Níveis séricos elevados de ácido úrico estão associados à oxidação de nucleosídeos em pacientes com diabetes mellitus tipo 2

Abstract

Uric acid, even in physiologic levels, is capable of causing damage to biomolecules through some mechanisms. Especially, hyperuricemia is capable of favor the formation of intracellular radical species, thus, contributing to the occurrence of products of nucleoside oxidation, including the 8-hydroxy-2’-deoxyguanosine (8- OHdG), a biomarker of this damage. It is known that patients with type 2 diabetes (T2D) have higher levels of nucleoside and deoxyribonucleic acid (DNA) oxidation compared to healthy individuals, however, little was explored in humans about the role of serum uric acid levels in promoting this damage in this population. Thus, the objective of this study was to evaluate the relationship between the levels of serum uric acid and the urinary concentrations of 8-OHdG, besides the influence of the glycemic control and other factors on this relationship, in patients with T2D and healthy individuals. In the University Hospital of Santa Maria, 61 patients were recruited, of those, 46 had T2D and were assisted at the Ambulatory of Endocrinology. The levels of uric acid, 8-OHdG and other parameters were measured. The patients were stratified according to the median of serum uric acid in the study population (< 5,3 mg/dL e ≥ 5,3 mg/dL). The patients with T2D who had higher levels of uric acid showed higher urinary levels of 8-OHdG compared to those with lower levels (20.0 [16.0–35.0] versus 16.6 [13.0–23.0] ng/mL, P=0.014, respectively). This association was not observed in the healthy individuals (P=0.483). Moreover, a significant positive correlation was observed between the two parameters (r = 0.40, P<0.01). Furthermore, the association was independent of factors such as hypertension, serum creatinine, body mass index, and gender. The glycemic control, inflammatory and oxidative parameters were similar in both groups, demonstrating that these factors did not contribute to the rise in 8-OHdG levels. According to the results, the association between the levels of serum uric acid and the urinary 8-OHdG in patients with T2D indicate that an elevation of uric acid can stimulate the nucleoside oxidation, independently of other factors.