Purpose: This study aims to investigate the relationship between serum uric acid levels and endothelial function, oxidative stress, and hemodynamic parameters, and to determine if uric acid levels provide additional insights beyond traditional factors like ageing and hypertension in volunteers with low cardiovascular risk factors. Serum uric acid is known for its antioxidant properties, but it may also contribute to cardiovascular risk.
Materials and methods: The study enrolled 40 male participants, divided into three groups based on age and blood pressure status. Group 1 comprised younger participants, group 2 included older individuals without hypertension, and group 3 consisted of older patients with hypertension. The study assessed endothelial function using laser Doppler imaging and measured acetylcholine- and sodium nitroprusside-induced hyperaemia. The heat microcirculatory response was also examined in the presence of L-NAME, an inhibitor of NOS synthase. The study evaluated oxidative stress and arterial stiffness by measuring allantoin, angiotensin II, Homocitrulline/Lysine, and Chloro-Tyrosine/Tyrosine ratios, as well as by performing non-invasive measurements of aortic augmentation indexes and carotid-femoral pulse wave velocity.
Results: The study found that uric acid levels did not differ significantly among the three groups. Augmentation indexes increased with ageing, but hypertension did not have an additional effect. Blood pressure and carotid-femoral pulse wave velocity differed among the groups, with the lowest values among younger participants and the highest values among older individuals with hypertension. Allantoin and angiotensin II levels did not differ among the groups. However, Homocitrulline/Lysine and Chloro-Tyrosine/Tyrosine ratios were significantly lower in young subjects. Correlation and multivariable analysis showed that uric acid had no effect on any of the studied parameters. Despite a strong association between ageing and systolic blood pressure with impaired endothelial function, oxidative stress, and arterial stiffness, only ageing retained a significant effect in the multivariable analysis.
Conclusion: In healthy or hypertensive adults with normal renal function, serum uric acid appears to be a futile bystander in endothelial function, oxidative stress, and arterial stiffness, in contrast to ageing, which reduces NO bioavailability. This study suggests that traditional factors such as ageing and hypertension should be the focus of clinical assessment and management of cardiovascular risk, rather than uric acid levels.
Keywords: https://clinicaltrials.gov/ct2/show/NCT03395977; Blood pressure; NCT03395977; age; arterial stiffness; cardiovascular risk factor; endothelium; oxidative stress; serum uric acid.
Plain Language SummaryOur study aimed to investigate the potential role of serum uric acid in endothelial function, oxidative stress, and arterial stiffness in healthy and hypertensive adults with normal renal function. We enrolled 40 males, divided into three groups based on age and blood pressure status, and assessed several parameters related to endothelial function, oxidative stress, and arterial stiffness.Our findings suggest that serum uric acid does not play a significant role in these parameters in healthy or hypertensive adults with normal renal function. Instead, ageing appears to be the primary factor contributing to impaired endothelial function, oxidative stress, and arterial stiffness.This study adds to the growing body of literature on the potential role of uric acid in cardiovascular risk and highlights the importance of considering age as a key factor in understanding endothelial dysfunction, oxidative stress, and arterial stiffness. Uric acid level should not be systematically determined in patients with low cardiovascular risk profile in clinical practice.