

BACKGROUND

The prognostic value of serum uric acid (SUA) for incident acute coronary syndrome (ACS) in hypertensive subjects is uncertain. Therefore, the present study examined the association between SUA and incident ACS in a large cohort of Chinese hypertensive adults.

METHODS

This was a retrospective cohort study, which enrolled 5473 Chinese community-dwelling hypertensive patients from 1 January 2012 to 31 December 2012. Study outcomes were ACS events, and patients were followed until 31 December 2016. Cox regression analyses were conducted to determine adjusted HRs and 95% CIs for baseline SUA tertiles (low, middle and high group) and for men and women separately.

RESULTS

A total of 5473 participants were included in the analysis (median follow-up was 4.5 years). Participants were divided into tertiles based on SUA levels. During follow-up, 9 (0.49%), 14 (0.77%) and 25 (1.37%) patients developed ACS in the lowest, middle and highest tertiles, respectively. When compared with the lowest tertile of SUA, the highest tertile of SUA was associated with ACS risk in all subjects and in men and women separately (HR: 2.62, 95% CI 1.14 to 7.01, p=0.0233; 2.15, 95% CI 1.08 to 6.04, p=0.021, and 3.49, 95% CI 1.25 to 7.74, p=0.017, respectively).

CONCLUSIONS

Higher SUA levels were independently associated with an elevated risk of ACS incidence. The relationship between SUA levels and ACS in hypertensive patients was J-shaped.

C-reactive protein promotes inflammation through TLR4/NF-κB/TGF-β pathway in HL-1 cells

Atrial fibrillation (AF) is the most common type of heart arrhythmia. Currently, the pathogenesis of AF is not fully understood yet. A growing body of evidence highlighted the strong association between inflammation and the pathogenesis of AF. C-reactive protein (CRP) is an inflammation marker with increased expression in AF. Therefore, the aim of this study was to determine if CRP promotes inflammation, which may sequentially mediate the onset of AF and the concurrent atrial fibrosis, through TLR4/NF-κB/TGF-β pathway. HL-1 cells were treated with either 25 or 50 μg/ml recombinant human CRP. TGF-β1 and NF-κB inhibitors were given either solely or together to the 50 μg/ml CRP-treated cells. Cell proliferation, apoptosis, the expression of apoptotic factors and TLR4, IL-6, TGF-β1, Smad2, and the phosphorylation of Smad2 were determined. Data showed that CRP induced dose-dependent inhibition on cell proliferation and promoted cell apoptosis, which was induced through both intrinsic and extrinsic pathways. Such effects were reversed by inhibiting TGF-β1 and/or NF-κB. Inhibition of TGF-β1 and/or NF-κB also reduced the expression of TLR4 and IL-6. Inhibition of NF-κB alone weakened the expression of TGF-β1 and phosphorylation of Smad2. Our study demonstrated that CRP is not only a marker, but also an important mediator in the induction of inflammation and likely the pathogenesis of AF. We for the first time reported CRP-induced activation and cross-talk between TLR4 and NF-κB/TGF-β1 signaling pathway in a cardiomyocyte model. Reducing CRP and targeting TLR4/NF-κB/TGF-β1 pathway may provide new insights in the therapeutic interventions to inflammation-induced AF.

Dietary Antioxidant Supplements and Uric Acid in Chronic Kidney Disease: A Review

Increased serum levels of uric acid have been associated with the onset and development of chronic kidney disease (CKD), cardiovascular disease, and mortality, through several molecular pathogenetic mechanisms, such as inflammation and oxidative stress. Oxidative stress is present even in the early stages of CKD, progresses parallelly with the deterioration of kidney function, and is even more exacerbated in end-stage renal disease patients undergoing maintenance hemodialysis. Although acting in the plasma as an antioxidant, once uric acid enters the intracellular environment; it behaves as a powerful pro-oxidant. Exogenous intake of antioxidants has been repeatedly shown to prevent inflammation, atherosclerosis and oxidative stress in CKD patients. Moreover, certain antioxidants have been proposed to exert uric acid-lowering properties. This review aims to present the available data regarding the effects of antioxidant supplements on both oxidative stress and uric acid serum levels, in a population particularly susceptible to oxidative damage such as CKD patients.

High Levels of Serum Uric Acid, Cystain C and Lipids Concentration and their Clinical Significance in Primary Gouty Arthritis Patients

OBJECTIVE

To investigate the changes of serum Uric Acid (sUA), lipids and Cystatin C (CysC) in primary gout patients, and to explore the clinical significance in gout patients.

METHODS

sUA, CysC, high-sensitivity C-reactive Protein (hsCRP) and other biochemical parameters were measured in 326 gout patient and 210 healthy control subjects, blood cell counts were also detected. Clinical data were collected from gout patients.

RESULTS

sUA, CysC, hsCRP, Body Mass Index (BMI), White Blood Cell (WBC) counts, neutrophil Granulocyte (GR), Monocyte (Mo), Triglycerides (TG), plasma Total Cholesterol (TC), Very Low Density Lipoprotein (VLDL), apolipoprotein B100 (apoB100), Blood Glucose (GLU), serum Creatinine (sCr) and Urea Nitrogen (BUN) were significantly increased in gout patients compared with HC subjects (P<0.01, respectively), while lymphocyte counts and High Density Lipoprotein- Cholesterol (HDL-C) were significantly decreased in gout patients compared with HC subjects (P<0.01, respectively). Positive correlations were observed between concentration of sUA and age, TG, VLDL, sCr and CysC (P<0.05, respectively). While negative correlations were observed between the concentration of sUA and HDL-C(P<0.01). Besides, Positive correlations were observed between concentration of CysC and WBC, GR, Mo, apoA1, GLU, sCr, BUN, sUA, hsCRP (P<0.05, respectively). While negative correlations were observed between the concentration of CysC and TC, LDL-C(P<0.01, respectively).

CONCLUSIONS

Blood lipid profile changes in gout patients. Gout patients who suffer from lipid metabolism disorder and vascular diseases might be associated with hyperuricemia, which leads to endothelial cell damage and vascular smooth muscle cell proliferation. CysC might be a marker for renal function damage and inflammation. Hyperuricemia is the risk factor of renal disorder in gout patients.

Impact of C-reactive protein on osteo-/chondrogenic transdifferentiation and calcification of vascular smooth muscle cells

Medial vascular calcification occurs during the aging process and is strongly accelerated by chronic kidney disease (CKD). Elevated C-reactive protein (CRP) levels are associated with vascular calcification, cardiovascular events and mortality in CKD patients. CRP is an important promoter of vascular inflammation. Inflammatory processes are critically involved in initiation and progression of vascular calcification. Thus, the present study explored a possible impact of CRP on vascular calcification. We found that CRP promoted osteo-/chondrogenic transdifferentiation and aggravated phosphate-induced osteo-/chondrogenic transdifferentiation and calcification of primary human aortic smooth muscle cells (HAoSMCs). These effects were paralleled by increased cellular oxidative stress and corresponding pro-calcific downstream-signaling. Antioxidants or p38 MAPK inhibition suppressed CRP-induced osteo-/chondrogenic signaling and mineralization. Furthermore, silencing of Fc fragment of IgG receptor IIa (FCGR2A) blunted the pro-calcific effects of CRP. Vascular CRP expression was increased in the klotho-hypomorphic mouse model of aging as well as in HAoSMCs during calcifying conditions. In conclusion, CRP augments osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells through mechanisms involving FCGR2A-dependent induction of oxidative stress. Thus, systemic inflammation may actively contribute to the progression of vascular calcification.

High serum uric acid level is a mortality risk factor in peritoneal dialysis patients: a retrospective cohort study

Background

The results remain controversial with regards to the impact of serum uric acid on clinical outcomes from peritoneal dialysis population. The aim of our study was to investigate the influence of serum uric acid levels on mortality in peritoneal dialysis patients.

Methods

Data on 9405 peritoneal dialysis patients from the Zhejiang Renal Data system were retrospectively analyzed. All demographic and laboratory data were recorded at baseline. The study cohort was divided into quintiles according to baseline uric acid level (mg/dL): Q1 (< 6.06), Q2 (6.06–6.67), Q3 (6.68–7.27) (reference), Q4 (7.28–8.03), and Q5 (≥8.04). Hazards ratio (HR) of all-cause and cardiovascular mortality was calculated.

Results

Mean serum uric acid was 7.07 ± 1.25 mg/dL. During a median follow-up of 29.4 (range, 3.0 to 115.4) months, 1226 (13.0%) patients died, of which 515 (5.5%) died of cardiovascular events. The Kaplan-Meier survival curves showed that patients in the middle uric acid quintile (Q3: 6.68–7.27) exhibited the highest patient and cardiovascular survival rates (log-rank test P < 0.05). Multivariate Cox regression analysis showed that, using Q3 as the reference, in the fully adjusted model, a higher uric acid level (Q4: 7.28–8.03, and Q5: ≥8.04) was significantly associated with higher all-cause mortality (Model 3; Q4: HR, 1.335, 95% CI, 1.073 to 1.662, P = 0.009; Q5: HR, 1.482, 95% CI, 1.187 to 1.849, P = 0.001), but not with cardiovascular mortality. The adverse effect of higher uric acid level (≥7.28 mg/dL) on all-cause mortality was more prominent in groups such as male, hypoalbuminemia, normal weight, non-diabetes mellitus at baseline rather than in their counterparts respectively.

Conclusions

A higher uric acid level was an independent risk factor for all-cause mortality in peritoneal dialysis patients.

Electronic supplementary material

The online version of this article (10.1186/s12986-019-0379-y) contains supplementary material, which is available to authorized users.

Exercise-Induced Acute Kidney Injury in a Police Officer with Hereditary Renal Hypouricemia

Hereditary renal hypouricemia is characterized by hypouricemia with hyper-uric acid clearance due to a defect in renal tubular transport. Patients with hereditary renal hypouricemia have a higher risk of exercise-induced acute kidney injury (EAKI) and reduced kidney function. Although the best preventive measure is avoiding exercise, there are many kinds of jobs that require occupational exercise. A 27-year-old male police officer suffered from stage 3 AKI after performing a 20-m multistage shuttle run test. His mother had previously been diagnosed as having renal hypouricemia at another facility. The patient had reported having hypouricemia during a health check at a previous police station, but his serum uric acid concentration was within the normal range at our hospital. After treatment, he recovered from EAKI and exhibited low serum uric acid and hyper-uric acid clearance. Since the patient desired to continue his career requiring strenuous exercise, it was difficult to establish a preventive plan against the recurrence of EAKI. Patients with hereditary renal hypouricemia who must undergo strenuous occupational anaerobic exercise are at higher risk of developing EAKI than other workers. The risks of EAKI among patients with hypouricemia should be considered when undergoing physical occupational training.

Serum uric acid as a marker of disease risk, severity, and survival in systemic sclerosis-related pulmonary arterial hypertension

The object of this paper is to assess associations between serum uric acid (UA) and pulmonary arterial hypertension (PAH) risk, disease severity, and mortality in a well-characterized cohort of systemic sclerosis (SSc) patients referred for evaluation of possible PAH. Consecutive SSc patients aged >18 years with serum UA drawn within two weeks of a diagnostic right heart catheterization (RHC) were included. Associations between baseline serum UA and PAH at RHC were examined using logistic regression and receiver operating characteristic curves. Relationships between UA levels and metrics of disease severity were assessed using Pearson and Spearman correlation. Associations between UA and survival were assessed using Kaplan-Meier analysis and Cox proportional hazard modeling. A total of 162 SSc patients were included; 82 received a diagnosis of PAH at RHC. Patients found to have PAH had significantly higher UA than those without PAH. Elevated baseline UA was associated with significantly increased odds of PAH diagnosis at RHC (odds ratio [OR] = 4.07, 95% confidence interval [CI] = 2.11-7.87, P < 0.001). Each mg/dL higher UA was associated with a 14% increase in mortality (hazard ratio [HR] = 1.14, 95% CI = 1.02-1.28, P < 0.05). In multivariable models adjusting for potential confounders of the relationship between UA and survival, UA > 6.3 mg/dL remained significantly associated with increased mortality (HR = 1.84, 95% CI = 1.02-3.32, P < 0.05). Among SSc patients with suspected PAH, elevated serum UA is associated with increased risk of SSc-PAH. Among individuals diagnosed with SSc-PAH by RHC, UA is associated with disease severity and survival. These results indicate UA is a useful predictor of PAH risk and prognosis in SSc.

Decline in serum uric acid predicts higher risk for mortality in peritoneal dialysis patients-a propensity score analysis

BACKGROUND

The level of serum uric acid (SUA) in treatment follow-up is associated with mortality in peritoneal dialysis (PD) patients, but it remains unknown if the longitudinal change in SUA affects mortality.

METHODS

309 PD patients who were not using UA-lowering agents were enrolled. The longitudinal change in SUA was estimated by comparing the values between the run-in and follow-up periods. Based the calculated values, the patients were divided into SUA decliner and SUA non-decliner. A propensity score (PS) was calculated using the parameters measured in run-in period. After PS matching, the time-to-event analysis was performed for all-cause death.

RESULTS

After PS matching, 86 patients of each group were left. A higher mortality of 19/86 existed in SUA decliner compared with SUA non-decliner which is 3/86 (p < 0.001). Kaplan-Meier analysis in sub-cohort showed worse survival in the SUA decliner. Standard and stratified Cox regression analysis both showed SUA decline to be an independent risk factor for all-cause death in PD patients.

CONCLUSIONS

The decline in SUA in the follow-up may predict the all-cause mortality of PD patients, the reason of which may result from reducing scavenging effects of SUA or may reflect general condition. More studies need to be done.

The case for uric acid-lowering treatment in patients with hyperuricaemia and CKD

Hyperuricaemia is common among patients with chronic kidney disease (CKD), and increases in severity with the deterioration of kidney function. Although existing guidelines for CKD management do not recommend testing for or treatment of hyperuricaemia in the absence of a diagnosis of gout or urate nephrolithiasis, an emerging body of evidence supports a direct causal relationship between serum urate levels and the development of CKD. Here, we review randomized clinical trials that have evaluated the effect of urate-lowering therapy (ULT) on the rate of CKD progression. Among trials in which individuals in the control arm experienced progressive deterioration of kidney function (which we define as ≥4 ml/min/1.73 m² over the course of the study - typically 6 months to 2 years), treatment with ULT conferred consistent clinical benefits. In contrast, among trials where clinical progression was not observed in the control arm, treatment with ULT was ineffective, but this finding should not be used as an argument against the use of uric acid-lowering therapy. Although additional studies are needed to identify threshold values of serum urate for treatment initiation and to confirm optimal target levels, we believe that sufficient evidence exists to recommend routine measurement of serum urate levels in patients with CKD and consider initiation of ULT among those who are hyperuricaemic with evidence of deteriorating renal function, unless specific contraindications exist.

Pulse wave velocity progression over a medium-term follow-up in hypertensives: Focus on uric acid

The role of uric acid (UA) on the arterial stiffness progression has been evaluated only in three studies. Our aim was to evaluate its role as a possible determinant of the pulse wave velocity (PWV) progression over a 3.7 ± 0.5 years follow-up period in hypertensive patients. Specific sex analysis was done due to the well-known sex interaction with UA levels. We enrolled 422 consecutive hypertensive outpatients. At baseline anamnestic, blood pressure (BP) and laboratory data as well as PWV were assessed. PWV was performed again at follow-up examination. Hyperuricemia was defined as a UA > 6 mg/dL for women and > 7 mg/dL for men. Baseline age was 53.2 ± 13 years, 58% were males, systolic and diastolic BP (SBP/DBP) 141.7 ± 17.7/86.8 ± 10.8 mm Hg, UA 5.2 ± 1.4 mg/dL, and PWV 8.5 ± 1.9 m/s. At follow-up, despite better BP values (-8.5 ± 24.6 for SBP and -7.5 ± 15.4 for DBP), PWV increases to 9.1 ± 2.3 m/s (P < 0.001) with mean ΔPWV of+ 0.5 ± 2.2 m/s. A total of 61 patients were hyperuricemic (14.4%), and they present higher PWV baseline (9.0 ± 2.5 vs 8.5 ± 1.8 m/s, P = 0.03) without significant differences in ΔPWV. Hyperuricemic female (6.2%, 11 patients) presents higher baseline PWV without significant differences in ΔPWV. No differences were found in arterial stiffness in hyperuricemic males (20.4%, 50 patients). UA showed association with baseline and ΔPWV in the whole population but it loses statistical significance at the linear regression model. Same figures were also for sex analysis. Our findings provide evidence that baseline UA levels are not determinants of PWV progression over a median follow-up of 3.8 years' in hypertensive patients.

Uric acid and the cardio-renal effects of SGLT2 inhibitors

Sodium/glucose co-transporter-2 (SGLT2) inhibitors, which lower blood glucose by increasing renal glucose elimination, have been shown to reduce the risk of adverse cardiovascular (CV) and renal events in type 2 diabetes. This has been ascribed, in part, to haemodynamic changes, body weight reduction and several possible effects on myocardial, endothelial and tubulo-glomerular functions, as well as to reduced glucotoxicity. This review evaluates evidence that an effect of SGLT2 inhibitors to lower uric acid may also contribute to reduced cardio-renal risk. Chronically elevated circulating uric acid concentrations are associated with increased risk of hypertension, CV disease and chronic kidney disease (CKD). The extent to which uric acid contributes to these conditions, either as a cause or an aggravating factor, remains unclear, but interventions that reduce urate production or increase urate excretion in hyperuricaemic patients have consistently improved cardio-renal prognoses. Uric acid concentrations are often elevated in type 2 diabetes, contributing to the "metabolic syndrome" of CV risk. Treating type 2 diabetes with an SGLT2 inhibitor increases uric acid excretion, reduces circulating uric acid and improves parameters of CV and renal function. This raises the possibility that the lowering of uric acid by SGLT2 inhibition may assist in reducing adverse CV events and slowing progression of CKD in type 2 diabetes. SGLT2 inhibition might also be useful in the treatment of gout and gouty arthritis, especially when co-existent with diabetes.

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.

Evolving spectrum of diabetic nephropathy

Diabetes remains an important health issue as more patients with chronic and uncontrolled diabetes develop diabetic nephropathy (DN), which classically presents with proteinuria followed by a progressive decrease in renal function. However, an increasing proportion of DN patients have a decline in kidney function and vascular complications without proteinuria, known as non-proteinuric DN (NP-DN). Despite the increased incidence of NP-DN, few clinical or experimental studies have thoroughly investigated the pathophysiological mechanisms and targeted treatment for this form of DN. In this review, we will examine the differences between conventional DN and NP-DN and consider potential pathophysiological mechanisms, diagnostic markers, and treatment for both DN and NP-DN. The investigation of the pathophysiology of NP-DN should provide additional insight into the cardiovascular factors influencing renal function and disease and provide novel treatments for the vascular complications seen in diabetic patients.

Prognostic factors associated with early gout flare recurrence in patients initiating urate-lowering therapy during an acute gout flare

Lowering serum urate levels below the threshold for crystal formation with urate-lowering therapy (ULT) has been associated with a lower risk for gout flare reoccurrences. However, gout patients on ULT still commonly suffer from recurring gout flares. The purpose of this study was to explore prognostic factors associated with gout flare recurrence within the first 3 months, in gout patients starting ULT during an acute gout flare. Post-hoc analysis of trial data on acute gout patients randomized to either gout flare standard of care or anakinra treatment were used, including baseline demographic, laboratory, clinical, and patient-reported variables, as well as 3-month follow-up data on gout flare recurrences. Only patients starting ULT at baseline were included. Using variable selection based on clinical relevance, univariate, and multivariate binary logistic regression analyses were done to examine predictors of gout flare reoccurrence. A total of 75 patients were included in this study, of which 36 (48%) experienced a gout flare ≤ 3 months post baseline. The multivariate regression analysis revealed that CRP levels > 30 mg/L (OR 9.47) and lack of prophylaxis when starting ULT (OR 11.56) were independently associated with gout flare recurrence. Similar results were found for the univariate regression analyses. Our results show that CRP levels > 30 mg/L and lack of prophylaxis when starting ULT were prognostic factors for early gout flare reoccurrence in patients starting ULT during an acute gout flare. KEY POINTS: • Gout flare recurrences were common within the first 3 months after starting urate-lowering therapy in gout patients. • Intake of prophylaxis when starting ULT had a strong protective effect on gout flare recurrences. • C-reactive protein level > 30 mg/L was an additional prognostic factor for early (≤ 3 months) gout flare reoccurrence in patients starting ULT during an acute gout flare.

Higher levels of serum uric acid influences hepatic damage in patients with non-alcoholic fatty liver disease (NAFLD)

BACKGROUND

recent evidence suggests a causal link between serum uric acid and the metabolic syndrome, diabetes mellitus, arterial hypertension, and renal and cardiac disease. Uric acid is an endogenous danger signal and activator of the inflammasome, and has been independently associated with an increased risk of cirrhosis.

AIM AND METHODS

six hundred and thirty-four patients from the nation-wide HEPAMET registry with biopsy-proven NAFLD (53% NASH) were analyzed to determine whether hyperuricemia is related with advanced liver damage in patients with non-alcoholic fatty liver disease (NAFLD). Patients were divided into three groups according to the tertile levels of serum uric acid and gender.

RESULTS

the cohort was composed of 50% females, with a mean age of 49 years (range 19-80). Patients in the top third of serum uric acid levels were older (p = 0.017); they had a higher body mass index (p < 0.01), arterial blood pressure (p = 0.05), triglyceridemia (p = 0.012), serum creatinine (p < 0.001) and total cholesterol (p = 0.016) and lower HDL-cholesterol (p = 0.004). According to the univariate analysis, the variables associated with patients in the top third were more advanced steatosis (p = 0.02), liver fibrosis (F2-F4 vs F0-1; p = 0.011), NASH (p = 0.002) and NAS score (p = 0.05). According to the multivariate logistic regression analysis, the top third of uric acid level was independently associated with steatosis (adjusted hazard ratio 1.7; CI 95%: 1.05-2.8) and NASH (adjusted hazard ratio 1.8; CI 95%: 1.08-3.0) but not with advanced fibrosis (F2-F4) (adjusted hazard ratio 1.09; CI 95%: 0.63-1.87).

CONCLUSION

higher levels of serum uric acid were independently associated with hepatocellular steatosis and NASH in a cohort of patients with NAFLD. Serum uric acid levels warrants further evaluation as a component of the current non-invasive NAFLD scores of histopathological damage.

Spontaneous Tumor Lysis Syndrome Secondary to Small-Cell Neuroendocrine Carcinoma of Unknown Origin: A Rare Case Report and Literature Review

Spontaneous tumor lysis syndrome (STLS), in the absence of prior chemo or radiation therapy, is rare with solid tumors. Here, we present a case of STLS secondary to a small-cell neuroendocrine tumor of unknown origin in a 66-year-old female patient who presented with abdominal discomfort. Computed tomography (CT) abdomen showed a large tumor mass with peritoneal metastasis, and she developed renal failure from STLS, resulting in the need for hemodialysis. Due to the progressive deterioration and the comorbidities, she opted for comfort care. Timely recognition and intervention of STLS is critical. Further studies evaluating STLS in solid tumor patients are recommended.

Association between rs2188380 and the risk of breast cancer in southwest Chinese population

Background

Previous studies have revealed that the single nucleotide polymorphism (SNP) rs2188380 was identified as a novel locus of gout. Interestingly, gout resulting from high serum uric acid (SUA) was also identified to be associated with the risk of breast cancer (BC). We hypothesized that maybe there was a relationship between rs2188380 and the risk of BC. Therefore, our study was conducted to investigate whether this novel gout‐related SNP (rs2188380) was associated with BC risk as well as the clinical and pathological characteristics in the southwest Chinese population.

Materials and methods

We performed a case‐control study including 104 breast cancer patients and 112 healthy controls to investigate whether rs2188380 is associated with BC risk in the southwest Chinese population. The genotyping was performed by the SNP scan method. General characteristics and clinicopathological characteristics of tumors were also included in the analysis. The statistical evaluations were performed using the Student t test, the chi‐square test or Fisher's exact test, and unconditional logistic regression analysis.

Results

The C/C genotype of rs2188380 might be related to BC risk to some extent compared with G/G genotype (OR = 9.241, 95% CI = 1.122‐76.101, P = 0.039). Furthermore, after adjusting the age, the association still existed (OR = 8.788, 95% CI = 1.063‐72.636, P = 0.044). However, no significant association was observed between rs2188380 and the clinicopathological characteristics of BC.

Conclusions

Our study primarily indicated that rs2188380 might have a potential association with BC risk to some extent. With a limited sample size and statistical power, further studies based on larger populations are needed to confirm the association.

Long-term prognostic impact of hyperuricemia in community

The debate whether an elevated level of serum uric acid (SUA) is an independent marker of cardiovascular risk is still going on. We examined morbidity and mortality related to SUA and hyperuricemia in a well-characterized population with very long follow-up. Study included 4696 participants (aged 30-59 years at baseline) of the coronary heart disease (CHD) Study of the Finnish Mobile Clinic Health Examination Survey. Adjusted hazard ratios (HRs) of hyperuricemia (defined as ≥360 µmol/l and ≥420 µmol/l) and SUA quintiles for mortality and adverse cardiovascular outcomes are reported. During the mean follow up of 30.6 years there were 2723 deaths, 887 deaths for CHD of which 340 were classified as sudden cardiac deaths, 1642 hospitalizations due to CHD and 798 hospitalizations due to congestive heart failure. After adjusting to baseline risk factors and presence of cardiovascular diseases as well as the use of diuretics there were no significant differences in the risk of any of the outcomes when analyzed either according to quintiles of SUA or using a cut-off point SUA ≥360 µmol/l for hyperuricemia. Only a rare finding of hyperuricemia SUA ≥420 µmol/l among women (n = 17, 0.9%) was independently associated with significantly higher risk of mortality (adjusted HR: 2.59, 95% CI: 1.54-4.34) and a combination end-point of major adverse cardiac events (MACEs) (HR: 2.69; 95% CI: 1.56-4.66). SUA was not an independent indicator of morbidity and mortality, with the exception of particularly high levels of SUA among women.

Urate-lowering therapy alleviates atherosclerosis inflammatory response factors and neointimal lesions in a mouse model of induced carotid atherosclerosis

Hyperuricemia (HU) is a cause of gout. Clinical studies show a link between HU and cardiovascular disease. However, the role of soluble serum urate (SU) on atherosclerosis development remains elusive. We aimed to use a new HU mouse model [Uricase/Uox knockout (KO)] to further investigate the relationship between HU and atherosclerosis. A mouse model by perivascular collar placement of induced carotid atherosclerosis was established in male Uox-KO mice. The Uox-KO mice had elevated SU levels and enhanced levels of atherosclerosis inflammatory response proteins. In contrast, Uox-KO mice with carotid atherosclerosis showed severe neointimal changes in histology staining consistent with increases in intimal area and increases in proliferating cell nuclear antigen (PCNA)- and F4/80-positive cells. Allopurinol reduced neointimal areas induced by the perivascular collar in hyperuricemic mice, accompanied by decreased expression of PCNA- and F4/80-positive cells. Urate-lowering treatment alleviated atherosclerosis inflammatory response factors and reactive oxygen species (ROS) intensities in both collar placement Uox-KO mice and urate-stimulated human umbilical vein endothelial cells (HUVECs). In vitro results using HUVECs showed ROS was induced by urate and ROS induction was abrogated using antioxidants. These data demonstrate that urate per se does not trigger atherosclerosis intima lesions in male mice. Urate worsens carotid neointimal lesions induced by the perivascular collar and urate-lowering therapy partially abrogates the effects. The current study warrants clinical studies on the possible benefits of urate-lowering therapy in atherosclerosis patients with HU.

Uric acid activates aldose reductase and the polyol pathway for endogenous fructose and fat production causing development of fatty liver in rats

Dietary, fructose-containing sugars have been strongly associated with the development of nonalcoholic fatty liver disease (NAFLD). Recent studies suggest that fructose also can be produced via the polyol pathway in the liver, where it may induce hepatic fat accumulation. Moreover, fructose metabolism yields uric acid, which is highly associated with NAFLD. Here, using biochemical assays, reporter gene expression, and confocal fluorescence microscopy, we investigated whether uric acid regulates aldose reductase, a key enzyme in the polyol pathway. We evaluated whether soluble uric acid regulates aldose reductase expression both in cultured hepatocytes (HepG2 cells) and in the liver of hyperuricemic rats and whether this stimulation is associated with endogenous fructose production and fat accumulation. Uric acid dose-dependently stimulated aldose reductase expression in the HepG2 cells, and this stimulation was associated with endogenous fructose production and triglyceride accumulation. This stimulatory mechanism was mediated by uric acid-induced oxidative stress and stimulation of the transcription factor nuclear factor of activated T cells 5 (NFAT5). Uric acid also amplified the effects of elevated glucose levels to stimulate hepatocyte triglyceride accumulation. Hyperuricemic rats exhibited elevated hepatic aldose reductase expression, endogenous fructose accumulation, and fat buildup that was significantly reduced by co-administration of the xanthine oxidase inhibitor allopurinol. These results suggest that uric acid generated during fructose metabolism may act as a positive feedback mechanism that stimulates endogenous fructose production by stimulating aldose reductase in the polyol pathway. Our findings suggest an amplifying mechanism whereby soft drinks rich in glucose and fructose can induce NAFLD.

Uric Acid and Acute Kidney Injury in the Critically Ill

Rationale & Objective

Uric acid is excreted by the kidney and accumulates in acute kidney injury (AKI). Whether higher plasma uric acid level predisposes to AKI or its complications is not known.

Study Design

Prospective observational cohort study.

Setting & Participants

2 independent cohorts of critically ill patients: (1) 208 patients without AKI admitted to the intensive care unit (ICU) at Brigham & Women's Hospital between October 2008 and December 2016; and (2) 250 participants with AKI requiring renal replacement therapy (RRT) who had not yet initiated RRT enrolled in the Acute Renal Failure Trial Network (ATN) Study.

Exposure

Plasma uric acid level upon ICU admission and before RRT initiation in the ICU and ATN Study cohorts, respectively.

Outcomes

Incident AKI and 60-day mortality in the ICU and ATN Study cohorts, respectively.

Analytical Approach

Logistic regression models were used to test the association of plasma uric acid level with incident AKI and 60-day mortality.

Results

In the ICU cohort, median plasma uric acid level was 4.7 (interquartile range [IQR], 3.6-6.4) mg/dL, and 40 patients (19.2%) developed AKI. Higher plasma uric acid levels associated with incident AKI, but this association was confounded by serum creatinine level and was not significant after multivariable adjustment (adjusted OR per doubling of uric acid, 1.50; 95% CI, 0.80-2.81). In the ATN Study cohort, median plasma uric acid level was 11.1 (IQR, 8.6-14.2) mg/dL, and 125 participants (50.0%) died within 60 days. There was no statistically significant association between plasma uric acid levels and 60-day mortality in either unadjusted models or after multivariable adjustment for demographic, severity-of-illness, and kidney-specific covariates (adjusted OR per doubling of uric acid, 1.15; 95% CI, 0.71-1.86).

Limitations

Heterogeneity of ICU patients.

Conclusions

Plasma uric acid levels upon ICU admission or before RRT initiation are not independently associated with adverse clinical outcomes in critically ill patients.

Age-differential association between serum uric acid and incident hypertension

Increasing evidence suggests a positive association between the serum uric acid (SUA) level and incident hypertension. However, the association has been inconsistent based on age, sex, body mass index, and lipid profiles. Thus, we investigated whether there is an interaction between SUA and other risk factors on incident hypertension in the Korean general population. In this study, 808 participants aged 40-79 years were included. They were free of hypertension and major cardiovascular disease at baseline. Incident hypertension was defined as systolic blood pressure (SBP) ≥ 140 mmHg, diastolic blood pressure (DBP) ≥ 90 mmHg, or use of antihypertensive medication. To investigate whether the association between SUA and incident hypertension is modified by other risk factors for hypertension, a generalized linear model and Z test were used. During the mean follow-up of 3.3 years, 11.5% of men and 10.7% of women developed hypertension. The association between SUA and incident hypertension was inconsistent according to participant age (p for interaction = 0.009). The association between SUA level and incident hypertension was positively significant among people aged < 55 years (relative risk 1.74 per 1.0 mg/dL of SUA; p = 0.002), but there was no significant association among people aged ≥ 55 years (p = 0.894). In a secondary analysis, the SUA level was not associated with an increase in SBP, but positively associated with DBP. We observed an age-differential association between SUA level and incident hypertension among Koreans. An increased SUA level can be a trigger for hypertension through early vascular changes in the middle-aged population.

Evaluation of the association between hyperuricemia and coronary artery disease: A STROBE-compliant article

The aim of the study was to assess the independent contribution of hyperuricemia to coronary artery disease (CAD) confirmed by coronary angiography (CAG), and to explore associations between serum uric acid (SUA) level and CAD.We performed a retrospective cohort study of 5069 patients who underwent CAG. Patients were divided into groups: hyperuricemia (n = 1178) versus nonhyperuricemia (n = 3891) and CAD (n = 3433) versus non-CAD (n = 1636).The incidence of CAD was higher in the hyperuricemia group than in the nonhyperuricemia group (71.5% vs 66.6%, P = .002). Hyperuricemia and CAD were significantly correlated in women (odds ratio = 1.509, 95% confidence interval, 1.106-2.057, P = .009). And there were trends, higher SUA quartiles were associated with higher percentage of CAD (62.3%, 68.0%, 68.9%, and 71.7% for quartiles 1, 2, 3, and 4, respectively, P < .001), and the incidence of 3-vessel disease increased (25.2%, 26.4%, 27.2%, and 31.1% for quartiles 1, 2, 3, and 4, respectively, P = .001) and that of normal vessel decreased (37.7%, 32.0%, 31.1%, and 28.3% for quartiles 1, 2, 3, and 4, respectively, P < .001) across quartiles, these trends were found in female group, but not in male group. The SUA level significantly increased as the number of diseased vessels increased (P < .001).There was an independent correlation between hyperuricemia and CAD in women. A higher SUA level was associated with a higher incidence of 3-vessel disease in women.

Serum Uric Acid as an Independent Risk Factor for the Presence and Severity of Early-Onset Coronary Artery Disease: A Case-Control Study

Serum uric acid (UA) is the final product of purine metabolism in humans. The present study is aimed at identifying the potential association between serum UA and early-onset coronary artery disease (EOCAD). The study population consisted of 1093 EOCAD patients aged ≤50 years, and 1117 age- and sex-matched apparently healthy people served as controls. The concentrations of UA were measured by uricase method. The severity of CAD was evaluated by Gensini score. The mean serum level of UA was 5.843 ± 1.479 mg/dl in EOCAD patients and 5.433 ± 1.529 mg/dl in controls. Serum UA levels were significantly higher in the EOCAD group than those in the control group (P < 0.001) and was an independent risk factor for EOCAD (OR = 1.100, 95% CI: 1.022-1.185). The early-onset myocardial infarction patients with 3-vessel disease had higher serum UA levels than those with 1- or 2-vessel disease. The serum UA levels of EOCAD patients with acute coronary syndrome were significantly higher than those with chronic coronary artery disease. EOCAD patients with hyperuricemia had higher Gensini scores than those without hyperuricemia. In addition, the serum UA levels were affected by drinking (P < 0.01) and were positively correlated with serum creatinine (r = 0.323) and weight (r = 0.327). Our results show that serum UA was an independent risk factor for EOCAD. The serum UA levels were associated with the presence and severity of EOCAD and suggested that UA may be involved in the progression of EOCAD.

Gout and the Risk of Incident Obstructive Sleep Apnea in Adults 65 Years or Older: An Observational Study

STUDY OBJECTIVES

To assess whether gout is associated with a higher risk of obstructive sleep apnea (OSA) in older adults.

METHODS

We used the 5% United States Medicare beneficiary sample from 2006-2012 to assess whether gout was independently associated with new diagnosis of OSA in adults 65 years or older, adjusting for demographics, medical comorbidity (Charlson-Romano index) and hypertension, hyperlipidemia and coronary artery disease, and the use of medications for cardiovascular diseases or gout (allopurinol, febuxostat).

RESULTS

Based on 10,448,472 person-years of follow-up in a cohort of 1.74 million adults 65 years or older, the crude incidence rates of OSA were 14.3 per 1,000 person-years in people with gout and 3.9 per 1,000 person-years in people without gout. In multivariable-adjusted analyses, gout was associated with higher risk of a new diagnosis of OSA during the follow-up, hazard ratio was 2.07 (95% confidence interval [CI] 2.00, 2.15). In sensitivity analyses that substituted continuous Charlson-Romano score with a categorical variable or individual Charlson-Romano comorbidities plus hypertension, hyperlipidemia and coronary artery disease, the main finding was confirmed, hazard ratios were 2.11 (95% CI 2.03, 2.18) and 1.79 (95% CI 1.73, 1.85).

CONCLUSIONS

The independent association of gout with a twofold higher risk of OSA in older adults indicates that common mechanisms may be shared by the two conditions. More studies are needed to investigate these mechanisms further.

Association of ideal cardiovascular health metrics with serum uric acid, inflammation and atherogenic index of plasma: A population-based survey

BACKGROUND AND AIMS

We aimed to evaluate the link between inflammatory score [consisting of C-reactive protein (CRP) and white blood cells], serum uric acid (SUA) and atherogenic index of plasma (AIP) and the cardiovascular health (CVH) score.

METHODS

We used the cross-sectional National Health and Nutrition Examination Survey database. Statistical analyses accounted for the survey design and sample weights.

RESULTS

Overall, there were 23,004 participants (mean age = 47.2 years, 46.5% males). Participants with an ideal CVH level had the highest ratio of poverty to income (3.62%, p < 0.001), as well as lower levels of CRP, SUA and AIP (p < 0.001 for all comparisons). In adjusted linear regression, a significant negative association was observed between inflammatory score (β = -0.052, p < 0.001), SUA (β = -0.041, p < 0.001) and AIP (β = -0.039, p < 0.001) and CVH score, i.e. participants with a better (greater) CVH score had a lower inflammatory score. Results from adjusted logistic regression showed reduction in the likelihood of "high-risk atherosclerosis" (defined as AIP ≥0.21) [intermediate: odds ratio (OR) = 0.90, 95% confidence interval (CI):0.85-0.95, ideal: OR = 0.81, 95%CI: 0.74-0.88] and "high CVD risk" (defined as CRP ≥3 mg/l) [intermediate: OR = 0.86, 95%CI:0.73-0.98, ideal: OR = 0.82, 95%CI:0.69-0.95] across the categories of CVH.

CONCLUSIONS

Our findings highlight that CVH metrics were associated with inflammatory score, SUA and AIP. Furthermore, participants with a better CVH score had a lower CVD risk. These results reinforce the importance of implementing healthy behaviours as proposed by the American Heart Association. If confirmed in clinical trials, this knowledge may have implications for CVD prevention and management.

The baseline levels and risk factors for high-sensitive C-reactive protein in Chinese healthy population

BACKGROUND

Recent studies show that C-reactive protein (CRP) is not only a biomarker but also a pathogenic mediator contributing to the development of inflammation and ageing-related diseases. However, serum levels of CRP in the healthy ageing population remained unclear, which was investigated in the present study.

METHODS

Serum levels of high sensitive C-reactive protein (hs-CRP), glucose (Glu), triglyceride (TG), cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), superoxide dismutase (SOD), serum creatinine (SCr), serum uric acid (SUA) were measured in 6060healthy subjects (3672 male and 2388 female, mean age:45.9 years) who received routine physical examination at Sun Yat-sen Memorial Hospital, Guangzhou, China.

RESULTS

In total of 6060 healthy people, serum levels of hs-CRP were significantly increased with ageing (P < 0.05), particularly in those with age over 45-year-old (1.31[0.69-2.75] vs 1.05[0.53-2.16]mg/L, P < 0.001). Interestingly, levels of serum hs-CRP were significantly higher in male than female population (1.24[0.65-2.57] vs 1.07[0.53-2.29]mg/L, P < 0.001). Correlation analysis also revealed that serum levels of hs-CRP positively correlated with age and SUA, but inversely correlated with serum levels of HDL-c and SOD (all P < 0.05).

CONCLUSIONS

Baseline levels of serum hs-CRP are increased with ageing and are significantly higher in male than female healthy population. In addition, elevated serum levels of hs-CRP are also associated with increased SUA but decreased HDL-c and SOD. Thus, serum levels of hs-CRP may be an indicator associated with ageing in healthy Chinese population.

Association between serum uric acid and arterial stiffness in a low-risk, middle-aged, large Korean population: A cross-sectional study

We investigated the association between serum uric acid (SUA) and brachial ankle pulse wave velocity (baPWV) in an apparently healthy population. We performed a cross-sectional study on middle-aged Koreans who completed a yearly health-screening program between January and December 2014. Subjects with coronary artery disease, diabetes, or hypertension were excluded. Linear regression analyses were used to study the relationship between SUA and baPWV. Multiple adjustments were made for variables based on clinical or statistical significance. Of 66,917 study participants (38,170 men and 28,747 women), the mean age was 39.4 ± 6.7 years and the average SUA level was 5.23 ± 1.4 mg/dL. SUA values were higher in men than in women (6.1 ± 1.2 mg/dL vs. 4.1 ± 0.8 mg/dL). SUA was linearly associated with baPWV in women and in men (P < .001, respectively). Multiple regression analyses remained significant for women with a positive association with baPWV across SUA quintiles in a dose-response manner (P < .001) while no longer for men with a J-shaped association between SUA quintiles and baPWV. When SUA modeled continuously, baPWV rose by 12.413 cm/s in women (P < .001) and by 6.588 cm/s in men (P < .001) for each 1 mg/dL increase of SUA. In a low-risk, middle-aged, large Korean population, higher SUA levels could have an unfavorable impact on arterial stiffness as measured by baPWV, and this association was stronger in women than in men.

Probiotic supplements prevented oxonic acid-induced hyperuricemia and renal damage

Hyperuricemia is highly prevalent and especially common in subjects with metabolic, cardiovascular and renal diseases. In chronic kidney disease, hyperuricemia is extremely common, and uric acid (UA) excretion relies on gut uricolysis by gut microbiota. Current therapy for lowering serum UA includes drugs that may produce undesired secondary effects. Therefore, this pilot study was designed to evaluate the potential of two probiotic supplements to reduce systemic uric acid concentrations. Secondary objectives were to assess whether the hypouricemic effect related to a therapeutic benefit on the hyperuricemia-induced renal damage and hypertension. Analysis of fecal microbiota was also performed. Groups of 6 rats each were followed for 5 weeks and allocated in the following treatment groups: C = Control; HU-ND = Oxonic acid-induced hyperuricemia (HU) +regular diet; HU-P = HU+placebo; HU-F1 = HU+ probiotics formula 1 and HU-F2 = HU+ probiotics formula 2. We confirmed that oxonic acid-induced hyperuricemia produced hypertension and renal functional and structural changes, along with modest changes in the overall composition of fecal microbiota. Both probiotic-containing diets prevented HU, elevated UA urinary excretion and intrarenal UA accumulation induced by oxonic acid. The hypouricemic effect conferred by probiotic supplementation also prevented the renal changes and hypertension caused by hyperuricemia. However, probiotic treatment did not restore the fecal microbiota. In conclusion, we demonstrated for the first time the ability of probiotics containing uricolytic bacteria to lower serum uric acid in hyperuricemic animals with beneficial consequences on blood pressure and renal disease. As probiotics supplements are innocuous for human health, we recommend clinical studies to test if probiotic supplements could benefit hyperuricemic individuals.

Gout and hearing impairment in the elderly: a retrospective cohort study using the US Medicare claims data

OBJECTIVES

To evaluate whether gout is associated with a higher risk of hearing loss in older adults.

DESIGN

Retrospective cohort study.

SETTING

USA.

PARTICIPANTS

5% random sample of US Medicare claims 2006-2012, representative of US adults aged 65 years or older.

PRIMARY AND SECONDARY OUTCOMES

Incident (new) hearing loss identified by the presence of at least two claims at least 4 weeks apart with an International Classification of Diseases, Ninth Revision, 389.xx, with no respective claim in the baseline 1-year observation period.

RESULTS

Among the 1.71 million eligible people, 89 409 developed incident hearing impairment. The crude incidence rates of incident hearing impairment in people with versus without gout were 16.9 vs. 8.7 per 1000 person-years. Using Cox regression analyses adjusted for demographics, medical comorbidity and common cardiovascular and gout medications, we found that gout was associated with a significantly higher HR of incident hearing impairment, HR was 1.44 (95% CI 1.40 to 1.49, p<0.0001). Findings were confirmed in sensitivity analyses that substituted continuous Charlson-Romano Index with categorical variable or all comorbidities and additionally cardiovascular risk factors, with minimal attenuation of HR.

CONCLUSIONS

Gout is associated with a higher risk of development of hearing loss in older adults. Future studies need to assess the underlying mechanisms of this association.

Preoperative serum uric acid predicts incident acute kidney injury following cardiac surgery

Background

Acute kidney injury (AKI) following cardiac surgery is a frequent complication and several risk factors increasing its incidence have already been characterized. This study evaluates the influence of preoperative increased serum uric acid (SUA) levels in comparison with other known risk factors on the incidence of AKI following cardiac surgery.

Methods

During a period of 5 month, 247 patients underwent elective coronary artery bypass grafting, valve replacement/ repair or combined bypass and valve surgery. Datas were prospectively analyzed. Primary endpoint was the incidence of AKI as defined by the AKI criteria comparing patients with preoperative serum uric acid (SUA) levels below versus above the median. Multivariate logistic regression analysis was used to identify independent predictors of postoperative AKI.

Results

Thirty (12.1%) of the 247 patients developed postoperative AKI, 24 of 30 (80%) had preoperative SUA- levels above the median (≥373 μmol/l) (OR: 4.680, CI 95% 1.840; 11.904, p = 0.001). In the multivariate analysis SUA levels above the median (OR: 5.497, CI 95% 1.772; 17.054, p = 0.003), cardiopulmonary bypass (CPB) time > 90 min (OR: 4.595, CI 95% 1.587; 13.305, p = 0.005), cardiopulmonary bypass (CPB) > 30 kg/m² (OR: 3.208, CI 95% 1.202; 8.562; p = 0.02), and preoperative elevated serum-creatinine levels (OR: 1.015, CI 95% 1.001; 1.029, p = 0.04) were independently associated with postoperative AKI.

Conclusions

Serum uric acid is an independent risk marker for AKI after cardiac surgery. From all evaluated factors it showed the highest odds ratio.