Relation of serum uric acid to cardiovascular disease

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.

Beneficial effects of SGLT2 inhibitors on fatty liver in type 2 diabetes: A common comorbidity associated with severe complications

Patients with type 2 diabetes mellitus (T2DM) are exposed to non-alcoholic fatty liver disease (NAFLD), a comorbidity associated with cardiovascular disease and chronic kidney disease, and which may progress to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Sodium-glucose cotransporter type-2 (SGLT2) inhibitors are glucose-lowering agents that improve glucose control while promoting weight loss and lowering serum uric acid levels. These agents may exert cardiovascular and renal protection in T2DM patients with established cardiovascular disease. Recent findings from both randomized controlled trials and open-label studies have also shown that SGLT2 inhibitors are able to reduce fatty liver content, as assessed by different imaging techniques, and improve biological markers of NAFLD, especially serum liver enzymes, in patients with T2DM. In addition, there are emerging data to suggest a mechanism beyond the reduction of hyperglycaemia and body weight, and a potential role for the decrease in low-grade inflammation and oxidative stress associated with SGLT2 inhibitor therapy. This positive effect of SGLT2 inhibitors on NAFLD complements their already well-known effects on cardiovascular and chronic kidney diseases.

Gender differences in association between uric acid and all-cause mortality in patients with chronic heart failure

Background

Elevated serum uric acid (SUA) is associated with poor prognosis in patients with cardiovascular disease, yet it is still not decided whether the role of SUA is causal or only reflects an underlying disease. The purpose of the study was to investigate if SUA was an independent predictor of 5-year all-cause mortality in a propensity score matched cohort of chronic heart failure (HF) outpatients. Furthermore, to assess whether gender or renal function modified the effect of SUA.

Methods

Patients (n = 4684) from the Norwegian Heart Failure Registry with baseline SUA were included in the study. Individuals in the highest gender-specific SUA quartile were propensity score matched 1:1 with patients in the lowest three SUA quartiles. The propensity score matching procedure created 928 pairs of patients (73.4% males, mean age 71.4 ± 11.5 years) with comparable baseline characteristics. Kaplan Meier and Cox regression analyses were used to investigate the independent effect of SUA on all-cause mortality.

Results

SUA in the highest quartile was an independent predictor of all-cause mortality in HF outpatients (hazard ratio (HR) 1.19, 95% confidence interval (CI) 1.03–1.37, p-value 0.021). Gender was found to interact the relationship between SUA and all-cause mortality (p-value for interaction 0.007). High SUA was an independent predictor of all-cause mortality in women (HR 1.65, 95% CI 1.24–2.20, p-value 0.001), but not in men (HR 1.06, 95% CI 0.89–1.25, p-value 0.527). Renal function did not influence the relationship between SUA and all-cause mortality (p-value for interaction 0.539).

Conclusions

High SUA was independently associated with inferior 5-year survival in Norwegian HF outpatients. The finding was modified by gender and high SUA was only an independent predictor of 5-year all-cause mortality in women, not in men.

Detection of uric acid based on doped ZnO/Ag2O/Co3O4 nanoparticle loaded glassy carbon electrode

Highly sensitive and selective uric acid sensor was fabricated using facile wet-chemically prepared ternary doped ZnO/Ag₂O/Co₃O₄ nanoparticles onto glassy carbon electrode by electrochemical approach, which introduced a prospective and reliable route to the future development of enzyme-free sensor by doped nanomaterials in broad scales.

The dose-response effects of uric acid on the prevalence of metabolic syndrome and electrocardiographic left ventricular hypertrophy in healthy individuals

BACKGROUND AND AIM

Hyperuricemia (HUA) is associated with the prevalence of metabolic syndrome (MetS) and cardiovascular risks in various populations. HUA is also able to induce cardiomyocyte hypertrophy in mouse models. However, the dose-response effects of serum uric acid (SUA) on the prevalence of MetS and electrocardiographic left ventricular hypertrophy (LVH) are unclear.

METHODS AND RESULTS

We retrospectively collected data from 18,932 individuals who underwent an annual health examination between 1/1/2016 and 12/31/2016. We excluded those with systemic diseases or missing questionnaires. The primary study endpoints were the prevalence of MetS and LVH, which were defined by the criteria for the Taiwanese population and the "SPRINT" trial. The cohort consisted of 17,913 individuals with a mean age of 31.2 years (SD 7.4) and a mean body mass index of 24.6 kg/m² (SD 3.6); 87.1% of the individuals were men. The prevalence rates of HUA, MetS, and LVH were 29.5%, 9.4%, and 0.32%, respectively, in the overall study population. The HUA group was predominantly male and had significantly poorer lifestyle choices and greater laboratory cardiometabolic biomarker values than did the normouricemic group. However, the frequencies of physical activity were comparable between the two groups. After adjusting for confounders, SUA was associated with MetS (OR:1.473, 95% CI:1.408-1.540, P < 0.001) and LVH (OR:1.301, 95% CI:1.064-1.591, P = 0.01).

CONCLUSION

We demonstrated that the dose-response effects of SUA are associated with the prevalence of MetS and electrocardiographic LVH in healthy individuals from Taiwan. Based on this evidence, future studies should investigate urate-lowering therapy and cardiovascular benefits in individuals with HUA (ClinicalTrials.gov number NCT03473951).

Serum Uric Acid Is Independently Associated with Coronary Calcification in an Asymptomatic Population

Detecting early-stage atherosclerosis is an important step towards cardiovascular disease prevention. Coronary artery calcium (CAC) score is a sensitive and non-invasive tool for detecting coronary atherosclerosis. Higher serum uric acid (SUA) levels are known to be associated with cardiovascular diseases. However, there is inconsistency regarding the independence of the association. The aim of our study was to assess the association of CAC and SUA in an asymptomatic population. CAC scans of 281 participants were analyzed in a voluntary screening program. A health questionnaire, physical examination, and laboratory tests were also performed. Participants with a history of cardiovascular disease were excluded from the analysis. 36.3% (n = 102) of the participants had no detectable CAC and 13.9% (n = 39) had a CAC score of > 300. SUA showed positive correlation with CAC score (0.175, p < 0.01). SUA was independently associated with Ca score > 300 (OR 5.17, p = 0.01) after the effects of conventional risk factors were eliminated.

Serum Uric Acid Levels are Associated with Cardiometabolic Risk Factors in Healthy Young and Middle-Aged Adults

Background

Observational studies have highlighted an association between serum uric acid (SUA) levels and cardiovascular risk factors. Despite the growing body of evidences, several studies were conducted in older individuals or in carriers of diseases susceptible to affect SUA levels and cardiometabolic risk markers.

Objective

To evaluate the relationship of SUA with body adiposity, metabolic profile, oxidative stress, inflammatory biomarkers, blood pressure and endothelial function in healthy young and middle-aged adults.

Methods

149 Brazilian adults aged 20-55 years, both sexes, underwent evaluation of body adiposity, SUA, fasting glucose and insulin, lipid profile, malondialdehyde (MDA), high sensitivity C-reactive protein (hs-CRP), adiponectin, blood pressure and endothelial function. Endothelial function was assessed by the reactive hyperemia index (RHI) derived from peripheral arterial tonometry method. Participants were allocated in two groups according to SUA levels: control group (CG; n = 130; men ≤ 7 mg/dL, women ≤ 6 mg/dL) and hyperuricemia group (HG; n = 19; men > 7 mg/dL, women > 6 mg/dL). A P-value < 0.05 was considered statistically significant.

Results

After adjustment for confounders, participants in HG compared with those in CG displayed higher body mass index (BMI): 34.15(33.36-37.19) vs.31.80 (26.26-34.42) kg/m²,p = 0.008, higher MDA: 4.67(4.03-5.30) vs. 3.53(3.10-4.07) ng/mL, p < 0.0001 and lower RHI: 1.68 ± 0.30 vs. 2.05 ± 0.46, p = 0.03). In correlation analysis adjusted for confounders, SUA was positively associated (p < 0.05) with BMI, waist circumference, LDL-cholesterol, triglycerides and MDA, and negatively associated (p < 0.05) with HDL-cholesterol, adiponectin and RHI.

Conclusions

This study suggests that in healthy young and middle-aged adults higher SUA levels are associated with higher body adiposity, unfavorable lipid and inflammatory phenotype, higher oxidative stress and impaired endothelial function.

Hyperuricemia and smoking in young adults suspected of coronary artery disease ≤ 35 years of age: a hospital-based observational study

Background

Coronary artery disease (CAD) is showing an increasing trend in young adults. Cigarette smoking has been shown to be a major cause of premature CAD. Previous studies have also shown that hyperuricemia (HUA) is associated with CAD; however, the interaction effect between HUA and smoking on CAD is uncertain. Therefore, this study was designed to determine the relationship and interactive effects of HUA and smoking on the risk of CAD in young adults ≤ 35 years of age.

Methods

In this observational study we consecutively included adults (18–35 years of age) with suspected CAD who underwent coronary angiography for the first time in our institution from January 2005 to December 2015. Patients with stenosis affecting ≥50% of the luminal diameter and acute myocardial infarction were considered to have CAD. A serum uric acid (SUA) level ≥ 7.0 mg / dl (420 mmol / L) in males and ≥ 6.0 mg / dl (357 mmol / L) in females was defined as hyperuricemia. We tested for an interaction between HUA and cigarrete smoking on CAD. The relationship between HUA, cigarrete smoking, and CAD was assessed by multivariate logistic regression analysis.

Results

A total of 1113 participants were included in this study; 771 participants were confirmed to have CAD. HUA was present in 34.8% of the participants. HUA was significantly higher in the CAD group (odds ratio [OR], 1.34; 95% confidence interval [CI], 1.02–1.76; p = 0.035). More smokers were in the CAD group (OR, 1.59; 95% CI, 1.22–2.07; p = 0.001). Based on multivariate regression analysis and after adjustment for age, BMI, high LDL-C level, low HDL-C level, hypercholesterolemia, hypertriglyceridemia, metabolic syndrome, diabetes mellitus, and hypertension, HUA was shown to be strongly associated with the presence of CAD in non-smokers (OR, 1.84; 95% CI, 1.03–3.29; p = 0.039). We further demonstrated that the interaction between HUA and cigarrete smoking achieved statistical significance for the presence of CAD (p = 0.008).

Conclusions

In the current study, HUA was shown to be associated with the presence of CAD in non-smokers ≤ 35 years of age.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0910-5) contains supplementary material, which is available to authorized users.

Effect of allopurinol on the glomerular filtration rate of children with chronic kidney disease

BACKGROUND

Hyperuricemia is a leading risk factor for the development of chronic kidney disease (CKD). We hypothesized that lowering serum uric acid (SUA) with allopurinol in hyperuricemic children with CKD may reduce the risk of CKD progression.

METHODS

A total of 70 children, aged 3-15 years, with elevated serum uric acid level (SUA) > 5.5 mg/dL and CKD stages 1-3 were prospectively randomized to receive allopurinol 5 mg/kg/day (study group, n = 38) or no treatment (control group, n = 32) for 4 months. The primary and secondary outcomes were changes in estimated glomerular filtration rate (eGFR) (> 10 mL/min/1.73m²) and the SUA (> 1.0 mg/dL) from baseline values, respectively.

RESULTS

Baseline age, gender, blood pressure (BP), body mass index (BMI), SUA, high-sensitive C-reactive protein (hsCRP), and eGFR were similar in allopurinol and control subjects. Allopurinol treatment resulted in a decrease in SUA, a decrease in systolic and diastolic BP, a decrease in hsCRP, and an increase in eGFR compared with the baseline values (p < 0.05 for all). No significant difference was observed in the control hyperuricemic subjects. In multiple regression analysis after incorporating variables (age, gender, BMI, systolic and diastolic BP, CRP, and SUA), eGFR was independently related to SUA both before and after treatments (p = 0.03 vs. p = 0.02, respectively). All patients in the study group tolerated allopurinol, and there were no adverse reactions observed by physical examination or reported by patients.

CONCLUSION

Urate-lowering therapy with allopurinol, over a 4-month period, can improve renal function in children with CKD stages 1-3.

Saponins from Sea Cucumber and Their Biological Activities

Sea cucumbers, belonging to the phylum Echinodermata, have been valued for centuries as a nutritious and functional food with various bioactivities. Sea cucumbers can produce highly active substances, notably saponins, the main secondary metabolites, which are the basis of their chemical defense. The saponins are mostly triterpene glycosides with triterpenes or steroid in aglycone, which possess multiple biological properties including antitumor, hypolipidemic activity, improvement of nonalcoholic fatty liver, inhibition of fat accumulation, antihyperuricemia, promotion of bone marrow hematopoiesis, antihypertension, etc. Sea cucumber saponins have received attention due to their rich sources, low toxicity, high efficiency, and few side effects. This review summarizes current research on the structure and activities of sea cucumber saponins based on the physiological and pharmacological activities from source, experimental models, efficacy, and mechanisms, which may provide a valuable reference for the development of sea cucumber saponins.

Effect and Mechanism of ShiZhiFang on Uric Acid Metabolism in Hyperuricemic Rats

Objective

To explore the effect and mechanism of ShiZhiFang on uric acid metabolism.

Methods

40 rats were divided into normal group, model group, ShiZhiFang group, and benzbromarone group. The hyperuricemic rat model was induced by yeast gavage at 15 g/kg and potassium oxonate intraperitoneal injection at 600 mg/kg for two weeks. During the next two weeks, ShiZhiFang group rats were given ShiZhiFang by gavage, and benzbromarone group rats were given benzbromarone by gavage. The serum uric acid, creatinine, blood urea nitrogen, XOD activity, urinary uric acid, urinary β₂-MG, and histopathological changes were observed in the rats of each group after treatment.

Results

The hyperuricemic model was established successfully and did not show the increase of serum creatinine and blood urea nitrogen. Compared with the model group, the serum uric acid, serum XOD activity, and urinary β₂-MG were significantly decreased (p < 0.05), and 24 h urinary uric acid excretion was significantly decreased (p < 0.01) in ShiZhiFang group, whereas the two treatment groups were of no statistical significant in above indicators (p > 0.05); renal histopathology showed that the lesions in two treatment groups were reduced compared to the model groups. The gene and protein expression of uric acid anion transporters rOAT1 and rOAT3 in the kidney was significantly higher than that in model group (p < 0.01).

Conclusion

The model is suitable for the study of primary hyperuricemia. The mechanisms of ShiZhiFang on uric acid metabolism in hyperuricemic rats may be involved in reducing the activity of serum XOD and promoting the transcription and expression of rOAT1 and rOAT3 in the kidney.

The validity, stability, and utility of measuring uric acid in saliva

AIM

Serum uric acid (UA) is associated with many health conditions, including kidney, cardiovascular, and metabolic disorders. We examined the validity and stability of salivary UA as a noninvasive measure of serum UA.

MATERIALS & METHODS

Using serum and salivary UA data from healthy adults (n = 99), we examined the UA serum-saliva correlation, and UA associations with adiponectin and C-reactive protein. Using longitudinal data from young adults (n = 182), we examined salivary UA stability.

RESULTS

We found robust positive serum-saliva correlations for UA. UA and adiponectin were inversely related in serum and saliva. Salivary UA was relatively stable; 62-66% of variance could be attributed to a latent trait-like component.

CONCLUSION

Salivary UA may be an important biomarker indexing health and disease risk.

Uric acid and cardiovascular disease

Uric acid (UA) is an end product of purine metabolism in humans and great apes. UA acts as an antioxidant and it accounts for 50% of the total antioxidant capacity of biological fluids in humans. When present in cytoplasm of the cells or in acidic/hydrophobic milieu in atherosclerotic plaques, UA converts into a pro-oxidant agent and promotes oxidative stress and through this mechanism participates in the pathophysiology of human disease including cardiovascular disease (CVD). Most epidemiological studies but not all of them suggested the existence of an association between elevated serum UA level and CVD, including coronary heart disease (CHD), stroke, congestive heart failure, arterial hypertension and atrial fibrillation as well as an increased risk for mortality due to CVD in general population and subjects with confirmed CHD. Evidence available also suggests an association between elevated UA and traditional cardiovascular risk factors, metabolic syndrome, insulin resistance, obesity, non-alcoholic fatty liver disease and chronic kidney disease. Experimental and clinical studies have evidenced several mechanisms through which elevated UA level exerts deleterious effects on cardiovascular health including increased oxidative stress, reduced availability of nitric oxide and endothelial dysfunction, promotion of local and systemic inflammation, vasoconstriction and proliferation of vascular smooth muscle cells, insulin resistance and metabolic dysregulation. Although the causality in the relationship between UA and CVD remains unproven, UA may be pathogenic and participate in the pathophysiology of CVD by serving as a bridging mechanism mediating (enabling) or potentiating the deleterious effects of cardiovascular risk factors on vascular tissue and myocardium.

Relationship Between Serum Uric Acid and Incident Hypertension in Patients with Type 2 Diabetes

BACKGROUND

Little is known about the relationship between high baseline serum uric acid (SUA) and incident hypertension in patients with type 2 diabetes (T2D).

OBJECTIVES

To evaluate the ability of baseline SUA to predict the incidence of hypertension in non-hypertensive patients with T2D.

METHODS

The association between SUA and mean 20-year incidence of hypertension was examined in 1,666 non-hypertensive patients with T2D from Isfahan Endocrine and Metabolism Research Center outpatient clinics, Iran. The primary outcome was incident hypertension defined as systolic blood pressure (BP) of 140 mmHg or higher and/or diastolic BP 90 mmHg or higher and/or use of antihypertensive medications. The mean (standard error (SE)) age of participants was 49.4 years (0.25 years) with a mean (SE) duration of diabetes of 6.1 years (0.15 years) at initial registration. We used multiple logistic regression to estimate the odds ratio (OR) for the incidence of hypertension across quartiles of SUA, and plotted a receiver operating characteristic (ROC) curve to assess discrimination.

RESULTS

The highest quartile of SUA was not associated with hypertension compared with the lowest quartile in multivariable adjusted models (OR: 1.22, 95% CI: 0.87, 1.73). The area under the ROC curve for SUA was 51.7% (95% CI: 48.9, 54.5).

CONCLUSIONS

High initial SUA levels are not a predictor of incident hypertension in an Iranian T2D population.

Genetic analysis of quantitative traits in the Japanese population links cell types to complex human diseases

Clinical measurements can be viewed as useful intermediate phenotypes to promote understanding of complex human diseases. To acquire comprehensive insights into the underlying genetics, here we conducted a genome-wide association study (GWAS) of 58 quantitative traits in 162,255 Japanese individuals. Overall, we identified 1,407 trait-associated loci (P < 5.0 × 10^-8), 679 of which were novel. By incorporating 32 additional GWAS results for complex diseases and traits in Japanese individuals, we further highlighted pleiotropy, genetic correlations, and cell-type specificity across quantitative traits and diseases, which substantially expands the current understanding of the associated genetics and biology. This study identified both shared polygenic effects and cell-type specificity, represented by the genetic links among clinical measurements, complex diseases, and relevant cell types. Our findings demonstrate that even without prior biological knowledge of cross-phenotype relationships, genetics corresponding to clinical measurements successfully recapture those measurements' relevance to diseases, and thus can contribute to the elucidation of unknown etiology and pathogenesis.

Hyperuricemia as a prognostic factor after acute coronary syndrome

BACKGROUND AND AIMS

Many studies have reported the independent association between uric acid and cardiovascular disease, its role as a risk predictor for outcomes in people with acute coronary syndrome remains controversial. This study aims to assess the association between hyperuricemia and medium/long-term clinical outcomes in people with acute coronary syndrome and determine whether adding hyperuricemia to the GRACE score improves its predictive capability.

METHODS

This cohort study included patients admitted for acute coronary syndrome between 2008 and 2013. Outcomes were cardiovascular and total mortality, and major cardiovascular events. We used a multivariate model to adjust for potential confounding covariates and presented event rates with Kaplan-Meier curves. After adding hyperuricemia to the GRACE score, we compared scores from the reclassification table and the net reclassification improvement.

RESULTS

1119 participants were included and followed-up for a mean of 36 months. Multivariate models showed hyperuricemia was independently associated with higher cardiovascular mortality (HR:1.91; 95% CI:1.32-2.76; p < 0.01), higher all-cause mortality (HR:1.59; 95% CI:1.18-2.15; p < 0.01) and higher major cardiovascular event rates (HR:1.36; 95% CI:1.11-1.67; p < 0.01). The hyperuricemia addition to GRACE score led to reclassifying 26% of the participants, and net reclassification improvement was 34%. However, the area under the curve increase was 0.009 and not statistically significant (p > 0.05).

CONCLUSIONS

Hyperuricemia is associated with higher medium/long-term mortality and major cardiovascular event rates in patients following acute coronary syndrome. The addition of hyperuricemia to the GRACE score seems to improve risk classification but the discrimination of the new predictive model did not change. Hyperuricemic patients had higher all-cause mortality in medium and high-risk score categories.

Association between Serum Uric Acid Level and Carotid Atherosclerosis in Chinese Individuals Aged 75 Years or Older: A Hospital-Based Case-Control Study

OBJECTIVES

To investigate the association between serum uric acid level and the presence and progression of carotid atherosclerosis in Chinese individuals aged 75 years or older.

DESIGN

Case-control study.

SETTING

In a teaching hospital.

PARTICIPANTS

Five hundred and sixty-four elderlies (75 years or above) who underwent general health screening in our hospital were enrolled.

MEASUREMENTS

The detailed carotid ultrasound results, physical examination information, medical history, and laboratory test results including serum uric acid level were recorded, these data were used to analyze the relationship between serum uric acid level and carotid atherosclerosis. Then, subjects who underwent the second carotid ultrasound 1.5-2 years later were further identified to analyzed the relationship between serum uric acid and the progression of carotid atherosclerosis.

RESULTS

A total of 564 subjects were included, carotid plaque was found in 482 (85.5%) individuals. Logistic regression showed that subjects with elevated serum uric acid (expressed per 1 standard deviation change) had significantly higher incidence of carotid plaque (odds ratio, 1.37; 95% confidence interval, 1.07-1.75; P= 0.012) after controlling for other factors. A total of 236 subjects underwent the follow-up carotid ultrasound. Linear regression showed that serum uric acid level (expressed per 1 standard deviation change; 1 standard deviation = 95.5 μmol/L) was significantly associated with percentage of change of plaque score (P = 0.008). Multivariable linear regression showed that 1 standard deviation increase in serum uric acid levels was expected to increase 0.448% of plaque score (P = 0.023).

CONCLUSION

The elevated serum uric acid level may be independently and significantly associated with the presence and progression of carotid atherosclerosis in Chinese individuals aged 75 years or older.

Cardiovascular effects of sodium glucose cotransporter 2 inhibitors

As the first cardiovascular (CV) outcome trial of a glucose-lowering agent to demonstrate a reduction in the risk of CV events in patients with type 2 diabetes mellitus (T2DM), the EMPAgliflozin Removal of Excess Glucose: Cardiovascular OUTCOME Event Trial in Type 2 Diabetes Mellitus Patients (EMPA-REG OUTCOME^®) trial, which investigated the sodium glucose cotransporter 2 (SGLT2) inhibitor empagliflozin, has generated great interest among health care professionals. CV outcomes data for another SGLT2 inhibitor, canagliflozin, have been published recently in the CANagliflozin CardioVascular Assessment Study (CANVAS) Program, as have CV data from the retrospective real-world study Comparative Effectiveness of Cardiovascular Outcomes in New Users of Sodium-Glucose Cotransporter-2 Inhibitors (CVD-REAL), which compared SGLT2 inhibitors with other classes of glucose-lowering drugs. This review discusses the results of these three studies and, with a focus on EMPA-REG OUTCOME, examines the possible mechanisms by which SGLT2 inhibitors may reduce CV risk in patients with T2DM.

Pharmacokinetic drug evaluation of empagliflozin plus linagliptin for the treatment of type 2 diabetes

INTRODUCTION

Type 2 diabetes mellitus has become a growing epidemic and therefore efficient treatment strategies that target its management are needed. The treatment of diabetic patients often requires the combination of antidiabetic drug classes. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) block glucose reabsorption in the proximal renal tubules. Dipeptidyl peptidase-4 inhibitors (DPP-4i) improve glucose metabolism by blocking the enzyme that degrades incretins leading to increased insulin secretion. Areas covered: The aim of the review is to present the available data on pharmacokinetic properties/pharmacodynamics, metabolic and cardiovascular effects of empagliflozin plus linagliptin combination. Expert opinion: Both empagliflozin and linagliptin have established safety and efficacy in the treatment of diabetes. Available data demonstrate the absence of pharmacological interactions when the two drugs are given together. The complementary mechanisms of action would be expected to provide additive benefits on carbohydrate metabolism variables, but the results from clinical trials have shown that the empagliflozin/linagliptin combination provides only mild improvements of glycated hemoglobin compared with either monotherapy. However, the single-tablet formulation of empagliflozin/linagliptin is expected to provide better compliance and thus improved glycaemic control coupled with a favourable safety profile. Thus, the fixed-dose combination of empagliflozin/linagliptin has the capacity to both effectively and safely manage diabetic patients.

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

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

Associations of estimated glomerular filtration rate and blood urea nitrogen with incident coronary heart disease: the Dongfeng-Tongji Cohort Study

Estimated glomerular filtration rate (eGFR) has been reported to be associated with risk of incident coronary heart disease (CHD), and blood urea nitrogen (BUN) has been shown to be a strong predictor of mortality in patients with heart failure (HF). However, such epidemiological evidence from Chinese population was still limited. We used Cox proportional-hazards regression models to investigate the associations of eGFR and BUN with risk of incident CHD in the prospective Dongfeng-Tongji (DFTJ) cohort. After fully adjusted for potential confounders, a 10-unit decline in eGFR was associated with higher risk for CHD (hazard ratio [HR] 1.05, 95% confidence interval [CI] 1.01-1.09); compared with individuals with normal eGFR levels (eGFR ≥ 90 ml/min per 1.73 m2), individuals with a mild-to-severe eGFR decline (15 to 60 ml/min per 1.73 m2) were at significantly greater risk for CHD (HR 1.25, 95% CI 1.05-1.48; P = 0.011). Compared with individuals in the lowest tertile of BUN, those in the highest tertile were at significantly greater risk for CHD (HR 1.17, 95% CI 1.03-1.33; P = 0.014). In conclusion, a mild-to-severe decline in eGFR or a raised level of BUN might be associated with increased risk of incident CHD in middle-aged and elderly Chinese populations.

The association between serum uric acid and the incidence of prediabetes and type 2 diabetes mellitus: The Rotterdam Study

Background

Limited evidence is available about the association between serum uric acid and sub-stages of the spectrum from normoglycaemia to type 2 diabetes mellitus. We aimed to investigate the association between serum uric acid and risk of prediabetes and type 2 diabetes mellitus.

Methods

Eligible participants of the Rotterdam Study (n = 8,367) were classified into mutually exclusive subgroups of normoglycaemia (n = 7,030) and prediabetes (n = 1,337) at baseline. These subgroups were followed up for incident prediabetes (n = 1,071) and incident type 2 diabetes mellitus (n = 407), respectively. We used Cox proportional hazard models to determine hazard ratios (HRs) for incident prediabetes among individuals with normoglycaemia and incident type 2 diabetes mellitus among individuals with prediabetes.

Results

The mean duration of follow-up was 7.5 years for incident prediabetes and 7.2 years for incident type 2 diabetes mellitus. A standard deviation increment in serum uric acid was significantly associated with incident prediabetes among individuals with normoglycaemia (HR 1.10, 95% confidence interval (CI) 1.01; 1.18), but not with incident type 2 diabetes mellitus among individuals with prediabetes (HR 1.07, 95% CI 0.94; 1.21). Exclusion of individuals who used diuretics or individuals with hypertension did not change our results. Serum uric acid was significantly associated with incident prediabetes among normoglycaemic women (HR 1.13, 95% CI 1.02; 1.25) but not among normoglycaemic men (HR 1.08, 95% CI 0.96; 1.21). In contrast, serum uric acid was significantly associated with incident type 2 diabetes mellitus among prediabetic men (HR 1.23, 95% CI 1.01; 1.48) but not among prediabetic women (HR 1.00, 95% CI 0.84; 1.19).

Conclusions

Our findings agree with the notion that serum uric acid is more closely related to early-phase mechanisms in the development of type 2 diabetes mellitus than late-phase mechanisms.

Uric acid levels correlate with the severity of diabetic sensorimotor polyneuropathy

INTRODUCTION

Diabetic sensorimotor polyneuropathy (DSP) is the most frequent complication in patients with diabetes mellitus (DM), and is associated with age, DM duration, and HbA1c levels. In addition, higher uric acid (UA) levels are reported in patients with DSP.

OBJECTIVES

To explore whether UA levels correlate with DSP severity.

METHODS

We extracted the demographic data, clinical history, neurological and electrophysiological examinations and laboratory findings of 115 patients diagnosed with DSP from January 2012 to December 2015.

RESULTS

The mean age of the total cohort was 62±13years, with 61% men. A positive correlation was demonstrated between uric acid levels and increasing sensory symptoms, and more abnormal electrophysiological findings and vibration perception thresholds. In addition, correlations with gait abnormality, the presence of paraproteinemia and creatine kinase levels were found.

DISCUSSION

Our study results show that uric acid levels correlate with clinical and electrophysiological severity of DSP, providing additional evidence for the relationship between the two, and a potential therapeutic target for DSP.

Elevated Serum Uric Acid Level Predicts Rapid Decline in Kidney Function

BACKGROUND

While elevated serum uric acid level (SUA) is a recognized risk factor for chronic kidney disease, it remains unclear whether change in SUA is independently associated with change in estimated glomerular filtration rate (eGFR) over time. Accordingly, we examined the longitudinal associations between change in SUA and change in eGFR over 5 years in a general Japanese population.

METHODS

This was a large, single-center, retrospective 5-year cohort study at St. Luke's International Hospital, Tokyo, Japan, between 2004 and 2009. We included 13,070 subjects (30-85 years) in our analyses whose data were available between 2004 and 2009. Of those, we excluded 492 subjects with eGFR <60 mL/min/1.73 m2 at baseline. In addition to examining the entire cohort (n = 12,578), we stratified our analyses by baseline eGFR groups: 60-90, 90-120, and ≥120 mL/min/1.73 m2. Linear and logistic regressions models were applied to examine the relationships between baseline and change in SUA, change in eGFR, and rapid eGFR decline (defined as the highest quartile of change in eGFR), adjusted for age, gender, body mass index, abdominal circumference, hypertension, dyslipidemia, and diabetes mellitus.

RESULTS

After multivariable adjustments including baseline eGFR, 1 mg/dL increase in baseline SUA was associated with greater odds of developing rapid eGFR decline (OR 1.27, 95% CI 1.17-1.38), and 1 mg/dL increase in SUA over 5 years was associated with 3.77-fold greater odds of rapid eGFR decline (OR 3.77, 95% CI 3.35-4.26).

CONCLUSIONS

Elevated baseline SUA and increasing SUA over time were independent risk factors for rapid eGFR decline over 5 years.

Blueberry Consumption Affects Serum Uric Acid Concentrations in Older Adults in a Sex-Specific Manner

Blueberries are rich in antioxidants and may protect against disease. Uric acid accounts for about 50% of the antioxidant properties in humans. Elevated levels of serum uric acid (SUA) or hyperuricemia is a risk factor for cardiovascular disease (CVD). The aim was to determine the effect of blueberries on SUA in older adults. Participants (n = 133, 65–80 years) experiencing mild cognitive impairment (MCI) were randomized in a double-blind 6-month clinical trial to either blueberry or placebo. A reference group with no MCI received no treatment. The mean (SD) SUA at baseline were 5.45 (0.9), 6.4 (1.3) and 5.8 (1.4) mg/dL in reference, placebo, and treatment groups, respectively. Baseline SUA was different in men and women (6.25 (1.1) vs. 5.35 (1.1), p = 0.001). During the first three months, SUA decreased in the blueberry group and was significantly different from the placebo group in both men and women (p < 0.0003). Sex-specific differences became apparent after 3 months, when only men showed an increase in SUA in the blueberry group and not in the placebo (p = 0.0006) between 3 and 6 months. At 6 months SUA had rebounded in both men and women and returned to baseline levels. Baseline SUA was correlated with CVD risk factors, waist circumference and triglycerides (p < 0.05), but differed by sex. Overall, 6 m SUA changes were negatively associated with triglycerides in men, but not in women. Group-wise association between 6 m SUA changes and CVD risk factors showed associations with diastolic blood pressure, triglycerides and high-density lipoprotein (HDL) cholesterol in women of the Blueberry group but not in men or any sex in the placebo group. In summary, blueberries may affect SUA and its relationship with CVD risk in a sex-specific manner.

Associations between Serum Uric Acid and the Remission of Non-Alcoholic Fatty Liver Disease in Chinese Males

Epidemiological studies suggest that higher serum uric acid (sUA) level is significantly associated with nonalcoholic fatty liver disease (NAFLD) development. However, little information is available on the relationships between sUA and NAFLD remission. In the present study, 841 NAFLD males (30-75 years) were recruited from a Chinese prospective cohort study (PMMJS) and followed up for five years. The baseline sUA levels of participants were categorized into four quartiles: 191 μmol/L≤ sUA ≤ 347 μmol/L, 347 μmol/L < sUA ≤ 392 μmol/L, 392 μmol/L < sUA ≤ 441 μmol/L and 441 μmol/L<SUA≤676 μmol/L. As the results show, participants with elevated sUA levels at baseline were significantly associated with the decreased rate of NAFLD remission at the end of study (p<0.0001). After adjustment, RR (95%CI) for remitted NAFLD comparing Q1 to Q3 vs Q4 of sUA were 2.95 (1.49-5.83), 2.40 (1.22-4.73) and 1.39 (0.67-2.86), respectively. Furthermore, the sensitivity analysis showed these significant associations were not affected even after exclusion of participants who had hypertension, diabetes mellitus, MetS and hyperlipidemia. Additionally, the presence of the lowest quartile of sUA levels was still significantly associated with remitted NAFLD when the study population was stratified according to the smoking, and the median values of age, ALT, AST, serum creatinine, HDL-C and LDL-C. Therefore, our present study extended the previous findings and suggested that modulation of sUA levels may attenuate the progression of NAFLD.

Relationship between serum uric acid and metastatic and nonmetastatic rectal cancer patients with undergoing no chemotherapy

The aim of this study was to investigate the role of uric acid (UA) in assessing rectal cancer metastasis.There were 475 newly diagnosed patients with complete data in our study, a total of 475 cases were reviewed, and divided into patients with metastasis and without metastasis.There were several statistical differences in age, tumor diameter, carcino-embryonic antigen (CEA), and C-reactive protein (CRP) between the 2 groups. Importantly, serum concentrations of UA in patients with lymphatic metastasis were found to be increased compared with patients without lymphatic metastasis (270.9 ± 52.99 vs 215.8 ± 43.55; P < 0.001). There were positive correlations of serum UA with creatinine (Cr), CRP, and CEA (r = 0.281, P = 0.023; r = 0.312, P = 0.001; r = 0.294, P = 0.017) in rectal cancer patients with metastasis. Multivariate analysis model revealed that elevated serum levels of UA were significant prognostic marker for lymphatic metastasis in patients with rectal cancer, independently of CRP, CEA, and tumor diameter (odds ratio 1.035, 95% CI 1.013-1.057, P = 0.002). In receiver-operating characteristic curve analysis, the area under the curve of serum UA in assessing metastatic rectal cancer patients was 0.803, with sensitivity of 0.864 and specificity of 0.739.Our results suggest that serum UA may be a novel marker in assessing tumor metastasis in patients with rectal cancer.

Serum uric acid as a predictor of future hypertension: Stratified analysis based on body mass index and age

BACKGROUND

Serum uric acid level is a predictor of future hypertension. However, its dependence on body mass index or age is unclear.

METHODS

We examined 26,442 Japanese males aged 18-60years free from hypertension or diagnosed cardiovascular disease at baseline followed up between 2000 and 2010. Participants were categorized into three groups according to the tertile of serum uric acid levels [mg/dL; 1st (reference): 0.1-5.3; 2nd: 5.4-6.2; 3rd: 6.3-11.6]. Incident hypertension was defined as newly detected blood pressure≥140/90mmHg and/or antihypertensive drugs initiation. Body mass index (<25kg/m(2) vs. ≥25kg/m(2)) and age (<40years vs. ≥40years) were stratified into two groups.

RESULTS

During a mean follow-up of 7.2years, there were 11,361 (43%) hypertension cases. Mean serum uric acid levels (mg/dL) at baseline in each group were 1st tertile, 4.6; 2nd tertile, 5.8; and 3rd tertile, 7.0. The cumulative incident hypertension rate was significantly higher in the 3rd tertile (50.8%) than in the 1st (37.4%). Multiple-adjusted hazard ratios (95% confidence interval) for incident hypertension compared with 1st tertile were 1.01 (0.96-1.05) and 1.15 (1.10-1.21) in the 2nd and 3rd tertile, respectively. There was a significant interaction between age and serum uric acid level (p for interaction=0.035). In subjects aged ≥40years, the 3rd serum uric acid group showed higher hazard ratios [1.48 (1.38-1.59)].

CONCLUSION

High serum uric acid level was associated with future hypertension in young and middle-aged Japanese males. This association was stronger among subjects ≥40years old.

Green tea consumption is associated with reduced incident CHD and improved CHD-related biomarkers in the Dongfeng-Tongji cohort

Prospective studies on the association of green tea with risk of coronary heart disease (CHD) incidence were scarce. This study examined whether green tea can reduce CHD incidence and have a beneficial effect on CHD-related risk markers in middle-aged and older Chinese population. We included 19 471 participants who were free of CHD, stroke or cancer at baseline from September 2008 to June 2010, and were followed until October 2013. Cox proportional hazard models were used to examine the hazard ratios (HR) of CHD incidence in relation to green tea consumption. Linear regression models were used to evaluate the effect of green tea on 5-year changes of CHD-related biomarkers. Compared with non-green tea consumers, the multivariable-adjusted HR for CHD was 0.89 (95% CI, 0.81-0.98) in green tea consumers. Particularly, the reduced risk of CHD incidence with green tea consumption was more evident among participants who were male, more than 60 years old, overweight, or with diabetes mellitus. In addition, green tea consumption improved multiple CHD-related risk markers including total cholesterol, HDL-cholesterol, triglycerides, mean platelet volume, and uric acid. In conclusion, green tea consumption was associated with a reduced risk of CHD incidence in the middle-aged and older Chinese populations, and the association might be partly due to altered CHD-related biomarkers.