Lessons from comparative physiology: could uric acid represent a physiologic alarm signal gone awry in western society?

Sugar and Dyslipidemia: A Double-Hit, Perfect Storm

The availability of sugar has expanded over the past 50 years, due to improved industrial processes and corn subsidies, particularly in the form of sweetened beverages. This correlates with a surge in the prevalence of cardiometabolic disorders, which has brought this issue back into the spotlight for public health. In this narrative review, we focus on the role of fructose in the genesis of cardiometabolic dyslipidemia (an increase in serum triglyceride-rich lipoproteins (TRL): VLDL, chylomicrons (CM), and their remnants) bringing together the most recent data on humans, which demonstrates the crucial interaction between glucose and fructose, increasing the synthesis while decreasing the catabolism of these particles in a synergistic downward spiral. After reviewing TRL metabolism, we discuss the fundamental principles governing the metabolism of fructose in the intestine and liver and the effects of dysregulated fructolysis, in conjunction with the activation of carbohydrate-responsive element-binding protein (ChREBP) by glucose and the resulting crosstalk. The first byproduct of fructose catabolism, fructose-1-P, is highlighted for its function as a signaling molecule that promotes fat synthesis. We emphasize the role of fructose/glucose interaction in the liver, which enhances de novo lipogenesis, triglyceride (TG) synthesis, and VLDL production. In addition, we draw attention to current research that demonstrates how fructose affects the activity of lipoprotein lipase by increasing the concentration of inhibitors such as apolipoprotein CIII (apoCIII) and angiopoietin-like protein 3 (ANGPTL3), which reduce the catabolism of VLDL and chylomicrons and cause the building up of their atherogenic remnants. The end outcome is a dual, synergistic, and harmful action that encourages atherogenesis. Thus, considering the growing concerns regarding the connection between sugar consumption and cardiometabolic disease, current research strongly supports the actions of public health organizations aimed at reducing sugar intake, including dietary guidance addressing "safe" limits for sugar consumption.

Antioxidative Effects of Black Currant and Cornelian Cherry Juices in Different Tissues of an Experimental Model of Metabolic Syndrome in Rats

A Western-style diet, rich in fat and simple sugars, is the main risk factor for a significant number of chronic diseases and disorders, as well as for a progression of metabolic syndrome (MetS). One of the key mechanisms involved in MetS development is increased oxidative stress caused by the accumulation of body fat. Some dietary polyphenols have shown a protective role in preventing oxidative-stress-induced damage. We investigated the difference in the oxidative response of plasma, liver, and visceral adipose tissue in rats fed with a high-fat high-fructose (HFF) diet for ten weeks, and the effectiveness of polyphenol-rich juices (black currant (BC) and cornelian cherry (CC)) in HFF-diet-induced oxidative stress prevention. The most prominent impact of the HFF diet on redox parameters was recorded in the liver, whereas adipose tissue showed the most potent protection mechanisms against oxidative stress. Consumption of both juices decreased advanced oxidation protein product (AOPP) level in plasma, increased paraoxonase1 (PON1) activity in the liver, and significantly decreased total oxidative status (TOS) in adipose tissue. BC exerted stronger antioxidative potential than CC and decreased the superoxide anion radical (O₂^•-) level in the liver. It also reduced TOS, total antioxidative status (TAS), and malondialdehyde (MDA) concentration in adipose tissue. The multiple linear regression analysis has shown that the best predictors of MetS development, estimated through the increase in visceral adiposity, were superoxide dismutase (SOD), AOPP, TOS, and TAS. The consumption of polyphenol-rich juices may provide a convenient approach for the systemic reduction of oxidative stress parameters.

Dysuricemia-A New Concept Encompassing Hyperuricemia and Hypouricemia

The importance of uric acid, the final metabolite of purines excreted by the kidneys and intestines, was not previously recognized, except for its role in forming crystals in the joints and causing gout. However, recent evidence implies that uric acid is not a biologically inactive substance and may exert a wide range of effects, including antioxidant, neurostimulatory, proinflammatory, and innate immune activities. Notably, uric acid has two contradictory properties: antioxidant and oxidative ones. In this review, we present the concept of "dysuricemia", a condition in which deviation from the appropriate range of uric acid in the living body results in disease. This concept encompasses both hyperuricemia and hypouricemia. This review draws comparisons between the biologically biphasic positive and negative effects of uric acid and discusses the impact of such effects on various diseases.

Diverse functions associate with non-coding polymorphisms shared between humans and chimpanzees

Background

Long-term balancing selection (LTBS) can maintain allelic variation at a locus over millions of years and through speciation events. Variants shared between species in the state of identity-by-descent, hereafter “trans-species polymorphisms”, can result from LTBS, often due to host–pathogen interactions. For instance, the major histocompatibility complex (MHC) locus contains TSPs present across primates. Several hundred candidate LTBS regions have been identified in humans and chimpanzees; however, because many are in non-protein-coding regions of the genome, the functions and potential adaptive roles for most remain unknown.

Results

We integrated diverse genomic annotations to explore the functions of 60 previously identified regions with multiple shared polymorphisms (SPs) between humans and chimpanzees, including 19 with strong evidence of LTBS. We analyzed genome-wide functional assays, expression quantitative trait loci (eQTL), genome-wide association studies (GWAS), and phenome-wide association studies (PheWAS) for all the regions. We identify functional annotations for 59 regions, including 58 with evidence of gene regulatory function from GTEx or functional genomics data and 19 with evidence of trait association from GWAS or PheWAS. As expected, the SPs associate in humans with many immune system phenotypes, including response to pathogens, but we also find associations with a range of other phenotypes, including body size, alcohol intake, cognitive performance, risk-taking behavior, and urate levels.

Conclusions

The diversity of traits associated with non-coding regions with multiple SPs support previous hypotheses that functions beyond the immune system are likely subject to LTBS. Furthermore, several of these trait associations provide support and candidate genetic loci for previous hypothesis about behavioral diversity in human and chimpanzee populations, such as the importance of variation in risk sensitivity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12862-022-02020-x.

Fructose Intake, Hypertension and Cardiometabolic Risk Factors in Children and Adolescents: From Pathophysiology to Clinical Aspects. A Narrative Review

Arterial hypertension, dyslipidemia, alterations in glucose metabolism and fatty liver, either alone or in association, are frequently observed in obese children and may seriously jeopardize their health. For obesity to develop, an excessive intake of energy-bearing macronutrients is required; however, ample evidence suggests that fructose may promote the development of obesity and/or metabolic alterations, independently of its energy intake. Fructose consumption is particularly high among children, because they do not have the perception, and more importantly, neither do their parents, that high fructose intake is potentially dangerous. In fact, while this sugar is erroneously viewed favorably as a natural nutrient, its excessive intake can actually cause adverse cardio-metabolic alterations. Fructose induces the release of pro-inflammatory cytokines, and reduces the production of anti-atherosclerotic cytokines, such as adiponectin. Furthermore, by interacting with hunger and satiety control systems, particularly by inducing leptin resistance, it leads to increased caloric intake. Fructose, directly or through its metabolites, promotes the development of obesity, arterial hypertension, dyslipidemia, glucose intolerance and fatty liver. This review aims to highlight the mechanisms by which the early and excessive consumption of fructose may contribute to the development of a variety of cardiometabolic risk factors in children, thus representing a potential danger to their health. It will also describe the main clinical trials performed in children and adolescents that have evaluated the clinical effects of excessive intake of fructose-containing drinks and food, with particular attention to the effects on blood pressure. Finally, we will discuss the effectiveness of measures that can be taken to reduce the intake of this sugar.

Phylogenetic articulation of uric acid evolution in mammals and how it informs a therapeutic uricase

The role of uric acid during primate evolution has remained elusive ever since it was discovered over 100 years ago that humans have unusually high levels of the small molecule in our serum. It has been difficult to generate a neutral or adaptive explanation in part because the uricase enzyme evolved to become a pseudogene in apes thus masking typical signals of sequence evolution. Adding to the difficulty is a lack of clarity on the functional role of uric acid in apes. One popular hypothesis proposes that uric acid is a potent antioxidant that increased in concentration to compensate for the lack of vitamin C synthesis in primate species ∼65 million years ago (Mya). Here, we have expanded on our previous work with resurrected ancient uricase proteins to better resolve the reshaping of uricase enzymatic activity prior to ape evolution. Our results suggest that the pivotal death-knell to uricase activity occurred between 20-30 Mya despite small sequential modifications to its catalytic efficiency for the tens of millions of years since primates lost their ability to synthesize vitamin C, and thus the two appear uncorrelated. We also use this opportunity to demonstrate how molecular evolution can contribute to biomedicine by presenting ancient uricases to human immune cells that assay for innate reactivity against foreign antigens. A highly stable and highly catalytic ancient uricase is shown to elicit a lower immune response in more human haplotypes than other uricases currently in therapeutic development.

Untargeted serum metabolites profiling in high-fat diet mice supplemented with enhanced palm tocotrienol-rich fraction using UHPLC-MS

Excessive high fat dietary intake promotes risk of developing non-alcoholic fatty liver disease (NAFLD) and predisposed with oxidative stress. Palm based tocotrienol-rich fraction (TRF) has been reported able to ameliorate oxidative stress but exhibited poor bioavailability. Thus, we investigated whether an enhanced formulation of TRF in combination with palm kernel oil (medium-chain triglycerides) (ETRF) could ameliorate the effect of high-fat diet (HFD) on leptin-deficient male mice. All the animals were divided into HFD only (HFD group), HFD supplemented with ETRF (ETRF group) and HFD supplemented with TRF (TRF group) and HFD supplemented with PKO (PKO group). After 6 weeks, sera were collected for untargeted metabolite profiling using UHPLC-Orbitrap MS. Univariate analysis unveiled alternation in metabolites for bile acids, amino acids, fatty acids, sphingolipids, and alkaloids. Bile acids, lysine, arachidonic acid, and sphingolipids were downregulated while xanthine and hypoxanthine were upregulated in TRF and ETRF group. The regulation of these metabolites suggests that ETRF may promote better fatty acid oxidation, reduce oxidative stress and pro-inflammatory metabolites and acts as anti-inflammatory in fatty liver compared to TRF. Metabolites regulated by ETRF also provide insight of its role in fatty liver. However, further investigation is warranted to identify the mechanisms involved.

CRISPR-Cas9-mediated reactivation of the uricase pseudogene in human cells prevents acute hyperuricemia

The utility of CRISPR-Cas9 to repair or reverse diseased states that arise from recent genetic mutations in the human genome is now widely appreciated. The use of CRISPR to "design" the outcomes of biology is challenged by both specialized ethicists and the general public. Less of a focus, however, is the ability of CRISPR to provide metabolic supplements or prophylactic molecules that improve long-term human health by overwriting ancient evolutionary events. Here, we use CRISPR to genomically integrate a functional uricase gene that encodes an enzymatically active protein into the human genome. These uricase-producing cells are able to reduce or even eliminate high concentrations of exogenous uric acid despite the enzyme being localized to peroxisomes. Our evolutionary engineered cells represent the first instance of the primate ape lineage expressing a functional uricase encoded in the genome within the last 20 million years. We anticipate that human cells expressing uricase will help prevent hyperuricemia (including gout) as well as hypertension and will help protect against fatty liver disease in the future.

Hyperuricemia-induced endothelial insulin resistance: the nitric oxide connection

Hyperuricemia, defined as elevated serum concentrations of uric acid (UA) above 416 µmol L^-1, is related to the development of cardiometabolic disorders, probably via induction of endothelial dysfunction. Hyperuricemia causes endothelial dysfunction via induction of cell apoptosis, oxidative stress, and inflammation; however, it's interfering with insulin signaling and decreased endothelial nitric oxide (NO) availability, resulting in the development of endothelial insulin resistance, which seems to be a major underlying mechanism for hyperuricemia-induced endothelial dysfunction. Here, we elaborate on how hyperuricemia induces endothelial insulin resistance through the disruption of insulin-stimulated endothelial NO synthesis. High UA concentrations decrease insulin-induced NO synthesis within the endothelial cells by interfering with insulin signaling at either the receptor or post-receptor levels (i.e., proximal and distal steps). At the proximal post-receptor level, UA impairs the function of the insulin receptor substrate (IRS) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) in the insulin signaling pathway. At the distal level, high UA concentrations impair endothelial NO synthase (eNOS)-NO system by decreasing eNOS expression and activity as well as by direct inactivation of NO. Clinically, UA-induced endothelial insulin resistance is translated into impaired endothelial function, impaired NO-dependent vasodilation, and the development of systemic insulin resistance. UA-lowering drugs may improve endothelial function in subjects with hyperuricemia.

Biological Responses to Short-Term Maximal Exercise in Male Police Officers

The specifics of short-term physical exercise are similar to the immediate reaction demands placed on police officers. Identifying the physiological predisposition to short-term high-intensity exercise in male law enforcement officers will assist in understanding their metabolism and make a significant contribution to a much more personal and individualized workout program. This will improve physical fitness of individual officers, improving their preparedness for such times of emergency. This cross-sectional study was conducted to investigate the responses of hematological (erythrocytes, hemoglobin, hematocrit, leucocytes, monocytes, neutrophils, lymphocytes), hormonal (testosterone, cortisol, melatonin), biochemical (glucose, uric-acid, lactate, creatine-phosphokinase) data to short-term maximal exercise in male police officers (n = 20). Blood samples were collected before- and after- the running-based anaerobic sprint test (RAST), and biological values were corrected for fluid shifts. Data were mean ± standard deviation of differences (= after minus before RAST). After the RAST, values of cortisol, lactate, neutrophils, lymphocytes, and monocytes increased significantly by 7.01 ± 37.36 mmol/l, 7.55 ± 1.67 mmol/l, 0.17 ± 0.26 103/µl, 0.61 ± 0.28 103/µl, and 0.10 ± 0.13 103/µl, respectively. After the RAST, values of melatonin, uric-acid, creatine-phosphokinase, hemoglobin, and hematocrit decreased significantly by -13.24 ± 4.60 pg/ml, -13.28 ± 14.35 µmol/l, -10.23 ± 10.13 IU/l, -2.01 ± 0.81 g/dl, and -4.46 ± 0.59%, respectively. Biological data of male police officers were affected by sprint test. Understanding changes in biological data following short-term maximal exercise can further assist in a better understanding of anaerobic metabolism, which will be helpful to find available methods for coaches to quantify training loads.

Role of Vitamin C in Prophylaxis and Treatment of Gout-A Literature Review

Gout, known as “the disease of the kings”, is the most frequent type of arthritis. It results from sustained hyperuricemia that leads to monosodium urate crystal deposition in joint structures and soft tissue. Environmental factors such as diet affect the incidence of gout; there is a known relationship between the occurrence of an acute attack of gout and the consumption of alcohol and meat; and a low purine diet is a widely recognized nonpharmacological method of supplementing the treatment and preventing recurrence of arthritis. This review aims to summarize the current knowledge about the role of vitamin C in prevention and treatment of gout. A PubMed/Medline database search on the role of vitamin C in purine metabolism was done. Reports from in vitro and animal studies seem to be promising and to allow explanation of the physiological relationship between vitamin C and uric acid. Most epidemiological studies indicate a significant correlation between high vitamin C intake and lower serum uric acid levels. Despite promising observations, there are few observational and interventional studies, and their results do not clearly define the benefits of a high daily intake of vitamin C in preventing the development and recurrence of gout.

Elevated salivary uric acid levels among adolescents with eating disorders

OBJECTIVE

Uric acid (UA) is increasingly recognized as having important physiological roles and associated with several peripheral and central pathophysiological outcomes, and might play a role in eating disorders (ED) pathogenesis. We investigated whether UA levels are altered among adolescents with ED.

METHODS

Morning salivary UA concentrations were compared between adolescents referred to treatment at the Herman Dana Center receiving a DSM-V diagnosis of an ED and matched healthy controls.

RESULTS

Salivary UA was significantly elevated among ED compared with control values (ED mean 3.9 ± 1.2 mg/dl, control mean 2.9 ± 1.9 mg/dl, t = - 3.13 df = 81, p = 0.003).

DISCUSSION

Salivary UA is elevated among adolescents with ED. Further studies are required to replicate and extend this finding and evaluate its generalizability as a state or trait marker as regards ED subtypes, other body fluids (plasma and cerebrospinal fluid), and recovery or premorbid stages, as well as its putative mechanistic relevance to ED.

LEVEL OF EVIDENCE

Level III, case-control analytic study.

[Asymptomatic Hyperuricemia and Risk Of Cardiovascular and Renal Diseases]

Asymptomatic hyperuricemia (HU) is common in the population and significantly contributes to the general cardiovascular risk. Despite extensive study of this condition there is still no conclusive answers to questions about detection of asymptomatic HU and its effect on the risk for development and progression of cardiovascular and kidney diseases. This review summarizes key information about these issues, which has been accumulated by the present time.

Metabolomics Analysis of Hippocampus and Cortex in a Rat Model of Traumatic Brain Injury in the Subacute Phase

Traumatic brain injury (TBI) is a complex and serious disease as its multifaceted pathophysiological mechanisms remain vague. The molecular changes of hippocampal and cortical dysfunction in the process of TBI are poorly understood, especially their chronic effects on metabolic profiles. Here we utilize metabolomics-based liquid chromatography coupled with tandem mass spectrometry coupled with bioinformatics method to assess the perturbation of brain metabolism in rat hippocampus and cortex on day 7. The results revealed a signature panel which consisted of 13 identified metabolites to facilitate targeted interventions for subacute TBI discrimination. Purine metabolism change in cortical tissue and taurine and hypotaurine metabolism change in hippocampal tissue were detected. Furthermore, the associations between the metabolite markers and the perturbed pathways were analyzed based on databases: 64 enzyme and one pathway were evolved in TBI. The findings represented significant profiling changes and provided unique metabolite-protein information in a rat model of TBI following the subacute phase. This study may inspire scientists and doctors to further their studies and provide potential therapy targets for clinical interventions.

An 1H NMR- and MS-Based Study of Metabolites Profiling of Garden Snail Helix aspersa Mucus

Metabolic profiling based on 1H nuclear magnetic resonance (NMR) spectroscopy was applied with the aim to investigate the functional role of the metabolites in lyophilized mucus from the garden snail Helix aspersa. Twenty metabolites were unambiguously identified by 1H, 1D TOCSY, 2D J-resolved, 2D COSY, and 2D HSQC NMR spectra with water suppression. The metabolic profiles of two fractions with low molecular weight (Mw < 1 kDa and Mw < 3 kDa) are very similar. Metabolites with known antioxidant, antibacterial, and antimicrobial activity were detected by NMR metabolic analysis of mucus samples from Helix aspersa. Some of them were confirmed by mass spectrometric analysis. The primary structure of several peptides was identified in low molecular weight fractions (Mw < 1 kDa) by tandem mass spectrometry.

Predictors of acute metabolic decompensation in children with maple syrup urine disease at the emergency department

Acute metabolic decompensation (AMD) of maple syrup urine disease (MSUD) must be promptly recognized and treated. In this study, we aimed to identify simple variables associated with AMD in children with MSUD for use in emergency settings. Data were collected retrospectively from 115 emergency visits of 29 children with MSUD over a 4-year period in a major referral hospital. Variables in visits with and without AMD were compared using t test, Mann-Whitney U test, and chi-square test. Logistic regression was used to identify independent variables associated with decompensations. Cut-off values of laboratory variables were determined with receiver operating characteristic curves and correlations with Spearman's rank correlation. Most important variables independently associated with AMD were poor feeding, malaise, anion gap, and especially uric acid, which correlated with leucine levels. Vomiting, dehydration, neurological signs, ketonuria, and ketoaciduria were also associated with AMD. Although sodium, chloride, and glucose were lower in AMD, they had little diagnostic value.Conclusion: In children with MSUD, uric acid and anion gap are key markers for AMD. Poor feeding and malaise are clues before the onset of neurological symptoms. These simple parameters can help determine the presence of AMD in emergency settings.What is Known:• In maple syrup urine disease, acute metabolic decompensations are characterized by gastrointestinal and neurological findings.• Diagnosis requires detection of significantly elevated leucine, which may take a long time or not be available.What is New:• Poor feeding, malaise, hyperuricemia, and high anion gap are parameters that can help diagnose acute decompensations in children with maple syrup urine disease at emergency departments.• Uric acid may be a biomarker for acute decompensations because of its high sensitivity, specificity, and its strong correlation with leucine.

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.

Uric acid and cardiometabolic diseases

Hyperuricemia, which has been considered as a cause of gout and nephrolithiasis has recently been suggested to be associated with hypertension, coronary heart disease, heart failure, atrial fibrillation, insulin resistance, and nonalcoholic fatty liver disease. Several clinical and experimental studies have supported uric acid (UA) as an independent risk factor for predicting disease development along with the traditional risk factors. The mechanism by which UA causes cardiometabolic disease has not been fully elucidated to date; however, it has been explained by several hypotheses such as oxidative stress, reduced nitric oxide bioavailability, inflammation, endothelial dysfunction, and so on. Although evidence of the preventive and therapeutic effects of UA lowering therapy on cardiometabolic diseases is still insufficient, it is expected to be considered as a new treatment strategy for such diseases through additional, carefully designed, large-scale clinical studies.

[Gout]

Gout is a chronic disease due to the deposition of monosodium urate microcrystals in joints and tissues. Its incidence and prevalence are increasing worldwide in close relation with the epidemic of obesity and metabolic syndrome. Gout is related to chronic hyperuricemia that should be treated to ensure the reduction or even the disappearance of acute attacks ("gout flares") and to reduce the size and number of tophi. If arthritis of the first metatarsophalangeal joint is the most typical form, other joints may be affected, including the spine. Demonstration of urate microcrystals arthritis allows diagnosis of gout but, in the absence of possibility of performing joint puncture, imaging may be useful for providing complementary diagnostic elements. Appropriate care is essential to reduce the number of flares and the evolution towards gouty arthropathy but also in terms of public health in order to reduce costs related to this pathology.

Influence of muscle mass on the serum uric acid levels in children and adolescents

BACKGROUND AND AIM

Uric acid (UA) is an end-product of purine catabolism and its increase in blood is a risk factor for several diseases. UA levels in men are usually higher than in women. This difference is partially due to sex hormones. We sought to investigate the onset of sexual difference in UA levels during pubertal development and the determinants of UA levels in children and adolescents.

METHODS AND RESULTS

The muscle mass and fat mass were measured by multi-frequency bioelectrical impedance in a cross-sectional study involving 823 children and adolescents (both sexes; 6-18 years). Serum UA was determined using a commercially available kit. UA levels started to become higher in boys (5.0 ± 1.0 mg/dL) than in girls (4.1 ± 0.9 mg/dL) around 13 years. Boys in the highest quartile of muscle mass presented higher UA levels (5.2 ± 0.7 mg/dL) when compared with the third (4.2 ± 0.7 mg/dL), second (3.7 ± 0.9 mg/dL) and first (3.4 ± 0.9 mg/dL). Similarly, girls in the highest quartile of muscle mass presented higher UA levels (4.2 ± 0.7 mg/dL) when compared with the second (3.8 ± 0.9 mg/dL) and first (3.3 ± 0.9 mg/dL). Muscle mass explained 43.0% and 7.7% of the variability of UA in boys and girls, respectively.

CONCLUSION

Sexual differences in serum UA levels begin at puberty and partially result from a direct influence of muscle mass.

The relationship between self-reported habitual snoring and hyperuricemia among Chinese urban adults: a cross-sectional study

BACKGROUND

Growing evidence suggests an independent relationship between habitual snoring and metabolic abnormalities. Currently, there are few data available on the association between snoring and hyperuricemia. Therefore, we evaluated the cross-sectional association between snoring and serum uric acid (UA) concentration and ascertain the effects of different snoring intensities on hyperuricemia among Chinese urban adults in Nanjing.

METHODS

We performed a cross-sectional study including 7699 participants (4197 men and 3502 women) from Nanjing Drum Tower Hospital aged ≥18 years over a two year (ie, 2016-2018) period. All participants were divided into four groups based on Snoring scores. Questionnaires, physical examinations and biochemical tests were conducted. Hyperuricemia was defined as levels of serum UA > 6.8 mg/dL in males and >6.0 mg/dL in females. We used a generalized linear model to investigate the association between snoring and serum UA concentration and logistic regression model to investigate the association between snoring and likelihood of having hyperuricemia in the age-, sex-adjusted model and in a multivariable model adjusting for demographic factor, plasma lipid profiles, blood glucose, blood pressure, smoking, and alcohol consumption.

RESULTS

The prevalence of hyperuricemia was 10.05% in the studied population and gradually increased across the snoring scores (P < 0.0001). We found that mild snoring, moderate, and severe snoring intensity were associated with high serum UA in the age-, sex-adjusted model and in a multivariable model adjusting for demographic and lifestyle/behavioral risk factors. The association was insisted with the addition of variables related to clinical outcomes such as diabetes, hypertension, and high-cholesterol levels.

CONCLUSIONS

Our results showed self-reported habitual snoring was associated with higher serum UA concentration among Chinese urban adults. Findings of this study indicate the significance of early detection and treatment of snoring to prevent hyperuricemia.

Severe Hypouricemia Impairs Endothelium-Dependent Vasodilatation and Reduces Blood Pressure in Healthy Young Men: A Randomized, Placebo-Controlled, and Crossover Study

Background

Uric acid (UA) is a plasmatic antioxidant that has possible effects on blood pressure. The effects of UA on endothelial function are unclear. We hypothesize that endothelial function is not impaired unless significant UA depletion is achieved through selective xanthine oxidase inhibition with febuxostat and recombinant uricase (rasburicase).

Methods and Results

Microvascular hyperemia, induced by iontophoresis of acetylcholine and sodium nitroprusside, and heating‐induced local hyperemia after iontophoresis of saline and a specific nitric oxide synthase inhibitor were assessed by laser Doppler imaging. Blood pressure and renin‐angiotensin system markers were measured, and arterial stiffness was assessed. CRP (C‐reactive protein), allantoin, chlorotyrosine/tyrosine ratio, homocitrulline/lysine ratio, myeloperoxidase activity, malondialdehyde, and interleukin‐8 were used to characterize inflammation and oxidative stress. Seventeen young healthy men were enrolled in a randomized, double‐blind, placebo‐controlled, 3‐way crossover study. The 3 compared conditions were placebo, febuxostat alone, and febuxostat together with rasburicase. The allantoin (μmol/L)/UA (μmol/L) ratio differed between sessions (P<0.0001). During the febuxostat‐rasburicase session, heating‐induced hyperemia became altered in the presence of nitric oxide synthase inhibition; and systolic blood pressure, angiotensin II, and myeloperoxidase activity decreased (P≤0.03 versus febuxostat). The aldosterone concentration decreased in the febuxostat‐rasburicase group (P=0.01). Malondialdehyde increased when UA concentration decreased (both P<0.01 for febuxostat and febuxostat‐rasburicase versus placebo). Other parameters remained unchanged.

Conclusions

A large and short‐term decrease in UA in humans alters heat‐induced endothelium‐dependent microvascular vasodilation, slightly reduces systolic blood pressure through renin‐angiotensin system activity reduction, and markedly reduces myeloperoxidase activity when compared with moderate UA reduction. A moderate or severe hypouricemia leads to an increase in lipid peroxidation through loss of antioxidant capacity of plasma.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT03395977.

The relationship between serum uric acid within the normal range and β-cell function in Chinese patients with type 2 diabetes: differences by body mass index and gender

Background

Elevated serum uric acid (SUA) has a positive correlation with insulin secretion and insulin resistance indexes. However, whether weight- and gender-specific differences regarding the relationship between SUA within the normal range and β-cell function and insulin resistance exist is unknown in type 2 diabetes mellitus (T2DM) patients.

Methods

A total of 380 patients with type 2 diabetes were divided into two groups as overweight/obesity (n = 268) and normal weight (n = 112). Each group were again divided into low (LSUA) and high normal SUA (HSUA). The HbA1c, C-peptide, SUA, creatinine, and lipids profiles were measured. HOMA2IR and HOMA%2B were estimated using fasting glucose and C-peptide by homeostasis model assessment (HOMA). Pearson’s correlations and multiple linear regression analyses were conducted to assess the associations between SUA levels and islet function indexes.

Results

In overweight/obesity subgroup, the levels of body mass index, fasting C-peptide (FCP), P2hCP, fasting CPI (FCPI), postprandial CPI (PPCPI), ΔC-peptide, HOMA2%B, and HOMA2IR were higher in HSUA group than in LSUA group. In contrast, the HbA1c, FBS, and P2hBS were lower in HSUA than in LSUA. In normal weight subgroup, there were no differences between the HSUA than LSUA group in terms of clinical characteristics. Pearson’s correlations indicated that there were no significant correlations between SUA and insulin secretory capacity in normal weight group, but in overweight/obesity group, SUA had positive significant correlations with P2hCP, FCPI, PPCPI, ΔC-peptide, and HOMA2%B. In the female group, there were no significant correlations between SUA and insulin secretory capacity. However, in the male group, SUA had positive significant correlations with insulin secretory capacity include P2hCP, FCPI, PPCPI, ΔC-peptide, and HOMA2%B. Multiple linear regression showed that SUA was significantly associated with HOMA2%B, but not with HOMA2IR in overweight/obesity and male group.

Conclusions

Our study shows that SUA levels within normal range were associated with β-cell function in T2DM patients with overweight/obesity or male. This finding supports that the association between SUA within normal range and insulin secretion ability differs by weight and sex.

Shortage of Cellular ATP as a Cause of Diseases and Strategies to Enhance ATP

Germline mutations in cellular-energy associated genes have been shown to lead to various monogenic disorders. Notably, mitochondrial disorders often impact skeletal muscle, brain, liver, heart, and kidneys, which are the body’s top energy-consuming organs. However, energy-related dysfunctions have not been widely seen as causes of common diseases, although evidence points to such a link for certain disorders. During acute energy consumption, like extreme exercise, cells increase the favorability of the adenylate kinase reaction 2-ADP -> ATP+AMP by AMP deaminase degrading AMP to IMP, which further degrades to inosine and then to purines hypoxanthine -> xanthine -> urate. Thus, increased blood urate levels may act as a barometer of extreme energy consumption. AMP deaminase deficient subjects experience some negative effects like decreased muscle power output, but also positive effects such as decreased diabetes and improved prognosis for chronic heart failure patients. That may reflect decreased energy consumption from maintaining the pool of IMP for salvage to AMP and then ATP, since de novo IMP synthesis requires burning seven ATPs. Similarly, beneficial effects have been seen in heart, skeletal muscle, or brain after treatment with allopurinol or febuxostat to inhibit xanthine oxidoreductase, which catalyzes hypoxanthine -> xanthine and xanthine -> urate reactions. Some disorders of those organs may reflect dysfunction in energy-consumption/production, and the observed beneficial effects related to reinforcement of ATP re-synthesis due to increased hypoxanthine levels in the blood and tissues. Recent clinical studies indicated that treatment with xanthine oxidoreductase inhibitors plus inosine had the strongest impact for increasing the pool of salvageable purines and leading to increased ATP levels in humans, thereby suggesting that this combination is more beneficial than a xanthine oxidoreductase inhibitor alone to treat disorders with ATP deficiency.

Blood biochemistry and haematology of migrating loggerhead turtles (Caretta caretta) in the Northwest Atlantic: reference intervals and intra-population comparisons

We documented blood biochemistry and haematology of healthy loggerhead turtles (Caretta caretta) in the Northwest (NW) Atlantic in order to establish clinical reference intervals (RIs) for this threatened population. Blood samples were analysed from migratory loggerheads captured off the Mid-Atlantic coast of the USA in 2011, 2012, 2013 and 2016 as part of a long-term research program. Blood variables were determined using a point-of-care analyser, and a veterinary diagnostic laboratory service. We calculated 95% RIs with associated 90% confidence intervals (CIs) for each blood variable. We compared results obtained from our study of migratory loggerheads with published data for similarly sized loggerheads resident at a seasonal temperate latitude foraging area. Significant differences in several blood variables between migratory and resident turtles provided insight on energetic and health status during different behavioural states. Temperature was significantly correlated with several blood variables: lactate, pCO₂, sodium, haemoglobin and lactate dehydrogenase. Our assessment of blood chemistry in healthy loggerhead turtles in the NW Atlantic provides a baseline for clinical comparisons with turtles impacted by anthropogenic and environmental threats, and highlights the importance of identifying unique aspects of biochemical and haematological profiles for sea turtles at the intra-population level.

Intermittent fasting exerts beneficial metabolic effects on blood pressure and cardiac structure by modulating local renin-angiotensin system in the heart of mice fed high-fat or high-fructose diets

Intermittent fasting (IF) sets the preference for fats as fuel and is linked to beneficial metabolic outcomes; however, the effects in the renin-angiotensin system (RAS) in the heart remains to be determined. We hypothesized that IF improves blood pressure and lipid profiles due to a less activated local RAS in the left ventricle of mice, irrespective of the dietary scheme. This study aimed to evaluate the effects of intermittent fasting on cardiovascular parameters and local RAS in the left ventricle (LV) of mice fed either a high-fat (HF) or high-fructose diet (HFru). Metabolic alterations were induced in C57BL/6 mice by providing them free access to a high-fat or a high-fructose (HFru) diet for 8 weeks. Following the 8-week metabolic alteration period, the mice were subjected to the IF protocol in which mice were deprived of food for 24 hours, every other day, for a period of 4 weeks. The IF protocol caused significant reduction in body weight, systolic blood pressure, blood glucose, total cholesterol, and triacylglycerol levels, in addition to augmenting the plasma and urinary uric acid levels, irrespective of the diet. Post IF protocol, beneficial LV remodeling was observed in animals fed either diet and included reduced LV mass, thickness, and cardiomyocyte cross-sectional area. These results comply with the improved RAS modulation, which favored ACE2/MAS receptor axis over the renin/ACE/AT1 axis. In conclusion, the significant decrease in weight brought about as a result of the IF protocol lead to modulation of the local RAS, with the consequential benefit of LV remodeling and reduction in blood pressure, irrespective of the diet.

Uric acid enhances longevity and endurance and protects the brain against ischemia

Among mammals, there is a positive correlation between serum uric acid (UA) levels and life span. Humans have high levels of UA because they lack a functional urate oxidase (UOX) enzyme that is present in shorter lived mammals. Here, we show that male and female mice with UOX haploinsufficiency exhibit an age-related elevation of UA levels, and that the life span of female but not male UOX+/- mice is significantly increased compared to wild-type mice. Serum UA levels are elevated in response to treadmill exercise in UOX+/- mice, but not wild-type mice, and the endurance of the UOX+/- mice is significantly greater than wild-type mice. UOX+/- mice exhibit elevated levels of brain-derived neurotrophic factor, reduced brain damage and improved functional outcome in a model of focal ischemic stroke. Levels of oxidative protein nitration and lipid peroxidation are reduced in muscle and brain tissues of UOX+/- mice under conditions of metabolic and oxidative stress (running in the case of muscle and ischemia in the case of the brain), consistent with prior evidence that UA can scavenge peroxynitrite and hydroxyl radical. Our findings reveal roles for UA in life span determination, endurance and adaptive responses to brain injury, and suggest novel approaches for protecting cells against injury and for optimizing physical performance.

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.

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.

Impacts of feeding preweaned calves milk containing drug residues on the functional profile of the fecal microbiota

Feeding drug residue-containing milk to calves is common worldwide and no information is currently available on the impact on the functional profile of the fecal microbiota. Our objective was to characterize the functional profile of the fecal microbiota of preweaned dairy calves fed raw milk with residual concentrations of antimicrobials commonly found in waste milk from birth to weaning. Calves were assigned to a controlled feeding trial being fed milk with no drug residues or milk with antibiotic residues. Fecal samples collected from each calf once a week starting at birth, prior to the first feeding in the trial, until 6 weeks of age. Antibiotic residues resulted in a significant difference in relative abundance of microbial cell functions, especially with genes linked with stress response, regulation and cell signaling, and nitrogen metabolism. These changes could directly impacts selection and dissemination of virulence and antimicrobial. Our data also identified a strong association between age in weeks and abundance of Resistance to Antibiotics and Toxic Compounds. Findings from this study support the hypothesis that drug residues, even at very low concentrations, impact the gut microbiota of calves and result in changes in the functional profile of microbial populations.

Clinical and Basic Evaluation of the Prognostic Value of Uric Acid in Traumatic Brain Injury

Background: As a major antioxidant in serum, uric acid (UA) was once considered only as the leading cause of gout; however, recent studies have validated its neuroprotective role in ischemic stroke. Because the potential protective effects of UA in traumatic brain injury (TBI) remain largely unknown, this study investigated the role of UA in TBI in both clinical patients and experimental animals. Methods: In TBI patients, serum UA concentrations were measured within 3 days after injury. Clinical outcomes at discharge were classified according to the Glasgow Outcome Scale: good outcome (4-5) and poor outcome (1-3). Risk factors for good outcome were identified via backward logistic regression analysis. For the animal study, a controlled cortical impact (CCI) injury model was established in mice. These mice were given UA at different doses intraperitoneally, and subsequent UA concentrations in mouse serum and brain tissue were determined. Neurological function, oxidative stress, inflammatory response, neuronal maintenance, cerebral blood flow, and lesion size were also assessed. Results: The serum UA level was significantly lower in TBI patients who had a good outcome (P<0.01), and low serum UA was an independent predictor of good outcome after TBI (P<0.01; odds ratio, 0.023; 95% confidence interval, 0.006-0.082). Consistently, decreased levels of serum UA were observed in both TBI patients and CCI animals (P<0.05), whereas the UA concentration was increased in CCI brain tissue (P<0.05). Administration of UA further increased the UA level in brain tissue as compared to that in control animals (P<0.05). Among the different doses administered, 16 mg/kg UA improved sensorimotor functional recovery, spatial learning, and memory in CCI mice (P<0.05). Moreover, oxidative stress and the inflammatory response were inhibited by UA treatment (P<0.05). UA treatment also improved neuronal maintenance and cortical blood flow (P<0.05) but not lesion size (P>0.05). Conclusions: UA acted to attenuate neuronal loss, cerebral perfusion impairment and neurological deficits in TBI mice through suppression of neuronal and vascular oxidative stress. Following TBI, active antioxidant defense in the brain may result in consumption of UA in the serum, and thus, a decreased serum UA level could be predictive of good clinical recovery.

Fructose Consumption, Lipogenesis, and Non-Alcoholic Fatty Liver Disease

Increased fructose consumption has been suggested to contribute to non-alcoholic fatty liver disease (NAFLD), dyslipidemia, and insulin resistance, but a causal role of fructose in these metabolic diseases remains debated. Mechanistically, hepatic fructose metabolism yields precursors that can be used for gluconeogenesis and de novo lipogenesis (DNL). Fructose-derived precursors also act as nutritional regulators of the transcription factors, including ChREBP and SREBP1c, that regulate the expression of hepatic gluconeogenesis and DNL genes. In support of these mechanisms, fructose intake increases hepatic gluconeogenesis and DNL and raises plasma glucose and triglyceride levels in humans. However, epidemiological and fructose-intervention studies have had inconclusive results with respect to liver fat, and there is currently no good human evidence that fructose, when consumed in isocaloric amounts, causes more liver fat accumulation than other energy-dense nutrients. In this review, we aim to provide an overview of the seemingly contradicting literature on fructose and NAFLD. We outline fructose physiology, the mechanisms that link fructose to NAFLD, and the available evidence from human studies. From this framework, we conclude that the cellular mechanisms underlying hepatic fructose metabolism will likely reveal novel targets for the treatment of NAFLD, dyslipidemia, and hepatic insulin resistance. Finally, fructose-containing sugars are a major source of excess calories, suggesting that a reduction of their intake has potential for the prevention of NAFLD and other obesity-related diseases.

Evolutionary Nephrology

Progressive kidney disease follows nephron loss, hyperfiltration, and incomplete repair, a process described as "maladaptive." In the past 20 years, a new discipline has emerged that expands research horizons: evolutionary medicine. In contrast to physiologic (homeostatic) adaptation, evolutionary adaptation is the result of reproductive success that reflects natural selection. Evolutionary explanations for physiologically maladaptive responses can emerge from mismatch of the phenotype with environment or evolutionary tradeoffs. Evolutionary adaptation to a terrestrial environment resulted in a vulnerable energy-consuming renal tubule and a hypoxic, hyperosmolar microenvironment. Natural selection favors successful energy investment strategy: energy is allocated to maintenance of nephron integrity through reproductive years, but this declines with increasing senescence after ~40 years of age. Risk factors for chronic kidney disease include restricted fetal growth or preterm birth (life history tradeoff resulting in fewer nephrons), evolutionary selection for APOL1 mutations (that provide resistance to trypanosome infection, a tradeoff), and modern life experience (Western diet mismatch leading to diabetes and hypertension). Current advances in genomics, epigenetics, and developmental biology have revealed proximate causes of kidney disease, but attempts to slow kidney disease remain elusive. Evolutionary medicine provides a complementary approach by addressing ultimate causes of kidney disease. Marked variation in nephron number at birth, nephron heterogeneity, and changing susceptibility to kidney injury throughout life history are the result of evolutionary processes. Combined application of molecular genetics, evolutionary developmental biology (evo-devo), developmental programming and life history theory may yield new strategies for prevention and treatment of chronic kidney disease.

Fructose Intake, Serum Uric Acid, and Cardiometabolic Disorders: A Critical Review

There is a direct relationship between fructose intake and serum levels of uric acid (UA), which is the final product of purine metabolism. Recent preclinical and clinical evidence suggests that chronic hyperuricemia is an independent risk factor for hypertension, metabolic syndrome, and cardiovascular disease. It is probably also an independent risk factor for chronic kidney disease, Type 2 diabetes, and cognitive decline. These relationships have been observed for high serum UA levels (>5.5 mg/dL in women and >6 mg/dL in men), but also for normal to high serum UA levels (5-6 mg/dL). In this regard, blood UA levels are much higher in industrialized countries than in the rest of the world. Xanthine-oxidase inhibitors can reduce UA and seem to minimize its negative effects on vascular health. Other dietary and pathophysiological factors are also related to UA production. However, the role of fructose-derived UA in the pathogenesis of cardiometabolic disorders has not yet been fully clarified. Here, we critically review recent research on the biochemistry of UA production, the relationship between fructose intake and UA production, and how this relationship is linked to cardiometabolic disorders.

The drug target genes show higher evolutionary conservation than non-target genes

Although evidence indicates that drug target genes share some common evolutionary features, there have been few studies analyzing evolutionary features of drug targets from an overall level. Therefore, we conducted an analysis which aimed to investigate the evolutionary characteristics of drug target genes. We compared the evolutionary conservation between human drug target genes and non-target genes by combining both the evolutionary features and network topological properties in human protein-protein interaction network. The evolution rate, conservation score and the percentage of orthologous genes of 21 species were included in our study. Meanwhile, four topological features including the average shortest path length, betweenness centrality, clustering coefficient and degree were considered for comparison analysis. Then we got four results as following: compared with non-drug target genes, 1) drug target genes had lower evolutionary rates; 2) drug target genes had higher conservation scores; 3) drug target genes had higher percentages of orthologous genes and 4) drug target genes had a tighter network structure including higher degrees, betweenness centrality, clustering coefficients and lower average shortest path lengths. These results demonstrate that drug target genes are more evolutionarily conserved than non-drug target genes. We hope that our study will provide valuable information for other researchers who are interested in evolutionary conservation of drug targets.

Effects of a Novel Fixed Combination of Nutraceuticals on Serum Uric Acid Concentrations and the Lipid Profile in Asymptomatic Hyperuricemic Patients : Results from the PICONZ-UA Study

INTRODUCTION

Asymptomatic hyperuricemia is not a current indication for therapy as the definite role of serum uric acid elevation as a cardiovascular risk factor is extremely likely but still controversial.

AIM

We designed a double blind, placebo-controlled, randomized study to assess the effects of a combination of nutraceuticals (ZinutriK^®, containing a fixed combination of kampferol, baicalin, caffeine, and rutin) on serum uric acid levels, lipid variables and the global cardiovascular risk profile.

METHODS

Sixteen individuals (mean age 59.0 ± 11.9 years, 4 women) with asymptomatic hyperuricemia completed the study.

RESULTS

ZinutriK^® treatment (4 weeks) reduced serum uric acid concentrations (from 7.9 + 0.9 to 7.0 + 0.7 mg/dL) when compared to both baseline and placebo (p < 0.006 and p < 0.001, respectively). Compared to both placebo and baseline, the same fixed combination of nutraceuticals also reduced circulating LDL cholesterol and increased HDL cholesterol concentrations within 4 weeks (p < 0.001 or less), thereby improving the Framingham risk score (p < 0.001 or less). Neither minor nor major side effects were observed.

CONCLUSIONS

This study represents the first demonstration that a short-term therapy with a fixed combination of different natural substances can significantly reduce serum uric acid concentrations in asymptomatic hyperuricemic patients, with no side effects and a significant improvement in the lipid pattern and then in the global cardiovascular risk profile.

Hyperferritinemia increases the risk of hyperuricemia in HFE-hereditary hemochromatosis

OBJECTIVES

Hyperuricemia is becoming increasingly frequent in the population, and is known to be sometimes the cause of gout. The impact of uric acid is still not clearly understood, however. The iron metabolism may interact with the uric acid metabolism. The aim of this study was to examine the relationship between the serum uric acid and serum ferritin levels in a cohort of hemochromatosis patients who were homozygous for the HFE p.Cys282Tyr mutation.

METHODS

738 patients with the HFE gene mutation Cys282Tyr in the homozygous state were included in the study. The variables measured during the initial evaluation were compared in univariate analysis by Student's t test. In multivariate analysis, linear stepwise regression was used.

RESULTS

In the group of hyperuricemic patients, ferritinemia was significantly higher than in the group of non-hyperuricemic patients (1576.7±1387.4μg/l vs. 1095.63±1319.24μg/l, P<0.005). With multivariate analysis, only ferritin and BMI independently explained the uricemia (R²=0.258) after adjustment for age, glycemia and CRP. The correlation between uricemia and log(ferritin) with partial regression correlation coefficients was 0.307 (P<0.01).

CONCLUSIONS

The increase in uricemia is associated with the increase in ferritin in a population of patients who were homozygous for the HFE gene mutation p.Cys282Tyr and this independently of factors commonly associated with hyperuricemia. The increase in uric acid associated with hyperferritinemia, could be a response to the visceral toxicity of excess non-transferrin bound iron linked to oxidative stress via the antioxidant properties of uric acid.

Uric acid stimulates proliferative pathways in vascular smooth muscle cells through the activation of p38 MAPK, p44/42 MAPK and PDGFRβ

Hyperuricemia and angiotensin II (Ang II) may have a pathogenetic role in the development of hypertension and atherosclerosis as well as cardiovascular disease (CVD) and its prognosis. The purpose of this study was to investigate whether uric acid can induce proliferative pathways of vascular smooth muscle cell (VSMC) that are thought to be responsible for the development of CVD. The phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), p44/42 mitogen-activated protein kinase (p44/42 MAPK) and platelet-derived growth factor receptor β (PDGFRβ) was measured by Elisa and Western blot techniques to determine the activation of proliferative pathways in primary cultured VSMCs from rat aorta. Results demonstrated that uric acid can stimulate p38 MAPK, p44/42 MAPK and PDGFRβ phosphorylation in a time- and concentration-dependent manner. Furthermore, treatment of VSMCs with the angiotensin II type I receptor (AT1R) inhibitor losartan suppressed p38 MAPK and p44/42 MAPK induction by uric acid. The stimulatory effect of uric acid on p38 MAPK was higher compared to that of Ang II. The results of this study show for the first time that uric acid-induced PDGFRβ phosphorylation plays a crucial role in the development of CVDs and that elevated uric acid levels could be a potential therapeutical target in CVD patients.

Biological mechanisms underlying evolutionary origins of psychotic and mood disorders

Psychotic and mood disorders are brain dysfunctions that are caused by gene environment interactions. Although these disorders are disadvantageous and involve behavioral phenotypes that decrease the reproductive success of afflicted individuals in the modern human society, the prevalence of these disorders have remained constant in the population. Here, we propose several biological mechanisms by which the genes associated with psychotic and mood disorders could be selected for in specific environmental conditions that provide evolutionary bases for explanations of when, why, and where these disorders emerged and have been maintained in humans. We discuss the evolutionary origins of psychotic and mood disorders with specific focuses on the roles of dopamine and serotonin in the conditions of social competitiveness/hierarchy and maternal care and other potential mechanisms, such as social network homophily and symbiosis.

Allantoin transport protein, PucI, from Bacillus subtilis: evolutionary relationships, amplified expression, activity and specificity

This work reports the evolutionary relationships, amplified expression, functional characterization and purification of the putative allantoin transport protein, PucI, from Bacillus subtilis. Sequence alignments and phylogenetic analysis confirmed close evolutionary relationships between PucI and membrane proteins of the nucleobase-cation-symport-1 family of secondary active transporters. These include the sodium-coupled hydantoin transport protein, Mhp1, from Microbacterium liquefaciens, and related proteins from bacteria, fungi and plants. Membrane topology predictions for PucI were consistent with 12 putative transmembrane-spanning α-helices with both N- and C-terminal ends at the cytoplasmic side of the membrane. The pucI gene was cloned into the IPTG-inducible plasmid pTTQ18 upstream from an in-frame hexahistidine tag and conditions determined for optimal amplified expression of the PucI(His6) protein in Escherichia coli to a level of about 5 % in inner membranes. Initial rates of inducible PucI-mediated uptake of 14C-allantoin into energized E. coli whole cells conformed to Michaelis-Menten kinetics with an apparent affinity (Kmapp) of 24 ± 3 μM, therefore confirming that PucI is a medium-affinity transporter of allantoin. Dependence of allantoin transport on sodium was not apparent. Competitive uptake experiments showed that PucI recognizes some additional hydantoin compounds, including hydantoin itself, and to a lesser extent a range of nucleobases and nucleosides. PucI(His6) was solubilized from inner membranes using n-dodecyl-β-d-maltoside and purified. The isolated protein contained a substantial proportion of α-helix secondary structure, consistent with the predictions, and a 3D model was therefore constructed on a template of the Mhp1 structure, which aided localization of the potential ligand binding site in PucI.

Applicability of visceral adiposity index in predicting metabolic syndrome in adults with obstructive sleep apnea: a cross-sectional study

Background

Obstructive sleep apnea (OSA) is severely affected by visceral adiposity (VA) that correlates to another disorder—metabolic syndrome (MetS). However, little is known concerning the relation of visceral adiposity index (VAI)—a novel and simple indicator of VA, with OSA and MetS. The objective of the study was to analyze the association of VAI with both disorders and applicability to identify OSA patients at risk of MetS.

Methods

Consecutive individuals undergoing polysomnography and biochemical tests were enrolled, and differences in all subjects grouped by apnea-hypopnea index (AHI) were analyzed. Spearman correlation was performed for assessing the relationship between VAI, OSA-related indices and metabolic score—total number of the positive diagnostic criteria of MetS. Receiver operating characteristic (ROC) curve was conducted to obtain a cut-off value of VAI for predicting incident MetS by sex. Then, the risk of MetS in OSA patients according to the cut-offs was attained by logistic regression.

Results

A total of 411 individuals were enrolled. Of whom, 361 subjects were diagnosed OSA (mild in 67 patients, moderate in 89 and severe in 205, respectively). A significant increasing trend based on AHI was observed in the variables of blood pressure, triglycerides, fasting glucose, incident MetS, metabolic score and VAI (all p < 0.05). Irrespective of gender, VAI was all significantly correlated with PSG characteristics as AHI, mean nocturnal oxygen saturation, the lowest oxygen saturation, metabolic score(all p < 0.05). A VAI of 2.282, 2.105, 2.511 (for all subjects, males and females, separately) were calculated to determine the occurrence of MetS. According to the cut-offs, OSA patients tended to suffer from greater risk in MetS (odds ratio [OR] = 10.237, p = 0.000; OR = 13.556, p = 0.000; OR = 21.458, p = 0.000).

Conclusions

The present study suggested that VAI was significantly associated with MetS and OSA. As a simple and alternative approach obtained in everyday practice, it may offer a powerful tool to identify patients with OSA at risk of MetS.

Purines: forgotten mediators in traumatic brain injury

Recently, the topic of traumatic brain injury has gained attention in both the scientific community and lay press. Similarly, there have been exciting developments on multiple fronts in the area of neurochemistry specifically related to purine biology that are relevant to both neuroprotection and neurodegeneration. At the 2105 meeting of the National Neurotrauma Society, a session sponsored by the International Society for Neurochemistry featured three experts in the field of purine biology who discussed new developments that are germane to both the pathomechanisms of secondary injury and development of therapies for traumatic brain injury. This included presentations by Drs. Edwin Jackson on the novel 2',3'-cAMP pathway in neuroprotection, Detlev Boison on adenosine in post-traumatic seizures and epilepsy, and Michael Schwarzschild on the potential of urate to treat central nervous system injury. This mini review summarizes the important findings in these three areas and outlines future directions for the development of new purine-related therapies for traumatic brain injury and other forms of central nervous system injury. In this review, novel therapies based on three emerging areas of adenosine-related pathobiology in traumatic brain injury (TBI) were proposed, namely, therapies targeting 1) the 2',3'-cyclic adenosine monophosphate (cAMP) pathway, 2) adenosine deficiency after TBI, and 3) augmentation of urate after TBI.

Serum Uric Acid and Prehypertension Among Adults Free of Cardiovascular Diseases and Diabetes

The association between serum uric acid (SUA) and prehypertension was evaluated in a racially admixed sample of civil servants aged 35 to 74 years, enrolled (2008-2010) in the Brazilian Longitudinal Study of Health (ELSA-Brasil). Of the 15 105 patients who enrolled in the study, we analyzed 3412 after excluding those who reported previous cardiovascular diseases, diabetes, or hypertension; were heavy drinkers; or had a body mass index (BMI) ≥35 kg/m2. Among the men, logistic regression, adjusted for age, race, income, birth weight, salt intake, insulin resistance, BMI, and renal function revealed odds ratios (ORs) and 95% confidence intervals (CIs) of prehypertension from the bottom quartile (referent) to the top quartile of SUA levels as follows: 0.84 (95% CI, 0.61-1.38), 0.97 (0.71-1.34) and 1.44 (1.04-2.0; P for trend .01). Analyzing for 1-standard deviation of change in SUA, the ORs were 1.19 (1.06-1.32). This association persisted in the subgroup analysis consisting of patients who were white, overweight, with a high salt intake but with normal renal function, and without metabolic syndrome. No association was found among women. In conclusion, SUA levels were associated with prehypertension among men.