Elevated serum leptin concentrations in women with hyperuricemia

Ghrelin and Leptin among Patients with Urolithiasis with Concomitant Hyperuricemia and Metabolic Syndrome

Introduction: The study evaluated the selected appetite hormones (ghrelin, leptin) and inflammatory parameters (tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6)) in patients with urolithiasis, metabolic syndrome (MetS), and hyperuricemia. Materials: 57 patients with urolithiasis, MetS and hyperuricemia (UP group) and 29 healthy people as the control group (CG group) were recruited to the study. All persons were 22-60 age. Methods: After preliminary testing, the qualified participants were evaluated for fasting serum levels of ghrelin, leptin, IL-6, and TNF-α. Results: Our results revealed differences between average values of leptin (p = 0.045), ghrelin (p < 0.001), IL-6 (p < 0.001), and TNF-α (p < 0.001) in the studied groups. Moreover, in the UP group, significant correlations were found between ghrelin and leptin; between these hormones and IL-6, and between leptin and uric acid (UA). Besides, leptin concentration increased significantly along with the changes in the body mass index (BMI) categories in the UP group. Conclusions: This study showed that patients with urolithiasis, concomitant MetS, and high UA levels may have problems managing appetite hormones.

Upregulation of Uric Acid Production and Caspase 3 Signalling Mediates Rohypnol-Induced Cardiorenal Damage

The global prevalence of illicit drug use is on the increase with attendant complications like cardiorenal collapse. One such substance of abuse is rohypnol. Despite its ban in most countries, it remains a popular substance of abuse. Whether or not rohypnol induces cardiorenal injury and the associated mechanism is yet to be elucidated. Therefore, the present study investigated the effect of rohypnol on cardiorenal integrity and functions, and glucolipid metabolism. Forty-eight male Wistar rats randomized into six groups (n = 8/group) received (per os) vehicle, low-dose (2 mg/kg) and high-dose (4 mg/kg) rohypnol once daily for twenty eight days, with or without a cessation period. Data revealed that rohypnol exposure irreversibly caused insulin resistance, hyperglycaemia, and dyslipidaemia. This was accompanied by reduced cardiorenal mass and impaired cardiorenal cytoarchitecture and function. Furthermore, rohypnol treatment promoted oxidative stress, inflammation, genotoxicity, and decreased cardiorenal activities of Na+-K+-ATPase, Ca2+-ATPase, and Mg2+-ATPase. These alterations were associated with enhanced uric acid generation and caspase 3 activity in the cardiorenal complex. Thus, this study reveals that rohypnol exposure triggers cardiorenal toxicity with incident insulin resistance, glucolipid and cardiorenal proton pump dysregulation, altered redox state, and inflammation via enhancement of uric acid generation and caspase 3-dependent mechanism.

Assessing the Causal Effects of Adipokines on Uric Acid and Gout: A Two-Sample Mendelian Randomization Study

Previous observational studies have highlighted associations between adipokines and hyperuricemia, as well as gout, but the causality and direction of these associations are not clear. Therefore, we attempted to assess whether there are causal effects of specific adipokines (such as adiponectin (ADP) and soluble leptin receptors (sOB-R)) on uric acid (UA) or gout in a two-sample Mendelian randomization (MR) analysis, based on summary statistics from large genome-wide association studies. The inverse-variance weighted (IVW) method was performed as the primary analysis. Sensitivity analyses (including MR-Egger regression, weighted median, penalized weighted median, and MR pleiotropy residual sum and outlier methods) were also performed, to ensure reliable results. In the IVW models, no causal effect was found for sOB-R (odds ratios (OR), 1.002; 95% confidence intervals (CI), 0.999–1.004; p = 0.274) on UA, or ADP (OR, 1.198; 95% CI, 0.865–1.659; p = 0.277) or sOB-R (OR, 0.988; 95% CI, 0.940–1.037; p = 0.616) on gout. The results were confirmed in sensitivity analyses. There was no notable directional pleiotropy or heterogeneity. This study suggests that these specific adipokines may not play causal roles in UA or gout development.

Codeine exerts cardiorenal injury via upregulation of adenine deaminase/xanthine oxidase and caspase 3 signaling

AIMS

Codeine treatment has been shown to be associated with glucolipid deregulation, though data reporting this are inconsistent and the mechanisms are not well understood. Perturbation of glutathione-dependent antioxidant defense and adenosine deaminase (ADA)/xanthine oxidase (XO) signaling has been implicated in the pathogenesis of cardiometabolic disorders. We thus, hypothesized that depletion of glutathione contents and upregulation of ADA/XO are involved in codeine-induced glucolipid deregulation. The present study also investigated whether or not codeine administration would induce genotoxicity and apoptosis in cardiac and renal tissues.

MATERIALS AND METHODS

Male New Zealand rabbits received per os distilled water or codeine, either in low dose (4 mg/kg) or high dose (10 mg/kg) for 6 weeks.

KEY FINDINGS

Codeine treatment led to reduced absolute and relative cardiac and renal mass independent of body weight change, increased blood glucose, total cholesterol (TC), triglycerides (TG), and low-density lipoprotein (LDL-C), as well as increased atherogenic indices and triglyceride-glucose index (TyG). Codeine administration significantly increased markers of cardiac and renal injury, as well as impaired cardiorenal functions. Codeine treatment also resulted in increased cardiac and renal malondialdehyde, Advanced Glycation Endproducts (AGE) and 8-hydroxydeoxyguanosine (8-OH-dG), and myeloperoxidase (MPO), ADA, XO, and caspase 3 activities. These observations were accompanied by impaired activities of cardiac and renal proton pumps.

SIGNIFICANCE

Findings of this study demonstrate that upregulation of ADA/XO and caspase 3 signaling are, at least partly, contributory to the glucolipid deregulation and cardiorenal injury induced by codeine.

Circulating leptin is associated with serum uric acid level and its tubular reabsorption in a sample of adult middle-aged men

PURPOSE

Leptin is associated with cardiovascular risk factors (e.g. hypertension, insulin resistance, kidney disease and excess body weight). Experimental studies showed that leptin might affect serum uric acid, by modulation of the uric acid excretion. However, there are few observational data on the relationship between leptin and uric acid in the general population. Therefore, the aim of the present study was to evaluate the relationship between leptin and uric acid and its excretion in a large middle-aged male general population.

METHODS

A sample of 930 adult male individuals (mean age: 52 years) without therapy for high uric acid was included in the analysis (the Olivetti Heart Study).

RESULTS

Uric acid was significantly and positively associated with blood pressure, BMI, waist circumference, insulin resistance, C-reactive protein and leptin (p < 0.01), while inversely with renal function (p = 0.01). The multivariate analysis confirmed the association between leptin and uric acid after adjustment for potential confounders (p < 0.01). After division for adiposity, this trend was confirmed separately for normal weight and excess body weight participants. Moreover, leptin was inversely associated with excretion of uric acid (p < 0.01), also in multivariate analysis (p = 0.03).

CONCLUSION

The results of this study indicate a positive association between circulating leptin levels and uric acid, independently of potential confounders, both in normal and excess body weight men. Furthermore, an inverse association between leptin and uric acid excretion was detected.

Plasma versus Erythrocyte Vitamin E in Renal Transplant Recipients, and Duality of Tocopherol Species

Redox imbalance is an adverse on-going phenomenon in renal transplant recipients (RTR). Vitamin E has important antioxidant properties that counterbalance its deleterious effects. However, plasma vitamin E affinity with lipids challenges interpretation of its levels. To test the hypothesis that erythrocyte membranes represent a lipids-independent specimen to estimate vitamin E status, we performed a cross-sectional study in a cohort of adult RTR (n = 113) recruited in a university setting (2015-2018). We compared crude and total lipids-standardized linear regression-derived coefficients of plasma and erythrocyte tocopherol species in relation to clinical and laboratory parameters. Strongly positive associations of fasting lipids with plasma tocopherol became inverse, rather than absent, in total lipids-standardized analyses, indicating potential overadjustment. Whilst, no variables from the lipids domain were associated with the tocopherol species measured from erythrocyte specimens. In relation to inflammatory status and clinical parameters with antioxidant activity, we found associations in directions that are consistent with either beneficial or adverse effects concerning α- or γ-tocopherol, respectively. In conclusion, erythrocytes offer a lipids-independent alternative to estimate vitamin E status and investigate its relationship with parameters over other biological domains. In RTR, α- and γ-tocopherol may serve as biomarkers of relatively lower or higher vulnerability to oxidative stress and inflammation, noticeably in opposite directions.

Management of hyperuricemia and gout in obese patients undergoing bariatric surgery

BACKGROUND

Hyperuricemia and gout represent important issues in the obese patients. Considering the epidemic trend of overweight and obesity in developed countries, the impact of these conditions is likely to increase. At present, bariatric surgery represents the most effective treatment for the management of severe obesity for reducing weight and the impact of associated comorbidities, but its effects on hyperuricemia and gout have not been fully elucidated.

METHODS

In this narrative review, we discuss the current knowledge about hyperuricemia and gout in obese patients undergoing bariatric surgery. We also suggest a useful approach to prevent gouty attacks in the perioperative period.

RESULTS

Weight loss seems to reduce hyperuricemia in the long-term follow-up, but there is evidence also of a high frequency of acute attacks early after surgery in patients with a diagnosis of gout.

CONCLUSION

Bariatric surgery has a high impact on hyperuricemia and gout. A perioperative approach is suggested, based on appropriate hydration, early physical resumption, urate lowering drugs and nonsteroidal anti-inflammatory drugs (NSAIDs), or colchicine and corticosteroids if NSAIDs are ineffective or not tolerated.

Metabolic syndrome, leptin-insulin resistance and uric acid: a trinomial foe for Algerian city-dweller adolescents' health

Background Adolescence is one of the critical periods where increased risk for long-term obesity-related complications is an important health concern. This highlights the need to perform early diagnostics based on precise biomarkers to decrease the risk of complications in adolescents with obesity. Objective To determine the relationships between serum levels of uric acid (UA), leptin and insulin with metabolic syndrome (MS) components in Algerian adolescents. Subjects Nondiabetic adolescents (n = 204). Methods Blood pressure (BP) and anthropometric measurements were performed using standardized techniques. Blood samples were taken for determination of glycemia, triglyceridemia, uricemia, cholesterolemia, leptinemia and insulinemia. Results The rate of MS among an excess weight group was 17.4% [95% confidence interval (CI)]. Serum levels of UA, leptin and insulin were significantly higher in the excess weight group compared to a normal weight group (279.4 ± 86.05 vs. 204.9 ± 50.34 μmol/L and 25.65 ± 14.01 vs. 4.09 ± 2.60 μg/L, p < 0.001; 24.58 ± 13.85 vs. 13.34 ± 6.41 μIU/L, p < 0.05). Serum levels of UA, leptin and insulin were significantly higher in adolescents with MS compared to those without MS (304.86 ± 111.41 vs. 224.72 ± 77.81 μmol/L, 30.26 ± 12.46 vs. 16.93 ± 14.97 μg/L and 30.91 ± 17.30 vs. 18.71 ± 10.14 μIU/L, p < 0.05, respectively). Significant correlations were found between UA and leptin with waist circumference (r = 0.50 and 0.76), diastolic blood pressure (r = 0.58 and 0.43), triglycerides (r = 0.42 and 0.35) and high-density lipoprotein-cholesterol (r = -0.36 and -0.35). Conclusion Serum levels of UA and leptin may be useful biomarkers for early diagnosis of the risk of MS in our Algerian adolescent population.

Atherogenic Index in Type 2 Diabetes and Its Relationship with Chronic Microvascular Complications

OBJECTIVE

This study was designed to investigate risk factors related to atherogenic index of plasma (AIP), as well as the relationship between AIP and chronic microvascular complications in patients with type 2 diabetes (T2DM).

METHODS

This study included 2523 patients with T2DM who had not been treated with lipid-lowering drugs and were admitted to the Department of Endocrinology at Zhongnan Hospital, Wuhan University, during the period from January 2015 to February 2018. Anthropometric indicators were measured after overnight fasting. Low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), and triglyceride (TG) were detected by enzymatic analysis. Standard 75 g oral glucose tolerance testing was performed to measure 0 and 2 hr plasma levels of glucose and insulin. Insulin sensitivity was assessed with HOMA-IR.

RESULTS

Increase in AIP was associated with an increased risk for hypertension (P < 0.05), HbA_1c (P < 0.05), HOMA-IR (P < 0.05), UA (P < 0.05), and decreased eGFR levels (P < 0.05). Furthermore, AIP values directly correlated with BMI (r = 0.182, P < 0.001), waist circumference (r = 0.129, P < 0.001), blood glucose index (FBG (r = 0.153, P < 0.001), PPBG (r = 0.117, P < 0.001), and HbA_1c (r = 0.074, P < 0.001)), insulin resistance (HOMA-IR; r = 0.112, P < 0.001), and uric acid (UA, r = 0.177, P < 0.001). Multiple logistic regression analysis showed that waist circumference, HOMA-IR, FBG, systolic blood pressure, and UA were independent risk factors for AIP (all P < 0.05). The prevalence of diabetic neuropathy and metabolic syndrome was significantly higher among patients with higher AIP.

CONCLUSION

AIP represents a clinically convenient indicator for the detection of T2DM with high risk of complications and associated diseases and thus is a good predictor and indicator for follow-up monitoring in the treatment of patients with high-risk type 2 diabetes.

Serum uric acid level as a determinant of the metabolic syndrome: A case control study

AIMS

To determine whether elevations of uric acid levels are associated with the cluster of disorders described in metabolic syndrome and to evaluate whether hyperuricemia may be considered a component of this syndrome.

METHODS

One year case-control study was conducted in Bikaner, Rajasthan, India from January to December 2013. The study population consisted of 200 subjects, 100 with metabolic syndrome (case) and 100 without metabolic syndrome (control) aged between 18 and 80 years, attending OPD at PBM Hospital were studied. Controls were age and sex matched to the cases. Blood tests and all physical variables were examined using standard methods. Subjects were divided into 6 groups according to their possession of 0, 1, 2, 3, 4 or 5 components of the metabolic syndrome. Statistical analysis was done using ANOVA, linear regression analysis and multivariate linear regression model.

RESULTS

Mean serum UA level was significantly associated with all components of metabolic syndrome (p<0.001) and had strong positive correlation (r=+0.66 to +0.77, p<0.0001) with all of them except serum HDL with which it showed strong negative correlation(r=-0.71, p<0.0001). It increased as the number of metabolic factors increased showing a highly significant trend (p<0.0001). On multivariate regression analysis UA contributed to 66.84% variance of metabolic syndrome.

CONCLUSION

The current multivariate regression analysis clearly infers that uric acid can be considered as a marker and potential modifier of metabolic syndrome.

The metabolic syndrome: an emerging risk state for cardiovascular disease

The common clustering of glucose intolerance, insulin resistance, abdominal adiposity, elevated blood pressure, and low HDL cholesterol is referred to as metabolic syndrome. Individuals with this syndrome have an increased risk of developing cardiovascular disease (CVD). The World Health Organisation and the National Cholesterol Education Programme’s Adult Treatment Panel III (NCEP-ATP III) have outlined specific diagnostic criteria for the diagnosis of the metabolic syndrome to help in the Identification of this syndrome in clinical practice. While the WHO criteria were specifically developed for use in research, the NCEP criteria are useful in clinical diagnosis of the metabolic syndrome. The metabolic syndrome is amenable to lifestyle modifications such as increased physical activity, weight loss, and possibly intake of low-glycemic foods. Drug therapy may be used to treat individual components of the syndrome such as elevated blood pressure and dyslipidemia. To control elevated glucose levels (when there is failure of lifestyle modification), medications such as metformin, thiazolidinedione derivatives and alpha glucosidase inhibitors may be used.

A Prospective Follow-Up of Adipocytokines in Cohort Patients With Gout: Association With Metabolic Syndrome But Not With Clinical Inflammatory Findings: Strobe-Compliant Article

The aim of this study was to determine the levels of leptin (Lep) and adiponectin (AdipoQ) in patients with gout and its relationship with joint inflammatory data and/or with metabolic syndrome (MetS) variables, during 1 year follow-up.Forty-one patients (40 males) with gout diagnosis, attending for the first time to a rheumatology department, were included. Evaluations were performed baseline, at 6 and 12 months. Variables included the following: demographic, clinical and laboratory data related to gout and associated diseases. Lep and AdipoQ determinations by the ELISA method were performed in frozen serum from each visit. The pharmacological and no-pharmacological treatment for gout and associated diseases was individualized for each patient according to published guidelines. Statistical analysis included Mann-Whitney U test, Fisher test, x, ANOVA, Cochran Q, Pearson and Spearman correlation tests, as well as linear regression.In the baseline evaluation, 29.2% had MetS (hypertriglyceridemia 66%, hypertension 44% and obesity 37%); patients with MetS had higher C reactive protein (CRP) levels [34.1 ± 28.6 vs. 12.2 ± 11.2 mg/dL, P = 0.033]. Although not significant, also had higher Lep and lower AdipoQ levels (3.2 ± 3.0 vs. 1.9 ± 1.2 ng/mL, P = 0.142 and 40.5 ± 26.8 vs. 38.0 ± 24.9 ng/mL, P = 0.877, respectively). During follow-up, our patients had significant improvement in serum uric acid (sUA) levels and variables evaluating pain and joint swelling (P ≤ 0.05). Metabolic abnormalities tended to persist or even worsen during the monitoring period: significant increase in total cholesterol (P = 0.004), tendency to higher triglycerides (P = 0.883) and slight improvement in glycaemia (P = 0.052). Lep values increased significantly during follow-up (P = 0.001) while AdipoQ levels diminished slightly (P = 0.317). Neither Lep nor AdipoQ values showed important correlation (r > 0.5) with metabolic variables or joint swelling.This study suggests that in patients with gout, concentrations of Lep and AdipoQ are more in line with the metabolic state than with clinical disease activity.

Positive relationship between total antioxidant status and chemokines observed in adults

Objective. Human evidence is limited regarding the interaction between oxidative stress biomarkers and chemokines, especially in a population of adults without overt clinical disease. The current study aims to examine the possible relationships of antioxidant and lipid peroxidation markers with several chemokines in adults. Methods. We assessed cross-sectional associations of total antioxidant status (TAS) and two lipid peroxidation markers malondialdehyde (MDA) and thiobarbituric acid reactive substances (TBARS) with a suite of serum chemokines, including CXCL-1 (GRO-α), CXCL-8 (IL-8), CXCL-10 (IP-10), CCL-2 (MCP-1), CCL-5 (RANTES), CCL-8 (MCP-2), CCL-11 (Eotaxin-1), and CCL-17 (TARC), among 104 Chinese adults without serious preexisting clinical conditions in Beijing before 2008 Olympics. Results. TAS showed significantly positive correlations with MCP-1 (r = 0.15751, P = 0.0014), MCP-2 (r = 0.3721, P = 0.0001), Eotaxin-1 (r = 0.39598, P < 0.0001), and TARC (r = 0.27149, P = 0.0053). The positive correlations remained unchanged after controlling for age, sex, body mass index, smoking, and alcohol drinking status. No associations were found between any of the chemokines measured in this study and MDA or TBARS. Similar patterns were observed when the analyses were limited to nonsmokers. Conclusion. Total antioxidant status is positively associated with several chemokines in this adult population.

Serum uric acid is associated with dietary and lifestyle factors in elderly women in suburban Guangzhou in Guangdong province of south China

OBJECTIVES

To estimate the prevalence of hyperuricemia and lifestyle risk factors for hyperuricemia in elderly women.

DESIGN

Cross-sectional study.

SETTING

The suburban area of Guangzhou, Guangdong province, China.

PARTICIPANTS

The study included 856 Chinese women aged 60 to 102 years who received their annual health examinations in the suburban area of Guangzhou, south China in 2002.

MEASUREMENTS

Information on anthropometric measurements and lifestyle factors were obtained via a questionnaire processed by the attending physicians or nurses. Blood biochemistry was performed after subjects fasted for 8-14 h. Unconditional logistic regression analysis was used to investigate associations between hyperuricemia, meat intake quintiles, physical activity quintiles, and alcohol intake quintiles.

RESULTS

The prevalence of hyperuricemia in the studied population was 12.01%. Alcohol, meat and seafood consumption; being overweight or obese; hypertension; and abnormal triglyceride levels were strongly associated with a higher prevalence of hyperuricemia. Physical activity was inversely related to the prevalence of hyperuricemia. The odds ratios for hyperuricemia for quintiles of physical activity were 1.00, 0.74, 0.72, 0.63, and 0.55 (P<0.01).

CONCLUSIONS

Our data suggest that the prevalence of hyperuricemia is high in elderly women in suburban Guangzhou in Guangdong province of South China. Obesity, meat and seafood intake and alcohol consumption are associated with a higher prevalence of hyperuricemia, whereas daily physical activity is inversely related to the prevalence of hyperuricemia.

Contribution of uric acid to cancer risk, recurrence, and mortality

Two risk factors for the development and progression of cancers that are amenable to life style modification are chronic inflammation and the metabolic syndrome. This review proposes two new targets that may mechanistically integrate inflammation and metabolic syndrome, have been largely ignored, and are known to be druggable. Recent evidence has demonstrated that elevated serum uric acid (hyperuricemia) is associated with excess cancer risk, recurrence, and mortality. Although uric acid (UA) can function as a systemic antioxidant, its pro-inflammatory properties have been postulated to play an important role in the pathogenesis of cancer. Furthermore, obesity, Type 2 Diabetes Mellitus (T2DM), and the metabolic syndrome (MetS) are also associated with excess cancer, chronic inflammation, and with hyperuricemia, suggesting that UA may represent an important link between these disorders and the development of cancer. While pharmacological modulation of hyperuricemia could in principal augment anti-cancer therapeutic strategies, some cancer cells express low intracellular levels of the enzyme Xanthine Oxidoreductase (XOR) that are associated with increased cancer aggressiveness and poor clinical outcome. Thus, systemic pharmacological inhibition of XOR may worsen clinical outcome, and specific strategies that target serum uric acid (SUA) without inhibiting tumor cell XOR may create new therapeutic opportunities for cancer associated with hyperuricemia. This review will summarize the evidence that elevated SUA may be a true risk factor for cancer incidence and mortality, and mechanisms by which UA may contribute to cancer pathogenesis will be discussed in the hope that these will identify new opportunities for cancer management.

Increased frequency of metabolic syndrome and its individual metabolic abnormalities in Japanese patients with primary gout

BACKGROUND

Gout patients are frequently complicated with hypertension, obesity, dyslipidemia, and/or impaired glucose tolerance, which are components of the metabolic syndrome and risks for atherosclerotic diseases.

OBJECTIVES

To determine the relationship between metabolic syndrome and gout, as well as plasma concentrations of adipocytokines in gout patients.

SUBJECTS AND METHODS

The frequency of metabolic syndrome as well as its constituents were investigated in 258 male gout patients and 111 males who attended an annual check-up examination. In addition, plasma concentrations of adipocytokines were measured in 107 of the patients.

RESULTS

Gout patients had a higher prevalence of metabolic syndrome as compared with the controls (36.4% vs. 15.3%, P < 0.0001). In addition, frequencies of individual metabolic abnormalities, such as waist circumference >85 cm, hypertension, and hypertriglyceridemia, were significantly increased in the gout patients as compared with the controls. Furthermore, uric acid over-production gout had a significantly higher prevalence of metabolic syndrome as compared with uric acid under-excretion gout (48.6% vs. 32.4%, P < 0.001). The plasma concentrations of leptin and plasminogen activator inhibitor-1 were significantly higher in the patients (P < 0.05, respectively), while that of adiponectin and the adiponectin/leptin ratio were significantly decreased in the gout patients as compared with the controls (P < 0.05, respectively).

CONCLUSION

A higher prevalence of metabolic syndrome in gout patients may in part contribute to susceptibility to atherosclerotic diseases. Therefore, more attention should be paid to the presence of metabolic syndrome in gout patients to reduce their risk for cardiovascular disease complications.

Association of serum uric acid level with non-alcoholic fatty liver disease: a cross-sectional study

BACKGROUND/AIM

Serum uric acid level has been suggested to be associated with factors that contribute to the metabolic syndrome. The aim of this study was to investigate the association of serum uric acid level with non-alcoholic fatty liver disease (NAFLD).

METHODS

A cross-sectional study was performed among the employees of Zhenhai Refining & Chemical Company Ltd., Ningbo, China.

RESULTS

The study included 8925 subjects (6008 men) with a mean age of 43 years. The prevalence rates of NAFLD and hyperuricemia were 11.78% and 14.71%, respectively. NAFLD patients had significantly higher serum uric acid levels than controls (370.3+/-86.6 vs. 321.1+/-82.6 micromol/L; P<0.001). The prevalence rate of NAFLD was significantly higher in subjects with hyperuricemia than in those without hyperuricemia (24.75% vs. 9.54%; P<0.001), and the prevalence rate increased with progressively higher serum uric acid levels (P value for trend <0.001). Multiple regression analysis showed that hyperuricemia was associated with an increased risk of NAFLD (odds ratio [OR]: 1.291, 95% confidence interval [CI]: 1.067-1.564; P<0.001).

CONCLUSION

Serum uric acid level is significantly associated with NAFLD, and elevated serum uric acid level is an independent risk factor for NAFLD.

Uric acid: the oxidant-antioxidant paradox

Uric acid, despite being a major antioxidant in the human plasma, both correlates and predicts development of obesity, hypertension, and cardiovascular disease, conditions associated with oxidative stress. While one explanation for this paradox could be that a rise in uric acid represents an attempted protective response by the host, we review the evidence that uric acid may function either as an antioxidant (primarily in plasma) or pro-oxidant (primarily within the cell). We suggest that it is the pro-oxidative effects of uric acid that occur in cardiovascular disease and may have a contributory role in the pathogenesis of these conditions.

Associations between serum uric acid and adipokines, markers of inflammation, and endothelial dysfunction

AIM

Serum uric acid is associated with the metabolic syndrome and its components, while its relationship with cardiovascular disease is controversial. The aim of the study was to evaluate the association between uric acid and adipokines, markers of inflammation, oxidative stress, and endothelial dysfunction, which are all linked to cardiovascular disease.

METHODS

The associations between uric acid and adiponectin, resistin, leptin, high-sensitivity-C-reactive protein (hs-CRP), interleukin-6, tumor necrosis factor-alpha, nitrotyrosine, Total Antioxidant Status (TAS), E-selectin, vascular adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) were cross-sectionally evaluated in a randomly collected sample of 100 men from a population-based cohort.

RESULTS

Subjects within the highest uric acid quartile showed a worse metabolic pattern and a higher prevalence of the metabolic syndrome [odds ratio (OR)=3.6; 95% confidence interval (CI) 1.6-8.2; p<0.001 for each 50 micromol/l uric acid increment in a logistic regression model after multiple adjustments]. Nitrotyrosine and adiponectin were significantly lower, while TAS, hs-CRP, E-selectin, ICAM-1, and VCAM-1 were higher in the groups with increased uric acid levels. In a multiple regression model, after adjustments for multiple confounders, uric acid levels were inversely associated with nitrotyrosine (p<0.001) and adiponectin (p=0.02), and directly with TAS (p<0.001), and E-selectin (p=0.006).

CONCLUSION

Serum uric acid showed opposite relationships, being associated with both beneficial (inverse association with nitrotyrosine, direct association with TAS) and detrimental (inverse association with adiponectin, direct association with E-selectin) markers, thus providing a possible explanation for the previously reported controversial and not linear association between uric acid and cardiovascular disease.

Prevalence of metabolic syndrome in long-term survivors of hematopoietic stem cell transplantation

Our purpose was to determine the prevalence and features of metabolic syndrome (MS) in a series of long-term hematopoietic stem cell transplantation (HSCT) survivors. We assessed the clinical, metabolic and endocrinological data, and plasma TNF, leptin, resistin and adiponectin levels relating to 85 HSCT recipients. MS was diagnosed on the basis of the National Cholesterol Education Program-Adult Treatment Panel III criteria. Its prevalence was compared with that observed in an Italian population, and its relationship with the clinical and laboratory parameters was assessed univariately and multivariately. Twenty-nine HSCT recipients had MS instead of the 12.8 expected (P<0.0001), with hypertriglyceridemia being the most common feature. Univariate analysis indicated that high insulin and leptin levels, low-adiponectin levels and hypogonadism were significantly related to a diagnosis of MS; multivariate analysis indicated plasma leptin, insulin resistance, age and hypogonadism. We conclude that HSCT recipients are at increased risk of a form of MS that has particular clinical features. Plasma leptin levels are independently related to MS, thus suggesting that leptin resistance may play a role as a pathogenetic clue, as in other conditions in which MS occurs as a secondary phenomenon. MS deserves consideration as a life-threatening complication in patients who are probably cured of their underlying disease.

Serum uric acid and leptin levels in metabolic syndrome: a quandary over the role of uric acid

This study investigates the impact of uric acid (UA) on the risk factors associated with metabolic syndrome. In addition, this study explores the relationship between UA and insulin resistance and serum leptin levels in metabolic syndrome. A total of 470 subjects (252 women and 218 men) were recruited from the Department of Health Management at Chang Gung Medical Center (Linkou, Taiwan). Metabolic syndrome was defined using a modified Adult Treatment Panel III (ATP III) definition. The formula for the homeostasis model assessment of insulin resistance (HOMA-IR) is as follows: fasting serum insulin (microU/mL) x fasting plasma glucose (mmol/L)/22.5. Diabetes mellitus was diagnosed in 45 subjects (9.6%); 82 subjects (17.4%) had hypertension. Hyperuricemia was diagnosed in 144 subjects (30.6%). Of these subjects, 115 (63 females and 52 males) (24.5%) were diagnosed as having metabolic syndrome. Patients with hyperuricemia had increased body mass index, waist-to-hip ratio, and triglyceride (Tg) level. The subjects also had lower high-density lipoprotein and greater hypertension. Hormone assays showed an elevation of leptin, immunoreactive insulin (IRI), and HOMA-IR in the hyperuricemia group. Uric acid appeared to be better correlated with Tg, blood pressure (both systolic and diastolic), obesity, immunoreactive insulin, and HOMA-IR. Uric acid did not correlate with leptin or blood glucose levels. Metabolic syndrome and Tg/high-density lipoprotein ratio showed a statistically significant difference in HOMA-IR using 3.8 as a cutoff value. Otherwise, there was no difference in leptin value. In conclusion, serum UA is significantly related to risk factors of metabolic syndrome except for blood glucose. Waist-to-hip ratio and HOMA-IR were statistically different in subjects with and without metabolic syndrome.

Association between serum uric acid level and peripheral arterial disease

BACKGROUND

Higher serum uric acid levels have been implicated in the development and progression of atherosclerotic cardiovascular disease. However, it is not clear whether serum uric acid levels are related to subclinical measures of cardiovascular disease, including peripheral arterial disease (PAD). We examined the association between increasing serum uric acid levels and PAD in the US general population.

METHODS

A cross-sectional study was conducted among 3987 National Health and Nutrition Examination Survey 1999-2002 participants aged > or =40 years, without clinical history of cardiovascular disease. Main outcome-of-interest was PAD defined as ankle-brachial index <0.9 (n=229).

RESULTS

Higher serum uric acid levels were positively associated with PAD, independent of smoking, body mass index (BMI), hypertension, diabetes, serum total cholesterol, serum creatinine, and other confounders. Multivariable odds ratio (OR) [95 percent confidence intervals (CI)] comparing serum uric acid levels > or =75th percentile (> or =380.8 micromol/L) to uric acid levels <50th percentile (<315.6 micromol/L) was 1.62 (1.08-2.44), p-trend=0.015. This association persisted in separate analysis among men and women. Further, the results were consistent in subgroup analyses by categories of age, current smoking, BMI, and diabetes mellitus.

CONCLUSIONS

Higher serum uric acid levels are associated with PAD in the US general population. These results suggest that PAD may be an important indicator of the reported association between higher serum uric acid levels and clinical cardiovascular disease. Future prospective studies are required to clarify the temporal nature of this relationship.

The association between hyperuricemia and the Trp64Arg polymorphism of the beta-3 adrenergic receptor

The object of this study was to determine the association of Trp64Arg polymorphism with hyperuricemia. This study is an age-matched, case-controlled study of 203 hyperuricemic and 203 normouricemic men. The frequency of genotypes was compared between the two groups. Possible confounding metabolic variables were included in a multiple logistic regression model for multivariate adjustment. The genotype frequencies of Trp64Trp, Trp64Arg, and Arg64Arg in hyperuricemic and normouricemic groups are respectively 130, 69, and 4 (64.0%, 34.0%, 2.0%) and 154, 45, and 4 (75.9%, 22.2%, 2.0%) (P = 0.029, Chi-square test). Simple logistic regression analysis indicated that the Trp64Arg genotype is significantly associated with hyperuricemia (OR = 1.816, 95% CI (1.167-2.827), P = 0.008). Multivariate analysis for controlling metabolic effects also showed a significant association with the occurrence of hyperuricemia (OR = 1.937, 95% CI (1.149-3.266), P = 0.013). Trp64Arg polymorphism of the beta-3 adrenergic receptor may be independently associated with hyperuricemia in males.

Elevated serum uric acid levels in metabolic syndrome: an active component or an innocent bystander?

Elevated serum uric acid (SUA) levels are commonly seen in patients with the metabolic syndrome (MetS). Several mechanisms, both direct and indirect, connect the increased SUA levels with the established diagnostic criteria of MetS. It is possible that the increased cardiovascular disease risk associated with the MetS is partially attributed to elevated circulating SUA concentration. Several drugs used in the treatment of MetS may alter SUA levels. Thus, lifestyle measures together with the judicious selection of drugs for the treatment of hypertension, dyslipidemia, and insulin resistance associated with MetS may result in a reduction of SUA levels and possibly cardiovascular disease risk. This review summarizes the pathophysiologic association between SUA and MetS and focuses on the prevention of hyperuricemia and its cardiovascular consequences.

Hyperuricemia and Associated Diseases

After introduction of urate-lowering therapy, asympotomatic hyperuricemia was treated with allopurinol or uricosuric agents in the belief that hyperuricemia and/or gout caused chronic kidney disease. Epidemiologic studies in the 1970s, however, failed to confirm the view that hyperuricemia and gout were independent risk factors for chronic kidney disease. As a result, urate-lowering pharmacotherapy is generally not recommended at the present time in the management of asymptomatic hyperuricemia even though recent epidemiological, experimental, and clinical studies have prompted reexamination of a causal role for hyperuricemia (with or without gout) in chronic kidney disease as well as other important disorders including cardiovascular disease, hypertension, and metabolic syndrome. The issue of such a role remains unresolved and this article reviews the current status of the relationship between hyperuricemia and associated disorders.

Atorvastatin reduces serum leptin concentration in hypercholesterolemic rabbits

BACKGROUND

Leptin may play an important role in the development of atherosclerosis. We evaluated the effect of atorvastatin on leptin secretion in vivo and in vitro.

METHODS

Sixteen rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into 2 groups: (1) high cholesterol diet for 6 weeks (n=8), and (2) the same cholesterol diet plus atorvastatin (2.5 mg/kg/day) for 6 weeks (n=8). A control group (n=5) was fed with normal diet for 14 weeks. Subcutaneous adipose was collected for RNA analysis. The direct effect of atorvastatin on leptin release was assayed in primary rabbit adipocytes. Leptin levels in serum and adipocytes culture supernatant were measured by ELISA. RT-PCR was used to evaluate leptin mRNA expressions in adipose and adipocytes.

RESULTS

Compared with control group, rabbits fed with high cholesterol diet showed higher levels of serum total cholesterol, LDL cholesterol and leptin, all of which were significantly reduced by atorvastatin treatment. Leptin mRNA expression of adipose was significant lower in rabbits treated with atorvastatin than those fed with high cholesterol diet continuously (0.81+/-0.31 vs. 1.23+/-0.36, P<0.05). Atorvastatin dose-dependently inhibited leptin secretion and mRNA expression in cultured adipocytes.

CONCLUSION

Atorvastatin can inhibit leptin release and mRNA expression, and reduces serum leptin level in hypercholesterolemic rabbits.

Recent trends of hyperuricemia and obesity in Japanese male adolescents, 1991 through 2002

The aim of the present study was to determine the change of serum uric acid (UA) levels in male adolescents and to characterize the relationship between UA levels and obesity or its related factors. This study was conducted in 17,155 students at enrollment in Okayama University from 1991 through 2002, in which the mean serum UA level as a whole was 5.64 +/- 0.009 mg/dL (mean +/- SEM) and the incidence of hyperuricemia (>/=7.6 mg/dL) was 4.13%. Serum UA levels were correlated with obesity-related indicators, including body mass index (BMI; r = 0.282, P <.0001) and skin-fold thickness (r = 0.286, P <.0001). The incidence of hyperuricemia was increased in parallel with BMI. In the last 4 years (1999 through 2002) of the study period, serum UA levels (5.76 mg/dL) and the incidence of hyperuricemia (4.5%) were significantly increased compared with those in the earlier period (1991 through 1994: 5.50 mg/dL and 3.5%, respectively). However, BMI has been rather gradually decreased throughout 12-year observation in all the subjects. Hyperuricemia was related to the presence of other risk factors, including hypercholesterolemia, liver function abnormality, and hypertension. The frequencies of such abnormalities were higher than euuricemic subjects and this trend was notable in the most recent students enrolled from 1999 through 2002. Hyperuricemia was even found in the group of non-obese male adolescents. Taking into consideration that hyperuricemia is associated with a high prevalence of lifestyle-related diseases in adults, it is of great importance to prevent hyperuricemia at the early stage in Japanese adolescents.

Primary prevention in rheumatology: the importance of hyperuricemia

Hyperuricemia (HU) is present in 5-30% of the general population, although the prevalence is higher among some ethnic groups and seems to be increasing worldwide. Classically, chronic HU has been considered a risk factor for gout or lithiasis and is associated with alcoholism, obesity, hypertension, dyslipidemia, hyperglycemia/diabetes mellitus, renal failure and intake of certain drugs. HU is also associated with cardiovascular diseases such as hypertension, vascular disease, pre-eclampsia, pulmonary arterial hypertension, stroke, heart failure, ischemic heart disease and also metabolic syndrome, renal disease and increased mortality. It is uncertain if these associations are dependent or not, especially cardiovascular and renal diseases. Patients with chronic HU and also those with gout require both medical investigation for associated diseases or drugs as well as nutritional counseling and life-style changes. HU should alert physicians to possible complications.

Effect of Fenofibrate on Uric Acid Metabolism in Japanese Hyperlipidemic Patients

Forty Type IIb or IV hyperlipidemic patients (serum triglyceride concentrations were higher than 150 mg/dl) were treated with fenofibrate (300 mg/day) for 12 weeks. Lipid profile and uric acid metabolism were evaluated before and after the treatment; the serum concentrations of total cholesterol and triglyceride respectively decreased from 224 +/- 41.9 mg/dl to 199 +/- 35.2 mg/dl and from 205 +/- 71.7 mg/dl to 134 +/- 67.5 mg/dl (p < 0.001). The uric acid concentrations in the serum also significantly decreased from 7.0 +/- 1.58 mg/dl to 5.2 +/- 1.57 mg/dl (p < 0.001). Fenofibrate treatment did not cause any change in the serum xanthine and hypoxanthine concentrations. Instead the urinary concentrations of uric acid decreased from 7.0 +/- 1.58 mg/dl to 5.2 +/- 1.57 mg/dl (p < 0.01), while the clearance ratio of uric acid and creatinin increased from 6.1 +/- 2.56 to 9.9 +/- 3.87 (p = 0.02) by the fenofibrate treatment. Fenofibrate decreases uric acid concentrations in the serum not as a result of inhibition of uric acid production but by increasing the urinary excretion of uric acid.

Decreased plasma adiponectin concentrations in women with dyslipidemia

Adiponectin, the gene product of the adipose most abundant gene transcript 1, is a novel adipocyte-derived peptide that has been considered to have antiinflammatory and antiatherogenic effects. To characterize the relationship between adiponectin and lipids metabolism, we measured fasting plasma adiponectin concentration by ELISA, serum total cholesterol, high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and apolipoprotein (apo) levels in 352 nondiabetic women, 16-86 yr old, with a wide range of body weight [body mass index (BMI), 14.8-36.3 kg/m(2)]. Plasma adiponectin concentrations in women with the highest tertile of TG (1.69 mM < or approximately) were decreased, compared with the middle (1.13 < or = approximately < 1.69) or lowest tertile of TG (approximately < 1.13) (5.9 +/- 0.5 vs. 7.5 +/- 0.3, 9.2 +/- 0.2 microg/ml; P < 0.005, 0.001). Plasma adiponectin with the lowest tertile of HDL-C (approximately < 1.16 mM) was decreased, compared with the middle (1.16 < or = approximately < 1.81) or highest tertile of HDL-C (1.81 < or approximately ) (5.7 +/- 0.5 vs. 7.8 +/- 0.2, 10.1 +/- 0.4 microg/ml; both P < 0.001). These relationships had similar tendencies after adjustment for BMI, body fat mass, age, or diastolic blood pressure. Adiponectin was negatively correlated with serum TG (r = -0.33, P < 0.0001), atherogenic index [(total cholesterol - HDL-C)/HDL-C] (r = -0.34, P < 0.0001), apo B (r = -0.45, P < 0.0001), or apo E (r = -0.29, P < 0.05), and positively correlated with serum HDL-C (r = 0.39, P < 0.0001) or apo A-I levels (r = 0.42, P < 0.002). Those negative relationships became stronger after adjusting for BMI or body fat mass. The slightly positive correlation between adiponectin and age, blood urea nitrogen, or creatinine levels was also observed (all P < 0.001). These results indicate that high-TGnemia and low-HDL-Cnemia are associated with low plasma adiponectin concentrations in nondiabetic women. Further efforts must now be targeted to determine whether adiponectin causes these lipid abnormalities and thus whether it is partly responsible for the atherogenic risk seen in the metabolic syndrome.