Hyperuricemia and metabolic syndrome in children with overweight and obesity

Association of serum uric acid with hypertriglyceridemia in children and adolescents: a cross-sectional study

BACKGROUND

Uric acid (UA), a liver-derived metabolite, is intimately tied to metabolic disorders. Although ample research underscores its connection with hypertriglyceridemia (HTG), studies focusing on adolescents remain limited. To fill the gaps in epidemiology,this study focused on analyzing the relationship between the levels of uric acid and HTG in a demographic sample comprising adolescents from the United States.

METHODS

In this study, a total of 4,435 participants through the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2020. The exposure variable was serum uric acid (SUA), the effect variable was HTG, and the covariates included demographic, questionnaire, physical examination and laboratory indicators. We utilized weighted logistic regression and meticulous subgroup evaluations to discern the intrinsic link between SUA and HTG. Stratified analyses augmented the validation of this association, while smooth curve fitting probed for potential nonlinear correlations.

RESULTS

The study included 4,435 participants. Male adolescents exhibit elevated SUA levels. After adjusting for all variables, the weighted multiple logistic regression model revealed that SUA was positively correlated with HTG risk (OR = 1.006, 95% CI: 1.005-1.007). This relationship was consistent across the three tertiles group of SUA (T1: OR = 1.006 [95% CI: 1.005-1.007]; T2: OR = 1.006 [95% CI: 1.005-1.007]; T3: OR = 1.004 [95% CI: 1.003-1.006]; P for trend < 0.001). Stratified analyses confirmed that the positive correlation between SUA and HTG risk was significant, irrespective of sex, age or race.

CONCLUSIONS

In American children and adolescents aged 12 to 18 years, there was a pronounced association between SUA and HTG. SUA could serve as a risk indicator for HTG. It is recommended that children diagnosed with HTG should be regularly tested for SUA levels. In addition, it is recommended that SUA be included in the comprehensive care of children diagnosed with HTG.

Factors Affecting Dyslipidemia among Korean Adolescents: An Analysis Using the 8th Korea National Health and Nutrition Examination Survey (2021)

A high prevalence of dyslipidemia has recently been shown not only in adults, but also in adolescents. When occurring in adolescence, dyslipidemia is a risk factor for cardiovascular disease in adulthood. This study aimed to identify significant factors affecting dyslipidemia in South Korean adolescents. We used data from the third year of the 8th Korea National Health and Nutrition Examination Survey (KNHANES VIII-3) on 381 Korean adolescents aged 12-18 years. The data were analyzed using frequency analysis, descriptive statistics, the Rao-Scott χ test, the t-test, and univariate and multivariate logistic regression using complex sample analysis. On a weighted population basis, 28.1% of the adolescents among the participants were identified as the group with dyslipidemia. Obesity, waist circumference, serum uric acid, and alanine aminotransferase (ALT) were significantly related to the prevalence of dyslipidemia. Physical activity 4-7 days a week was related to a decrease in the prevalence of dyslipidemia only in male adolescents. The results of this study can be used as evidence for the risk assessment of adolescent dyslipidemia and the establishment of systematic health management guidelines according to risk factors for the prevention of adolescent dyslipidemia.

Epidemiological Impact of Metabolic Syndrome in Overweight and Obese European Children and Adolescents: A Systematic Literature Review

The prevalence of overweight and obesity is continuously increasing, both in the adult and pediatric populations, posing a substantial challenge to public health. Understanding the epidemiological burden of metabolic syndrome (MetS) among children, particularly regarding its complications and long-term effects in adulthood, is crucial for identifying effective preventive measures and enhancing the clinical care of obese children. Therefore, by searching two databases, a systematic review was conducted in order to evaluate studies that specifically addressed the epidemiological MetS impact among overweight/obese European children and adolescents. Overall, 15 studies were considered. The epidemiological data concerning the MetS impact were contingent on the diagnostic criteria used and varied across countries, resulting in a prevalence range of 1.44% to 55.8%. Spanish studies were the most numerous (34%), revealing a country prevalence rate ranging from 2.5% to 19.6%. Males (prevalence range: 1.4-55.8%) and subjects with overweight/obesity (prevalence range: 12.9-55.8%) were mainly affected. Obesity emerged as the main risk factor in the MetS development and the consequent onset of cardiovascular complications and diabetes. Knowing the MetS burden and its risk factors could improve their prevention, detection, and treatment, and guide the development of targeted public health interventions to appropriately address the health needs of younger patients.

In Vitro Mimicking of Obesity-Induced Biochemical Environment to Study Obesity Impacts on Cells and Tissues

Obesity represents a heavy burden for modern healthcare. The main challenge facing obesity research progress is the unknown underlying pathways, which limits our understanding of the pathogenesis and developing therapies. Obesity induces specific biochemical environments that impact the different cells and tissues. In this piece of writing, we suggest mimicking obesity-induced in vivo biochemical environments including pH, lipids, hormones, cytokines, and glucose within an in vitro environment. The concept is to reproduce such biochemical environments and use them to treat the tissue cultures, explant cultures, and cell cultures of different biological organs. This will allow us to clarify how the obesity-induced biochemistry impacts such biological entities. It would also be important to try different environments, in terms of the compositions and concentrations of the constitutive elements, in order to establish links between the effects (impaired regeneration, cellular inflammation, etc.) and the factors constituting the environment (hormones, cytokines, etc.) as well as to reveal dose-dependent effects. We believe that such approaches will allow us to elucidate obesity mechanisms, optimize animal models, and develop therapies as well as novel tissue engineering applications.

Investigating the relationship between serum uric acid to high-density lipoprotein ratio and metabolic syndrome

Aims

This study aimed to determine a parameter to more easily diagnose metabolic syndrome and predict its probability of occurrence in high‐risk individuals.

Methods

In this cross‐sectional study, data related to the study population in the Kerman Coronary Artery Disease Risk Factor Study (KERCADRS) were examined. Subjects were divided into two groups with and without metabolic syndrome, and the relevant factors such as the ratios of uric acid to high‐density lipoprotein (HDL) (UHR) in these two groups were compared, and the best cut‐off point was determined.

Results

Data related to 817 people including 96 people with metabolic syndrome and 721 people without metabolic syndrome were analysed. The mean UHR was significantly higher in patients with metabolic syndrome (14.76 ± 6.33%) compared with those without metabolic syndrome (10.0 ± 3.10%) (p < .001). People with high UHR are 2.9 times more at risk of metabolic syndrome and the best cut‐off point was 9.50% with 86% sensitivity and 55% specificity.

Conclusions

According to our study, UHR is also helpful in diagnosing metabolic syndrome and can also be used to screen people at risk for metabolic syndrome.

A sex-related mediating effect of uric acid in the association between body composition and blood pressure in children and adolescents

The increase in blood pressure (BP) during somatic growth might have direct determinants but also mediating factors. We investigated whether uric acid (UA) and other metabolic factors would mediate the association between body composition components and BP. A cross-sectional study was conducted in 928 children and adolescents (aged 6-18 years), in which body composition and blood biochemistry were evaluated. Structural equation modeling was performed to test the direct and indirect pathways between systolic blood pressure (SBP) and body composition parameters. Muscle mass (MM) showed a strong direct effect on BP, regardless of sex. In girls, a mediating pathway through UA was not significant, but the association between fat mass (FM) and MM with SBP was mediated by the cluster of metabolic factors. In boys, both MM and FM were associated with SBP through a mediating pathway via UA, but not via the cluster of metabolic factors. The association between body composition and BP in children and adolescents has a complex design and also has a sex-specific mediating component. The increase in the UA levels may affect BP levels early in boys. Also, metabolic changes elicited by FM contribute to the increase in BP at an early age in girls. Novelty: MM showed a strong direct effect on BP, regardless of sex. In girls, the association between FM and MM with SBP was mediated by the cluster of metabolic factors. In boys, both MM and FM were associated with SBP through a mediating pathway via UA.

Hyperuricemia induces lipid disturbances mediated by LPCAT3 upregulation in the liver

Potential underlying molecular mechanisms for uric acid-induced lipid metabolic disturbances had not been elucidated clearly. This study investigated the effects and underlying mechanisms of uric acid on the development of lipid metabolic disorders. We collected blood samples from 100 healthy people and 100 patients with hyperuricemia for whom serum lipid analysis was performed. Meanwhile, a mouse model of hyperuricemia was generated, and lipidomics was performed on liver tissues, comparing control and hyperuricemia groups, to analyze lipid profiles and key metabolic enzymes. Uric acid directly induced serum lipid metabolic disorders in both humans and mice based on triglycerides, total cholesterol, and low-density lipoprotein cholesterol. Through lipidomic analysis, 46 lipids were differentially expressed in hyperuricemic mouse livers, and the phosphatidylcholine composition was altered, which was mediated by LPCAT3 upregulation. High-uric acid levels-induced p-STAT3 inhibition and SREBP-1c activation in vivo and in vitro. Moreover, LPCAT3-knockdown significantly attenuated uric acid-induced p-STAT3 inhibition, SREBP-1c activation, and lipid metabolic disorders in L02 cells. In conclusion, uric acid induces lipid metabolic disturbances through LPCAT3-mediated p-STAT3 inhibition and SREBP-1c activation. LPCAT3 could be a key regulatory factor linking hyperuricemia and lipid metabolic disorders. These results might provide novel insights into the clinical treatment of hyperuricemia.

Combined effects of dietary zinc at 3 years of age and obesity at 7 years of age on the serum uric acid levels of Korean children

BACKGROUND/OBJECTIVES

To assess the longitudinal associations of the antioxidant capacity of zinc and body mass index (BMI) with serum uric acid (SUA) in South Korean children.

SUBJECTS/METHODS

Using follow-up data from the Ewha Birth and Growth Cohort, we included subjects who were seen at 3 and 7 years of age (n = 183; 90 boys, 93 girls). Daily zinc intake and BMI were assessed at 3 and 7 years of age. SUA measured at 7 years was used as the outcome variable. Using a general linear model, the effects of dietary zinc intake and BMI on SUA were assessed. We also assessed the combined effect of early dietary zinc intake and BMI on SUA in children.

RESULTS

The dietary zinc intake at 3 years of age was negatively correlated (ρ = −0.18, P = 0.04), whereas the BMI at 7 years of age was positively correlated (r = 0.18, P = 0.01), with the SUA level at 7 years of age. The dietary zinc intake level at 3 years of age and the BMI level at 7 years of age were, together, significantly related to SUA in children at 7 years of age. SUA was lower in group 1 (normal-weight, high-zinc group) than in the other two groups (group 2: normal-weight, low-zinc and overweight, high-zinc group; and group 3: overweight, low-zinc group). Our results demonstrate the combined effect of zinc intake and BMI on SUA. The combined association remained significant in both the crude and adjusted models (P < 0.01).

CONCLUSIONS

SUA was related to combined BMI and dietary zinc intake, and increased zinc intake and normal body weight had a beneficial effect on reducing SUA in children.

Excess serum uric acid is associated with metabolic syndrome in obese adolescent patients

Purpose

Obesity is a significant cause of morbidity in adolescents. Excess serum uric acid (SUA) has been associated with metabolic syndrome (MS) among adults. We evaluated the relationship among SUA and markers of insulin resistance (IR) and low-grade inflammation in obese adolescents with and without MS.

Methods

The study was a retrospective chart review of obese patients seen in the LeBonheur Endocrine clinic seen in clinic between September 2016 and December 2017. MS was defined as according to the International Diabetes Federation. Body mass index standard deviation score (BMI SDS), systolic blood pressure (SBP), diastolic blood pressure (DBP), body composition, fasting lipids, glucose, high sensitivity c-reactive protein (hs-CRP), serum uric acid (SUA), HbA1c, alanine transferase (ALT), aspartate transferase (AST), insulin and homeostatic model assessment for insulin resistance (HOMA-IR) were extracted from the charts of the 100 obese adolescents (57% female).

Results

Hyperuricemia (SUA >357 umol/L) was present in 41.8% of entire cohort without significant ethnic/racial and/or gender differences. Adolescents with HUA had higher FM, SBP, HbA1c, insulin and HOMA-IR (p < 0.05). While SUA was positively correlated with FM, SBP, HOMA-IR and HbA1c, and triglyceride:HDL-C ratio (TG:HDL-C) (p < 0.05). MS was identified in 32.8% of cohort. MS showed significantly higher FM, SBP, DBP, SUA, ALT, insulin, HOMA-IR, and TG:HDL-c ratio than non-MS subgroup (p < 0.05). FM was positively correlated with SUA, HOMA-IR and hsCRP (p < 0.01).

Conclusions

In our study, those with hyperuricemia (HUA) showed elevated markers of metabolic syndrome including BP, serum glucoses, IR and triglycerides. In our cohort, SUA appears to correlate with MS comorbidities.

Association of serum uric acid concentration with components of pediatric metabolic syndrome: A systematic review and meta-analysis

Background:

Hyperuricemia is implicated in the pathogenesis of inflammatory diseases and metabolic disorders. Metabolic syndrome (MetS) in childhood is one of the most important causes of different noncommunicable diseases in adulthood. This study aimed to systematically review the association between serum uric acid (UA) concentration and components of pediatric MetS.

Materials and Methods:

In this meta-analysis and systematic review, related articles were gathered by searching English databases including PubMed, Web of Science, Scopus, and Google Scholar. We used the following keywords: uric acid, metabolic syndrome, hypertension, fasting blood sugar (FBS), hyperglycemia; the search was limited to English language and included observational and cohort studies performed among children or adolescents. Pooled relative risks (odds ratio [OR]) and corresponding 95% confidence interval (95% CI) were extracted. A random-effect model was used.

Results:

On the basis of 34 eligible studies, the pooled correlation between UA with metabolic components including FBS (r = 0.24, 95% CI = 0.09–0.40), fasting insulin (r = 0.26, 95% CI = 0.15–0.37), and hyperglycemia (r for triglyceride and UA = 0.23, 95% CI = 0.19–0.38) (r for high-density lipoprotein and UA = −0.28, 95% CI = −0.37 to −0.20) was statistically significant. The association of both diastolic blood pressure (DBP) and systolic blood pressure (SBP) was statistically significant with UA (r for SBP and UA = 0.34, 95% CI = 0.24–0.43; r for DBP and UA = 0.18, 95% CI = 0.11–0.25). The OR between risk of abdominal obesity with UA was statistically significant (OR = 2.62, 95% CI = 1.41–3.84).

Conclusion:

Serum UA concentration is associated with major components of the pediatric MetS. Its measurement and control should be underscored in at-risk children and adolescents.

Hyperuricemia in Children and Adolescents: Present Knowledge and Future Directions

Recent evidence suggests that hyperuricemia is an important condition in children and adolescents, particularly in association with noncommunicable diseases. This review aims to summarize our current understanding of this condition in pediatric patients. An analysis of serum uric acid reference values in a healthy population indicates that they increase gradually with age until adolescence, with differences between the sexes arising at about 12 years of age. This information should be taken into consideration when defining hyperuricemia in studies. Gout is extremely rare in children and adolescents, and most patients with gout have an underlying disease. The major causes of hyperuricemia are chronic conditions, including Down syndrome, metabolic or genetic disease, and congenital heart disease, and acute conditions, including gastroenteritis, bronchial asthma (hypoxia), malignant disorders, and drug side effects. The mechanisms underlying the associations between these diseases and hyperuricemia are discussed, together with recent genetic information. Obesity is a major cause of hyperuricemia in otherwise healthy children and adolescents. Obesity is often accompanied by metabolic syndrome; hyperuricemia in obese children and adolescents is associated with the components of metabolic syndrome and noncommunicable diseases, including hypertension, insulin resistance, dyslipidemia, and chronic kidney disease. Finally, strategies for the treatment of hyperuricemia, including lifestyle intervention and drug administration, are presented.

Clinical implication of serum uric acid level in pegylated interferon and ribavirin combination therapy for chronic hepatitis C infection

BACKGROUND/AIMS

Combined treatment of pegylated interferon-α (PEG-IFN) and ribavirin (RBV) has long been accepted as the standard treatment for chronic hepatitis C virus (HCV) infection. Many predictive factors for treatment response have been identified. The aim of this study was to evaluate the efficacy and safety of combined PEG-IFN plus RBV and to examine the value of serum uric acid as a predictive factor in the treatment of chronic hepatitis C.

METHODS

A total of 74 patients chronically infected with HCV were enrolled between December 2004 and June 2009. Patients received subcutaneous PEG-IFN (α-2a: 180 μg once a week) in combination with RBV (1,000 to 1,200 mg daily depending on body weight). We evaluated treatment responses represented by early virologic response (EVR), end-of-treatment response (ETR), sustained virologic response (SVR), and relapse, as well as diverse adverse events. Various viral and host features were also assessed to clarify factors associated with treatment response.

RESULTS

During treatment, EVR was achieved in 26 patients (26/33, 78.8%) with HCV genotype 1. ETR and SVR were achieved in 59 (77.6%) and 56 patients (73.6%), respectively, across all genotypes. Genotype 2/3, lower HCV RNA, and lower uric acid were associated with higher SVR.

CONCLUSIONS

The treatment response to combination therapy with PEG-IFN plus RBV was effective, especially in genotype 2/3. Uric acid might be useful as a predictive factor for response to therapy for chronic hepatitis.

Prevalence of hyperuricemia and its related risk factors among preschool children from China

To estimate the prevalence of hyperuricemia and its major risk factors among Chinese preschool children. A cross-sectional survey was carried out in six central urban districts of Tianjin from March to June 2015. A cluster sampling was employed to obtain a random sample of preschool children. A total of 4073 children aged from 3 to 6 years participated in this survey. Logistic regression was used to obtain odds ratios and 95% confidence intervals. The overall mean serum uric acid concentrations was 243.0 ± 53.2 μmol/L, corresponding to a mean concentrations of 247.3 ± 53.7 μmol/L among boys and 238.3 ± 52.4 μmol/L among girls. The overall prevalence of serum uric acid ≥ 310 μmol/L among children was 10.1%. Boys, obesity, diastolic blood pressure, and serum triglyceride concentrations were associated with the increased risk of hyperuricemia in univariable models, although the statistically significant association between diastolic blood pressure, serum triglyceride concentrations and hyperuricemia disappeared in multivariable models. The prevalence of hyperuricemia among children aged from 3 to 6 years was relatively high. Several metabolic syndrome components were associated with the risk of hyperuricemia.

Evaluation of uric acid levels, thyroid function, and anthropometric parameters in Japanese children with Down syndrome

Down syndrome, caused by trisomy 21, is characterized by congenital abnormalities as well as mental retardation. From the neonatal stage through adolescence, patients with Down syndrome often have several complications. Thus, it is important to attain knowledge of the prevalence of these comorbidities in children with Down syndrome. We, therefore, evaluated the biochemical data, thyroid function, and anthropometric parameters, and analyzed the association among them in Japanese children and early adolescents with Down syndrome. There was no difference in the prevalence of obesity and overweight between boys and girls. The level of uric acid was higher in boys than in girls. Moreover, the prevalence of hyperuricemia was also higher in boys than in girls (approximately 32% and 10%, respectively). The prevalence of subclinical hypothyroidism in children with Down syndrome was approximately 20%, with no significant sex differences. The levels of uric acid and dehydroepiandrosterone-sulfate were positively associated with age, while the levels of thyroid-stimulating hormone and free thyroxine had a negative association with age. Overall, children with Down syndrome, exhibit a higher incidence of hyperuricemia. Therefore, uric acid levels, as well as thyroid function, from childhood to early adulthood should be monitored in this patient cohort.

Association between serum uric acid and metabolic syndrome components in prepubertal obese children (Tanner Stage I) from Nuevo León, Mexico - a preliminary study

BACKGROUND

Metabolic syndrome (MetS) is a major risk factor for cardiovascular disease and diabetes. Previous studies in obese children demonstrating a positive association between serum uric acid (sUA) and components of MetS are confounded by lack of uniformity in age and pubertal status of children. Therefore, we have examined the role of sUA in MetS and its components in pre-pubertal children (Tanner Stage I, age ≤ 9 years).

METHODS

Pre-pubertal obese children (32 boys, 27 girls, age 6-9 years) were recruited from Nuevo Leon, Mexico. For comparison, an equal number of children with normal body mass index (BMI) in the same age range (22 Boys, 39 girls, age 6-9 years) were also recruited from the same community. Presence of MetS and its components was defined according to the criteria of International Diabetes Federation. Fasting blood was analyzed for lipids, glucose, insulin, and uric acid.

RESULTS

Among the obese children, sUA was positively associated with insulin resistance and hypertriglyceridemia and negatively associated with high density lipoprotein-cholesterol (HDLc). Subjects were three times more likely to have a MetS diagnosis per one unit (md/dL) difference in sUA. Of the 59 obese pre-pubertal children, 20 were classified as having MetS defined by the presence of abdominal obesity and two or more of other components described under methods. Of these, 57.1% (20/61) had sUA between 5.1 and 7.1 mg/dl.

CONCLUSIONS

The findings of this study clearly indicate a positive relationship between uric acid and MetS and its components in pre-pubertal obese children with Tanner stage I and ≤9 years of age.

Percentiles of serum uric acid and cardiometabolic abnormalities in obese Italian children and adolescents

BACKGROUND

To investigate the association of serum uric acid (SUA) with cardiometabolic abnormalities in Caucasian overweight/obese children (<10 years of age) versus adolescents (≥10 years of age) by drawing age and gender specific percentiles of uric acid.

METHODS

Cross-sectional evaluation of 1364 Caucasian overweight/obese patients (age 4.1-17.9 years; 726 males, 53%; 560 children, 41%).

RESULTS

SUA levels were significantly lower in children than in adolescents (4.74 ± 1.05 vs. 5.52 ± 1.49 mg/dl, p < 0.001) and peaked in 12-14 years-old boys and 10-12 years-old girls. In children with levels of SUA in the highest quartile (N = 75, 13%), OR for high triglycerides was 4.145, 95% CI 1.506-11.407 (p = 0.009). In adolescents with SUA in the highest quartile (N = 274, 34%), ORs for insulin resistance was 2.399 (95%CI 1.4-4.113; p < 0.001); for impaired fasting glucose 2.184 (95% CI 0.877-5.441; p = 0.07); for impaired glucose tolerance 2.390 (95% CI 1.405-4.063; p = 0.001); and for high triglycerides 1.8, (95%CI 0.950-3.420; p = 0.05). Multivariable random-effect linear regression models demonstrated that waist circumference and age (p < 0.0001 for both) are the variables most significantly predicting SUA levels, followed by triglycerides (p = 0.005) and 2 h glucose (p = 0.03) while HOMA-IR and BMI z-score did not predict SUA.

CONCLUSIONS

High uric acid is associated with metabolic abnormalities and particularly with waist circumference very early in childhood.

Association between body mass index and salivary uric acid among Mexican-origin infants, youth and adults: Gender and developmental differences

Uric acid (UA) is the end product of the metabolic breakdown of purine nucleotides. Recent studies have measured UA in saliva in relation to obesity and chronic disease risk. Given the increasing prevalence of metabolic syndrome among Latino youth, we examined gender and age differences in salivary uric acid (sUA) and weight in a sample of Mexican-origin children (n = 65, 2 months to 18 years, 49% female) and adults (n = 46, 19-58 years, 72% female). We measured weight, height, waist, and hip circumference and collected saliva samples (later assayed for sUA). Structural equation models estimated the relationship between age, developmental stage, and weight outcomes in relation to sUA levels between genders, while controlling for race. Results demonstrate that increased sUA levels were related to higher BMI percentiles in females of all ages (β = 0.43, p < .001). There were significant differences in sUA levels between developmental stages for girls, with female toddlers having the highest sUA levels (β = .28, p = .02). In an interaction between BMI z-score and gender between youth and adults, BMI has a larger effect on increasing sUA levels among younger girls (β = 0.27, p < .03) and adult women (β = 0.33, p = .02). Levels of sUA may be gender-specific in relation to BMI and developmental stage.

Uric acid regulates hepatic steatosis and insulin resistance through the NLRP3 inflammasome-dependent mechanism

BACKGROUND & AIMS

Hyperuricemia significantly increases risk of non-alcoholic fatty liver disease (NAFLD) and insulin resistance. However, the mechanisms responsible for this association are as yet unclear. This study aimed to investigate the effects and underlying mechanisms of uric acid on development of NAFLD and insulin resistance.

METHODS

We initially analyzed the impact of uric acid on the development of hepatic steatosis and insulin resistance in mice and in two cell models, HepG2 and L02. Subsequently, we studied the role of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome in uric acid-induced fat accumulation and insulin signaling impairment.

RESULTS

We found that uric acid directly induces hepatocyte fat accumulation, insulin resistance, and insulin signaling impairment both in vivo and in vitro. We also found that uric acid-induced NLRP3 inflammasome activation, whereas lowering uric acid by allopurinol inhibited NLRP3 inflammasome activation in a high fat diet mouse model of NAFLD. Moreover, knocking down NLRP3 expression significantly attenuated uric acid-induced fat accumulation both in HepG2 cells and L02 cells. Knocking down NLRP3 expression also rescued uric acid-induced insulin signaling impairment in both cell types.

CONCLUSIONS

Uric acid regulates hepatic steatosis and insulin resistance through the NLRP3 inflammasome. Uric acid may be a new therapeutic target for NAFLD and insulin resistance.

Models Predictive of Metabolic Syndrome Components in Obese Pediatric Patients

BACKGROUND AND AIMS

Components of metabolic syndrome (MetS) are complications caused by abdominal obesity and insulin resistance (IR). Diagnosis of MetS by clinical indicators could help to identify patients at risk of cardiovascular disease and type 2 diabetes. We undertook this study to propose predictive indicators of MetS in obese children and adolescents.

METHODS

A cross-sectional study was carried out. After obtaining informed consent and the registration of the study with an institutional research committee, 172 obese patients from an Obesity Clinic, aged 6-15 years, were included. Variables included were waist circumference (WC), glucose, high-density lipoprotein (HDL), triglycerides (TGL), blood pressure, insulin resistance (by homeostatic model assessment HOMA-index), acanthosis nigricans (AN), uric acid, serum glutamic oxaloacetic transaminase (GOT) and alanine transaminase, and hepatic sonogram. International standards for age and sex variables were used. Multivariate analysis was applied.

RESULTS

Variables predicted components of MetS in children: HOMA-IR (insulin resistance by HOMA index) was increased by 2.4 in hepatic steatosis, by 0.6 for each unit of SUA (serum uric acid), and by 0.009 for every mg/dL of triglycerides. In adolescents, every cm of waist circumference increased systolic blood pressure by 0.6 mmHg, and each unit of SUA increased it by 2.9 mmHg.

CONCLUSIONS

Serum uric acid and waist circumference are useful and accessible variables that can predict an increased risk of cardiovascular disease in obese pediatric patients.

[Hyperuricaemia and metabolic syndrome in obese children and adolescents]

INTRODUCTION

Hyperuricaemia has been suggested as an additional metabolic factor in adult obese patients, but it has not been sufficiently studied in paediatric.

OBJECTIVES

To assess the relationship between serum uric acid levels (SUAL) with the level of general and visceral obesity, and other biochemical parameters in children and adolescents of Santiago, Chile.

SUBJECTS AND METHOD

A cross sectional study was conducted on 770 children and adolescents (ages: 6-15 y.) from a public school in Santiago, Chile, of whom 227 (29%) were obese (BMI>2 SD, WHO growth standards). Ninety subjects were randomly selected and 77 with no other chronic disease (41 males) accepted to participate. Data was collected on weight, stature, abdominal circumference (AC), visceral adiposity using ultrasound, and other biochemical measurements including fasting glucose, insulin, serum lipids, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and SUAL.

RESULTS

The mean SUAL was 0.200±0.065 mmol/L, and was increased in children with hyperinsulinism (adjusted by age: 0.221±0.075 vs. 0.183±0.054 mmol/L; P<.01), with no significant differences according to HOMA. Differences were also found between children with ALT>or<26 U/mL: 0.238±0.070 vs. 0.178±0.054 mmol/L, P<.001. The logistic regression showed the increased SUAL was only associated with increased ALT. No significant differences were found in general or visceral adiposity measurements or fatty liver.

CONCLUSIONS

Children and adolescents from Santiago, Chile have higher uric acid serum uric acid levels as well as an association with increased ALT and insulin. It is demonstrated in this study that uric acid should be measured in obese children and adolescents, and in their follow up.

[The role of uric acid in the insulin resistance in children and adolescents with obesity]

Objective:

To investigate the association between serum uric acid levels and insulin resistance in children and adolescents with obesity.

Methods:

Cross-sectional study with 245 children and adolescents (134 obese and 111 controls), aged 8-18 years. The anthropometric variables (weight, height and waist circumference), blood pressure and biochemical parameters were collected. The clinical characteristics of the groups were analyzed by t-test or chi-square test. To evaluate the association between uric acid levels and insulin resistance the Pearson's test and logistic regression were applied.

Results:

The prevalence of insulin resistance was 26.9%. The anthropometric variables, systolic and diastolic blood pressure and biochemical variables were significantly higher in the obese group (p<0.001), except for the high-density-lipoprotein cholesterol. There was a positive and significant correlation between anthropometric variables and uric acid with HOMA-IR in the obese and in the control groups, which was higher in the obese group and in the total sample. The logistic regression model that included age, gender and obesity, showed an odds ratio of uric acid as a variable associated with insulin resistance of 1.91 (95%CI 1.40-2.62; p<−0.001).

Conclusions:

The increase in serum uric acid showed a positive statistical correlation with insulin resistance and it is associated with and increased risk of insulin resistance in obese children and adolescents.

Serum uric acid concentrations and SLC2A9 genetic variation in Hispanic children: the Viva La Familia Study

BACKGROUND

Elevated concentrations of serum uric acid are associated with increased risk of gout and renal and cardiovascular diseases. Genetic studies in adults have consistently identified associations of solute carrier family 2, member 9 (SLC2A9), polymorphisms with variation in serum uric acid. However, it is not known whether the association of serum uric acid with SLC2A9 polymorphisms manifests in children.

OBJECTIVE

The aim was to investigate whether variation in serum uric acid is under genetic influence and whether the association with SLC2A9 polymorphisms generalizes to Hispanic children of the Viva La Familia Study.

DESIGN

We conducted a genomewide association study with 1.1 million genetic markers in 815 children.

RESULTS

We found serum uric acid to be significantly heritable [h(2) ± SD = 0.45 ± 0.08, P = 5.8 × 10(-11)] and associated with SLC2A9 variants (P values between 10(-16) and 10(-7)). Several of the significantly associated polymorphisms were previously identified in studies in adults. We also found positive genetic correlations between serum uric acid and BMI z score (ρG = 0.45, P = 0.002), percentage of body fat (ρG = 0.28, P = 0.04), fat mass (ρG = 0.34, P = 0.02), waist circumference (ρG = 0.42, P = 0.003), and waist-to-height ratio (ρG = 0.46, P = 0.001).

CONCLUSIONS

Our results show that variation in serum uric acid in Hispanic children is under considerable genetic influence and is associated with obesity-related phenotypes. As in adults, genetic variation in SLC2A9 is associated with serum uric acid concentrations, an important biomarker of renal and cardiovascular disease risk, in Hispanic children.

Serum uric acid levels are associated with high blood pressure in Chinese children and adolescents aged 10-15 years

OBJECTIVE

The present study examined the association between uric acid levels and high blood pressure in a multiethnic study of Chinese children and adolescents.

METHODS

The participants were divided into four different groups according to the uric acid quartiles. Three logistic regression models were conducted to investigate the relationship between the high blood pressure and uric acid levels. Model 1 adjusted age, sex and ethnicity. Model 2 adjusted age, sex, ethnicity, total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, estimated glomerular filtration rate, fasting glucose and waist circumference. Model 3 adjusted all the confounding factors in model 2 except the waist circumference and BMI. The concentrations of uric acid in high blood pressure participants and normotensive participants were compared with or without adjustment for confounding factors.

RESULTS

A total of 3778 participants aged 10-15 years from the Xinjiang Congenital Heart Disease Survey were included in the present study. The percentages of the high blood pressure in the four different uric acid quartiles were 7.4, 8.6, 9.6 and 11.8%, respectively. In model 1, 2 and 3 of the logistic regression, the participants in the third and fourth uric acid quartiles had significantly higher chance of suffering the high blood pressure when compared with the participants in the first uric acid quartile [odds ratio 1.608, 1.587, 1.597, P = 0.005, 0.015, 0.015, respectively, between participants in the first quartile and the third quartile; odds ratio 1.981, 1.945, 1.810, P = 0.001, 0.002, 0.007, respectively, between participants in the first quartile and the fourth quartile). The concentrations of serum uric acid were 220.7 μmol/l in high blood pressure participants and 204.1 μmol/l in normotensive participants (P = 0.024). After adjustment for confounding factors, the concentrations of serum uric acid were 219.7 vs. 204.5 μmol/l in one model (P < 0.001) and 219.3 vs. 204.5 μmol/l in the other model (P < 0.001).

CONCLUSIONS

Among Chinese children and adolescents, increasing levels of serum uric acid are associated with high blood pressure.

PHEX mimetic (SPR4-peptide) corrects and improves HYP and wild type mice energy-metabolism

CONTEXT

PHEX or DMP1 mutations cause hypophosphatemic-rickets and altered energy metabolism. PHEX binds to DMP1-ASARM-motif to form a complex with α5β3 integrin that suppresses FGF23 expression. ASARM-peptides increase FGF23 by disrupting the PHEX-DMP1-Integrin complex. We used a 4.2 kDa peptide (SPR4) that binds to ASARM-peptide/motif to study the DMP1-PHEX interaction and to assess SPR4 for the treatment of energy metabolism defects in HYP and potentially other bone-mineral disorders.

DESIGN

Subcutaneously transplanted osmotic pumps were used to infuse SPR4-peptide or vehicle (VE) into wild-type mice (WT) and HYP-mice (PHEX mutation) for 4 weeks.

RESULTS

SPR4 partially corrected HYP mice hypophosphatemia and increased serum 1.25(OH)2D3. Serum FGF23 remained high and PTH was unaffected. WT-SPR4 mice developed hypophosphatemia and hypercalcemia with increased PTH, FGF23 and 1.25(OH)2D3. SPR4 increased GAPDH HYP-bone expression 60× and corrected HYP-mice hyperglycemia and hypoinsulinemia. HYP-VE serum uric-acid (UA) levels were reduced and SPR4 infusion suppressed UA levels in WT-mice but not HYP-mice. SPR4 altered leptin, adiponectin, and sympathetic-tone and increased the fat mass/weight ratio for HYP and WT mice. Expression of perlipin-2 a gene involved in obesity was reduced in HYP-VE and WT-SPR4 mice but increased in HYP-SPR4 mice. Also, increased expression of two genes that inhibit insulin-signaling, ENPP1 and ESP, occurred with HYP-VE mice. In contrast, SPR4 reduced expression of both ENPP1 and ESP in WT mice and suppressed ENPP1 in HYP mice. Increased expression of FAM20C and sclerostin occurred with HYP-VE mice. SPR4 suppressed expression of FAM20C and sclerostin in HYP and WT mice.

CONCLUSIONS

ASARM peptides and motifs are physiological substrates for PHEX and modulate osteocyte PHEX-DMP1-α5β3-integrin interactions and thereby FGF23 expression. These interactions also provide a nexus that regulates bone and energy metabolism. SPR4 suppression of sclerostin and/or sequestration of ASARM-peptides improves energy metabolism and may have utility for treating familial rickets, osteoporosis, obesity and diabetes.