Essential hypertension, progressive renal disease, and uric acid: a pathogenetic link?

Salivary uric acid dynamics are associated with stress response hormones among African Americans in an urban sample

Acute physiological responses to psychosocial stressors are a potential pathway underlying racial disparities in stress-related illnesses. Uric acid (UA) is a potent antioxidant that has been linked to disparities in stress-related illnesses, and recent research has shown that UA is responsive to acute social stress. However, an examination of the relationships between the purinergic system and other commonly measured stress systems is lacking. Here, we measure and characterize associations of salivary uric acid (sUA) with markers of hypothalamic-pituitary-adrenal (HPA) axis activation, sympathetic-adreno-medullar (SAM) axis activation, and acute inflammation. A community sample of 103 African Americans (33 male, 70 female) completed the Trier Social Stress Test to induce social-evaluative threat. Passive drool collected before, during, and after the stressor task provided salivary reactivity measures of UA (sUA), cortisol, dehydroepiandrosterone sulfate (DHEAS), salivary alpha amylase (sAA - a surrogate marker of SAM activity) and C-reactive protein (sCRP). Multiple regressions revealed that total activation of cortisol, DHEAS, and sCRP were each positively associated with higher total activation of sUA. Additionally, DHEAS reactivity was positively associated with sUA reactivity. Relationships between HPA-axis markers and sUA were especially observed among younger and male participants. Overall, findings suggest potential coordination of stress systems with sUA in response to acute stress, which may further the contributions of biological stress processes to racial health disparities.

Uric acid and acute kidney injury in high-risk patients for developing acute kidney injury undergoing cardiac surgery: A prospective multicenter study

PURPOSE

It is unclear whether preoperative serum uric acid (SUA) elevation may play a role in the development of acute kidney injury (AKI) associated with cardiac surgery (CSA-AKI). We conducted a cohort study to evaluate the influence of preoperative hyperuricemia on AKI in patients at high risk for developing SC-AKI.

DESIGN

Multicenter prospective international cohort study.

SETTING

Fourteen university hospitals in Spain and the United Kingdom.

PARTICIPANTS

We studied 261 consecutive patients at high risk of developing CSA-AKI, according to a Cleveland score ≥ 4 points, from July to December 2017.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

AKIN criteria were used for the definition of AKI. Multivariable logistic regression models and propensity score-matched pairwise analysis were used to determine the adjusted association between preoperative hyperuricemia (≥7 mg/dL) and AKI. Elevated preoperative AUS (≥7 mg/dL) was present in 190 patients (72.8%), whereas CSA-AKI occurred in 145 patients (55.5%). In multivariable logistic regression models, hyperuricemia was not associated with a significantly increased risk of AKI (adjusted Odds Ratio [OR]: 1.58; 95% confidence interval [CI]: 0.81-3; P = .17). In propensity score-matched analysis of 140 patients, the hyperuricemia group experienced similar adjusted odds of AKI (OR 1.05, 95%CI 0.93-1.19, P = .37).

CONCLUSIONS

Hyperuricemia was not associated with an increased risk of AKI in this cohort of patients undergoing cardiac surgery at high risk of developing CSA-AKI.

Renal macrophages induce hypertension and kidney fibrosis in Angiotensin II salt mice model

The immune system is involved in hypertension development with different immune cells reported to have either pro or anti-hypertensive effects. In hypertension, immune cells have been thought to infiltrate blood pressure-regulating organs, resulting in either elevation or reduction of blood pressure. There is controversy over whether macrophages play a detrimental or beneficial role in the development of hypertension, and the few existing studies have yielded conflicting results. This study aimed to determine the effects of angiotensin II (Ang II) salt-induced hypertension on renal immune cells and to determine whether renal macrophages are involved in the induction of hypertension. Hypertension was induced by administration of Ang II and saline for two weeks. The effects of hypertension on kidney immune cells were assessed using flow cytometry. Macrophage infiltration in the kidney was assessed by immunohistochemistry and kidney fibrosis was assessed using trichrome stain and kidney real time-qPCR. Liposome encapsulated clodronate was used to deplete macrophages in C57BL/6J mice and investigate the direct role of macrophages in hypertension induction. Ang II saline mice group developed hypertension, had increased renal macrophages, and had increased expression of Acta2 and Col1a1 and kidney fibrotic areas. Macrophage depletion blunted hypertension development and reduced the expression of Acta2 and Col1a1 in the kidney and kidney fibrotic areas in Ang II saline group. The results of this study demonstrate that macrophages infiltrate the kidneys and increase kidney fibrosis in Ang II salt-induced hypertension, and depletion of macrophages suppresses the development of hypertension and decreases kidney fibrosis. This indicates that macrophages play a direct role in hypertension development. Hence macrophages have a potential to be considered as therapeutic target in hypertension management.

J-shaped Association between Serum Uric Acid Levels and the Prevalence of a Reduced Kidney Function: A Cross-sectional Study Using Japanese Health Examination Data

Objective While an association between a reduced kidney function and hyperuricemia has been reported, its association with hypouricemia is not well understood. The present study therefore investigated this association. Methods Using a large Japanese health examination dataset, we performed a multivariable logistic regression analysis to assess the association between serum uric acid (SUA) levels and a reduced kidney function. The covariates included the age, body mass index, alcohol intake, and the presence of hypertension, dyslipidemia, or diabetes. Patients This study included 227,672 patients (104,854 men; 46.1%), and the analyses were performed separately for men and women. The patients were classified into 5 groups: hypouricemia (SUA ≤2.0 mg/dL) (1st) and four other (2nd-5th) groups with SUA levels of ≤2.0, 2.1-5.1, 5.2-5.9, 6.0-6.8, ≥6.9 mg/dL in men and ≤2.0, 2.1-3.7, 3.8-4.4, 4.5-5.1, ≥5.2 mg/dL in women, respectively. Results The characteristics of the study population were as follows: men, age 55.9±14.9 years old, SUA 5.9±1.3 mg/dL, estimated glomerular filtration rate (eGFR) 80.0±17.2 mL/min/1.73 m2, and a reduced kidney function (eGFR <60.0 mL/min/1.73 m2) 9.4%; women, age 57.3±15.0 years old, SUA 4.5±1.1 mg/dL, eGFR 81.2±18.0 mL/min/1.73 m2, and a reduced kidney function 9.4%. Compared with the 2nd group, the other 4 groups groups had a significantly higher prevalence of a reduced kidney function [odds ratio (OR), 2.58; 95% confidence interval (CI), 1.64-4.06 in men; OR, 1.66; 95% CI, 1.16-2.39 in women]. Conclusion The prevalence of a reduced kidney function was high in both men and women in the hypouricemia and high-SUA groups. SUA levels and the prevalence of a reduced kidney function showed a J-shaped association.

Effect of Raphanus raphanistrum on chronic kidney disease induced by ethanol in animal model rats

Abstract The aim of this study is to investigate the effect of Raphanus raphanistrum (radish) on chronic kidney disease damage by reactive oxygen species or free radicals in animal model rats. Total of 18 rats were used in this study, divided into 3 groups and each group consist of 6 rats. Group 1 control (C), group 2 model (M) and group 3 test (T). Model and test group were treated with alcohol to produce chronic kidney disease by reactive oxygen spices for 9 weeks a dose of 1 ml. After that test group was treated with Raphanus raphanistrum juice for 4 weeks 80mg/kg body weight to determine it effect. Raphanus raphanistrum juice effect on behavior of rats through increases the locomotor activity and anxiety. The serum creatinine and uric acid level were significantly improved in T group. The reactive oxygen enzyme test shows that Super Oxide Dismutase (SOD) and Glutathione Peroxidase (GPx) was increase in T group. The Glutathione S-Transferases (GST) and Catalase (CAT) enzyme level was nearly same in C and T groups. This study concludes that compound 1,1-diphenyl-2-picrylhydrazyl found in Raphanus raphanistrum juice and possess strong antioxidant activity on Chronic kidney disease induce by ethanol through reactive oxygen species. There is need of more researches to determine the use of natural compound to treat different disease.

Comparison Between Early-Onset and Common Gout: A Systematic Literature Review

INTRODUCTION

Gout is an inflammatory, metabolic disease associated with a high comorbidity burden including cardiovascular disease, hypertension, type 2 diabetes, hyperlipidemia, renal disease, and metabolic syndrome. Approximately 9.2 million Americans have gout, making prognosis and treatment outcome predictors highly important. About 600,000 Americans have early-onset gout (EOG), generally defined as first gout attack at ≤ 40 years of age. However, data on EOG clinical features, comorbidity profile, and treatment response are sparse; this systematic literature review provides insight.

METHODS

PubMed and American College of Rheumatology (ACR)/European Alliance of the Associations for Rheumatology (EULAR) abstract archives were searched for early-onset gout, "early onset gout," and ("gout" AND "age of onset"). Duplicate, foreign language, single case report, older (before 2016), and irrelevant/data insufficient publications were excluded. The age of diagnosis categorized patients as having common gout (CG, generally > 40 years) or EOG (generally ≤ 40 years). Applicable publications were extensively reviewed/discussed among authors for inclusion/exclusion consensus.

RESULTS

A total of 283 publications were identified, with 46 (35 articles, 10 abstracts) reviewed and 17 (12 articles, 5 abstracts) ultimately included. Eleven reported clinical characteristics, with 6 EOG-CG retrospective/cross-sectional comparisons. Gout diagnosis preceded cardiometabolic comorbidity and renal comorbidities were less prevalent in EOG than CG patients. EOG patients had more severe disease (more gout flares, polyarticular disease), higher pre-therapy serum urate (SU), and worse oral urate-lowering therapy response. Genetics-focused publications reported higher incidences of dysfunctional urate transporter mutations in EOG patients.

CONCLUSIONS

This review suggests that EOG is more recalcitrant to urate-lowering therapy, is associated with urate transporter defects, and carries heavy disease burden. Therefore, early rheumatology referral and urate-lowering in a treat-to-target fashion may benefit EOG patients. Interestingly, EOG patients had fewer cardiometabolic comorbidities at diagnosis than CG patients, presenting a potential "window of opportunity" to attenuate cardiometabolic comorbidity development with SU control. Preventing gout-related suffering and health burden is particularly important in these young EOG patients who will live with gout and its sequelae for decades.

Kidney disease in adults with Prader-Willi syndrome: international cohort study and systematic literature review

Background

Prader-Willi syndrome (PWS) is a rare, complex, genetic disorder characterized by hyperphagia, hypotonia, delayed psychomotor development, low muscle mass and hypothalamic dysfunction. Adults with PWS often have obesity, hypertension and type 2 diabetes mellitus (DM2), known risk factors for cardiovascular disease (CVD) and chronic kidney disease (CKD). Early symptoms of CVD and CKD may be masked by intellectual disability and inability to express physical complaints. Furthermore, kidney diseases are often asymptomatic. Therefore, renal and cardiovascular disease might be missed in patients with PWS. Microalbuminuria is an early sign of microvascular damage in the kidneys and other vascular beds. Therefore, we screened our adult PWS cohort for the presence of elevated urinary albumin and (micro)albuminuria.

Methods

We retrospectively collected anthropometric measurements, blood pressure, medical history, medication use, urine dipstick and biochemical measurements form electronic patient files. In addition, we performed a systematic literature review on kidney disease in PWS.

Results

We included 162 adults with genetically confirmed PWS (56% male, median age 28 years), of whom 44 (27%) had DM2. None had known CVD. All subjects had normal estimated glomerular filtration rate (eGFR) according to non-PWS reference intervals. Elevated urinary albumin or (micro)albuminuria was present in 28 (18%); 19 out of 75 (25%) had an increased urinary albumin-to-creatinine ratio (UACR) and 10 out of 57 (18%) had an increased urinary protein-to-creatinine ratio. Elevated urinary albumin was present at a young age (median age 26 (IQR 24-32) years) and was associated with an significantly higher BMI and LDL-cholesterol levels and higher prevalence of DM2, hypertension and dyslipidemia than those with normal UACR (p=0.027, p=0.019, p<0.001, p<0.001, p=0.011 and respectively).

Conclusion

Upon screening, one in every five adults with PWS had increased urinary albumin or (micro)albuminuria, early signs of microvascular disease. All had normal eGFR, according to non-PWS reference intervals, and none had a formal diagnosis of CVD. As muscle mass is low in PWS, creatinine levels and eGFR may be spuriously normal. Urinalysis in this patient group can be used as a screening tool for microvascular (kidney) disease. We propose an algorithm for the detection and management of microvascular disease in adults with PWS.

Positive correlation between fatty liver index and hyperuricemia in hypertensive Chinese adults: a H-type hypertension registry study

Background

Few studies have examined the relationship between fatty liver index (FLI) and hyperuricemia (HUA). This study explores the relationship between FLI and HUA in hypertensive patients.

Methods

A total of 13,716 hypertensive subjects were included in the current study. FLI, a simple index calculated from triglycerides (TG), waist circumference (WC), body mass index (BMI), and γ -glutamyltransferase (GGT), was used as a useful predictor of nonalcoholic fatty liver disease (NAFLD) distribution. HUA was defined as serum uric acid ≥ 360 μmol/L for females and ≥ 420 μmol/L for males.

Results

The mean value of total FLI was 31.8 ± 25.1. Multiple logistic analyses revealed a significant positive correlation between FLI and HUA (OR, 1.78; 95% CI: 1.69-1.87). A subgroup analysis demonstrated that the correlation between FLI (< 30 vs. ≥ 30) and HUA was significant in both sexes (P for interaction = 0.006). Further analyses stratified by sex indicated a positive correlation between FLI and HUA prevalence among male and female subjects. However, the correlation between FLI and HUA was stronger in female subjects than in males (male: OR, 1.70; 95% CI: 1.58-1.83; female: 1.85; 95% CI: 1.73-1.98).

Conclusion

This study demonstrates a positive correlation between FLI and HUA in hypertensive adults, but stronger in females than males.

Association between hyperuricemia and acute kidney injury in critically ill patients with sepsis

BACKGROUND

Sepsis-related AKI is related to short-term mortality and poor long-term prognoses, such as chronic renal insufficiency, late development of end-stage renal disease, and long-term mortality. In this study, we aimed to investigate the association of hyperuricemia with acute kidney injury (AKI) in patients with sepsis.

METHODS

The retrospective cohort study included 634 adult sepsis patients hospitalized in the intensive care unit (ICU) of the First Affiliated Hospital of Guangxi Medical University from March 2014 to June 2020 and the ICU of the Second Affiliated Hospital of Guangxi Medical University from January 2017 to June 2020. Based on the first serum uric acid level within 24 h of admission to the ICU, patients were divided into groups with or without hyperuricemia, and the incidence of AKI within seven days of ICU admission was compared between the two groups. The univariate analysis analyzed the effect of hyperuricemia on sepsis-related AKI, and the multivariable logistic regression model analysis was used.

RESULTS

Among the 634 patients with sepsis, 163 (25.7%) developed hyperuricemia, and 324 (51.5%) developed AKI. The incidence of AKI in the groups with and without hyperuricemia was 76.7% and 42.3%, respectively, with statistically significant differences (2 = 57.469, P < 0.001). After adjusting for genders, comorbidities (coronary artery disease), organ failure assessment (SOFA) score on the day of admission, basal renal function, serum lactate, calcitonin, and mean arterial pressure, hyperuricemia was showed to be an independent risk factor for AKI in patients with sepsis (OR = 4.415, 95%CI 2.793 ~ 6.980, P < 0.001). For every 1 mg/dL increase in serum uric acid in patients with sepsis, the risk of AKI increased by 31.7% ( OR = 1.317, 95%CI 1.223 ~ 1.418, P < 0.001).

CONCLUSION

AKI is a common complication in septic patients hospitalized in the ICU, and hyperuricemia is an independent risk factor for AKI in septic patients.

The association between serum uric acid and cognitive performance in patients with ischemic stroke is modified by estimated glomerular filtration rate

The relationship between serum uric acid (SUA) and poor cognitive performance in patients with ischemic stroke is unclear. We hypothesized that the severity of renal function mediates the association between SUA and cognitive dysfunction.A retrospective analysis of 608 patients with ischemic stroke was conducted between 2016 and 2020. SUA was obtained from inpatient medical records. Global cognitive function via mini-mental state exam (MMSE) and Montreal Cognitive Assessment (MoCA) was determined one month after hospital discharge. The relationship between SUA and cognitive function was assessed by multiple linear and logistic regression analyses. Patients had a mean age of 66.6 years (SD: 4.1 years), and 52% were male. The mean SUA level was 298.6 ± 75.4 μmol/L. SUA increases were significantly positively associated with lower MMSE and MoCA scores and increased risk of moderate-severe cognitive impairment one month after stroke (p < 0.01), even after adjusting for factors including age, gender, BMI, diabetes and hypertension history. Adding a term for estimated glomerular filtration rate (eGFR) attenuated these associations such that SUA was no longer associated with cognitive performance. A fully adjusted stronger negative association between SUA and cognitive performance was found in those who had lower eGFR, with a significant eGFR interaction for MMSE (p-interaction = 0.016) and MoCA (p-interaction = 0.005). In patients with ischemic stroke, SUA showed an inverse association with cognitive function among those who have lower eGFR. The renal function might mediate the association between SUA and cognitive dysfunction.

The Role of Ketone Bodies in Various Animal Models of Kidney Disease

The kidney is a vital organ that carries out significant metabolic functions in our body. Due to the complexity of its role, the kidney is also susceptible to many disease conditions, such as acute kidney injury (AKI) and chronic kidney disease (CKD). Despite the prevalence and our increased understanding of the pathophysiology of both AKI and CKD as well as the transition of AKI to CKD, no well-established therapeutics have been applied clinically to these conditions, rendering an urgent need for a novel potential therapeutic target to be developed. In this article, we reviewed the function of ketone bodies in some common kidney conditions, such as drug-induced nephrotoxicity, ischemia and reperfusion injury, fibrosis development, diabetic kidney disease, kidney aging, hypertension, and CKD progression. All the selected studies reviewed were performed in animal models by primarily utilizing rodents, which also provide invaluable sources for future clinical applications. Ketone bodies have shown significant renal protective properties via attenuation of oxidative stress, increased expression of anti-inflammatory proteins, gene regulation, and a reduction of apoptosis of renal cells. A physiological level of ketone bodies could be achieved by fasting, a ketogenic diet, and an exogenous ketone supplement. Finally, the limitations of the long-term ketogenic diet were also discussed.

Risk factors and management of hyperuricemia after renal transplantation

Hyperuricemia (HUA) is a common complication after renal transplantation. Currently, there is no uniform consensus on factors which increase the risk for and treatment of HUA in renal transplant recipients. The purpose of this review is to summarize current and proposed risk factors and strategies to manage HUA after renal transplantation in order to assist renal function protection and prolong graft survival time.

Metabolic Syndrome Predicts Response to Neoadjuvant Chemotherapy in Breast Cancer

Purpose

This research investigated the predictive role of metabolic syndrome (MetS) in breast cancer neoadjuvant chemotherapy (BCNACT) response.

Methods

One hundred fifty primary breast cancer (BC) patients who underwent neoadjuvant chemotherapy (NACT) were included retrospectively. MetS, MetS components [waist circumference (WC), fasting blood glucose (FBG), blood pressure, triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C)], serum lipid, and other MetS-related laboratory indicators within two weeks before BCNACT were evaluated. Univariate, multivariate, and subgroup analyses were performed to determine the predictors of BCNACT pathologic complete response (pCR), clinical response, and pathologic response. The effectiveness of the model was evaluated via receiver operating characteristic curve (ROC) and calibration curve. External validation was performed through 135 patients.

Results

Univariate analysis revealed that MetS before BCNACT predicted poor BCNACT response (pCR, P = 0.003; clinical response, P = 0.033; pathologic response, P < 0.001). Multivariate analysis confirmed that MetS before BCNACT predicted lower pCR rate (P = 0.041). Subgroup analysis showed that this relationship was significant in estrogen receptor (ER) (−) (RR = 0.266; 95% CI, 0.074–0.954), human epidermal growth factor 2 (HER2) (−) (RR = 0.833; 95% CI, 0.740–0.939) and TNBC (RR = 0.833; 95% CI, 0.636–0.995). Multivariate analysis of external validation confirmed that pretreatment MetS was associated with a lower pCR rate (P = 0.003), and subgroup analysis also confirmed that this relationship had significant statistical differences in ER (−), HER2 (−), and TNBC subgroups.

Conclusions

MetS before BCNACT predicted a lower pCR rate. Intervention on MetS status, especially in ER (−), HER2 (−), and TNBC subgroups, is expected to improve the response rate of BCNACT further.

Perirenal adipose afferent nerves sustain pathological high blood pressure in rats

Hypertension is a pathological condition of persistent high blood pressure (BP) of which the underlying neural mechanisms remain obscure. Here, we show that the afferent nerves in perirenal adipose tissue (PRAT) contribute to maintain pathological high BP, without affecting physiological BP. Bilateral PRAT ablation or denervation leads to a long-term reduction of high BP in spontaneous hypertensive rats (SHR), but has no effect on normal BP in control rats. Further, gain- and loss-of-function and neuron transcriptomics studies show that augmented activities and remodeling of L1-L2 dorsal root ganglia neurons are responsible for hypertension in SHR. Moreover, we went on to show that calcitonin gene-related peptide (CGRP) is a key endogenous suppressor of hypertension that is sequestered by pro-hypertensive PRAT in SHRs. Taken together, we identify PRAT afferent nerves as a pro-hypertensive node that sustains high BP via suppressing CGRP, thereby providing a therapeutic target to tackle primary hypertension.

SGLT2 Inhibition and Uric Acid Excretion in Patients with Type 2 Diabetes and Normal Kidney Function

Background and objectives: Sodium glucose transporter 2 (SGLT2)-inhibitor-induced uric acid lowering may contribute to kidney protective effects of the drug-class in people with type 2 diabetes. This study investigates mechanisms of plasma uric acid lowering by SGLT2-inhibitors in people with type 2 diabetes with a focus on urate transporter (URAT)1. Methods: We conducted an analysis of two randomized, clinical trials. First, in the Renoprotective Effects of Dapagliflozin in Type 2 Diabetes (RED) study, 44 people with type 2 diabetes were randomized to dapagliflozin or gliclazide for 12 weeks. Plasma uric acid, fractional uric acid excretion and hemodynamic kidney function were measured in the fasted state and during clamped eu- or hyperglycemia. Second, in the Uric Acid Excretion study (UREX) study, 10 people with type 2 diabetes received 1-week empagliflozin, benzbromarone and their combination in a cross-over design and effects on plasma uric acid, fractional uric acid excretion and 24-hr uric acid excretion were measured. Results: In the RED study, compared to the fasted state (5.3±1.1mg/dL), acute hyperinsulinemia and hyperglycemia significantly reduced plasma uric acid by 0.2±0.3 and 0.4±0.3 mg/dL (both p<0.001), while increasing fractional uric acid excretion (by 3.2±3.1% and 8.9±4.5% respectively (both p<0.001). Dapagliflozin reduced plasma uric acid by 0.8±0.8mg/dL, 1.0±1.0mg/dL and by 0.8±0.7mg/dL during fasting, hyperinsulinemic-euglycemic and hyperglycemic conditions (p<0.001), whereas fractional uric acid excretion in 24-hr urine increased by 3.0±2.1% (p<0.001) and 2.6±4.5% during hyperinsulinemic-euglycemic conditions (p=0.003). Fractional uric acid excretion strongly correlated to fractional glucose excretion (r= 0.35, p=0.02). In the UREX study, empagliflozin and benzbromarone both significantly reduced plasma uric acid and increased fractional uric acid excretion. Effects of combination therapy did not differ from benzbromarone monotherapy. Conclusion: In conclusion, SGLT2-inhibitors induce uric acid excretion, which is strongly linked to urinary glucose excretion and which is attenuated during concomitant pharmacological blockade of URAT1.

Impacts of Road Deicing Application on Sodium and Chloride Concentrations in Philadelphia Region Drinking Water

Historical application of roadway deicing agents (e.g., road salt and brines) has led to an increase in sodium and chloride concentrations in surface water over time. Numerous studies have explored the impacts of road salt on freshwater aquatic organisms such as amphibians and benthic macroinvertebrates; however, the public health risk associated with consuming drinking water with elevated sodium has been largely unexplored in the literature. Yet, sodium ingestion, primarily through diet, has been linked to adverse human health conditions, such as hypertension. This study documents weekly sodium and chloride concentrations in municipal tap water from three municipalities within the Philadelphia metropolitan area during winter 2018-2019 (November through March). A late winter peak in sodium and chloride concentrations was observed for all three municipalities immediately following successive snow events coupled with daily high temperatures above 0°C. Among municipalities, mean and peak sodium and chloride concentrations were associated with relatively higher development in upstream areas. Observed sodium concentrations ranged from 1 to 6.4x the USEPA recommended guideline of 20 mg/L for individuals restricted to a total sodium intake of 500 mg/day. Additionally, the contribution of sodium ingestion from water consumption to the recommended daily sodium intake limits for adults ranged from 3.5% to 18.8% for non-restricted and 4.2%-33.3% for "low salt" (i.e., <1,500 mg/day) diets, respectively. The study results coupled with a records review for 40 U.S. municipalities in snow affected regions indicate the need for real-time communication between water utilities and the general public regarding sodium exposure risk during winter months.

Excess comorbidities in gout: the causal paradigm and pleiotropic approaches to care

Gout is a common hyperuricaemic metabolic condition that leads to painful inflammatory arthritis and a high comorbidity burden, especially cardiometabolic-renal (CMR) conditions, including hypertension, myocardial infarction, stroke, obesity, hyperlipidaemia, type 2 diabetes mellitus and chronic kidney disease. Substantial advances have been made in our understanding of the excess CMR burden in gout, ranging from pathogenesis underlying excess CMR comorbidities, inferring causal relationships from Mendelian randomization studies, and potentially discovering urate crystals in coronary arteries using advanced imaging, to clinical trials and observational studies. Despite many studies finding an independent association between blood urate levels and risk of incident CMR events, Mendelian randomization studies have largely found that serum urate is not causal for CMR end points or intermediate risk factors or outcomes (such as kidney function, adiposity, metabolic syndrome, glycaemic traits or blood lipid concentrations). Although limited, randomized controlled trials to date in adults without gout support this conclusion. If imaging studies suggesting that monosodium urate crystals are deposited in coronary plaques in patients with gout are confirmed, it is possible that these crystals might have a role in the inflammatory pathogenesis of increased cardiovascular risk in patients with gout; removing monosodium urate crystals or blocking the inflammatory pathway could reduce this excess risk. Accordingly, data for CMR outcomes with these urate-lowering or anti-inflammatory therapies in patients with gout are needed. In the meantime, highly pleiotropic CMR and urate-lowering benefits of sodium-glucose cotransporter 2 (SGLT2) inhibitors and key lifestyle measures could play an important role in comorbidity care, in conjunction with effective gout care based on target serum urate concentrations according to the latest guidelines.

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

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

The association between uric acid and erectile dysfunction: A systematic review and Meta-analysis

The main purpose of this systematic review and meta-analysis was to explore the association between uric acid (UA) and erectile dysfunction (ED). Databases including PubMed, Cochrane Library and Web of Science were retrieved to identify studies published in English up to 31 June 2021. We preregistered this meta-analysis in the PROSPERO (registration number CRD42021267035). Two independent authors extracted the relevant data from all enrolled articles. We evaluated the quality of enrolled studies using the Newcastle-Ottawa Scale (NOS). The standardized mean difference (SMD), as well as the corresponding 95% confidence intervals (95% CIs), was used to assess the difference between ED patients and healthy subjects. A total of five studies were enrolled for our meta-analysis to explore the association of UA with ED. The pooled SMD of the UA level difference between ED patients and healthy subjects was 0.42 (95% CI:0.09, 0.74, p < 0.001). There were no individual data that significantly influenced the pooled SMDs in the sensitivity analysis. There was no evidence of publication bias. This novel meta-analysis confirmed that UA was an independent risk factor for ED, which suggested that the erectile function of patients with elevated uric acid should be evaluated by clinicians.

Soluble expression of bioactive recombinant porcine-human chimeric uricase mutant employing MBP-SUMO fusion system

Urate oxidase is a promising biological medicine for hyperuricemia treatment, but immunogenicity obstructs the development of its clinical application. The recombinant porcine-human chimeric uricase mutant named dHU-wPU is a humanized chimeric uricase based on wild porcine uricase (wPU), which can effectively reduce the limitation of potential immunogenicity with a high homology (92.76%) to deduced human uricase (dHU). Unfortunately, the insoluble expression form of dHU-wPU in E. coli increases the difficulty of production. In this study, we described a more convenient method to efficiently obtain recombinant dHU-wPU protein from E. coli. Combination small ubiquitin-related modifier protein (SUMO) and maltose-binding protein (MBP) was employed to achieve the soluble expression of dHU-wPU. MBP-SUMO-dHU-wPU fusion protein was not only overexpressed in a soluble form, but also showed high purification and cleavage efficiency. Subsequently, we optimized the culture conditions of shake flasks and expanded the production of MBP-SUMO-dHU-wPU fusion protein in a 5 L bioreactor. Finally, about 15 mg of recombinant dHU-wPU was obtained from 1 L M9 fermentation culture by using two-step affinity chromatography, with a SDS-PAGE purity over 90%. In vitro activity analysis showed that dHU-wPU had better ability to catalyze uric acid than wPU.

Synergistic association of hyperuricemia and hyperhomocysteinemia with chronic kidney disease in middle-aged adults and the elderly population

Chronic kidney disease (CKD) is a major global public health issue. Both hyperhomocysteinemia (HHcy) and hyperuricemia are independent risk factors for CKD. In this study, we evaluated the association of HHcy and hyperuricemia with CKD in the middle-aged and elderly populations in Taiwan.In this cross-sectional study, we collected the data of 5910 patients aged ≥50 years after their self-paid health examination at a single medical center. Homocysteine (Hcy) levels were divided into 4 quartiles (Q1, <8.2; Q2, 8.2-9.8; Q3, 9.9-11.7; and Q4, >11.7 μM/L). Renal function was determined using the Chronic Kidney Disease Epidemiology Collaboration equation. Patients were considered to have CKD if their estimated glomerular filtration rate was < 60 mL/min/1.73 m2.The prevalence of CKD significantly increased with the quartiles of uric acid (UA) and Hcy. In multiple logistic regression analysis, the odds ratios (ORs) of CKD increased with the quartiles of Hcy, independent of UA. There was 22.9 in Q4 in the normal serum UA group and 18.3 in the hyperuricemia group compared with Q1 of Hcy. Both hyperuricemia (OR 2.9) and Q4 of Hcy (OR 8.1) were significant independent risk factors for CKD. Furthermore, hyperuricemia and HHcy had significant synergistic association (synergy index, 1.7) with CKD.The ORs of CKD increased with the quartiles of Hcy, independent of hyperuricemia. Hyperuricemia and HHcy had synergistic association with CKD.

Erectile dysfunction in hyperuricemia: A prevalence meta-analysis and meta-regression study

BACKGROUND

Whether and to what extent an association exists between hyperuricemia and erectile dysfunction (ED) has not yet been fully determined.

OBJECTIVE

To define pooled prevalence estimates and correlates of erectile dysfunction in men with hyperuricemic disorders.

MATERIALS AND METHODS

A thorough search of Medline, Scopus, and Cochrane Library databases was performed. Data were combined using random-effects models and the between-study heterogeneity was assessed by Cochrane's Q and I² tests. A funnel plot was used to assess publication bias.

RESULTS

Overall, 8 studies included gave information about 85,406 hyperuricemic men, of whom 5023 complained of erectile dysfunction, resulting in a pooled erectile dysfunction prevalence estimate of 33% (95% Confidence Interval: 13-52%; I² = 99.9%). The funnel plot suggested the presence of a publication bias. At the meta-regression analyses, among the available covariates that could affect estimates, only type 2 diabetes mellitus was significantly associated with a higher prevalence of erectile dysfunction (β = 0.08; 95% Confidence Interval: 0.01, 0.15, p = 0.025). At the sub-group analysis, the pooled erectile dysfunction prevalence decreased to 4% (95% Confidence Interval: 0%-8%) when only the largest studies with the lowest prevalence of type 2 diabetes mellitus were included and increased up to 50% (95% Confidence Interval: 17%-84%) when the analysis was restricted to studies enrolling smaller series with higher prevalence of type 2 diabetes mellitus.

CONCLUSIONS

A not negligible proportion of men with hyperuricemia can complain of erectile dysfunction. While a pathogenetic contribution of circulating uric acid in endothelial dysfunction cannot be ruled out, the evidence of a stronger association between hyperuricemia and erectile dysfunction in type 2 diabetes mellitus points to hyperuricemia as a marker of systemic dysmetabolic disorders adversely affecting erectile function.

Sex-Specific Association of Uric Acid and Kidney Function Decline in Taiwan

An elevated serum urate concentration is associated with kidney damage. Men’s uric acid levels are usually higher than women’s. However, postmenopausal women have a higher risk of gout than men, and comorbidities are also higher than in men. This study examined the sex differences in the relationship between hyperuricemia and renal progression in early chronic kidney disease (CKD) and non-CKD, and further examined the incidence of CKD in non-CKD populations among patients over 50 years of age. We analyzed 1856 women and 1852 men participating in the epidemiology and risk factors surveillance of the CKD database. Women showed a significantly higher risk of renal progression and CKD than men within the hyperuricemia group. After adjusting covariates, women, but not men resulted in an hazard ratio (HR) for developing renal progression (HR = 1.12; 95% CI 1.01–1.24 in women and HR = 1.03; 95% CI 0.93–1.13 in men) and CKD (HR = 1.11; 95% CI 1.01–1.22 in women and HR = 0.95; 95% CI 0.85–1.05 in men) for each 1 mg/dL increase in serum urate levels. The association between serum urate levels and renal progression was stronger in women. Given the prevalence and impact of kidney disease, factors that impede optimal renal function management in women and men must be identified to provide tailored treatment recommendations.

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

AIMS

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

MATERIALS AND METHODS

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

KEY FINDINGS

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

SIGNIFICANCE

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

Impact of gut microbiota: How it could play roles beyond the digestive system on development of cardiovascular and renal diseases

In recent years, a significant interest in gut microbiota-host crosstalk has increased due to the involvement of gut bacteria on host health and diseases. Gut dysbiosis, a change in the gut microbiota composition alters host-microbiota interactions and induces gut immune dysregulation that have been associated with pathogenesis of several diseases, including cardiovascular diseases (CVD) and chronic kidney diseases (CKD). Gut microbiota affect the host, mainly through the immunological and metabolism-dependent and metabolism-independent pathways. In addition to these, the production of trimethylamine (TMA)/trimethylamine N-oxide (TMAO), uremic toxins and lipopolysaccharides (LPS) by gut microbiota are involved in the pathogenesis of CVD and CKD. Given the current approaches and challenges that can reshape the bacterial composition by restoring the balance between host and microbiota. In this review, we discuss the complex interplay between the gut microbiota, and the heart and the kidney, and explain the gut-cardiovascular axis and gut-kidney axis on the development and progression of cardiovascular diseases and chronic kidney diseases. In addition, we discuss the interplay between gut and kidney on hypertension or cardiovascular pathology.

Vitamin D deficiency is not associated with increased oxidative stress in chronic kidney disease pre-dialysis patients

INTRODUCTION

The progressive decline in 25-hydroxyvitamin D [25(OH)D] in chronic kidney disease (CKD) limits the kidney ability of synthesizing the vitamin. Vitamin D deficiency as defined by KDIGO (25(OH)D <20 ng/mL) is prevalent in CKD patients and associated to oxidative stress (OS). We studied a possible association between vitamin D deficiency and OS in pre-dialysis patients.

METHODS

A cross-sectional study with 206 CKD patients was carried out. Laboratory tests for 25(OH)D, 1,25(OH)2D, inflammatory markers, and OS were added to routine tests including creatinine, albumin, calcium, phosphorus, alkaline phosphatase, iPTH, glucose, hemoglobin, uric acid, total cholesterol, LDL, HDL, and triglycerides.

RESULTS

Vitamin D deficiency was present in 55 CKD patients and normal vitamin D levels were seen in 149 patients. There was a significant association between vitamin D and estimated glomerular filtration rate (eGRF). Homocysteine levels were best predicted by eGRF, sex, and age; high sensitivity C-reactive protein (hsCRP) by staging and BMI; nitric oxide metabolites (NOx) were increased in late disease; leptin was influenced by BMI and higher in women than man; and adiponectin levels were higher in women.

CONCLUSIONS

OS biomarkers were not correlated with vitamin D deficiency but increased NOx were seen in stages 4-5 CKD patients. Even though a relatively large number of CKD patients was included and a broad number of OS and inflammatory biomarkers were used in this studied we failed to find an association between vitamin D levels and eGRF. More studies are needed to evaluate the influence of vitamin D status in OS in pre-dialysis CKD patients.

Oxidative stress mitigation by antioxidants - An overview on their chemistry and influences on health status

The present review paper focuses on the chemistry of oxidative stress mitigation by antioxidants. Oxidative stress is understood as a lack of balance between the pro-oxidant and the antioxidant species. Reactive oxygen species in limited amounts are necessary for cell homeostasis and redox signaling. Excessive reactive oxygenated/nitrogenated species production, which counteracts the organism's defense systems, is known as oxidative stress. Sustained attack of endogenous and exogenous ROS results in conformational and oxidative alterations in key biomolecules. Chronic oxidative stress is associated with oxidative modifications occurring in key biomolecules: lipid peroxidation, protein carbonylation, carbonyl (aldehyde/ketone) adduct formation, nitration, sulfoxidation, DNA impairment such strand breaks or nucleobase oxidation. Oxidative stress is tightly linked to the development of cancer, diabetes, neurodegeneration, cardiovascular diseases, rheumatoid arthritis, kidney disease, eye disease. The deleterious action of reactive oxygenated species and their role in the onset and progression of pathologies are discussed. The results of oxidative attack become themselves sources of oxidative stress, becoming part of a vicious cycle that amplifies oxidative impairment. The term antioxidant refers to a compound that is able to impede or retard oxidation, acting at a lower concentration compared to that of the protected substrate. Antioxidant intervention against the radicalic lipid peroxidation can involve different mechanisms. Chain breaking antioxidants are called primary antioxidants, acting by scavenging radical species, converting them into more stable radicals or non-radical species. Secondary antioxidants quench singlet oxygen, decompose peroxides, chelate prooxidative metal ions, inhibit oxidative enzymes. Moreover, four reactivity-based lines of defense have been identified: preventative antioxidants, radical scavengers, repair antioxidants, and those relying on adaptation mechanisms. The specific mechanism of a series of endogenous and exogenous antioxidants in particular aspects of oxidative stress, is detailed. The final section resumes critical conclusions regarding antioxidant supplementation.

Uric acid and risk of diabetic kidney disease

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease (ESKD) in the Western world. Better control of glycemia and blood pressure, including renin-angiotensin system blockade (RASB), appear to have slowed DKD progression rate but have been unable to substantially decrease the annual incidence of new cases of DKD related ESKD. Thus, new treatment targets are needed. Higher levels of serum uric acid (SUA) have been associated with increased risk and progression of DKD in persons with types 1 (T1D) and 2 (T2D) diabetes and of chronic kidney disease (CKD) in general. This review presents the epidemiological, clinical, and clinical trial evidence regarding the hypothesis that SUA reduction could slow progression of DKD and/or CKD in general.

Biological Evaluation of Golden Delicious Apples Exposure to UV Lights in Rats

BACKGROUND AND OBJECTIVE

Anthocyanin is responsible for the red color of apple. Ultraviolet light plays a key role in activating the genes responsible for anthocyanin biosynthesis. However, the most important concern is using UV light irradiation on fruit to increase anthocyanins level and its nutritional quality. In this study, the accumulation of anthocyanin in green apple using UV-B and UV-C was investigated and its biological influence was evaluated in rats.

MATERIAL AND METHOD

Green Golden delicious apples were irradiated with doses of UV-C and UV-B light for a period of 3 h/day each for 3 days. Two Groups of rats were fed on balanced diet or balanced diet supplemented with 10% apple exposure to UV (AP-UV) for a month.

RESULTS

The HPTLC and spectrophotometric determination of anthocyanin revealed that color development was significantly increased by 90% in treated apple compared to the control apples. Histological difference was observed between the 2 groups. Plasma levels of uric acid, the activity of transaminases (ALT and AST) as well as malondialdehyde (MDA) were significantly elevated in AP-UV rats. Plasma total cholesterol, triglycerides and creatinine level did not differ among the 2 groups. Liver MDA and catalase levels were eminent in AP-UV rats compared to control. Gene expression of selected inflammatory cytokines (TNF-α, IL-6 and IL-1β) was significantly up-regulated in liver of AP-UV rats in comparison to control rats.

CONCLUSION

The result revealed that there is a health-hazard linked to feeding rats on diet containing irradiated-apple with UV-B and UV-C, which represented by body weight reduction, inflammation development, liver function and oxidative stress elevation.

Fructose and Uric Acid: Major Mediators of Cardiovascular Disease Risk Starting at Pediatric Age

Recently, there has been a growing interest in epidemiological and clinical studies supporting a pathogenetic role of fructose in cardio-metabolic diseases, especially in children and adolescents. In the present review, we summarize experimental data on the potential biological mechanisms linking fructose and uric acid in the development of insulin resistance, metabolic syndrome, obesity, diabetes, hypertension, non-alcoholic fatty liver disease and chronic renal disease, thereby contributing to an increase in cardiovascular risk at pediatric age.

Uric acid and hypertension: a focused review and practical recommendations

: Uric acid levels are higher in humans than in other mammals. Best known as an extracellular antioxidant, uric acid also increases salt sensitivity, fat storage, and lipogenesis. Xanthine oxidase-related oxidative stress may also induce endothelial dysfunction and renal vasoconstriction. Renal structure abnormalities contribute to salt-sensitive and uric acid-independent hypertension. Maternal hyperuricemia during pregnancy and hyperuricemia early in life are likewise independent risk factors for hypertension. Genetic polymorphism is potentially involved in the activity of xanthine oxidoreductase, but further studies are needed. Xanthine oxidase inhibition consistently decreases blood pressure in younger hypertensive patients, albeit modestly. Hyperuricemia affects one out of five adults as a result of the Western diet, insulin resistance, and renal dysfunction. This review advocates lifestyle changes to maintain uric acid levels within the normal range in young (pre)hypertensive individuals or normotensives with a family history of hypertension, metabolic disorders, or obesity; moreover, antihypertensive medications that increase uric acid levels should be avoided.

1,3-Butanediol attenuates hypertension and suppresses kidney injury in female rats

Thirty-seven million people in the United States are estimated to have chronic kidney disease (CKD). Hypertension (HTN) is the second leading risk factor for developing kidney disease. A recent study reported that increasing levels of β-hydroxybutyrate levels by administration of its precursor, 1,3-butanediol, decreased salt-induced HTN in male Dahl salt-sensitive (S) rats. The effect of 1,3-butanediol on hypertensive kidney disease in female rats or the absence of high salt has not been investigated. This study tested the hypothesis that 1,3-butanediol attenuates HTN and the progression of CKD in female S-SHR(11) rats. The S-SHR(11) strain is a congenic rat strain generated from genetic modification of the Dahl S rat, previously characterized as a model of accelerated renal disease. Rats received 1,3-butanediol (20% via drinking water) or control for 10 wk and were maintained on a 0.3% NaCl rodent diet (n = 12-14 rats/group). Blood pressure was measured after 6 and 9 wk of treatment by tail-cuff plethysmography; after 10 wk, urine and tissues were collected. Activity of the treatment was confirmed by measuring plasma β-hydroxybutyrate levels, which were greater in the treated group. The 1,3-butanediol-treated group had lower systolic blood pressure, proteinuria, plasma creatinine, and renal fibrosis after 9 wk of treatment compared with controls. The treated group had significantly smaller spleens and increased the renal anti-inflammatory molecules interleukin-10 and granulocyte-macrophage colony-stimulating factor, suggesting reduced inflammation. The present data demonstrate that 1,3-butanediol lowers blood pressure and renal injury in female rats and could be a novel nutritional intervention for the treatment of CKD.

Uric acid in CKD: has the jury come to the verdict?

Epidemiological studies show that hyperuricemia independently predicts the development of chronic kidney disease (CKD) in individuals with normal kidney function both in the general population and in subjects with diabetes. As a matter of fact, an unfavorable role of uric acid may somewhat be harder to identify in the context of multiple risk factors and pathogenetic mechanisms typical of overt CKD such as proteinuria and high blood pressure. Although the discrepancy in clinical results could mean that urate lowering treatment does not provide a constant benefit in all patients with hyperuricemia and CKD, we believe that the inconsistency in the results from available meta-analysis is mainly due to inadequate sample size, short follow-up times and heterogeneity in study design characterizing the randomized controlled trials included in the analyses. Therefore, available data support the view that hyperuricemia has a damaging impact on kidney function, while preliminary evidence suggests that treatment of so-called asymptomatic hyperuricemia may be helpful to slow or delay the progression of chronic kidney.

Xanthine oxidoreductase activity correlates with vascular endothelial dysfunction in patients with type 1 diabetes

AIMS

Xanthine oxidoreductase (XOR) is an enzyme regulating uric acid synthesis and generation of reactive oxygen species. Several studies suggested relationship between XOR and atherosclerotic diseases; however, few previous studies have directly examined the relationship between XOR and vascular endothelial dysfunction in patients with type 1 diabetes mellitus (T1DM). The aim of this study was to evaluate the relationship between XOR activity and vascular endothelial function in patients with T1DM.

METHODS

Seventy-one patients with T1DM participated in the study and underwent assessments, including plasma XOR activity and flow-mediated dilation (FMD), to measure vascular endothelial function.

RESULTS

The natural logarithm value of XOR activity (ln-XOR) was 3.03 ± 0.99 pmol/h/mL, and FMD was 5.5% ± 2.4%. FMD was inversely and significantly correlated with ln-XOR (correlation coefficient: r = - 0.396, P < 0.001), UA (r = - 0.252, P = 0.034), and asymmetric dimethylarginine (ADMA) (r = - 0.414, P < 0.001). ln-XOR showed positive correlation with HbA1c (r = 0.292, P = 0.013), ALT (r = 0.658, P < 0.001), and ADMA (r = 0.363, P = 0.002). Stepwise multiple regression analysis showed that ln-XOR (standard partial regression coefficient: β = - 0.254, P = 0.018) was an independent explanatory variable of FMD.

CONCLUSIONS

The results of this study showed for the first time that XOR activity is associated with glycemic control in patients with T1DM and that XOR activity is associated with vascular endothelial dysfunction.

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

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

Uric Acid Level as a Predictor of Long-Term Mortality in Advanced Age Population

BACKGROUND

Hyperuricemia is associated with the development, progression and outcome of several diseases. The purpose of this study is to evaluate the serum uric acid (UA) levels as a predictor of long-term mortality in an older population (age 60 years and above).

MATERIALS AND METHODS

Patients older than 60 years who were hospitalized in the departments of geriatrics and internal medicine in Shaare Zedek Medical Center in Jerusalem during a period of 4 months (March-June 2014) were included in this observational study. Association between hyperuricemia and long-term mortality were analyzed using multiple logistic regression, Kaplan-Meier and Cox proportional hazards regressions analysis.

RESULTS

A total of 624 patients were included in our study with mean age of 77.2 ± 14.6 years. Overall, 381 patients died during the follow-up period (61.1%). Mortality rate in the hyperuricemic group (> 7 mg/dL) was higher (69.1%) than in the normouricemic group 58.4%. (P = 0.004). The median survival for hyperuricemic patients was significantly shorter compared to normouricemic patients (606 and 1018 days, respectively, P < 0.0001). High levels of UA were significantly associated with higher long-term mortality in patients with cardiovascular disease at their admission (P < 0.000).

CONCLUSIONS

Elevated levels of UA in older patients in acute settings is a predictor of long-term mortality.

Association between serum uric acid and chronic kidney disease in patients with hypertension: A multicenter nationwide cross-sectional study

INTRODUCTION

Current data on the role of hyperuricemia as a risk factor for renal progression in patients with hypertension is inconclusive. This study aimed to assess the association of uric acid and chronic kidney disease (CKD) in hypertensive patients using a nationwide patient sample.

METHODS

We conducted a nationwide cross-sectional study based on the DM/HT study of the Medical Research Network of the Consortium of Thai Medical Schools. This study evaluated adult patients with hypertension from 831 Thailand public hospitals in the year 2014. Serum uric acid (SUA) was categorized into quintiles (≤4.5, 4.6 to 5.4, 5.5 to 6.2, 6.3 to 7.4, ≥7.5 mg/dL). CKD was defined as estimated glomerular filtration rate of ≤ 60 mL/min/1.73 m² . Multivariate logistic regression was performed to assess the association between SUA and CKD using uric acid of ≤4.5 mg/dL as the reference group.

RESULTS

A total of 9776 hypertensive patients with available SUA were included in the analysis. The mean SUA was 6.1±1.8 mg/dL. The prevalence of CKD in hypertensive patients was 31.8%. SUA of 4.6 to 5.4, 5.5 to 6.2, 6.3 to 7.4, and ≥7.5 mg/dL were associated with an increased CKD with ORs of 1.57 (95% CI 1.28 to 1.92), 2.15 (95% CI 1.74 to 2.66), 3.31 (95% CI 2.72 to 4.04), and 7.11 (95% CI 5.76 to 8.78), respectively. The restricted cubic spline showed significant increased CKD prevalence when uric acid ≥4.6 mg/dL.

CONCLUSION

Higher SUA was associated with increased CKD prevalence in patients with hypertension. SUA should be monitored in hypertensive patients for CKD prevention.

Threshold Effects of Serum Uric Acid on Chronic Kidney Disease in US Women without Hypertension and Diabetes: A Cross-Sectional Study

Background: Serum uric acid (SUA) has been associated with increased risk of chronic kidney disease (CKD) in observational studies; however, data in women without hypertension and diabetes are sparse. Purpose: To examine the association between SUA and CKD among women without hypertension and diabetes. Methods: In this cross-sectional study of 6,776 US women without hypertension and diabetes from the National Health and Nutrition Examination Survey (1999–2006), we investigated the relationship between SUA and CKD using multivariable logistic regression models. Moreover, a generalized additive model and smooth curve fitting (penalized spline method) and a 2 piecewise logistic regression models were conducted to address for nonlinearity. Results: The prevalence of CKD was 8.3%. Multiple logistic analyses showed that per 1 mg/dL increase in SUA was associated with 39% increased prevalence of CKD. Analyses using restricted cubic spline confirmed that the association between SUA and CKD was nonlinear. Further, threshold and saturation effect analysis showed that the inflection point of SUA was 4.5 mg/dL. The ORs (95% CIs) were 0.84 (0.66–1.08) on the left side of inflection point and 1.87 (1.56–2.24) on the right side of inflection point, respectively. Subgroup analysis showed that the stronger association between SUA and CKD was observed in elder women with never/former smoking and higher fasting blood glucose levels (all p values for interaction <0.05). Conclusion: Our study suggested threshold effects of SUA on the prevalence of CKD among US women without hypertension and diabetes. SUA levels >4.5 mg/dL were positively and independently associated with CKD.

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

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

Uric acid variability at midlife as an independent predictor of coronary heart disease and all-cause mortality

Background

Serum uric acid (SUA) has long been associated with cardiovascular disease. Variability of serum uric acid (SUA) has seldom been examined in association with long-term morbidity and mortality. Therefore, we aimed to investigate the association between SUA variability and long-term all-cause and specific-cause mortality.

Methods

Among 10,059 men, aged 40–65, tenured civil servants and municipal employees in Israel, 8822 participants who were examined in 1963, 1965 and 1968 had assessment of diabetic and coronary morbidity status and SUA levels. We conducted analysis examining whether the standard deviations (SD) of Z-scores of SUA across study visits predicted coronary heart disease (CHD) and mortality. Hazard ratios (HR) associated with the SD of SUA-Z were calculated for stroke, CHD mortality and all-cause mortality associated with quartiles of the above variability.

Results

Multivariate analysis of 18-year CHD mortality yielded a significant association with the 1963–1968 SD of SUA-Z with age adjusted HR of CHD mortality of 0.97 (95% CI, 0.8–1.19), 1.05 (95% CI, 0.87–1.28) and 1.37 (95% CI, 1.15–1.65) for quartiles 2 to 4 respectively). The results of all-cause mortality similarly and strongly indicated increasing age-adjusted mortality risk with increasing SD of SUA-Z: HR = 1.08 (95% CI, 0.97–1.21), 1.15 (1.03–1.28) and 1.37 (1.23–1.51). No association was observed between the SD of SUA-Z and stroke mortality.

Conclusion

In this cohort of tenured male workers, with diverse occupations, higher variability of SUA measurement taken over 5 years was clearly predictive of 18-year CHD and all-cause mortality, above and beyond the SUA levels proper.

Genome-Wide Association Study of Metabolic Syndrome Reveals Primary Genetic Variants at CETP Locus in Indians

Indians, a rapidly growing population, constitute vast genetic heterogeneity to that of Western population; however they have become a sedentary population in past decades due to rapid urbanization ensuing in the amplified prevalence of metabolic syndrome (MetS). We performed a genome-wide association study (GWAS) of MetS in 10,093 Indian individuals (6,617 MetS and 3,476 controls) of Indo-European origin, that belong to our previous biorepository of The Indian Diabetes Consortium (INDICO). The study was conducted in two stages-discovery phase (N = 2,158) and replication phase (N = 7,935). We discovered two variants within/near the CETP gene-rs1800775 and rs3816117-associated with MetS at genome-wide significance level during replication phase in Indians. Additional CETP loci rs7205804, rs1532624, rs3764261, rs247617, and rs173539 also cropped up as modest signals in Indians. Haplotype association analysis revealed GCCCAGC as the strongest haplotype within the CETP locus constituting all seven CETP signals. In combined analysis, we perceived a novel and functionally relevant sub-GWAS significant locus-rs16890462 in the vicinity of SFRP1 gene. Overlaying gene regulatory data from ENCODE database revealed that single nucleotide polymorphism (SNP) rs16890462 resides in repressive chromatin in human subcutaneous adipose tissue as characterized by the enrichment of H3K27me3 and CTCF marks (repressive gene marks) and diminished H3K36me3 marks (activation gene marks). The variant displayed active DNA methylation marks in adipose tissue, suggesting its likely regulatory activity. Further, the variant also disrupts a potential binding site of a key transcription factor, NRF2, which is known for involvement in obesity and metabolic syndrome.

Uric acid and the cardio-renal effects of SGLT2 inhibitors

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

High-intensity aerobic training lowers blood pressure and modulates the renal renin-angiotensin system in spontaneously hypertensive rats

Background: This study aimed to verify the effects of high-intensity aerobic training (HIAT) on BP control and renin-angiotensin system (RAS) components in renal tissue of SHR. Ten SHRs received HIAT or control for 8-weeks. At the end of the training, the SBP showed a reduction of ~ 30mmHg (p < .01) in HIAT and increased by ~ 15 mmHg in the  control group. HIAT resulted in a higher release of nitrite, IL-6, ACE2 and ATR2. These results indicated an association between BP, NO and renal RAS.Abbreviations: JAA: writing, carried out all experimental procedures, performed statistical analysis, original draft and revised manuscript DMS: data interpretation, formal analysis, writing, editing and revised manuscript BAP: carried all experimental procedures, revised manuscritpt CPCG: carried all experimental procedures, revised manuscritpt MEN: experimental procedures, revised manuscript and data interpretation RWP: drafted and revised manuscript RCA: writing, experimental procedures, revised manuscript JP: writing, data interpretation and revised manuscript OLF: writing, original draft and revised manuscript.

The potential of N-glycosylation profiles as biomarkers for monitoring the progression of Type II diabetes mellitus towards diabetic kidney disease

Background

On a global scale, type II diabetes mellitus (T2DM) remain a major health problem and it is the driver for chronic kidney disease (CKD). Despite this association, we still do not have sufficient biomarkers to anticipate better outcomes. N-glycosylation profiles are robust biomarkers and can be used for early monitoring of the progression of T2DM towards CKD.

Methods

In this cross-sectional study, we recruited 241 T2DM patients from January to May 2016. Demographic and anthropometric data were collected, following which fasting blood samples were collected for clinical analyses. Renal function decline was determined by estimation of glomerular filtration rate (eGFR) and N-glycosylation profiles were analysed by Ultra-performance liquid chromatography (UPLC).

Results

The prevalence of undiagnosed CKD was 31.53%. Compared to men, women had a statistically significantly higher HbA1c (p = 0.031), TG (p = 0.015), HDL-c (p < 0.0001), creatinine (<0.0001), urea (p < 0.028) and uric acid (p < 0.0001). T2DM patients with undiagnosed CKD had higher serum creatinine (145.75 ± 50.83 vs 88.59 ± 19.46, p < 0.0001), higher uric acid (361.10 ± 115.37 vs 294.54 ± 97.75; p < 0.0001) and higher urea (5.17 ± 2.35 vs 3.58 ± 1.19; p < 0.0001). After performing logistic regression and adjusting for age, sex and BMI, three N-glycan peaks [OR (95%CI): (GP12 (0.05(0.01-0.54), p = 0.013)); GP16 (0.61(0.43-0.87), p = 0.006)); GP22 (0.60(0.39-0.92), p = 0.018)) were associated with renal function.

Conclusion

There was an increased prevalence of undiagnosed CKD among T2DM patients. This prevalence is the consequence of uncontrolled modifiable risk factors, which collectively may lead to end stage renal disease (ESRD). Although, the identified N-glycans could not adequately predict incident CKD, our investigation indicates the potential role of N-glycosylation in renal function and that their inclusion may improve risk stratification for CKD.