Is there anything good in uric acid?

Gut microecology: effective targets for natural products to modulate uric acid metabolism

Gut microecology,the complex community consisting of microorganisms and their microenvironments in the gastrointestinal tract, plays a vital role in maintaining overall health and regulating various physiological and pathological processes. Recent studies have highlighted the significant impact of gut microecology on the regulation of uric acid metabolism. Natural products, including monomers, extracts, and traditional Chinese medicine formulations derived from natural sources such as plants, animals, and microorganisms, have also been investigated for their potential role in modulating uric acid metabolism. According to research, The stability of gut microecology is a crucial link for natural products to maintain healthy uric acid metabolism and reduce hyperuricemia-related diseases. Herein, we review the recent advanced evidence revealing the bidirectional regulation between gut microecology and uric acid metabolism. And separately summarize the key evidence of natural extracts and herbal formulations in regulating both aspects. In addition,we elucidated the important mechanisms of natural products in regulating uric acid metabolism and secondary diseases through gut microecology, especially by modulating the composition of gut microbiota, gut mucosal barrier, inflammatory response, purine catalyzation, and associated transporters. This review may offer a novel insight into uric acid and its associated disorders management and highlight a perspective for exploring its potential therapeutic drugs from natural products.

Impact of Hyperuricemia and Urate-Lowering Agents on Cardiovascular Diseases

The association between hyperuricemia and cardiovascular diseases has been studied for many years. Research has shown a link between high uric acid levels and increased risk of including coronary artery disease hypertension and other cardiovascular conditions. Urate-lowering therapy, particularly with xanthine oxidase inhibitors like allopurinol, has shown promising results in reducing blood pressure in individuals with hyperuricemia and hypertension. Clinical trials and studies have demonstrated significant reductions in both systolic and diastolic blood pressure with urate-lowering treatment. Urate-lowering treatment has shown a favorable effect on reducing systolic blood pressure and major adverse cardiovascular events in patients with previous cardiovascular disease. In terms of cardiovascular safety, clinical trials have indicated that xanthine oxidase inhibitors such as febuxostat are non-inferior to allopurinol and do not increase the risk of death or serious adverse events. Overall, these findings highlight the importance of managing hyperuricemia and utilizing urate-lowering therapy to mitigate the adverse cardiovascular effects associated with elevated uric acid levels.

Robust positive association between serum urate and the risk of chronic obstructive pulmonary disease: hospital-based cohort and Mendelian randomisation study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and hyperuricaemia are both characterised by systemic inflammation. Preventing chronic diseases among the population with common metabolic abnormality is an effective strategy. However, the association of hyperuricaemia with the higher incidence and risk of COPD remains controversial. Therefore, replicated researches in populations with distinct characteristics or demographics are compellingly warranted.

METHODS

This cohort study adopted a design of ambispective hospital-based cohort. We used propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) to minimise the effects of potential confounding factors. A Cox regression model and restricted cubic spline (RCS) model were applied further to assess the effect of serum urate on the risk of developing COPD. Finally, we conducted a two-sample Mendelian randomisation (MR) analysis to explore evidence of causal association.

RESULTS

There is a higher incidence in the population with hyperuricaemia compared with the population with normal serum urate (22.29/1000 person-years vs 8.89/1000 person-years, p=0.009). This result is robust after performing PSM (p=0.013) and IPTW (p<0.001). The Cox model confirms that hyperuricaemia is associated with higher risk of developing COPD (adjusted HR=3.35 and 95% CI=1.61 to 6.96). Moreover, RCS shows that the risk of developing COPD rapidly increases with the concentration of serum urate when it is higher than the reference (420 µmol/L). Finally, in MR analysis, the inverse variance weighted method evidences that a significant causal effect of serum urate on COPD (OR=1.153, 95% CI=1.034 to 1.289) is likely to be true. The finding of MR is robust in the repeated analysis using different methods and sensitivity analysis.

CONCLUSIONS

Our study provides convincing evidence suggesting a robust positive association between serum urate and the risk of developing COPD, and indicates that the population with hyperuricaemia is at high risk of COPD in the Chinese population who seek medical advice or treatment in the hospital.

Association Between Blood Selenium Levels and Stroke: A Study Based on the NHANES (2011-2018)

At present, the association between circulating selenium and stroke is still in dispute. Thus, this study aimed to ascertain the association with a larger sample size than the previous study, based on the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018. In total, 13755 adults over the age of 20 years were included in our study. Multivariate logistic regression models were applied to analyze the correlation between blood selenium levels and stroke. The smooth curve fitting was performed to test the dose-response effects between blood selenium levels and stroke. After adjusting for all confounders, blood selenium levels were negatively associated with stroke (odds ratio [OR] = 0.57, 95% confidence interval [CI]: 0.37-0.87, P = 0.014). In the fully adjusted model, the highest tertile of blood selenium levels was negatively associated with stroke compared with the lowest tertile (OR = 0.70, 95% CI: 0.53-0.93, P for trend = 0.016). Moreover, the relationship between blood selenium levels and stroke was linear. In subgroup analyses, we observed that the test for interactions was significant for body mass index (BMI) and uric acid (P for interaction < 0.05). The negative relationship was stronger in participants with BMI 25-30 kg/m2 (OR = 0.23, 95% CI: 0.13-0.44, P < 0.001). Therefore, in American adults, the relationship between blood selenium levels and stroke was negative, with a linear tendency. In the future, a cohort study is warranted to further confirm this relationship.

Serum uric acid is independently associated with hypertension in patients with polymyositis and dermatomyositis

Serum uric acid (UA), as an antioxidant, has been associated with hypertension in the general population. Hypertension is highly prevalent in patients with polymyositis and dermatomyositis (PM/DM). Owning elevated levels of reactive oxygen species, patients with PM/DM have lower concentrations of UA in comparison with healthy people. We explored a potential association between UA levels and hypertension in PM/DM and evaluated whether this association is independent of hypertension risk factors, PM/DM characteristics and relevant drugs. A total of 472 PM/DM patients were assessed. UA and related laboratory data were measured. Demographic, hypertension-related factors, PM/DM characteristics and drug use were assessed as potential covariates. Results were analyzed using logistic models to test the independence of the association between UA and hypertension. UA levels were higher in hypertension subjects compared to non-hypertensive PM/DM patients [284.70 (239.93-357.38) vs 264.00(222.50-322.75), p = .017]. When adjusted for hypertension risk factors, PM/DM characteristics and drugs, the odds of being a hypertensive PM/DM patient per 1 μmol/L UA increase were significantly increased: odds ratio = 1.473 (95% confidence interval:1.063-2.042, p = .020). This cross-sectional study suggests that UA levels are independently associated with hypertension in PM/DM patients.

Characterizations of microRNAs involved in the molecular mechanisms underlying the therapeutic effects of noni (Morinda citrifolia L.) fruit juice on hyperuricemia in mice

Background

Hyperuricemia is generally defined as the high level of serum uric acid and is well known as an important risk factor for the development of various medical disorders. However, the medicinal treatment of hyperuricemia is frequently associated with multiple side-effects.

Methods

The therapeutic effect of noni (Morinda citrifolia L.) fruit juice on hyperuricemia and the underlying molecular mechanisms were investigated in mouse model of hyperuricemia induced by potassium oxonate using biochemical and high-throughput RNA sequencing analyses.

Results

The levels of serum uric acid (UA) and xanthine oxidase (XOD) in mice treated with noni fruit juice were significantly decreased, suggesting that the noni fruit juice could alleviate hyperuricemia by inhibiting the XOD activity and reducing the level of serum UA. The contents of both serum creatinine and blood urine nitrogen of the noni fruit juice group were significantly lower than those of the model group, suggesting that noni fruit juice promoted the excretion of UA without causing deleterious effect on the renal functions in mice. The differentially expressed microRNAs involved in the pathogenesis of hyperuricemia in mice were identified by RNA sequencing with their target genes further annotated based on both Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases to explore the metabolic pathways and molecular mechanisms underlying the therapeutic effect on hyperuricemia by noni fruit juice.

Conclusion

Our study provided strong experimental evidence to support the further investigations of the potential application of noni fruit juice in the treatment of hyperuricemia.

Role of uric acid as a biomarker of cognitive function in schizophrenia during maintenance period

Background

Previous studies involving uric acid (UA) in some specialized disease populations have found that high UA is associated with enhanced patient function. The mechanism to explain this association may be that UA, an important antioxidant, exerts neuroprotective effects. Patients with schizophrenia (SCZ) have severe oxidative stress abnormalities, and cognitive impairment is a major obstacle to their rehabilitation. Only few studies have been conducted on UA and cognitive impairment in SCZ. This study aims to clarify the relationship between UA and cognitive impairment and explore whether UA could be used as a potential biological marker of cognition in SCZ during maintenance period.

Methods

A total of 752 cases of SCZ during maintenance period from Baiyun Jingkang Hospital were included. Cognition was measured using the Mini-Mental State Examination scale. UA was measured using the Plus method. The participants were grouped on the basis of UA to evaluate the association of cognition with low-normal (3.50-5.07 mg/dL for men, 2.50-4.19 mg/dL for women), middle-normal (5.07-6.39 mg/dL for men, 4.19-5.18 mg/dL for women), high-normal (6.39-7.00 mg/dL for men, 5.18-6.00 mg/dL for women), and high (>7.00 mg/dL for men, >6.00 mg/dL for women) levels of UA. Multiple logistic regression and linear regression models and restricted cubic spline (RCS) were utilized to evaluate the relationship.

Results

Uric acid was positively associated with cognitive function. Subgroup analyses showed that high UA was associated with enhanced cognition in participants with low anticholinergic cognitive burden (ACB).

Conclusion

Uric acid may be used as a simple objective biological indicator to assess cognition in SCZ during maintenance period.

Clinical and biochemical indices of people with high-altitude experience linked to acute mountain sickness

BACKGROUND

Acute mountain sickness (AMS) is a major health issue for people travelling to high altitudes. This study was designed to comprehensively evaluate the changes in clinical characteristics and biochemical indices of high-altitude travelers and determine whether these changes were associated with AMS.

METHODS

A total of 14 clinical indices and 52 biochemical indices were determined in 22 subjects before and during acute high-altitude exposure. Six hours after passive ascent to 3648 m (Lhasa, China), the Lake Louise Scoring (LLS) system 2018 was used to assess AMS, which was defined as headache with a total LLS ≥3.

RESULTS

Before travelling to high altitudes, uric acid (UA), platelet distribution width (PDW), mitral peak E velocity (MVE), and ejection fraction (EF) were significantly higher in AMS-resistant individuals than in AMS-susceptible ones (all p < 0.05). A good predictive value of UA (0.817, 95% CI: 0.607-1.000) and PDW (0.844, 95% CI: 0.646-1.000) for AMS-susceptible subjects was found. With high-altitude experience, 14 subjects were diagnosed as having AMS. Compared with non-AMS, the changes in UA and number of neutrophils in AMS presented a significant difference (all p < 0.05). The high-altitude-induced changes in UA, area under the curve, specificity, and sensitivity for identifying AMS were 0.883 (95% CI: 0.738-1.000), 83.30%, and 90.00%, respectively.

CONCLUSION

Human presents a compensatory physiological and biochemical response to high-altitude travel at early phase. The UA concentration before travel and its trend with high-altitude experience exhibited good performance for identifying AMS.

Serum uric acid is not associated with appendicular muscle mass index in young and middle-aged adults: Results from NHANES 2011-2012

BACKGROUND

Recent studies have evaluated the association between uric acid (UA) and muscle mass in older adults; however, little is known about this relationship in young and middle-aged individuals. Our aim was to investigate whether serum UA is associated with appendicular muscle mass index (AMMI) in young and middle-aged individuals. We also aimed to evaluate whether this association is sex-specific.

METHODS

A cross-sectional study was performed with young and middle-aged individuals aged from 20 to 59 years from National Health and Nutrition Examination Survey (NHANES) 2011-2012. A total of 2255 individuals (1440 young and 815 middle-aged individuals; 1167 men and 1088 women) were evaluated. Body composition was assessed by Dual Energy X-ray absorptiometry (DXA) and AMMI was calculated using the arms plus legs lean mass divided by the height squared. UA levels were measured by colorimetric method. Regression analyzes were performed to evaluate whether AMMI is associated with the tertiles of UA levels after adjustments for potential confounders.

RESULTS

In the unadjusted analyzes, serum UA was positively associated with AMMI for total sample, young, and middle-aged individuals of both sexes. However, after adjustments for confounders, UA levels were no longer associated with AMMI independent of the age-rage and sex.

CONCLUSION

Serum UA is not associated with AMMI in young or middle-aged individuals independent of the sex.

Digital Quantification Method for Sensitive Point-of-Care Detection of Salivary Uric Acid Using Smartphone-Assisted μPADs

Uric acid (UA) is an important biomarker for many diseases. A sensitive point-of-care (POC) testing platform is designed for the digital quantification of salivary UA based on a colorimetric reaction on an easy-to-build smartphone-assisted microfluidic paper-based analytical device (SμPAD). UA levels are quantified according to the color intensity of Prussian blue on the SμPAD with the aid of a MATLAB code or a smartphone APP. A color correction method is specifically applied to exclude the light effect. Together with the engineering design of SμPADs, the background calibration function with the APP increases the UA sensitivity by 100-fold to reach 0.1 ppm with a linear range of 0.1-200 ppm. The assay time is less than 10 min. SμPADs demonstrate a correlation of 0.97 with a commercial UA kit for the detection of salivary UA in clinical samples. SμPADs provide a sensitive, fast, affordable, and reliable tool for the noninvasive POC quantification of salivary UA for early diagnosis of abnormal UA level-associated health conditions.

Comparison of Hematological Parameters Between First-Episode Schizophrenia and Anti-NMDAR Encephalitis

Background: First-episode schizophrenia (FES) and anti-NMDAR encephalitis are different disorders with similar psychiatric symptoms, and both diseases are associated with the inflammatory system. In this study, we compared hematological parameters and inflammation ratios in anti-NMDAR encephalitis, FES, and healthy control.

Methods: We enrolled 106 patients (53 FES patients and 53 anti-NMDAR encephalitis patients) and 59 healthy controls. The values of the neutrophil–lymphocyte ratio (NLR), platelet–lymphocyte ratio (PLR), monocyte–lymphocyte ratio (MLR), and systemic immune-inflammation index (SII) were used to evaluate inflammation. Other parameters such as the white blood cell (WBC), platelet (PLT), uric acid (UA), total bilirubin (TBIL), total bile acid (TBA), and serum albumin counts were also used to compare inflammation ratios between these two diseases.

Results: SII, NLR, PLR, MLR, and serum albumin levels were statistically significantly different between these three groups (p < 0.05). The values of SII, NLR, PLR, and MLR were significantly higher in the anti-NMDAR encephalitis group than those in the FES group (p < 0.05), and the values in both diseases were more increased than those in HC (p < 0.05). The serum albumin level was significantly lower in anti-NMDAR encephalitis than in FES (p < 0.05). WBC, neutrophil, lymphocyte, and monocyte counts showed significantly higher levels in the anti-NMDAR encephalitis group and FES group separately (p < 0.05). Other parameters like TBA, TBIL, and UA showed no difference between groups.

Conclusion: In summary, this is a relatively new study that is innovative by comparing some inflammation markers of peripheral blood in two diseases with clinically psychotic symptoms. These two diseases are related to the inflammatory system, proving that NMDAR dysfunction is related to psychotic symptoms. Besides, NLR, PLR, MLR, and serum albumin can be used as biomarkers to distinguish the two diseases. The serum albumin level in patients with anti-NMDAR encephalitis was lower than that in patients with schizophrenia.

Uricaemia and associated health determinants in a paediatric population in Mexico

BACKGROUND AND AIM

Uric acid (UA) is a product of the catabolism of purines, and its increase in blood may be related to the development of cardiometabolic diseases. Whether UA is the result or causal determinant of the appearance of risk factors for cardiometabolic disease is not yet known. UA levels among the young student population in San Luis Potosi have increased in recent years, which may be indicative of a serious future public health concern. Therefore, the objective of this study was to evaluate the association of sociodemographic, lifestyle and cardiometabolic determinants with UA levels in children and adolescents in San Luis Potosí.

METHODS AND RESULTS

A total of 730 students (54.1% female and 45.9% male, 6-19 years old) participated in the study. The subjects attended one of five public schools located in San Luis Potosí. Venous blood samples were collected, blood serum was separated by centrifugation, and UA concentrations were measured with an automated analytical platform. UA was associated with most of the independent variables studied. It presented a positive correlation with body mass index (r = 0.363, p < 0.01). Male sex, socioeconomic status, total screen time, exercise, adequate sleep, systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol explained 23%-39% (p < 0.001) of the variability of plasma concentrations of UA in children and adolescents.

CONCLUSION

Early detection of these determinants will prevent future diseases. Moreover, it will help with the implementation of preventive strategies that could improve the health of this population.

A New Predictor of Mortality in ST-Elevation Myocardial Infarction: The Uric Acid Albumin Ratio

Several studies have shown that high uric acid (UA) and low serum albumin (SA) values increase the risk of cardiovascular disease and mortality in ST-elevation myocardial infarction (STEMI). We determined whether the uric acid/albumin ratio (UAR) is a predictor of mortality in STEMI patients. All patients who presented at our center with a diagnosis of STEMI and underwent percutaneous intervention from 2015 to 2020 were screened consecutively; 4599 patients were included. A Cox proportional hazards model was used to evaluate UAR, and adjusted predictors obtained from laboratory findings and clinical characteristics contributed to mortality. Also, a regression model was presented with a directed acyclic graph (DAG). The median age of the patients was 58 years (IQR [interquartile range]: 50–67); 3581 patients (77.9%) were male. The incidence of mortality in the entire patient group was 11.9%. Median follow-up duration of all groups was 42 months. Multivariate Cox proportional regression (model-1) analysis showed age (increase 50 to 67 years; HR [hazard ratio]: 1.34, 95% CI 1.18–1.52) and UAR (increase 1.15–1.73; HR: 1.33, 95% CI 1.16–1.52) were associated with mortality. UAR may be a prognostic factor for mortality in STEMI patients and an easily accessible parameter to identify high-risk patients.

Hyperuricemia in Psoriatic Arthritis: Epidemiology, Pathophysiology, and Clinical Implications

Psoriatic arthritis (PsA) represents the articular component of the systemic psoriatic disease and the extra-cutaneous disorder most frequently found in patients with psoriasis. Besides the articular involvement, PsA is associated with several metabolic abnormalities such as insulin resistance, hypertension, diabetes and hyperuricemia. Uric acid is the final product of purine metabolism and the etiological substrate of gout. Accumulating evidence highlights the emerging role of hyperuricemia as a major cardiovascular risk factor. Moreover, different studies evaluated the interplay between hyperuricemia and psoriatic disease, suggesting that individuals affected by psoriasis or PsA might present higher serum levels of uric acid and that hyperuricemia might affect severity of clinical manifestations and degree of inflammation in PsA patients. In this review, we focus on the bidirectional relationship between uric acid and PsA, analyzing how uric acid may be involved in the pathogenesis of psoriasis/PsA and how clinical manifestations of PsA and inflammatory mediators are affected by uric acid concentrations. Finally, the effects of anti-rheumatic drugs on uric acid levels and the potential benefit of urate-lowering therapies on psoriasis and PsA were summarized.

Relationship Between Change in Serum Uric Acid and Ischemic Stroke in Chinese Hypertensive Patients

Background: Limited studies focused on the association between serum uric acid (SUA) change with ischemic stroke, and their results remain controversial. The present study aimed to investigate the relationship between change in SUA with ischemic stroke among hypertensive patients.

Method: This was a retrospective cohort study. We recruited adult hypertensive patients who had two consecutive measurements of SUA levels from 2013 to 2014 and reported no history of stroke. Change in SUA was assessed as SUA concentration measured in 2014 minus SUA concentration in 2013. Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). The Kaplan–Meier analysis and log-rank test were performed to quantify the difference in cumulative event rate. Additionally, subgroup analysis and interaction tests were conducted to investigate heterogeneity.

Results: A total of 4,628 hypertensive patients were included, and 93 cases of ischemic stroke occurred during the mean follow-up time of 3.14 years. Participants were categorized into three groups according to their SUA change tertiles [low (SUA decrease substantially): <-32.6 μmol/L; middle (SUA stable): ≥-32.6 μmol/L, <40.2 μmol/L; high (SUA increase substantially): ≥40.2 μmol/L]. In the fully adjusted model, setting the SUA stable group as reference, participants in the SUA increase substantially group had a significantly elevated risk of ischemic stroke [HR (95% CI), 1.76 (1.01, 3.06), P = 0.0451], but for the SUA decrease substantially group, the hazard effect was insignificant [HR (95% CI), 1.31 (0.75, 2.28), P = 0.3353]. Age played an interactive role in the relationship between SUA change and ischemic stroke. Younger participants (age < 65 years) tended to have a higher risk of ischemic stroke when SUA increase substantially.

Conclusion: SUA increase substantially was significantly correlated with an elevated risk of ischemic stroke among patients with hypertension.

Uric Acid as a Predictor for Early Allograft Dysfunction after Living Donor Liver Transplantation: A Prospective Observational Study

Early allograft dysfunction (EAD) is a postoperative complication that may cause graft failure and mortality after liver transplantation. The objective of this study was to examine whether the preoperative serum uric acid (SUA) level may predict EAD. We performed a prospective observational study, including 61 donor/recipient pairs who underwent living donor liver transplantation (LDLT). In the univariate and multivariate analysis, SUA ≤4.4 mg/dL was related to a five-fold (odds ratio (OR): 5.16, 95% confidence interval (CI): 1.41–18.83; OR: 5.39, 95% CI: 1.29–22.49, respectively) increased risk for EAD. A lower preoperative SUA was related to a higher incidence of and risk for EAD. Our study provides a new predictor for evaluating EAD and may exert a protective effect against EAD development.

Prognostic impacts of serum uric acid levels in patients with chronic heart failure: insights from the CHART-2 study

AIMS

Prognostic impacts of serum uric acid (UA) levels in patients with chronic heart failure (CHF) remain inconclusive, especially for the whole range of serum UA levels.

METHODS AND RESULTS

In the Chronic Heart Failure Registry and Analysis in the Tohoku District-2 (CHART-2) study, we enrolled 4652 consecutive patients with CHF and classified them into four groups based on baseline serum UA levels by the Classification and Regression Tree: G1 (<3.8 mg/dL, N = 313), G2 (3.8-7.1 mg/dL, N = 3070), G3 (7.2-9.2 mg/dL, N = 1018), and G4 (>9.2 mg/dL, N = 251). Mean age was 71 ± 12, 69 ± 12, 68 ± 13, and 69 ± 15 years in G1, G2, G3, and G4, respectively (P < 0.001). During the median follow-up of 6.3 years, in G1, G2, G3, and G4, 111 (35%), 905 (29%), 370 (36%), and 139 (55%) patients died and 79 (25%), 729 (24%), 300 (29%), and 115 (46%) experienced heart failure hospitalization, respectively (both P < 0.001). G1 was characterized by a significantly high prevalence of women as compared with G2, G3, and G4 (59%, 32%, 24%, and 23%, respectively). Serum creatinine levels (0.8 ± 0.4, 0.9 ± 0.4, 1.2 ± 0.6, and 1.4 ± 0.8 mg/dL, respectively), prevalence of atrial fibrillation (34%, 39%, 45%, and 50%, respectively), and diuretics use (36%, 45%, 67%, and 89%, respectively) increased from G1, G2, G3 to G4 (all P < 0.001), while left ventricular ejection fraction decreased from G1, G2, G3 to G4 (59 ± 15, 58 ± 15, 54 ± 15, and 52 ± 17%, respectively, P < 0.001). Multivariable Cox proportional hazards models showed that, as compared with G2, both G1 and G4 had increased incidence of all-cause death [adjusted hazard ratio (aHR) 1.34, 95% confidence interval (CI) 1.08-1.67, P = 0.009; aHR 1.28, 95% CI 1.02-1.61, P = 0.037, respectively] and heart failure admission (aHR 1.39, 95% CI 1.09-1.78, P = 0.008 and aHR 1.35, 95% CI, 1.06-1.71, P = 0.014, respectively). This U-shaped relationship was evident in the elderly patients. Furthermore, abnormal transitions to either higher or lower levels of serum UA from G2 were associated with increased mortality (aHR 1.29, 95% CI 1.06-1.57, P = 0.012; aHR 1.57, 95% CI 1.12-2.20, P = 0.009).

CONCLUSIONS

These results demonstrate that serum UA levels have the U-shaped prognostic effects and abnormal transitions to either higher or lower levels are associated with poor prognosis in the elderly patients with CHF.

Elevated serum uric acid is associated with a greater inflammatory response and with short- and long-term mortality in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND AND AIMS

Despite elevated serum uric acid (eSUA) has been identified as independent risk factor for cardiovascular diseases, its prognostic value in the setting of ST-segment elevation myocardial infarction (STEMI) is still controversial. Although the mechanisms of this possible relationship are unsettled it has been suggested that eSUA could trigger the inflammatory response. This study sought to investigate the association between eSUA with short- and long-term mortality and with inflammatory response in patients with STEMI treated with primary percutaneous coronary intervention (pPCI).

METHODS AND RESULTS

Blood samples were collected on admission and at 24 and 48 h after pPCI: the inflammatory biomarkers C-reactive protein (CRP), neutrophil count and neutrophil to lymphocytes ratio (NLR) were considered. Baseline eSUA was defined as ≥6.8 mg/dl. Cumulative 30-days and 1-year mortalities were estimated using the Kaplan-Meyer analysis. Multivariable analyses were performed by Cox proportional hazard models. In the 2369 patients with STEMI considered, 30-day mortality was 5.8% among patients with eSUA and 2% among patient with normal SUA level (p < 0.001); 1-year mortality was 8.5% vs 4%, respectively (p < 0.001). At multivariable analyses eSUA was an independent predictor of 30-day mortality (HR 1.196, 95%CI 1.006-1.321, p = 0.042) and 1-year mortality (HR 1.178, 95%CI 1.052-1.320, p = 0.005). eSUA patients presented higher values in on admission CRP (p < 0.001) and in neutrophil count and NLR at 24 h (respectively, p = 0.020 and p < 0.001) and at 48 h (p = 0.018 and p < 0.001) compared to patients with normal SUA levels.

CONCLUSIONS

Elevated serum uric acid is associated with higher short- and long-term mortality and with a greater inflammatory response after reperfusion in patients with STEMI treated with primary PCI.

Identification of Pre-Diagnostic Metabolic Patterns for Glioma Using Subset Analysis of Matched Repeated Time Points

Simple Summary

Reprogramming of cellular metabolism is a major hallmark of cancer cells, and play an important role in tumor initiation and progression. The aim of our study is to discover circulating early metabolic markers of brain tumors, as discovery and development of reliable predictive molecular markers are needed for precision oncology applications. We use a study design tailored to minimize confounding factors and a novel machine learning and visualization approach (SMART) to identify a panel of 15 interlinked metabolites related to glioma development. The presented SMART strategy facilitates early molecular marker discovery and can be used for many types of molecular data.

Abstract

Here, we present a strategy for early molecular marker pattern detection—Subset analysis of Matched Repeated Time points (SMART)—used in a mass-spectrometry-based metabolomics study of repeated blood samples from future glioma patients and their matched controls. The outcome from SMART is a predictive time span when disease-related changes are detectable, defined by time to diagnosis and time between longitudinal sampling, and visualization of molecular marker patterns related to future disease. For glioma, we detect significant changes in metabolite levels as early as eight years before diagnosis, with longitudinal follow up within seven years. Elevated blood plasma levels of myo-inositol, cysteine, N-acetylglucosamine, creatinine, glycine, proline, erythronic-, 4-hydroxyphenylacetic-, uric-, and aceturic acid were particularly evident in glioma cases. We use data simulation to ensure non-random events and a separate data set for biomarker validation. The latent biomarker, consisting of 15 interlinked and significantly altered metabolites, shows a strong correlation to oxidative metabolism, glutathione biosynthesis and monosaccharide metabolism, linked to known early events in tumor development. This study highlights the benefits of progression pattern analysis and provide a tool for the discovery of early markers of disease.

Crocodylus porosus: a potential source of anticancer molecules

Background

Cancer remains a global threat resulting in significant morbidity and mortality despite advances in therapeutic interventions, suggesting urgency for identification of anticancer agents. Crocodiles thrive in polluted habitat, feed on germ-infested meat, are exposed to carcinogenic heavy metals, are the very few species to survive the catastrophic Cretaceous–Paleogene extinction event, yet have a prolonged lifespan and rarely been reported to develop cancer. Therefore, we hypothesised that animals living in polluted environments such as crocodiles possess anticancer molecules/mechanisms.

Methods

Crocodylus porosus was procured, blood collected, dissected and lysates prepared from internal organs. Organ lysates and sera were tested for growth inhibition, cytotoxic effects and cell survival against HeLa, PC3 and MCF7 cells and subjected to liquid chromatography mass spectrometry. RNA transcriptome analysis and differential gene analysis were performed using Galaxy Bioinformatics.

Results

Sera exhibited potent growth inhibition and cytotoxic effects against cancer cells. 80 molecules were detected from C. porosus and 19 molecules were putatively identified. Additionally, more than 100 potential anticancer peptides were identified from sera using bioinformatics based on peptide amino acid composition, binary profile, dipeptide composition and pseudo-amino acid composition. Following transcriptome analysis, 14 genes in treated HeLa cells, 51 genes in treated MCF7 cells and 2 genes in treated PC3 cells, were found to be expressed, compared with untreated controls.

Conclusion

Animals residing in polluted milieus are an unexploited source for prospective pharmaceutical drugs, and could lead to identification of novel antitumour compound(s) and/or further understanding of the mechanisms of cancer resistance.

Uric acid levels in subjects with schizophrenia: A systematic review and meta-analysis

The association between schizophrenia (SZ) and uric acid (UA) levels has been suggested for many years, but without solid evidence. Therefore, we conducted a systematic review and meta-analysis of all case-control studies examining the serum and plasma UA levels in SZ subjects in comparison to those in healthy controls. Relevant studies published before October 29, 2018, were searched in the main electronic databases, and 17 studies were finally included into the meta-analysis after screening with the criteria. Our results revealed that there were no statistically significant differences of the UA levels between SZ subjects and healthy controls. Further subgroup analyses of the antipsychotic status reported the same finding. Subgroup analyses of clinical status showed that UA levels were decreased in subjects with first episode psychosis (FEP). The subgroup analyses of gender and ethnicity demonstrated that UA levels were decreased in male subjects and in Americans with SZ. Overall, these findings strengthen the clinical evidence that FEP is accompanied by increased oxidative stress response. Reduced UA levels may be a potential risk factor for SZ in male and in the Americans. However, whether there is a causal relationship between the reduced UA levels and the development of SZ deserves further investigation.

Association of sleep quality and sleep duration with serum uric acid levels in adults

OBJECTIVE

To date, the association between sleep duration or sleep quality and hyperuricemia has remained unclear. In addition, sleep duration and quality were not considered concomitantly in previous studies. Thus, this study was aimed toward an examination of the association of sleep duration and quality with uric acid level in a Taiwanese population.

METHODS

A total of 4,555 patients aged ≥18 years were enrolled in this study. The sleep duration was classified into three groups: short (<7 h), normal (7-9 h), and long (≥9 h). The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality, and poor sleep quality was defined as a global PSQI score of >5.

RESULTS

Poor sleepers were younger and had lower body mass index, blood pressure, uric acid, blood sugar, cholesterol, creatinine level, shorter sleep duration, and engaged in less exercise but had a higher white blood cell count and prevalence of smoking as compared to good sleepers. There were also differences in body mass index, blood pressure, uric acid, blood sugar, lipid profiles, and sleep quality among subjects with different sleep durations. After adjusting for other variables, poor sleep quality was associated with lower uric acid levels. In addition, short sleep duration was positively associated with higher uric acid levels.

CONCLUSIONS

Poor sleep quality was related to lower uric acid levels, whereas short sleep duration was associated with higher uric acid levels.

Phytochemical Screening and Anti-Hyperuricemia Activity Test In Vivo of Ethanolic Extract of Shallot (Allium cepa L.) Skin

Uric acid is the final product of purine metabolism that will be excreted through urine, feces, and sweat. Excessive production of uric acid can cause hyperuricemia, known as gout. The skin of shallots (Allium cepa L.) is one of the household wastes that are very rarely used by the community. Ethanol extract of shallot skin (EESS) was tested for phytochemical screening and anti-hyperuricemia activity using potassium oxonate. Mice were divided into five groups (Allopurinol, Na-CMC, EESS 200 mg/kg BW, 300 mg/kg BW, and 400 mg/kg BW) and uric acid levels were observed at 2-hour intervals for six hours. Phytochemical screening shows that EESS has potential compounds in the treatment of gout. Tests to reduce uric acid levels showed that EESS has better potential than allopurinol at concentrations of 300 mg/kg BW and 400 mg/kg BW after six hours of induction in reducing uric acid levels.

High Concentrations of Uric Acid and Angiotensin II Act Additively to Produce Endothelial Injury

Renin angiotensin (Ang) system (RAS) activation in metabolic syndrome (MS) patients is associated with elevated uric acid (UA) levels, resulting in endothelial system dysfunction. Our previous study demonstrated that excessive UA could cause endothelial injury through the aldose reductase (AR) pathway. This study is the first to show that a high concentration of Ang II in human umbilical vein endothelial cells (HUVECs) increases reactive oxygen species (ROS) components, including O₂^·- and H₂O₂, and further aggravates endothelial system injury induced by high UA (HUA). In a MS/hyperuricemia model, nitric oxide (NO) production was decreased, followed by a decrease in total antioxidant capacity (TAC), and the concentration of the endothelial injury marker von Willebrand factor (vWF) in the serum was increased. Treatment with catalase and polyethylene glycol covalently linked to superoxide dismutase (PEG-SOD) to individually remove H₂O₂ and O₂^·- or treatment with the AR inhibitor epalrestat decreased ROS and H₂O₂, increased NO levels and TAC, and reduced vWF release. Taken together, these data indicate that HUA and Ang II act additively to cause endothelial dysfunction via oxidative stress, and specific elimination of O₂^·- and H₂O₂ improves endothelial function. We provide theoretical evidence to prevent or delay endothelial injury caused by metabolic diseases.

[Relationship between central obesity and oxidative stress in premenopausal versus postmenopausal women]

Introduction

Background: endocrine changes in midlife women produce an increase in central obesity and oxidative stress, thus it is possible that obese postmenopausal women exhibit a higher oxidative stress than premenopausal women. Objective: to evaluate the relationship between central obesity and oxidative stress in premenopausal compared with postmenopausal women using different indices. Methods: this is a cross-sectional study that included 237 pre- and 255 post-menopausal women (40-60 years old). As oxidative stress markers we measured plasma malondialdehyde and serum uric acid levels, erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), and total plasma antioxidant status. We also measured height, weight, and waist and hip circumferences, and we calculated body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR). Results: we found over 30% of women within the obesity range, whereas 50% were placed in the overweight category in both groups. Plasma malondialdehyde and serum uric acid levels were higher in women with overweight or obesity than in women with normal weight regardless of menopausal status. We found a positive correlation between WHtR and malondialdehyde level (r = 0.298, p < 0.0001) and serum uric acid level (r = 0.263, p < 0.0001), and a negative correlation with erythrocyte GPx activity (r = -0.148, p < 0.01). If we use a WHtR > 0.6, malondialdehyde and uric acid levels increase regardless of menopausal status. The other indices measured did not show any relationship. Conclusion: our findings suggest that there is an association between central obesity, as measured with WHtR, and increased oxidative stress regardless of menopausal status.

Management of asymptomatic hyperuricemia: Integrated Diabetes & Endocrine Academy (IDEA) consensus statement

AIM

The definition and management of asymptomatic hyperuricemia has been an area of controversy for many decades. Debate persists regarding the benefit of treating all cases of asymptomatic hyperuricemia and hence, unsurprisingly there are no clear clinical practice guidelines from our country.

PARTICIPANTS

Ten members consisting of eminent physicians, endocrinologists, nephrologist and a rheumatologist were selected by the Integrated Diabetes & Endocrine Academy (IDEA) for a closed meeting with the aim to come to a consensus.

EVIDENCE

A literature search was performed using PubMed and Cochrane library following which published articles in indexed peer review journals were selected.

CONSENSUS PROCESS

Each participant voiced their opinion after reviewing the available data and a consensus was reached after three meetings by voting.

CONCLUSION

Recommendations were made on important areas such as definition, investigation and management of asymptomatic hyperuricemia.

U-shaped association between serum uric acid concentration and mortality in hypertrophic cardiomyopathy patients

Background. No study has examined the effect of low serum uric acid (SUA) concentrations on mortality in hypertrophic cardiomyopathy (HCM) patients. The aim of the present study was to assess the relations between both low and high SUA concentrations and the risk of mortality across the full range of SUA concentrations in a retrospective cohort of HCM patients.Methods. A total of 454 HCM patients were enrolled in the study, and SUA concentrations were measured at baseline. The primary and secondary endpoints were all-cause mortality and HCM-related mortality, respectively. The associations between SUA concentrations and endpoints were analysed.Results. During a median follow-up of 3.8 years, there were 80 (17.6%) all-cause mortality events, and 52 of them (11.5%) were ascribed to HCM-related mortality. Patients with SUA concentrations of 250-350 µmol/L had the lowest all-cause mortality rate (11.8%) and HCM-related mortality rate (5.0%). Both low and high SUA concentrations were associated with increased all-cause and HCM-related mortality. Adjusted HRs were 2.52 (95% CI 1.13-5.61, p = 0.024) and 4.86 (95% CI 1.74-13.58, p = 0.003) for all-cause mortality and HCM-related mortality in the lowest SUA group (<250 µmol/L) when compared with the reference group (250-350 µmol/L), respectively. The corresponding HRs in the highest SUA group (≥450 µmol/L) were 2.73 (95% CI 1.42-5.23, p = 0.003) and 4.14 (95% CI 1.70-10.13, p = 0.002), respectively.Conclusions. Both low and high SUA concentrations were significantly associated with increased risk of all-cause mortality and HCM-related mortality, which supported a U-shaped association between SUA concentrations and mortality in HCM patients.

Activation of Human Monocytes by Colloidal Aluminum Salts

Subunit vaccines often contain colloidal aluminum salt-based adjuvants to activate the innate immune system. These aluminum salts consist of micrometer-sized aggregates. It is well-known that particle size affects the adjuvant effect of particulate adjuvants. In this study, the activation of human monocytes by hexagonal-shaped gibbsite (ø = 210 ± 40 nm) and rod-shaped boehmite (ø = 83 ± 827 nm) was compared with classical aluminum oxyhydroxide adjuvant (alum). To this end, human primary monocytes were cultured in the presence of alum, gibbsite, or boehmite. The transcriptome and proteome of the monocytes were investigated by using quantitative polymerase chain reaction and mass spectrometry. Human monocytic THP-1 cells were used to investigate the effect of the particles on cellular maturation, differentiation, activation, and cytokine secretion, as measured by flow cytometry and enzyme-linked immunosorbent assay. Each particle type resulted in a specific gene expression profile. IL-1ß and IL-6 secretion was significantly upregulated by boehmite and alum. Of the 7 surface markers investigated, only CD80 was significantly upregulated by alum and none by gibbsite or boehmite. Gibbsite hardly activated the monocytes. Boehmite activated human primary monocytes equally to alum, but induced a much milder stress-related response. Therefore, boehmite was identified as a promising adjuvant candidate.

Crystallized but not soluble uric acid elicits pro-inflammatory response in short-term whole blood cultures from healthy men

Several epidemiological studies have pointed at serum uric acid (SUA) as an independent risk factor for mortality, diabetes, hypertension, cardiovascular and kidney disease; however, no clear pathogenic pathway is established. Uric acid (UA) crystals show pro-inflammatory properties and can thus create or contribute to the state of chronic low-grade inflammation, a widely accepted pathogenic mechanism in several of the above-mentioned pathologies. On the other hand, soluble uric acid possesses antioxidant properties that might attenuate inflammatory responses. We aimed to explore the net effects of experimentally rising SUA in human whole blood cultures on several mediators of inflammation. Production of TNF-α, IL-1ß, IL-1RA, MCP-1 and IL-8 was assessed upon addition of 200 µM UA, 500 µM UA or monosodium urate (MSU) crystals in the presence or absence of 5 ng/ml lipopolysaccharide (LPS). RT-qPCR and multiplex bead based immunoassay were used to measure mRNA expression and cytokine release at 2 and 4 h of culture, respectively. ¹⁴C labeled UA was used to assess intracellular uptake of UA. We show that crystallized, but not soluble, UA induces production of pro-inflammatory mediators in human whole blood. Soluble UA is internalized in blood cells but does not potentiate or reduce LPS-induced release of cytokines.

Effects of pre- or post-exercise whey protein supplementation on oxidative stress and antioxidant enzymes in older women

BACKGROUND

Oxidative stress is an imbalance between antioxidant system and production of free radicals and has been associated with the age-related deleterious changes. The defense system can be modulated by exercise and nutrition.

OBJECTIVE

The purpose of this investigation was to evaluate the effect of whey protein supplementation pre- or post-resistance training on oxidative stress and antioxidant enzyme activity in pre-conditioned older women.

METHODS

In a randomized, double-blind, and placebo-controlled design, 70 older women (≥60 years) were randomly assigned to one of the following three groups: whey protein-placebo (WP-PLA, n = 24), placebo-whey protein (PLA-WP, n = 23), and placebo-placebo (PLA-PLA, n = 23). Each group received 35 g of whey product or placebo pre- and post-training. The RT program was carried out over 12 weeks (3x/week; 3x 8-12 repetitions maximal). Oxidative stress and blood markers were assessed before and after intervention period. ANOVA for repeated measures was used for data analysis.

RESULTS

There was a significant time effect (P < 0.05), with all groups showing improvements in all oxidative stress markers and antioxidant enzyme activity. A significant (P < 0.001) interaction time vs group was observed for uric acid, with both WP-PLA and PLA-WP presenting greater reductions compared with the PLA-PLA, without differences between the timing of protein intake (WP-PLA: -8.3%; PLA-WP: -11.0%; PLA-PLA:-2.0%).

CONCLUSION

In already pre-conditioned older women, whey protein supplementation reduces plasma uric acid concentration with no further effect on antioxidant enzyme activity and oxidative stress markers. ClinicalTrials.gov: NCT03247192.

Nonenzymatic Serum Antioxidant Capacity in IBD and Its Association with the Severity of Bowel Inflammation and Corticosteroids Treatment

Background and objectives: Oxidative stress signalling plays a monumental role in inflammatory bowel disease (IBD). Reduction of oxidative stress might control inflammation, block tissue damage, and reverse natural history of IBD. We assessed the serum concentrations of free thiols (FT) and uric acid (SUA), together constituting a large part of nonenzymatic serum antioxidant capacity, as well as total antioxidant status (TAS) with reference to IBD phenotype, activity, co-occurrence of anemia, and treatment with azathioprine (AZA) and corticosteroids (CS). Additionally, we appraised the potential of uric acid, thiol stress, and TAS as mucosal healing (MH) markers in ulcerative colitis. Materials and methods: SUA, FT, and TAS were measured colorimetrically using, respectively, uricase, Ellman's and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) methods. Results: The study group consisted of 175 individuals: 57 controls, 71 ulcerative colitis (UC), and 47 Crohn's disease (CD) patients. When compared to controls, SUA levels were significantly lower in patients with CD, and FT and TAS levels were significantly lower in patients with CD and UC. In UC patients, SUA, FT, and TAS inversely correlated with the severity of bowel inflammation. As MH markers, SUA displayed better overall accuracy and higher specificity than FT. In active CD, FT, and SUA were significantly lower in patients with anemia. FT was significantly lower in patients treated with corticosteroids. Conclusions: IBD patients, regardless the disease phenotype, have systemic thiol stress, depleted total antioxidant capacity, and reduced concentrations of uric acid, reflecting, to various degrees, clinical and local disease activity as well as presence of anaemia, the most common extraintestinal manifestation of IBD. Evaluation of systemic total antioxidant status may be useful in noninvasive assessment of mucosal healing. Our findings on thiol stress provide an additional aspect on adverse effects of corticosteroids therapy.

Nonenzymatic Serum Antioxidant Capacity in IBD and Its Association with the Severity of Bowel Inflammation and Corticosteroids Treatment

Background and objectives: Oxidative stress signalling plays a monumental role in inflammatory bowel disease (IBD). Reduction of oxidative stress might control inflammation, block tissue damage, and reverse natural history of IBD. We assessed the serum concentrations of free thiols (FT) and uric acid (SUA), together constituting a large part of nonenzymatic serum antioxidant capacity, as well as total antioxidant status (TAS) with reference to IBD phenotype, activity, co-occurrence of anemia, and treatment with azathioprine (AZA) and corticosteroids (CS). Additionally, we appraised the potential of uric acid, thiol stress, and TAS as mucosal healing (MH) markers in ulcerative colitis. Materials and methods: SUA, FT, and TAS were measured colorimetrically using, respectively, uricase, Ellman’s and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) methods. Results: The study group consisted of 175 individuals: 57 controls, 71 ulcerative colitis (UC), and 47 Crohn’s disease (CD) patients. When compared to controls, SUA levels were significantly lower in patients with CD, and FT and TAS levels were significantly lower in patients with CD and UC. In UC patients, SUA, FT, and TAS inversely correlated with the severity of bowel inflammation. As MH markers, SUA displayed better overall accuracy and higher specificity than FT. In active CD, FT, and SUA were significantly lower in patients with anemia. FT was significantly lower in patients treated with corticosteroids. Conclusions: IBD patients, regardless the disease phenotype, have systemic thiol stress, depleted total antioxidant capacity, and reduced concentrations of uric acid, reflecting, to various degrees, clinical and local disease activity as well as presence of anaemia, the most common extraintestinal manifestation of IBD. Evaluation of systemic total antioxidant status may be useful in noninvasive assessment of mucosal healing. Our findings on thiol stress provide an additional aspect on adverse effects of corticosteroids therapy.

Emerging Role of Purine Metabolizing Enzymes in Brain Function and Tumors

The growing evidence of the involvement of purine compounds in signaling, of nucleotide imbalance in tumorigenesis, the discovery of purinosome and its regulation, cast new light on purine metabolism, indicating that well known biochemical pathways may still surprise. Adenosine deaminase is important not only to preserve functionality of immune system but also to ensure a correct development and function of central nervous system, probably because its activity regulates the extracellular concentration of adenosine and therefore its function in brain. A lot of work has been done on extracellular 5′-nucleotidase and its involvement in the purinergic signaling, but also intracellular nucleotidases, which regulate the purine nucleotide homeostasis, play unexpected roles, not only in tumorigenesis but also in brain function. Hypoxanthine guanine phosphoribosyl transferase (HPRT) appears to have a role in the purinosome formation and, therefore, in the regulation of purine synthesis rate during cell cycle with implications in brain development and tumors. The final product of purine catabolism, uric acid, also plays a recently highlighted novel role. In this review, we discuss the molecular mechanisms underlying the pathological manifestations of purine dysmetabolisms, focusing on the newly described/hypothesized roles of cytosolic 5′-nucleotidase II, adenosine kinase, adenosine deaminase, HPRT, and xanthine oxidase.

AST-120 Reduces Neuroinflammation Induced by Indoxyl Sulfate in Glial Cells

Chronic kidney disease (CKD) involves multiple organ dysfunction, and the neurological complications that are often present in CKD patients support the idea of a crosstalk between the kidneys and the brain. Evidence suggests a possible role for products accumulating in these patients as uremic toxins in various CKD complications, including neurodegeneration. Indoxyl sulfate (IS), derived from tryptophan metabolism, is well-known as a uremic nephron-vascular toxin, and recent evidence suggests it also has a role in the immune response and in neurodegeneration. Inflammation has been associated with neurodegenerative diseases, as well as with CKD. In this study, we demonstrated that sera of CKD patients induced a significant inflammation in astrocyte cells which was proportional to IS sera concentrations, and that the IS adsorbent, AST-120, reduced this inflammatory response. These results indicated that, among the uremic toxins accumulating in serum of CKD patients, IS significantly contributed to astrocyte inflammation. Moreover, being also chronic inflammation associated with CKD, here we reported that IS further increased inflammation and oxidative stress in primary central nervous system (CNS) cells, via Nuclear Factor-κB (NF-κB) and Aryl hydrocarbon Receptor (AhR) activation, and induced neuron death. This study is a step towards elucidating IS as a potential pharmacological target in CKD patients.

Decreased Serum Bilirubin Levels and Increased Uric Acid Levels are Associated with Ulcerative Colitis

Background

In recent years, emerging evidence has suggested that ulcerative colitis occurs as a consequence of an imbalance between oxidative stress and antioxidant capacity. The objective of this study was to investigate whether serum total bilirubin and serum uric acid levels were associated with ulcerative colitis.

Material/Methods

We conducted a retrospective case-control study which included 170 patients with ulcerative colitis and 200 healthy individuals. Concentrations of serum total bilirubin and serum uric acid were obtained from biochemical information and segregated into quartiles. Logistic regression analysis was adopted to explore the correlations between levels of the 2 biochemical markers and the risk of ulcerative colitis.

Results

Compared with healthy controls, patients with ulcerative colitis exhibited lower levels of serum bilirubin (9.30 umol/L versus 12.49 umol/L respectively, P<0.001). Multivariate logistic regression showed that the lowest quartile of total serum bilirubin was independently associated with the occurrence of ulcerative colitis (OR=2.56, 95%CI: 1.54–4.25, P<0.001). Similarly, ulcerative colitis patients exhibited higher concentrations of serum uric acid (338 umol/L versus 300 umol/L respectively, P=0.041). Multivariate logistic regression showed that the highest quartile of serum uric acid was independently associated with ulcerative colitis risk (OR=1.20, 95%CI: 1.05–1.77, P=0.045). Furthermore, a negative association was observed between serum total bilirubin and serum uric acid in patients with ulcerative colitis.

Conclusion

Lower levels of serum total bilirubin and higher levels of serum uric acid are associated with ulcerative colitis patients compared to healthy controls.

Dietary Probiotic Effect of Lactococcus lactis WFLU12 on Low-Molecular-Weight Metabolites and Growth of Olive Flounder (Paralichythys olivaceus)

The use of probiotics is considered an attractive biocontrol method. It is effective in growth promotion in aquaculture. However, the mode of action of probiotics in fish in terms of growth promotion remains unclear. The objective of the present study was to investigate growth promotion effect of dietary administration of host-derived probiotics, Lactococcus lactis WFLU12, on olive flounder compared to control group fed with basal diet by analyzing their intestinal and serum metabolome using capillary electrophoresis mass spectrometry with time-of flight (CE-TOFMS). Results of CE-TOFMS revealed that 53 out of 200 metabolites from intestinal luminal metabolome and 5 out of 171 metabolites from serum metabolome, respectively, were present in significantly higher concentrations in the probiotic-fed group than those in the control group. Concentrations of metabolites such as citrulline, tricarboxylic acid cycle (TCA) intermediates, short chain fatty acids, vitamins, and taurine were significantly higher in the probiotic-fed group than those in the control group. The probiotic strain WFLU12 also possesses genes encoding enzymes to help produce these metabolites. Therefore, it is highly likely that these increased metabolites linked to growth promotion in olive flounder are due to supplementation of the probiotic strain. To the best of our knowledge, this is the first study to show that dietary probiotics can greatly influence metabolome in fish. Findings of the present study may reveal important implications for maximizing the efficiency of using dietary additives to optimize fish health and growth.

Characteristics of hyperuricemia in older adults in China and possible associations with sarcopenia

OBJECTIVE

This cross-sectional study aimed to investigate the characteristics and epidemiology of hyperuricemia in older adults in China and evaluate possible associations between hyperuricemia and sarcopenia.

METHODS

Three hundred and eighty-eight study subjects (>60 years old) meeting the inclusion criteria received blood tests and standardized examinations for bone mineral density, muscle mass, muscle strength, and physical performance. Data including demographic and clinical characteristic and comorbidity were also collected. All data were analyzed retrospectively.

RESULTS

In the study population, higher uric acid levels were significantly correlated with higher muscle mass, grip strength, and bone density, but were unrelated to physical performance. When uric acid levels were separated into quartiles and the population was divided by sex, the correlation of uric acid to muscle mass was retained in some quartiles for both men and women, and the correlation to handgrip was only retained for one quartile for men. The correlation to bone density was retained in women in all analyses.

CONCLUSION

In the population as a whole, higher uric acid levels were significantly correlated with higher muscle mass, grip strength, and bone density, but had no relationship to physical performance. Differences between men and women in these relationships need to be studied further.

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.

Uric acid and allopurinol aggravate absence epileptic activity in Wistar Albino Glaxo Rijswijk rats

Uric acid has a role in several physiological and pathophysiological processes. For example, uric acid may facilitate seizure generalization while reducing uric acid level may evoke anticonvulsant/antiepileptic effects. Allopurinol blocks the activity of xanthine oxidase, by which allopurinol inhibits catabolism of hypoxanthine to xanthine and uric acid and, as a consequence, decreases the level of uric acid. Although the modulation of serum uric acid level is a widely used strategy in the treatment of certain diseases, our knowledge regarding the effects of uric acid on epileptic activity is far from complete. Thus, the main aim of this study was the investigation of the effect of uric acid on absence epileptic seizures (spike-wave discharges: SWDs) in a model of human absence epilepsy, the Wistar Albino Glaxo/Rijswijk (WAG/Rij) rat. We investigated the influence of intraperitoneally (i.p.) injected uric acid (100 mg/kg and 200 mg/kg), allopurinol (50 mg/kg and 100 mg/kg), a cyclooxygenase 1 and 2 (COX-1 and COX-2) inhibitor indomethacin (10 mg/kg) and inosine (500 mg/kg) alone and the combined application of allopurinol (50 mg/kg) with uric acid (100 mg/kg) or inosine (500 mg/kg) as well as indomethacin (10 mg/kg) with uric acid (100 mg/kg) and inosine (500 mg/kg) with uric acid (100 mg/kg) on absence epileptic activity. We demonstrated that both uric acid and allopurinol alone significantly increased the number of SWDs whereas indomethacin abolished the uric acid-evoked increase in SWD number. Our results suggest that uric acid and allopurinol have proepileptic effects in WAG/Rij rats.

Association between serum uric acid, high sensitive C-reactive protein and pro-oxidant-antioxidant balance in patients with metabolic syndrome

There is persuasive evidence that oxidative stress and inflammation are features of the metabolic syndrome (MetS). We have investigated the relationship between serum pro-oxidant-antioxidant balance (PAB), serum uric acid, and high sensitive C-reactive protein (hs-CRP) in 7,208 participants from the MASHAD study cohort, who were categorized as having MetS, or not, using International Diabetes Foundation (IDF) criteria. Serum hs-CRP was measured by Polyethylene glycol (PEG)-enhanced immunoturbidimetry method using an Alycon analyzer (ABBOTT, Chicago, IL, USA). A colorimetric method was used to determine serum PAB. Serum PAB values were significantly higher in the individuals with MetS compared to those without (P < 0.001). Furthermore, there was a step-wise increase in mean serum PAB concentrations as the number of components of the MetS increased. The combination of features of MetS had different association with serum PAB and hs-CRP. Multiple linear regression analysis showed that body mass index (BMI, B = 2.04, P < 0.001), physical activity level (PAL, B = 18.728, P = 0.001), serum uric acid (B = -1.545, P = 0.003), and serum C-reactive protein (B = 0.663, P < 0.001) were associated with serum PAB in individuals with MetS. Multiple logistic regression analysis showed that serum PAB (B = 0.002, P < 0.001, CI = 1.001-1.003), serum C-reactive protein (B = 0.007, P < 0.015, CI = 1.001-1.013), and serum uric acid (B = 0.207, P < 0.001, CI = 1.186-1.277) were all significantly associated with MetS. Serum PAB was strongly associated with serum uric acid and serum hs-CRP. Moreover, serum PAB as well as serum uric acid and serum hs-CRP were independently associated with MetS. Individual features of MetS were also associated with serum hs-CRP and PAB. © 2018 BioFactors, 44(3):263-271, 2018.

Anorexia nervosa and uric acid beyond gout: An idea worth researching

Uric acid is best known for its role in gout-the most prevalent inflammatory arthritis in humans-that is also described as an unusual complication of anorexia nervosa (AN). However, beyond gout, uric acid could also be involved in the pathophysiology and psychopathology of AN, as it has many biological functions serving as a pro- and antioxidant, neuroprotector, neurostimulant, and activator of the immune response. Further, recent research suggests that uric acid could be a biomarker of mood dysfunction, personality traits, and behavioral patterns. This article discusses the hypothesis that uric acid in AN may not be a mere innocent bystander determined solely by AN behavior and its medical complications. In contrast, the relation between uric acid and AN may have evolutionary origin and may be reciprocal, where uric acid regulates some features and pathophysiological processes of AN, including weight and metabolism regulation, oxidative stress, immunity, mood, cognition, and (hyper)activity.

Dietary Potential Renal Acid Load Is Positively Associated with Serum Uric Acid and Odds of Hyperuricemia in the German Adult Population

Background

Initial interventional data indicate that a reduction in dietary acid load (e.g., by an increased consumption of alkalizing fruit and vegetables) can increase renal uric acid excretion and decrease serum uric acid (SUA).

Objective

Against this background, we examined the association between dietary potential renal acid load (PRAL) and SUA in a representative population sample.

Methods

Cross-sectional analyses were performed in 6894 participants (aged 18-79 y) of the German Health Interview and Examination Survey for Adults (DEGS1). Dietary intake was assessed with a food-frequency questionnaire. Nutritive acid load and the intake of uric acid equivalents (UAEs) were characterized by assigning PRAL and UAE values to reported food consumption. In multiple linear regression models, the associations of PRAL, UAEs, and relevant food groups with SUA were analyzed. Multiple logistic regressions were used to calculate ORs for hyperuricemia comparing lower and upper tertiles of the predictors.

Results

After adjustment for relevant confounders, PRAL (P = 0.003), alcohol (P < 0.0001), and UAE (P = 0.03) intakes were positively associated with SUA, whereas the intake of dairy products and fruit and vegetables was inversely associated (both P < 0.0001). Subgroup analyses among participants without interacting medication use confirmed these results. In addition, participants with lower PRAL had lower odds for hyperuricemia (OR: 0.60; 95% CI: 0.43, 0.83).

Conclusions

Apart from observing known dietary influences on SUA, we found in this population-based, cross-sectional study in adults that low PRAL may represent a potentially SUA-reducing dietary pattern. This highlights dietary alkalization as a possible nonpharmacologic option to influence elevated SUA concentrations.

Serum Uric Acid in Chronic Obstructive Pulmonary Disease: A Hospital Based Case Control Study

Introduction

Airway inflammation and imbalance between oxidant/anti-oxidant mechanisms are postulated to play a major role in the pathogenesis and exacerbation of Chronic Obstructive Pulmonary Disease (COPD). Previous studies on the role of serum Uric Acid (UA) in COPD subjects have been both confounding and inconclusive.

Aim

To measure the serum UA levels among COPD subjects and to correlate with different stages of the disease.

Materials and Methods

The study included 39 stable COPD subjects (21 males, 18 females; 13 smokers, 26 nonsmokers; age group; 40 to 60 years) and compared with 46 control subjects from the general population. Serum UA levels were measured by enzymatic colorimetric assay in fully automated analyser (Cobas Integra 400+, Roche, Germany) using commercially available kits from Roche. This was further correlated with duration and severity of COPD {determined as per Global Initiative for Obstructive Lung Disease (GOLD) criteria}.

Results

The mean age of COPD and control subjects was 62.97±11.30 and 48.76±12.71 years, respectively (p<0.001). COPD cases had significantly higher level of UA compared to control subjects (4.85±1.67 vs. 2.32±0.93 mg/dl, respectively, p<0.001). Female subjects with COPD had higher levels of UA compared to their male counterparts (5.15±1.89 vs. 4.59±1.45 mg/dl, respectively, p=0.3). Similar insignificant (p=0.56) trend was also observed among control subjects. Hyperuricaemia correlated significantly (p< 0.05) with advance duration (≥ 10 years) of COPD; whereas, statistically insignificant trend was observed for GOLD stage 3/4 versus stage 1/2 disease. Nonsmokers were having higher uric acid level than smokers. Alcohol intake did not affect the level of uric acid in COPD cases (p=0.79).

Conclusion

Serum uric acid is a simple, cost effective biochemical test which may be useful in risk stratification of subjects with newly diagnosed chronic obstructive pulmonary disease. Hyperuricaemia is associated with advance duration and stage of COPD.

Diet-independent relevance of serum uric acid for blood pressure in a representative population sample

A direct relationship between serum uric acid and blood pressure (BP) has been reported, but the possible confounding impact of diet on this association is unclear. The authors performed a cross-sectional analysis in the representative German Health Interview and Examination Survey for Adults (n=6788, aged 18-79 years). In adjusted regression models considering dietary factors, each 1-mg/dL higher uric acid value was associated with a 1.10-mm Hg (P=.0002) and a 0.60-mm Hg (P=.04) higher systolic BP among participants younger than 50 years and participants 50 years and older, respectively. For diastolic BP, uric acid was a significant predictor (β=0.71 mm Hg, P=.0001) among participants younger than 50 years and for participants 50 years and older without antihypertensive treatment. Adjusted odds ratios of hypertension for participants with hyperuricemia were broadly similar in younger (odds ratio, 1.71; P=.02) and older (odds ratio, 1.81; P=.0003) participants. Uric acid is a significant predictor of systolic BP and hypertension prevalence in the general adult population in Germany independently of several known dietary BP influences.

Serum uric acid levels and multiple health outcomes: umbrella review of evidence from observational studies, randomised controlled trials, and Mendelian randomisation studies

Objective To map the diverse health outcomes associated with serum uric acid (SUA) levels.Design Umbrella review.Data sources Medline, Embase, Cochrane Database of Systematic Reviews, and screening of citations and references.Eligibility criteria Systematic reviews and meta-analyses of observational studies that examined associations between SUA level and health outcomes, meta-analyses of randomised controlled trials that investigated health outcomes related to SUA lowering treatment, and Mendelian randomisation studies that explored the causal associations of SUA level with health outcomes.Results 57 articles reporting 15 systematic reviews and144 meta-analyses of observational studies (76 unique outcomes), 8 articles reporting 31 meta-analyses of randomised controlled trials (20 unique outcomes), and 36 articles reporting 107 Mendelian randomisation studies (56 unique outcomes) met the eligibility criteria. Across all three study types, 136 unique health outcomes were reported. 16 unique outcomes in meta-analyses of observational studies had P<10-6, 8 unique outcomes in meta-analyses of randomised controlled trials had P<0.001, and 4 unique outcomes in Mendelian randomisation studies had P<0.01. Large between study heterogeneity was common (80% and 45% in meta-analyses of observational studies and of randomised controlled trials, respectively). 42 (55%) meta-analyses of observational studies and 7 (35%) meta-analyses of randomised controlled trials showed evidence of small study effects or excess significance bias. No associations from meta-analyses of observational studies were classified as convincing; five associations were classified as highly suggestive (increased risk of heart failure, hypertension, impaired fasting glucose or diabetes, chronic kidney disease, coronary heart disease mortality with high SUA levels). Only one outcome from randomised controlled trials (decreased risk of nephrolithiasis recurrence with SUA lowering treatment) had P<0.001, a 95% prediction interval excluding the null, and no large heterogeneity or bias. Only one outcome from Mendelian randomisation studies (increased risk of gout with high SUA levels) presented convincing evidence. Hypertension and chronic kidney disease showed concordant evidence in meta-analyses of observational studies, and in some (but not all) meta-analyses of randomised controlled trials with respective intermediate or surrogate outcomes, but they were not statistically significant in Mendelian randomisation studies.Conclusion Despite a few hundred systematic reviews, meta-analyses, and Mendelian randomisation studies exploring 136 unique health outcomes, convincing evidence of a clear role of SUA level only exists for gout and nephrolithiasis.

Effects of a whey protein supplementation on oxidative stress, body composition and glucose metabolism among overweight people affected by diabetes mellitus or impaired fasting glucose: A pilot study

Obesity and diabetes mellitus type 2 (DM2) are characterized by chronic inflammation and oxidative stress [Donath et al. 2013] and this leads to cardiovascular diseases [Hulsmans & Holvoet 2010]. Whey proteins (WP) have antioxidant [Chitapanarux et al. 2009], anti-inflammatory [Sugawara et al. 2012] and hypoglycemic activities [Mignone et al. 2015], while data on weight, body composition [Frestedt et al. 2008; Aldrich et al. 2011] and blood pressure are conflicting [Kawase et al. 2000; Lee et al. 2007]. WP have unpleasant taste and smell [Patel 2015], but a new WP isolate (ProLYOtin®) seems to be more palatable. 40 g/die of ProLYOtin® were supplemented to overweight people (n=31) with impaired fasting glucose/DM2 for 12 weeks. Markers of antioxidant status (total antioxidant status, glutathione peroxidase, glutathione reductase, uric acid), oxidative damage (thiobarbituric acid reactive substances, advanced oxidation protein products, 8-hydroxydeoxyguanosine), inflammation (interleukin-6, high sensitive reactive protein C) and glicemic status (fasting glucose, insulin, glycated hemoglobin), anthropometric data (weight, height, waist circumference), body composition (body cell mass, fat mass), blood pressure, hand grip strength and skin autofluorescence were measured before and at the end of supplementation. Isolate palatability was evaluated. An increase in glutathione peroxidase, a decrease in uric acid and no change in glutathione reductase, total antioxidant status, oxidative damage, inflammation and glucose markers were found. Significant improvements in anthropometric parameters and fat mass were detected. There wasn't any change in blood pressure, skin autofluorescence and physical performance. Two-thirds of subjects judged the supplement positively. ProLYOtin® seems suitable for treatment of OS and overweight.