Uric Acid Is Associated With Inflammatory Biomarkers and Induces Inflammation Via Activating the NF-κB Signaling Pathway in HepG2 Cells

Treatment with a PPAR-γ Agonist Protects Against Hyperuricemic Nephropathy in a Rat Model

Purpose

Hyperuricemia is an independent risk factor for renal damage and can promote the progression of chronic kidney disease (CKD). In the present study, we employ a rat model to investigate the effects of rosiglitazone (RGTZ), a peroxisome proliferator-activated receptor-gamma agonist, on the development of hyperuricemic nephropathy (HN), and we elucidate the mechanisms involved.

Methods

An HN rat model was established by oral administration of a mixture of adenine and potassium oxonate daily for 3 weeks. Twenty-four rats were divided into 4 groups: sham treatment, sham treatment plus RGTZ, HN, and HN treated with RGTZ.

Results

Administration of RGTZ effectively preserved renal function, decreased urine microalbumin, and inhibited interstitial fibrosis and macrophage infiltration in a rat HN model. RGTZ treatment also inhibited TGF-β and NF-κB pathway activation, decreased expression of fibronectin, collagen I, α-SMA, vimentin, MCP-1, RANTES, TNF-α, and IL-1β, and increased E-cadherin expression in the kidneys of HN rats. Furthermore, RGTZ treatment preserved expression of OAT1 and OAT3 in the kidney of HN rats.

Conclusion

RGTZ attenuates the progression of HN through inhibiting TGF-β signaling, suppressing epithelial-to-mesenchymal transition, reducing inflammation, and lowering serum uric acid levels by preserving expression of urate transporters.

Uric acid and kidney damage in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organs; lupus nephritis (LN) is one of the most severe complications of SLE. In the kidneys, an intense inflammatory reaction affects the glomeruli and tubular interstitium. Uric acid has been considered a key molecule in the pathogenesis of some conditions such as metabolic syndrome, hypertension, and kidney disease as it is produced by injured cells and promotes immune-inflammatory responses. In this regard, high serum uric acid concentrations may be involved in the activation of some inflammatory pathways, associated with kidney damage in SLE. Therefore, the purpose of this article was to review the main physiological mechanisms and clinical data on the association between serum uric acid and kidney damage in SLE. Scientific evidence indicates that hyperuricemia has the potential to be an adjuvant in the development and progression of kidney manifestations in SLE. Uric acid may promote the activation of inflammatory pathways and the formation and deposition of autoantibodies in kidneys, leading to a reduction of glomerular filtration rate. Other potential mechanisms of this association include the presence of polymorphisms in the urate transporters, metabolic syndrome, use of some medications, and other situations associated with a reduced renal excretion of uric acid.

U-Shaped Association between Sleep Duration, C-Reactive Protein, and Uric Acid in Korean Women

Serum high-sensitivity C-reactive protein (hsCRP) and serum uric acid (SUA) are biomarkers that predict chronic inflammation and cardiovascular dysfunction. Therefore, we aimed to investigate the association between sleep duration, hsCRP, and SUA in Korean women. Cross-sectional data from the Seventh Korea National Health and Nutrition Examination Survey was analyzed. The odds ratio (OR) and 95% confidence intervals (CIs) for an association between higher hsCRP (>2.0 mg/L) or higher SUA (>5.6 mg/dL) and sleep duration were calculated using multiple logistic regression analyses after adjusting for potential confounders. In total, 6151 women were included in the analysis. There was a U-shaped relationship between continuous sleep duration, hsCRP, and SUA. Compared to those who slept for 7-8 h, the ORs (95% CIs) for higher hsCRP were 1.43 (0.95-2.16) in short sleepers and 1.64 (1.09-2.48) in long sleepers after adjusting for confounders. Compared with those who slept for 7-8 h, the ORs (95% CIs) for higher SUA were 1.54 (1.04-2.26) in short sleepers and 1.94 (1.27-2.96) in long sleepers after adjusting for confounders. We found a U-shaped association between sleep duration, hsCRP, and SUA in Korean women. 7-8 h sleep was associated with lower level of hsCRP and SUA in Korean women.

Impact of monocyte to high-density lipoprotein ratio on prevalent hyperuricemia: findings from a rural Chinese population

BACKGROUND

Monocyte to high-density lipoprotein cholesterol ratio (MHR) is a novel inflammatory marker that has been used to predict various inflammation-related diseases. This study aims to explore the association between MHR and prevalent hyperuricemia in a rural Chinese population.

METHODS

8163 eligible participants (mean age: 54.13 years, males: 45.71%) from northeast China were enrolled in this cross-sectional study between 2012 to 2013. MHR was determined as blood monocyte count ratio to high-density lipoprotein cholesterol concentration.

RESULTS

The prevalence of hyperuricemia was 12.86%. After adjusting for potential confounding factors, per SD increase of MHR caused a 25.2% additional risk for hyperuricemia, and the top quartile of MHR had an 82.9% increased risk for hyperuricemia compared with the bottom quartile. Additionally, smooth curve fitting and subgroup analyses showed a linear and robust association between MHR and prevalent hyperuricemia respectively. Finally, after introducing MHR into the established model of risk factors, the AUC displayed a significant improvement (0.718 vs 0.724, p = 0.008). Furthermore, Category-free net reclassification improvement (0.160, 95% CI: 0.096-0.224, P < 0.001) and integrated discrimination improvement (0.003, 95% CI: 0.002-0.005, P < 0.001) also demonstrated significant improvements.

CONCLUSIONS

The present study suggests that MHR was positively and independently correlated with prevalent hyperuricemia among rural Chinese adults. Our results also implicate an important value for MHR in optimizing the risk stratification of hyperuricemia.

Saikosaponin a attenuates hyperlipidemic pancreatitis in rats via the PPAR-γ/NF-κB signaling pathway

The therapeutic effect of saikosaponin a (SSa) on hyperlipidemic pancreatitis (HP) is not completely understood. The aim of the present study was to investigate the therapeutic effect and the underlying mechanism of SSa using a rat model of HP. Following successful establishment of the HP rat model, different doses of SSa (low dose group, 10 mg/kg or high dose group, 20 mg/kg) were administrated. Histopathological examination, the wet/dry (W/D) ratio and myeloperoxidase (MPO) activity of the pancreatic tissues were assessed. The lipid, amylase (AMY), lipase and proinflammatory cytokine profiles in serum, as well as the expression of peroxisome proliferator-activated receptor (PPAR)-γ and the NF-κB signaling pathway-related proteins in pancreatic tissues were evaluated. The results showed that SSa effectively attenuated pancreatic pathological injury and reduced both the W/D ratio and MPO activity compared to the HP model rats. SSa also improved lipid metabolism by significantly decreasing the serum levels of total cholesterol and triglycerides (P<0.05). Following the administration of SSa, the activity of AMY and lipase, as well as the levels of the proinflammatory cytokines tumor necrosis factor-α, interleukin (IL)-1β and IL-6 were reduced, particularly in the high dosage group (P<0.05). Furthermore, SSa activated PPAR-γ expression and suppressed the NF-κB signaling pathway in pancreatic tissues. The present study suggested that SSa attenuated HP in rats by increasing lipid metabolism and inhibiting the release of proinflammatory cytokines via the NF-κB inflammatory pathway. The results from the present study indicated that SSa might be a promising therapeutic agent for the treatment of HP.

Hyperlipidemia-induced lipotoxicity and immune activation in rats are prevented by curcumin and rutin

We assessed the effects of curcumin, rutin, and the association of rutin and curcumin in organs of hyperlipidemic rats. Rutin and curcumin have notable antioxidant and anti-inflammatory actions, so we hypothesized that their association would enhance their beneficial effects. Hyperlipidemia results in lipotoxicity and affects several organs. Lipotoxicity is not only an outcome of lipid accumulation in non-adipose tissues but also a result of the hyperlipidemia-associated inflammation and oxidative stress. Wistar rats were treated with rutin and curcumin for 30 days before the induction of acute hyperlipidemia by Poloxamer-407. After 36 h, the animals were euthanized for collection of blood and organs. Untreated hyperlipidemic rats showed higher uric acid and albumin levels in the serum and increased spleen size and ADA activity. Rutin, curcumin and the association reduced the spleen size by 20% and ADA activity by 23, 28, and 27%, respectively. Rats pretreated with rutin showed reduced lipid damage in the liver (40%) and the kidney (44%), and the protein damage was also reduced in the liver (75%). The lipid damage was decreased by 40% in the liver, and 56% in the kidney of rats pretreated with curcumin. The association reduced lipid damage by 50% and 36%, and protein damage by 77% and 64% in the liver and kidney, respectively. Rutin better prevented the decrease in the antioxidant defenses, increasing SOD by 34%, CAT by 246% and GST by 84% in the liver, as well as SOD by 119% and GST by 190% in the kidney. Also, analyses of blood and spleen parameters of untreated and pretreated non-hyperlipidemic rats showed no signs of immunotoxicity. Despite showing protective effects, the association did not perform better than the isolated compounds. Here, we showed that rutin and/or curcumin reestablished the immune homeostasis and redox balance disrupted by hyperlipidemia in peripheral organs of rats.

Benzbromarone mitigates cisplatin nephrotoxicity involving enhanced peroxisome proliferator-activated receptor-alpha (PPAR-α) expression

AIM

Despite the great efficacy reported for cisplatin as a widely used chemotherapeutic agent, its clinical use is limited by the challenge of facing its serious side effect; nephrotoxicity. In this study, the effect of the benzbromarone on peroxisome proliferator-activated receptor-alpha (PPAR-α) was investigated against cisplatin nephrotoxicity.

MAIN METHODS

Rats were administered benzbromarone (10 mg/kg/day; p.o.) for 14 days, and cisplatin (6.5 mg/kg; i.p.) as a single dose on the 10th day. Blood and kidney tissue samples were collected for determination of kidney function, biochemical and molecular markers, as well as histopathological investigation.

KEY FINDINGS

Benzbromarone improved kidney function, that was evidenced by reduced serum creatinine and blood urea nitrogen to nearly the half, compared to the group administered cisplatin alone. The protein expression of PPAR-α was enhanced with benzbromarone treatment, along with a considerable suppression of oxidative stress as benzbromarone reduced mRNA expression of NADPH oxidase, while increased the anti-oxidant HO-1 protein expression associated with enhancing Nrf2. Besides, it displayed a marked anti-inflammatory effect involved suppression of p38 MAPK/NF-κB p65 signaling pathway and its downstream targets. Moreover, benzbromarone retarded apoptosis associated with reducing the pro-apoptotic (Bax) and enhancing the anti-apoptotic (Bcl-2) protein expressions. The protective effects of benzbromarone were also confirmed by histopathological results.

SIGNIFICANCE

Our data confirm the relation between PPAR-α, and the deleterious effects induced by cisplatin. It can also be suggested that enhancing PPAR-α expression by benzbromarone is a promising therapeutic approach that overcomes cisplatin nephrotoxicity, involving regulation of different signaling pathways: Nrf2/HO-1, p38 MAPK/NF-κB p65, and Bax/Bcl-2.

Association between anemia and hyperuricemia: results from the Korean National Health and Nutrition Examination Survey

Hyperuricemia and anemia share several comorbidities, but the association between the two conditions remains unclear. The purpose of this study was to investigate the association between hyperuricemia and anemia. Data of 10794 subjects from the Korean National Health and Nutrition Examination Survey conducted in 2016-2017 were analyzed using multivariate logistic regression analyses. An association between anemia and hyperuricemia was not evident in subjects without chronic kidney disease (CKD). In patients with CKD, anemia increased the risk of hyperuricemia by 2-fold. This association remained significant when adjusting for the glomerular filtration rate. In subgroup analyses, the association of anemia with hyperuricemia was significant in subjects aged ≥65 years, and in those with diabetes or hypertension. Subgroup analyses of CKD patients showed similar results. In the current study using data from Korean representative samples, anemia in subjects with CKD was associated with a 2-fold increase in the risk of hyperuricemia, which remained significant even after adjustment for renal function.

The association between C-reactive protein and common blood tests in apparently healthy individuals undergoing a routine health examination

BACKGROUND

C-reactive protein (CRP) is considered a marker of inflammation. We sought to evaluate the association between CRP level and commonly use blood tests in apparently healthy population.

METHODS

A cross-sectional study of all visits in a routine health examination center between 1/2002 and 7/2018. CRP, complete blood count and chemistry blood panel were evaluated in each visit. Visits of individuals who had CRP above the 99th percentile or use statins were excluded. Correlation between CRP and blood tests was evaluated in the whole cohort as well as in sub-populations.

RESULTS

Blood parameters of 33,261 visits were included. Moderate positive correlation between CRP and white blood cells count (r = 0.269), neutrophils count (r = 0.275), triglycerides (r = 0.275), alkaline phosphatase (r = 0.221) and gamma glutamyl transpeptidase (r = 0.220) was evaluated. Correlation with triglycerides was stronger in female then in males (r = 0.38 vs. 0.25). Uric acid was positively correlated in females and males. In participants under 30 years, inverse correlation with hemoglobin, creatinine and albumin levels and positive correlation with cholesterol were documented.

CONCLUSION

Significant moderate association between CRP and several blood tests was evaluated in apparently healthy population. This information should be used for further studies of the relationship between inflammation and biological processes.

Nonlinear relationship between serum uric acid and body mass index: a cross-sectional study of a general population in coastal China

Background

Conflicting evidence exists on the relationship between body mass index (BMI) and serum uric acid (SUA). Therefore, we aimed to evaluate the SUA–BMI relationship in a large-scale epidemiological survey in coastal China.

Methods

This survey was conducted among the general population in the coastal region of China from September 2014 to January 2015. SUA Levels were measured by the automatic Sysmex Chemix-180 biochemical analyzer.

Results

A total of 6098 men (BMI: 24.58 ± 3.74 kg/m²) and 7941 women (24.56 ± 3.64 kg/m²) were included in this study. A stronger positive BMI-SUA association was found for men than women (all P-values < 0.05). The piecewise linear spline models indicated a U-shaped relationship of SUA-BMI association for both men and women; and the lowest turning points were at 19.12 kg/m² for men and 21.3 kg/m² for women. When BMIs were lower than the nadir point, each 1 kg/m² increase in BMI related to a 7.74-fold (95% CI − 14.73, − 0.75) reduction for men and 2.70-fold reduction (− 4.47, − 0.94) for women in SUA levels. Once the BMI was higher than the nadir point, each 1 kg/m² increase in BMI was related to a 5.10-fold (4.44, 5.77) increment for men and 3.93-fold increment (3.42, 4.43) for women in SUA levels. The regression coefficient differences between the two stages were 12.84 (5.66, 20.03) for men and 6.63 (4.65, 8.61) for women.

Conclusions

A U-shaped relationship between BMI and SUA was found for both men and women; the association was stronger for men than women.

Hyperuricemia and long-term mortality in patients with acute myocardial infarction undergoing percutaneous coronary intervention

Background

Although serum uric acid (UA) was regarded to be involved in cardiovascular disease, the role of serum UA (SUA) as a risk factor in acute myocardial infarction (AMI) is controversial. We investigated whether hyperuricemia was linked with long-term mortality in patients with AMI who underwent percutaneous coronary intervention (PCI).

Methods

Patients with AMI who received PCI were consecutively included. The definition of preprocedural hyperuricemia was a SUA level >7 mg/dL (417 mmol/L) in males and >6 mg/dL (357 mmol/L) in females. All-cause mortality was assessed during 2.3-year median follow up period.

Results

One thousand and five patients with AMI undergoing PCI were enrolled in a single center study, 307 (30.5%) patients had hyperuricemia. After adjusting for potential confounding factors, the multivariable analysis indicated that preprocedural hyperuricemia was related to an increased risk of all-cause mortality during the 2.3-year follow-up (HR: 1.97; 95% CI: 1.11-3.49; P=0.019).

Conclusions

Preprocedural hyperuricemia, independently from chronic kidney disease (CKD), is a significant and independent predictor of long-term mortality for patients with AMI who underwent PCI.

Serum Uric Acid - Risk Factor for Acute Ischemic Stroke and Poor Outcomes

Over the last decades several studies among the adult population have attempted to establish a correlation between the risk of stroke incidence and serum uric acid (SUA) concentration, and how these levels influence the patient’s neurological outcome after a stroke. But, to date, the results are conflicting. In this review, an extensive literature search was performed through PubMed for articles published until May 2019 to review the association. The study selection was narrowed by searching PubMed database using the Medical Subject Headings (MesH) and associated keywords. Only articles conducted in English and on human subjects were included. We considered an article for this review if it had statistics on either the incidence, stroke mortality or post-stroke functional outcomes along with serum uric acid levels in adults.

This review includes 21 articles with data of 33,580 cases of stroke and 1,100,888 participants. We can divide the articles reviewed into two separate cohorts of studies. One relates serum uric acid levels to stroke frequency and mortality, while the other is associated with serum uric acid and outcomes for stroke survivors. Based on our review, no significant relationship is observed with uric acid exhibiting protective effects on stroke outcome. Large clinical trials are advised to provide well-defined solutions to further assess the benefits of uric acid level lowering treatment in patients of vascular events, such as a stroke. However, we confidently report that increasing uric acid levels poses a higher risk for incidence of stroke.

Effects of Uric Acid on Diabetes Mellitus and Its Chronic Complications

With the deepening of the researches on uric acid, especially in the study of metabolic diseases, uric acid has been found to be closely related to obesity, metabolic syndrome, nonalcoholic fatty liver disease, diabetes, and other metabolic diseases. Uric acid causes a series of pathophysiological changes through inflammation, oxidative stress, vascular endothelial injury, and so on and thus subsequently promotes the occurrence and development of diseases. This review confirmed the positive correlation between uric acid and diabetes mellitus and its chronic complications through the pathogenesis and clinical studies aspects.

High Levels of Serum Uric Acid, Cystain C and Lipids Concentration and their Clinical Significance in Primary Gouty Arthritis Patients

OBJECTIVE

To investigate the changes of serum Uric Acid (sUA), lipids and Cystatin C (CysC) in primary gout patients, and to explore the clinical significance in gout patients.

METHODS

sUA, CysC, high-sensitivity C-reactive Protein (hsCRP) and other biochemical parameters were measured in 326 gout patient and 210 healthy control subjects, blood cell counts were also detected. Clinical data were collected from gout patients.

RESULTS

sUA, CysC, hsCRP, Body Mass Index (BMI), White Blood Cell (WBC) counts, neutrophil Granulocyte (GR), Monocyte (Mo), Triglycerides (TG), plasma Total Cholesterol (TC), Very Low Density Lipoprotein (VLDL), apolipoprotein B100 (apoB100), Blood Glucose (GLU), serum Creatinine (sCr) and Urea Nitrogen (BUN) were significantly increased in gout patients compared with HC subjects (P<0.01, respectively), while lymphocyte counts and High Density Lipoprotein- Cholesterol (HDL-C) were significantly decreased in gout patients compared with HC subjects (P<0.01, respectively). Positive correlations were observed between concentration of sUA and age, TG, VLDL, sCr and CysC (P<0.05, respectively). While negative correlations were observed between the concentration of sUA and HDL-C(P<0.01). Besides, Positive correlations were observed between concentration of CysC and WBC, GR, Mo, apoA1, GLU, sCr, BUN, sUA, hsCRP (P<0.05, respectively). While negative correlations were observed between the concentration of CysC and TC, LDL-C(P<0.01, respectively).

CONCLUSIONS

Blood lipid profile changes in gout patients. Gout patients who suffer from lipid metabolism disorder and vascular diseases might be associated with hyperuricemia, which leads to endothelial cell damage and vascular smooth muscle cell proliferation. CysC might be a marker for renal function damage and inflammation. Hyperuricemia is the risk factor of renal disorder in gout patients.

Higher Pro-Inflammatory Dietary Score is Associated with Higher Hyperuricemia Risk: Results from the Case-Controlled Korean Genome and Epidemiology Study_Cardiovascular Disease Association Study

In previous studies, the elevated dietary inflammatory index (DII®) scores have been consistently associated with several chronic diseases. However, the relationship with hyperuricemia remains unknown. The aim of this study was to determine if the DII is associated with hyperuricemia risk. The study included 13,701 participants (men 5102; women 8599) in a large-scale cross-sectional study in South Korea. A validated semi-quantitative food frequency questionnaire (SQFFQ) was used to measure dietary intake, and blood samples were obtained to determine hyperuricemia. As the DII score increased, the hyperuricemia risk increased among women (OR 1.35, 95% CI 1.03-1.77, p trend = 0.02). However, no significant results were found for men. Women with lower BMI scores had higher risks of hyperuricemia with higher DII scores (OR 1.62, 95% CI 1.05-2.52, p trend = 0.03). As the DII increased, however, only women who consumed alcohol ("past or current drinkers") had higher risks of hyperuricemia (OR 1.92, 1.22-3.02, p trend = 0.004). Among the DII components, intake of flavonoids showed a significant association with the hyperuricemia risk in women (OR 0.75, 0.59-0.96, p trend = 0.03). Our results suggest that higher intake of pro-inflammatory diet is significantly associated with higher risk of hyperuricemia among women. These results reinforce the importance of less pro-inflammatory habitual dietary patterns in lowering the risk of hyperuricemia and secondary afflictions such as cardiovascular diseases.

Uraemic syndrome of chronic kidney disease: altered remote sensing and signalling

Uraemic syndrome (also known as uremic syndrome) in patients with advanced chronic kidney disease involves the accumulation in plasma of small-molecule uraemic solutes and uraemic toxins (also known as uremic toxins), dysfunction of multiple organs and dysbiosis of the gut microbiota. As such, uraemic syndrome can be viewed as a disease of perturbed inter-organ and inter-organism (host-microbiota) communication. Multiple biological pathways are affected, including those controlled by solute carrier (SLC) and ATP-binding cassette (ABC) transporters and drug-metabolizing enzymes, many of which are also involved in drug absorption, distribution, metabolism and elimination (ADME). The remote sensing and signalling hypothesis identifies SLC and ABC transporter-mediated communication between organs and/or between the host and gut microbiota as key to the homeostasis of metabolites, antioxidants, signalling molecules, microbiota-derived products and dietary components in body tissues and fluid compartments. Thus, this hypothesis provides a useful perspective on the pathobiology of uraemic syndrome. Pathways considered central to drug ADME might be particularly important for the body's attempts to restore homeostasis, including the correction of disturbances due to kidney injury and the accumulation of uraemic solutes and toxins. This Review discusses how the remote sensing and signalling hypothesis helps to provide a systems-level understanding of aspects of uraemia that could lead to novel approaches to its treatment.

Beneficial effects of SGLT2 inhibitors on fatty liver in type 2 diabetes: A common comorbidity associated with severe complications

Patients with type 2 diabetes mellitus (T2DM) are exposed to non-alcoholic fatty liver disease (NAFLD), a comorbidity associated with cardiovascular disease and chronic kidney disease, and which may progress to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. Sodium-glucose cotransporter type-2 (SGLT2) inhibitors are glucose-lowering agents that improve glucose control while promoting weight loss and lowering serum uric acid levels. These agents may exert cardiovascular and renal protection in T2DM patients with established cardiovascular disease. Recent findings from both randomized controlled trials and open-label studies have also shown that SGLT2 inhibitors are able to reduce fatty liver content, as assessed by different imaging techniques, and improve biological markers of NAFLD, especially serum liver enzymes, in patients with T2DM. In addition, there are emerging data to suggest a mechanism beyond the reduction of hyperglycaemia and body weight, and a potential role for the decrease in low-grade inflammation and oxidative stress associated with SGLT2 inhibitor therapy. This positive effect of SGLT2 inhibitors on NAFLD complements their already well-known effects on cardiovascular and chronic kidney diseases.

A New Insight into the Roles of MiRNAs in Metabolic Syndrome

Metabolic syndrome (MetS), which includes several clinical components such as abdominal obesity, insulin resistance (IR), dyslipidemia, microalbuminuria, hypertension, proinflammatory state, and oxidative stress (OS), has become a global epidemic health issue contributing to a high risk of type 2 diabetes mellitus (T2DM). In recent years, microRNAs (miRNAs), used as noninvasive biomarkers for diagnosis and therapy, have aroused global interest in complex processes in health and diseases, including MetS and its components. MiRNAs can exist stably in serum, liver, skeletal muscle (SM), heart muscle, adipose tissue (AT), and βcells, because of their ability to escape the digestion of RNase. Here we first present an overall review on recent findings of the relationship between miRNAs and several main components of MetS, such as IR, obesity, diabetes, lipid metabolism, hypertension, hyperuricemia, and stress, to illustrate the targeting proteins or relevant pathways that are involved in the progress of MetS and also help us find promising novel diagnostic and therapeutic strategies.

Increases in circulating levels of ketone bodies and cardiovascular protection with SGLT2 inhibitors: Is low-grade inflammation the neglected component?

Recent clinical trials have demonstrated a strong cardiovascular (CV) protective effect of sodium/glucose cotransporter (SGLT) 2 inhibitors, a recently introduced class of hypoglycaemic agents. The improvement in glycated haemoglobin and other conventional risk factors explains only a portion of the observed reduction in CV risk. A relevant feature of SGLT2-inhibitor-treated diabetic patients is the increase in circulating levels of ketone bodies, which has been proposed to mediate part of the beneficial effects of this class of drugs, mainly through their bioenergetic properties. However, ketone bodies are emerging as potent anti-inflammatory molecules, and inflammation is a recognized risk factor for the development of CV events. In this framework, we hypothesize that, through their unique mechanism of action and by increasing circulating ketone bodies, SGLT2 inhibitors indirectly target the IL-1β pathway and thus produce a consistent amelioration of low-grade inflammation, a clinically relevant phenomenon in diabetic patients with high CV risk. This attenuation could slow the progression of CV disease and especially the atherosclerotic process, which is sensitive to environmental changes, even over a short time period. To test this conceptual structure, it would be necessary to measure circulating pro-inflammatory molecules in patients treated with SGLT inhibitors. The addition of inflammatory markers to the list of clinical data measured in FDA-requested, large CV outcome trials could provide supplementary information regarding potential secondary effects of new anti-hyperglycaemic drugs, considering that the inflammatory process is an often neglected cornerstone of CV diseases.

Effects of SGLT2 inhibitors on systemic and tissue low-grade inflammation: The potential contribution to diabetes complications and cardiovascular disease

Chronic low-grade inflammation is a recognized key feature associated with type 2 diabetes mellitus (T2DM) and its complications. In prospective randomized trials, sodium-glucose cotransporter type 2 (SGLT2) inhibitors have demonstrated benefits related to several cardiovascular and renal risk factors, including HbA_1c, blood pressure, body weight, renal hyperfiltration, and improvement of cardiorenal outcomes. SGLT2 inhibitors may improve adipose tissue function and induce decreases in serum leptin, TNF-α and IL-6 while increasing adiponectin. While data on high-sensitivity C-reactive protein and other inflammatory markers are relatively scarce in humans, in animals, a number of reports have shown reductions in cytokine and chemokine concentrations in parallel with protective effects against progression of atherosclerotic lesions. Experimental findings also suggest that part of the renoprotective effects of SGLT2 inhibition may be related to anti-inflammatory actions at the kidney level. Underlying mechanisms to explain this anti-inflammatory effect are multiple, but may involve weight loss, and reduction in adipose tissue inflammation, slight increase in ketone bodies and diminution of uric acid levels or attenuation of oxidative stress. However, further studies in diabetes patients with specific assessment of inflammatory markers are still necessary to determine the specific contribution of the anti-inflammatory action of SGLT2 inhibitors to the reduction of cardiovascular and renal complications and mortality observed with this class of antidiabetic drugs.

The baseline levels and risk factors for high-sensitive C-reactive protein in Chinese healthy population

BACKGROUND

Recent studies show that C-reactive protein (CRP) is not only a biomarker but also a pathogenic mediator contributing to the development of inflammation and ageing-related diseases. However, serum levels of CRP in the healthy ageing population remained unclear, which was investigated in the present study.

METHODS

Serum levels of high sensitive C-reactive protein (hs-CRP), glucose (Glu), triglyceride (TG), cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), superoxide dismutase (SOD), serum creatinine (SCr), serum uric acid (SUA) were measured in 6060healthy subjects (3672 male and 2388 female, mean age:45.9 years) who received routine physical examination at Sun Yat-sen Memorial Hospital, Guangzhou, China.

RESULTS

In total of 6060 healthy people, serum levels of hs-CRP were significantly increased with ageing (P < 0.05), particularly in those with age over 45-year-old (1.31[0.69-2.75] vs 1.05[0.53-2.16]mg/L, P < 0.001). Interestingly, levels of serum hs-CRP were significantly higher in male than female population (1.24[0.65-2.57] vs 1.07[0.53-2.29]mg/L, P < 0.001). Correlation analysis also revealed that serum levels of hs-CRP positively correlated with age and SUA, but inversely correlated with serum levels of HDL-c and SOD (all P < 0.05).

CONCLUSIONS

Baseline levels of serum hs-CRP are increased with ageing and are significantly higher in male than female healthy population. In addition, elevated serum levels of hs-CRP are also associated with increased SUA but decreased HDL-c and SOD. Thus, serum levels of hs-CRP may be an indicator associated with ageing in healthy Chinese population.

One-Hour Postload Hyperglycemia: Implications for Prediction and Prevention of Type 2 Diabetes

CONTEXT

Recently, a value of 1-hour postload glucose concentration (1-h-PG) ≥155 mg/dL (8.6 mmol/L) in individuals with normal glucose tolerance (NGT) has been found to be associated with an increased risk for future type 2 diabetes mellitus (T2DM). In this review, we analyze the implication of 1-h-PG determination in prediction of T2DM and cardiovascular disease.

DESIGN

A literature search was performed using MEDLINE. We included all English studies published up to February 2018 in peer-reviewed journals that examined the relationship between 1-h-PG and diabetes, cardiometabolic alterations, organ damage, and cardiovascular disease.

RESULTS

Several longitudinal studies have consistently shown that 1-h-PG ≥155 mg/dL can recognize individuals at increased risk for future T2DM among subjects with NGT. Additionally, we describe the pathophysiological abnormalities associated with 1-h-PG ≥155 mg/dL including impaired insulin sensitivity, β-cell dysfunction, and increased glucose intestinal absorption, which are known to be involved in T2DM pathogenesis. Importantly, numerous studies have demonstrated that a value of 1-h-PG ≥155 mg/dL in individuals with NGT is not only linked to an increased risk for future T2DM, but also able to identify those having a worse cardiovascular phenotype and an increased risk of adverse cardiovascular outcomes.

CONCLUSIONS

Although 1-h-PG determination is not currently recommended by the American Diabetes Association for identifying high-risk individuals, the available evidence indicates that a value of 1-h-PG ≥155 mg/dL may be a useful tool to recognize, among subjects with NGT, those at increased risk of T2DM and cardiovascular disease.

Higher serum levels of uric acid are associated with a reduced insulin clearance in non-diabetic individuals

AIMS

Decreased insulin clearance has been reported to be associated with insulin resistance-related disorders and incident type 2 diabetes. The aim of this study was to evaluate whether higher levels of uric acid (UA), a known risk factor of type 2 diabetes, are associated with a reduced insulin clearance.

METHODS

440 non-diabetic individuals were stratified in tertiles according to serum UA levels. Insulin clearance and skeletal muscle insulin sensitivity were assessed by euglycemic hyperinsulinemic clamp. Hepatic insulin resistance was estimated by the liver IR index.

RESULTS

Subjects with higher levels of UA displayed an unfavorable metabolic phenotype with a worse lipid profile, increased levels of 2-h post-load glucose levels, fasting, and 2-h post-load insulin levels, hsCRP, liver IR index, and lower levels of eGFR and skeletal muscle insulin sensitivity, in comparison to individuals with lower UA levels. Moreover, subjects with higher UA concentrations exhibited decreased levels of insulin clearance even after adjustment for age, gender, BMI, eGFR, and skeletal muscle insulin sensitivity. In a multivariate regression analysis model including several confounding factors, UA concentration was an independent predictor of insulin clearance (β = - 0.145; P = 0.03). However, when liver IR index was included in the model, the independent association between UA levels and insulin clearance was not retained. Accordingly, in a mediation analysis, liver IR index was a mediator of the negative effects of UA levels on insulin clearance (t = - 2.55, P = 0.01).

CONCLUSIONS

Higher serum levels of UA may affect insulin clearance by impairing hepatic insulin sensitivity.

Cellular Stresses and Stress Responses in the Pathogenesis of Insulin Resistance

Insulin resistance (IR), a key component of the metabolic syndrome, precedes the development of diabetes, cardiovascular disease, and Alzheimer's disease. Its etiological pathways are not well defined, although many contributory mechanisms have been established. This article summarizes such mechanisms into the hypothesis that factors like nutrient overload, physical inactivity, hypoxia, psychological stress, and environmental pollutants induce a network of cellular stresses, stress responses, and stress response dysregulations that jointly inhibit insulin signaling in insulin target cells including endothelial cells, hepatocytes, myocytes, hypothalamic neurons, and adipocytes. The insulin resistance-inducing cellular stresses include oxidative, nitrosative, carbonyl/electrophilic, genotoxic, and endoplasmic reticulum stresses; the stress responses include the ubiquitin-proteasome pathway, the DNA damage response, the unfolded protein response, apoptosis, inflammasome activation, and pyroptosis, while the dysregulated responses include the heat shock response, autophagy, and nuclear factor erythroid-2-related factor 2 signaling. Insulin target cells also produce metabolites that exacerbate cellular stress generation both locally and systemically, partly through recruitment and activation of myeloid cells which sustain a state of chronic inflammation. Thus, insulin resistance may be prevented or attenuated by multiple approaches targeting the different cellular stresses and stress responses.

Uric acid is an independent predictor of cardiac allograft vasculopathy after heart transplantation

BACKGROUND

Cardiac allograft vasculopathy (CAV) is a major complication after heart transplantation (HT). Uric acid (UA) may play a role in CAV due to its role in stimulating T-cell-mediated immunity. Sirolimus is associated with CAV attenuation through a number of mechanisms, including immune-mediated effects. We aimed to determine whether UA is an independent predictor of CAV and whether conversion to sirolimus as primary immunosuppression modulates UA levels.

METHODS

We retrospectively analyzed a cohort of 224 patients who underwent HT between 2004 and 2015 and had serial coronary intravascular ultrasound (IVUS) studies. Serum UA levels were measured at baseline and last follow-up IVUS in all participants. CAV progression was assessed by measuring the change in plaque volume (ΔPV) and plaque index (ratio of plaque volume to vessel volume [ΔPI]) between last follow-up and baseline IVUS after correction for time of follow-up.

RESULTS

Patients with high (≥7 mg/dl) compared with low (<7 mg/dl) UA had increased median ΔPV (0.33 [interquartile range 0.08 to 0.93] vs 0.07 [-0.17 to 0.38] mm³/mm/year; p < 0.001) and ΔPI (2.0% [0.31% to 3.9%] vs 0.33% [-1.2% to 2.0%]; p < 0.001). Elevated UA levels were associated with a significantly increased risk of developing significant CAV progression (ΔPV >0.50 mm³/mm) (hazard ratio 2.2, 95% confidence interval 1.1 to 4.6; p = 0.037). Sirolimus resulted in decreased UA levels (5.8 ± 1.4 vs 5.2 ± 1.5; p = 0.002) and patients converted to sirolimus and had low UA levels had the least CAV progression (p < 0.001). After adjustment for potential confounders, change in UA level was also an independent predictor of CAV progression.

CONCLUSIONS

UA is an independent predictor of CAV after HT. Sirolimus is associated with decreased UA levels and may explain one of the mechanisms by which sirolimus attenuates CAV progression.

Uric acid is associated with long-term adverse cardiovascular outcomes in patients with acute coronary syndrome undergoing percutaneous coronary intervention

BACKGROUND AND AIMS

Evidence links uric acid (UA) with the promotion of cardiovascular disease. We assessed the prognostic value of UA on long-term major adverse outcomes (MACE) in patients with acute coronary syndrome (ACS), undergoing percutaneous coronary intervention (PCI).

METHODS

As primary endpoint, we assessed the association of UA (continuous and dichotomized) with MACE, including cardiovascular death, myocardial infarction (MI) and stroke, using Cox regression and propensity matching. As secondary endpoints, the influence of hyperuricemia (defined as UA levels > 6.0 mg/dl in women, and >7.0 mg/dl in men) was analysed separately for cardiovascular death, MI, and stroke. The incremental prognostic value of UA was tested using the net reclassification improvement (NRI), and the integrated discrimination improvement (IDI).

RESULTS

We included 1215 patients. Hyperuricemia was present in 356 (29.3%) patients. Mean follow-up was 5.5 years. UA (HR 1.091 [1.035-1.150]; p = 0.001) and hyperuricemia (HR 1.750 [1.388-2.207]; p < 0.001) were significantly associated with MACE. Results were consistent between Cox regression and propensity matched analysis. Patients with hyperuricemia had a 1.6-fold increased relative risk for cardiovascular death (p = 0.005) and a 1.5-fold increased risk for MI (p = 0.032). For stroke, hyperuricemia only constituted a confounder (HR 1.104; p = 0.970). The prognostic accuracy of an established risk prediction model was significantly increased by adding UA (continuous NRI p = 0.004; categorical NRI p = 0.029; IDI p = 0.002).

CONCLUSIONS

Our data suggest an independent association of elevated UA with long-term MACE in ACS patients undergoing PCI. Whether lowering UA might be beneficial remains to be elucidated in large clinical trials.

Uric Acid Impairs Insulin Signaling by Promoting Enpp1 Binding to Insulin Receptor in Human Umbilical Vein Endothelial Cells

High levels of uric acid (UA) are associated with type-2 diabetes and cardiovascular disease. Recent pieces of evidence attributed to UA a causative role in the appearance of diabetes and vascular damage. However, the molecular mechanisms by which UA induces these alterations have not been completely elucidated so far. Among the mechanisms underlying insulin resistance, it was reported the role of a transmembrane glycoprotein, named either ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) or plasma cell antigen 1, which is able to inhibit the function of insulin receptor (I_R) and it is overexpressed in insulin-resistant subjects. In keeping with this, we stimulated human umbilical vein endothelial cells (HUVECs) with insulin and UA to investigate the effects of UA on insulin signaling pathway, testing the hypothesis that UA can interfere with insulin signaling by the activation of ENPP1. Cultures of HUVECs were stimulated with insulin, UA and the urate transporter SLC22A12 (URAT1) inhibitor probenecid. Akt and endothelial nitric oxide synthase (eNOS) phosphorylation levels were investigated by immunoblotting. ENPP1 binding to I_R and its tyrosine phosphorylation levels were tested by immunoprecipitation and immunoblotting. UA inhibited insulin-induced Akt/eNOS axis. Moreover, UA induced ENPP1 binding to I_R that resulted in an impairment of insulin signaling cascade. Probenecid reverted UA effects, suggesting that UA intracellular uptake is required for its action. In endothelial cells, UA directly interferes with insulin signaling pathway at receptor level, through ENPP1 recruitment. This evidence suggests a new molecular model of UA-induced insulin resistance and vascular damage.

Inflammageing and metaflammation: The yin and yang of type 2 diabetes

Type 2 diabetes mellitus (T2DM) is characterised by chronic low-grade inflammation, recently referred to as 'metaflammation', a relevant factor contributing to the development of both diabetes and its complications. Nonetheless, 'canonical' anti-inflammatory drugs do not yield satisfactory results in terms of prevention of diabetes progression and of cardiovascular events, suggesting that the causal mechanisms fostering metaflammation deserve further research to identify new druggable targets. Metaflammation resembles ageing-induced low-grade inflammation, previously referred to as inflammageing, in terms of clinical presentation and the molecular profile, pointing to a common aetiology for both conditions. Along with the mechanisms proposed to fuel inflammageing, here we dissect a plethora of pathological cascades triggered by gluco- and lipotoxicity, converging on candidate phenomena possibly explaining the enduring pro-inflammatory program observed in diabetic tissues, i.e. persistent immune-system stimulation, accumulation of senescent cells, epigenetic rearrangements, and alterations in microbiota composition. We discuss the possibility of harnessing these recent discoveries in future therapies for T2DM. Moreover, we review recent evidence regarding the ability of diets and physical exercise to modulate selected inflammatory pathways relevant for the diabetic pathology. Finally, we examine the latest findings showing putative anti-inflammatory mechanisms of anti-hyperglycaemic agents with proven efficacy against T2DM-induced cardiovascular complications, in order to gain insights into quickly translatable therapeutic approaches.

Baseline and changes in serum uric acid independently predict glucose control among community-dwelling women

BACKGROUND

Elevated serum uric acid (SUA) levels are associated with glucose control. However, whether baseline and changes in SUA predict long-term follow-up glucose control [e.g., glycated hemoglobin (HbA1c)] remains unclear.

METHODS

The subjects comprised 393 women aged 71 ± 8 years and 279 men aged 71 ± 10 years from a rural village. We have identified participants who underwent a similar examination 11 years prior, and subjects were divided into four groups based on the tertiles of baseline and changes in SUA, and examined the relationship between baseline and changes in SUA, and glucose control evaluated by follow-up HbA1c after 11-years.

RESULTS

In both genders, follow-up SUA were significantly higher in Group 4 (i.e., women: Group 4, baseline SUA ≥ 4.0 mg/dL and changes in SUA ≥ 0.8 mg/dL; men: Group 4, ≥ 5.3 mg/dL and ≥ 0.4 mg/dL) than in the other Groups, but eGFR was significantly lower. Only in women, there were significant differences among the four groups regarding follow-up HbA1c, and follow-up HbA1c was highest in Group 4. In addition, the interaction between baseline and changes in SUA (F = 5.391, p = 0.021) as well as baseline low-density lipoprotein cholesterol (LDL-C) (F = 13.793, p < 0.001), estimated glomerular filtration ratio (F = 10.715, p = 0.001), HbA1c (F = 118.285, p < 0.001), SUA (F = 9.457, p = 0.002), and changes in SUA (F = 7.757, p = 0.006) was a significant and independent determinant of follow-up HbA1c. Multivariate-adjusted follow-up HbA1c (p = 0.002) were significantly higher in Group 4 than the other groups.

CONCLUSIONS

These results suggested that combined assessment of baseline and changes in SUA provides increased information for long-term predictive glucose control, independent of other confounding factors in community-dwelling women.

Total Bilirubin in Prognosis for Mortality in End-Stage Renal Disease Patients on Peritoneal Dialysis Therapy

Background

Evidence regarding bilirubin's antioxidant properties and predictive roles is growing. However, it is unclear whether serum bilirubin would have a prognostic impact on survival of patients with regular peritoneal dialysis.

Methods and Results

We used the Taiwan Renal Registry Data System utilizing its 2005‐2012 data set. Data from patients on regular peritoneal dialysis were retrieved. The primary end point of observation was 3‐year mortality. A total of 3704 patients (mean age 53.5 years, 44% male) were enrolled, and these patients were divided according to baseline serum total bilirubin levels (<0.3, 0.3‐0.4, 0.4‐0.5, 0.5‐0.6, >0.6 mg/dL). Serum total bilirubin level was linearly related to age, incidence of hypertension, and type 2 diabetes mellitus. At the end of the observation period with a mean follow‐up of 2.12±1.07 years, 1095 (30.6%) deaths were detected. Serum total bilirubin level and 3‐year mortality rate presented a U‐shaped relationship. Those with serum total bilirubin 0.5 to 0.6 mg/dL had the lowest 3‐year mortality rate (24%). After adjustment for age, sex, underlying systemic disorders, medications, and laboratory discrepancies, serum total bilirubin still played an independent role for predicting 3‐year mortality.

Conclusions

Baseline serum total bilirubin level is significantly associated with 3‐year mortality among patients receiving regular peritoneal dialysis.

OTUD7B upregulation predicts a poor response to paclitaxel in patients with triple-negative breast cancer

Paclitaxel is a first-line chemotherapeutic for patients with breast cancer, particularly triple-negative breast cancer (TNBC). Molecular markers for predicting pathologic responses to paclitaxel treatment is thus urgently needed since paclitaxel resistance is still a clinical issue in treating TNBCs. We investigated the transcriptional profiling of consensus genes in HCC38 (paclitaxel-sensitive) and MDA-MB436 (paclitaxel-resistant) TNBC cells post-treatment with paclitaxel. We found that OTUD7B was downregulated in HCC38 but upregulated in MDA-MB436 cells after paclitaxel treatment at cytotoxic concentrations. Moreover, our data showed that OTUD7B expression causally correlated with IC₅₀ of paclitaxel in a panel of TNBC cell lines. Moreover, we found that OTUD7B upregulation was significantly detected in primary breast cancer tissues compared to normal breast tissues but inversely correlated with tumor growth in TNBC cells. Besides, the increased levels of OTUD7B transcript appeared to causally associate with invasive potentials in TNBC cells. In assessments of recurrence/metastasis-free survival probability, high-levels of OTUD7B transcripts strongly predicted a poor prognosis and unfavorable response to paclitaxel-based chemotherapy in patients with TNBCs. In silico analysis suggested that OTUD7B regulation, probably owing to miR-1180 downregulation, may negatively regulate the NF-κB-Lin28 axis which in turn triggers Let-7 microRNA-mediated caspase-3 downregulation, thereby conferring paclitaxel resistance in TNBCs. These findings suggest that OTUD7B may be a useful biomarker for predicting the anti-cancer effectiveness of paclitaxel and could serve as a new drug target for enhancing the canceridal efficiency of paclitaxel against TNBCs.

The role of hyperuricemia on vascular endothelium dysfunction

Hyperuricemia appears to be associated with an increased risk for cardiovascular disease and associated mortality. Population epidemiological data support a causal link between hyperuricemia and cardiovascular disease. Endothelium injury could be one of the potential mechanisms in hyperuricemia-induced cardiovascular disease. However, the specific role of uric acid (UA) in the impairment of vascular relaxation and its signal transduction pathway has not been examined. The authors investigated the role of UA on vascular relaxation, nitric oxide (NO) production and expression of proinflammatory cytokines. Brachial flow-mediated dilation and nitroglycerine-mediated dilation were measured by B-mode ultrasound with 10 megahertz linear-array transducer from 21 patients with hyperuricemia and 16 control subjects. Human umbilical vein endothelial cells (ECs) were incubated with UA (5-15 mg/dl) with or without nuclear factor (NF)-κB inhibitor II. Hyperuricemia inhibited brachial flow-mediated dilation. While UA significantly inhibited NO expression with time course- and dose- dependent manner in the cultured ECs, 10 mg/dl UA also increased expression of inflammation cytokine interleukin (IL)-6, IL-8 and tumor necrosis factor-α in vitro. These abnormalities were associated with UA-induced activation of transcription factor NF-κB. Furthermore, NF-κB inhibitor II prevented UA-induced reduction of NO and increased inflammation cytokines. These data suggested hyperuricemia-induced endothelium injury and vascular dysfunction by a reduction of NO and expression of inflammatory cytokines through the NF-κB pathway.