Overnight changes in uric acid, xanthine oxidoreductase and oxidative stress levels and their relationships with sleep-disordered breathing in patients with coronary artery disease

Current updates and future perspectives in uric acid research, 2024

Uric acid, the final product of purine metabolism, plays a significant role in hypertension Research on uric acid has advanced significantly, particularly regarding its links to hypertension and cardiovascular disease (CVD). Our 2023 review covered the relationship between uric acid, hypertension; and CVD, however, numerous new studies have emerged since then. This paper provides an update, summarizing recent findings over the past two years on hyperuricemia and its association with hypertension, preeclampsia, arteriosclerosis, kidney disease, sleep-disordered breathing, CVD, and so on. Hyperuricemia, often driven by reduced uric acid excretion or increased production, is influenced by genetic factors and lifestyle habits, including high-purine foods, alcohol, and fructose intake. While hyperuricemia has been proposed to contribute to hypertension and CVD through mechanisms like inflammasome activation and oxidative stress, its causal role remains debated. Further clinical and basic science studies on hyperuricemia and purine metabolism are necessary to clarify its impact on CVD and guide therapeutic approaches.

Associations of elevated cardiac biomarkers with hyperuricemia and mortality in US adults without prevalent cardiovascular disease

Background

NT-proBNP (N-terminal pro-B-type natriuretic peptide), high-sensitivity cardiac troponin T (hs-troponin T), and high-sensitivity cardiac troponin I (hs-troponin I) have been widely recognized as significant cardiac biomarkers, and are increasingly being recommended for early risk identification in cardiovascular high-risk populations. The aim of our study was to evaluate the prevalence of elevated cardiac biomarkers (NT-proBNP, hs-troponin T, hs-troponin I) and their association with the risk of hyperuricemia in the general US adults without known cardiovascular disease. We further studied whether elevated cardiac biomarkers are associated with an increased risk of all-cause and cardiovascular mortality in individuals with or without hyperuricemia.

Methods

The study population came from the adults (age ≥20y) without prevalent cardiovascular disease in NHANES (National Health and Nutrition Examination Survey) 1999 to 2004. We evaluated the prevalence of elevated cardiac biomarkers among adults with or without hyperuricemia, and conducted a comprehensive multivariate logistic regression analysis to ascertain the association between elevated cardiac biomarkers and hyperuricemia risk. Multivariate Cox regression model and Kaplan-Meier curve, risk competition model and Cumulative Incidence Function(CIF) were used respectively to examine the associations between elevated cardiac biomarkers with all-cause and cardiovascular mortality.

Results

In general US adults without known cardiovascular disease, the prevalence of hyperuricemia was 16.35%. The age-adjustd prevalence of elevated NT-proBNP (≥125 pg/mL), hs-troponin T (≥6 ng/L), and hs-troponin I (male ≥6, female ≥4 ng/L) was 16.70%, 49.80%, and 11.91%, respectively, among adults with hyperuricemia. Adjusted multivariable logistic regression analysis revealed a statistically significant association between elevated levels of NT-proBNP, hs-troponin T, and hs-troponin I and hyperuricemia, and different clinical categories observed grade differences on the same cardiac biomarker. Elevated NT-proBNP, hs-troponinT and hs-troponinI were each significantly positively associated with the cumulative incidence of all-cause and cardiovascular mortality in adults with or without hyperuricemia. Compared to those with elevated cardiac biomarkers only, adults with hyperuricemia and elevated cardiac biomarkers faced the highest risk of all-cause and cardiovascular mortality.

Conclusions

Our study identified that elevated cardiac biomarkers pose a high burden on hyperuricemia risk in the general population without known cardiovascular disease, and further provides important information on long-term mortality risk in these populations. Routine testing of cardiac biomarkers may be useful for early risk identification and prognostic assessment in adults with hyperuricemia.

Mediterranean Diet and Cardiovascular Disease: The Moderating Role of Adequate Sleep-Results from the ATTICA Cohort Study (2002-2022)

The relationship between diet, sleep duration and cardiovascular disease (CVD) has not been well understood. The aim of the present study was to test the potential modifying role of sleep duration in the association between adherence to the Mediterranean-type diet (MD) and CVD risk. The study consisted of n = 313 initially free-of-CVD adults, from the ATTICA cohort study (2002-2022), with available information on sleep habits. Sleep habits were categorized as inadequate and adequate sleep duration (< or ≥7 h/day, respectively). In multi-adjusted analysis, MD adherence was inversely associated with CVD risk [Hazard Ratio-HR per 1/55 in MedDietScore: 0.80, 95% Confidence Interval-CI: 0.65, 0.98]. A significant interaction between sleep duration and MedDietScore was observed (p < 0.001). In subgroup analysis, the protective association between MD adherence and CVD risk was found only in participants who slept adequately, i.e., >7 h/day [HR:0.80, 95%CI: 0.65, 0.98]. Those who had a high adherence to the MD along with adequate sleep habits, had a 70% reduced 20-year CVD risk [HR:0.30, 95%CI: 0.11, 0.80], compared to those who had a low MD adherence and inadequate sleep habits. Sleep duration should be a part of an individual's lifestyle, together with dietary and other habits, to effectively evaluate CVD risk for future events.

Diurnal Variations in Serum Uric Acid, Xanthine, and Xanthine Oxidoreductase Activity in Male Patients with Coronary Artery Disease

Hyperuricemia is influenced by diet and can cause gout. Whether it is a potential risk factor for cardiovascular disease (CVD) remains controversial, and the mechanism is unclear. Similar to CVDs, gout attacks occur more frequently in the morning and at night. A possible reason for this is the diurnal variation in uric acid (UA), However, scientific data regarding this variation in patients with CVD are not available. Thus, we aimed to investigate diurnal variations in serum levels of UA and plasma levels of xanthine, hypoxanthine, and xanthine oxidoreductase (XOR) activity, which were measured at 18:00, 6:00, and 12:00 in male patients with coronary artery disease. Thirty eligible patients participated in the study. UA and xanthine levels significantly increased from 18:00 to 6:00 but significantly decreased from 6:00 to 12:00. By contrast, XOR activity significantly increased both from 18:00 to 6:00 and 6:00 to 12:00. Furthermore, the rates of increase in UA and xanthine levels from night to morning were significantly and positively correlated. In conclusion, UA and xanthine showed similar diurnal variations, whereas XOR activity showed different diurnal variations. The morning UA surge could be due to UA production. The mechanism involved XOR activity, but other factors were also considered.