Association between Serum Uric Acid Levels, Nutritional and Antioxidant Status in Patients on Hemodialysis

Association of serum uric acid levels with risk of epilepsy: A national population-based study

BACKGROUND

Uric acid (UA) serves as a crucial endogenous antioxidant in the body, offering protection against oxidative stress, whichmaycontributetoepilepsypathogenesis. The association between serum UA levels and epilepsy remains uncertain. This study aimed to examine the potential connections between serum UA levels and epilepsy in US adults.

METHODS

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2013-2018, a cross-sectional analysis was conducted. Weighted logistic regression analyses were employed to assess the potential link between serum UA levels and the risk of epilepsy. Additionally, sensitivity analyses were conducted to evaluate the reliability of the results.

RESULTS

We included 15,373 participants, of whom 136 (0.79 %) had epilepsy. Following adjustment for multiple variables, participants with serum UA levels <4.1 mg/dl had an odds ratio of 2.24 (95 % CI: 1.12-4.47, P = 0.023) for epilepsy compared to those with serum UA levels of 5.8-6.5 mg/dl. The results of the sensitivity analyses corroborated the initial findings.

CONCLUSIONS

Our study revealed a significant association between lower serum UA levels and heightened risks of epilepsy, suggesting that low UA levels may serve as an independent risk factor for epilepsy. A marginal increase in UA levels within the normal range may act as a protective factor against epilepsy.

Hyperuricemia and its related diseases: mechanisms and advances in therapy

Hyperuricemia, characterized by elevated levels of serum uric acid (SUA), is linked to a spectrum of commodities such as gout, cardiovascular diseases, renal disorders, metabolic syndrome, and diabetes, etc. Significantly impairing the quality of life for those affected, the prevalence of hyperuricemia is an upward trend globally, especially in most developed countries. UA possesses a multifaceted role, such as antioxidant, pro-oxidative, pro-inflammatory, nitric oxide modulating, anti-aging, and immune effects, which are significant in both physiological and pathological contexts. The equilibrium of circulating urate levels hinges on the interplay between production and excretion, a delicate balance orchestrated by urate transporter functions across various epithelial tissues and cell types. While existing research has identified hyperuricemia involvement in numerous biological processes and signaling pathways, the precise mechanisms connecting elevated UA levels to disease etiology remain to be fully elucidated. In addition, the influence of genetic susceptibilities and environmental determinants on hyperuricemia calls for a detailed and nuanced examination. This review compiles data from global epidemiological studies and clinical practices, exploring the physiological processes and the genetic foundations of urate transporters in depth. Furthermore, we uncover the complex mechanisms by which the UA induced inflammation influences metabolic processes in individuals with hyperuricemia and the association with its relative disease, offering a foundation for innovative therapeutic approaches and advanced pharmacological strategies.

The compelling role of allopurinol in hyperuricemia-induced epilepsy: Unrecognized like tears in rain

Epilepsy is a common neurological disease characterized by the recurrent, paroxysmal, and unprovoked seizures. It has been shown that hyperuricemia enhances and associated with the development and progression of epilepsy through induction of inflammation and oxidative stress. In addition, uric acid is released within the brain and contributes in the development of neuronal hyperexcitability and epileptic seizure. Brain uric acid acts as damage associated molecular pattern (DAMP) activates the immune response and induce the development of neuroinflammation. Therefore, inhibition of xanthine oxidase by allopurinol may reduce hyperuricemia-induced epileptic seizure and associated oxidative stress and inflammation. However, the underlying mechanism of allopurinol in the epilepsy was not fully elucidated. Therefore, this review aims to revise from published articles the link between hyperuricemia and epilepsy, and how allopurinol inhibits the development of epileptic seizure.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

Elevated serum uric acid is associated with cognitive improvement in older American adults: A large, population-based-analysis of the NHANES database

Background

The many studies revealing a connection between serum uric acid (SUA) and dementia have reported conflicting results. This study sought to investigate the relations between SUA and cognitive function in older adults.

Materials and methods

The sample was 2,767 American adults aged ≥60 years from the National Health and Nutrition Examination Survey 2011-2014. Cognitive performance was evaluated by the Consortium to Establish a Registry for Alzheimer's Disease test, animal fluency test, digit symbol substitution test, and composite z-score. Multivariate linear regression analyses were conducted to estimate the association between SUA and cognitive function.

Results

SUA level and cognitive function were significantly, positively correlated. Age significantly correlated with the association between SUA and cognitive function.

Conclusion

These findings support a connection between SUA and cognition, showing a positive link between SUA and cognitive scores among older American adults. We contend that a slight rise in uric acid within the normal range is advantageous for enhanced cognition. To confirm the precise dose-time-response relation, more tests will be needed.

A Brief Review of Natural Products with Urate Transporter 1 Inhibition for the Treatment of Hyperuricemia

Hyperuricemia is a common disease caused by a high level of uric acid. Urate transporter 1 (URAT1) is an important protein and mediates approximately 90% of uric acid reabsorption. Therefore, the URAT1 inhibitor is a class of uricosuric medicines widely used in the clinic for the treatment of hyperuricemia. To find the new medicine with stronger URAT1 inhibition and lower toxicity, researchers have been exploring natural products. This study systematically summarizes the natural products with URAT1 inhibition. The results show that many natural products are potential URAT1 inhibitors, such as flavonoids, terpenoids, alkaloids, coumarins, stilbenes, and steroids, among which flavonoids are the most promising source of URAT1 inhibitors. It is worth noting that most studies have focused on finding natural products with inhibition of URAT1 and have not explored their activities and mechanisms toward URAT1. By reviewing the few existing studies of the structure-activity relationship and analyzing common features of natural products with URAT1 inhibition, we speculate that the rigid ring structure and negative charge may be the keys for natural products to produce URAT1 inhibition. In conclusion, natural products are potential URAT1 inhibitors, and exploring the mechanism of action and structure-activity relationship will be an important research direction in the future.

Oxidative Stress Biomarkers and Their Association with Mortality among Patients Infected with SARS-CoV-2 in Mexico

Background

Activation of the immune system response is associated with the generation of oxidative stress (OS). Several alterations are involved in OS, such as excessive production of reactive oxygen species (ROS) and decreased antioxidant activity, which together lead to an imbalance in redox status. The role of OS during SARS-CoV-2 infection is not fully understood. The aim of this study was to determine OS biomarkers and assess their usefulness as a predictor of mortality in COVID-19 patients.

Methods

Baseline characteristics and serum samples were collected from hospitalized COVID-19 patients and compared with healthy controls. The serum OS biomarkers, including malondialdehyde (MDA) and total antioxidant capacity (TAC), were assessed by spectrophotometric and oxygen radical absorbance capacity (ORAC) methods, respectively.

Results

A total of 152 individuals were analyzed (COVID-19 patients vs. healthy controls). Compared with healthy controls (n = 76), patients infected with SARS-CoV-2 (n = 76) presented higher levels of MDA (p < 0.001) and decreased TAC (p < 0.001). A total of 37 (49%) patients with COVID-19 died. The area under the receiver operating characteristic (ROC) curve (AUC) estimated that the combination of the OS biomarkers (MDA+TAC) (AUC = 0.6394, p = 0.037) was a significant predictor of mortality. A higher level of MDA was associated with mortality (HR, 1.05, 95% CI, 1.00-1.10, p = 0.045).

Conclusion

This study concludes that OS is increased in patients with COVID-19 and is associated with mortality. To our knowledge, this is the first evidence of the expression of OS biomarkers and their association with mortality among the Mexican population.

The dose-response relationship between sex hormones and hyperuricemia in different gender: NHANES 2013-2016

OBJECTIVES

To access the dose-response relationship between sex hormones and hyperuricemia (HUA), and to find the cut-off value in different gender.

METHODS

9,685 participants were derived from the database of National Health and Nutrition Examination Survey (NHANES). Restricted cubic spline (RCS) analysis were applied to explore the relationship between sex hormones and HUA after adjusting for confounding factors by propensity score match (PSM). Logistic regression was used to estimate the odds ratio (OR) and 95% CI.

RESULTS

The prevalence of HUA was 15.13% in female participants and 22.30% in male participants. Logistic regression analysis showed that estradiol (E2) was independently associated with HUA for a P value of 0.003 and 0.01in female and male participants, respectively. Testosterone (T) was only independently associated with HUA in male participants (P&lt;0.001) but not in female participants (P = 0.59). RCS analysis showed a dose-response relationship between sex hormones and HUA. The risk of HUA increased as E2 lower than 29.6pg/mL in female participants and T lower than 389.1ng/dL in male participants. E2 higher than 23.6pg/ml was an independent risk factor for HUA in male participants.

CONCLUSION

A dose-response relationship was found between sex hormones and HUA. The cut-off value of E2 in male and female participants was 29.6pg/mL and 23.6pg/mL, respectively, and the cut-off value of T in male participants was 389.1ng/dL. These results provide a reference for preventing HUA and hormone supplement therapy.

Correlation analysis of low-level serum uric acid and cardiovascular events in patients on peritoneal dialysis

Background

The impact of serum uric acid (SUA) on development of cardiovascular disease (CVD) in patients undergoing peritoneal dialysis (PD) remains controversial, especially the impact of hypouricemia (HUA) on CVD. The aim of our study was to investigate the influence of low-level SUA on cardiovascular (CV) events in PD patients.

Methods

A retrospective cohort study was conducted.728 PD patients from February 1, 2010 to May 31, 2019 were enrolled. All demographic and laboratory data were collected at baseline and 6 months after PD treatment. The study cohort was divided into four groups according to SUA level (μmol/L) after 6 months of PD: Group1 (< 360), Group2 (360–420), Group3 (420–480), Group4 (≥ 480). The clinical characteristics of each group were analyzed. With Group2 as reference, logistic regression analysis was performed to investigate the correlation between SUA levels and risk of CV events in patients undergoing PD. Use Kaplan–Meier method to generate CV events risk graph.

Results

728 patients were enrolled in this study, including 403 (55.4%) males and 325 (44.6%) females, with an average age of 48.66 ± 13.98 years; of which 158 (21.7%) patients developed CV events. Multivariate COX regression showed that after adjusting for multiple clinical factors, Group1 (HR = 1.92, 95% CI 1.17–3.15, P = 0.01), Group3 (HR = 1.89, 95% CI 1.13–3.15, P = 0.015), and Group4 (HR = 2.38, 95% CI 1.35–4.19, P = 0.003) are all independent risk factors for developing CV events. The Kaplan–Meier risk curve of CV events showed that the risk of CV events in the Group1, Group3 and Group4 were significantly higher (Log-Rank = 12.67; P = 0.005). Restricted cubic spline (RCS) showed that SUA level is non-linearly associated with the risk of CV events, showing an U-shaped curve (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\chi_{4}^{2}$$\end{document}χ42=13.3 P = 0.01).

Conclusions

Our study suggested that patients with SUA level less than 360 μmol/L also exhibited the higher risk for developing CV events, an U-shaped association between SUA level and risk of CV events in patients undergoing PD. Both SUA levels below 360 μmol/L and above 420 μmol/L were found to be significant risk factors for developing CV events in patients undergoing long-term PD.