Could Tear Fluid Urate Be a Predictor for Ocular Inflammation in Asymptomatic Hyperuricemia and Gout Patients?

Background: Uric acid is a result of purine metabolism. Hyperuricemia can be caused by either excessive urate production or inadequate elimination. Asymptomatic hyperuricemia is estimated to occur in up to 21% of the general population and 25% of hospitalized patients. Objectives: This study aimed to investigate the presence of pro-inflammatory cytokines and their relationship to uric acid level in the tear fluid of individuals with hyperuricemia and gout. Patients and methods: For this investigation, a total of 90 control volunteers, 80 patients with hyperuricemia, including 65 with asymptomatic hyperuricemia, and 15 participants with gout were enrolled. After stimulation, capillary action microcaps were used to collect each patient's tears for analysis. Chemiluminescence was used to gauge the amount of uric acid in the tears. Using an enzyme-linked immunosorbent test, serum & tear interleukin-1beta (IL-1β) as well as tumor necrosis factor alpha (TNF-α) levels were measured. Also, serum & tear urate levels correlation with TNF-α and IL-1β were determined. Results: In comparison to control group, the hyperuricemia group had significantly higher tear urate levels (0.72±0.17 mg/dl vs. 1.65±0.4 mg/dl, P<0.001) and considerably higher levels of IL-1β (210.0±51.9 pg/ml vs. 143.4±29.6 pg/ml, P<0.001). Tear urate and IL-1β levels were independently positively correlated, according to multiple linear regression analysis (B=0.191, P < 0.001). However, no meaningful relationships between serum or tear urate and TNFα-level were discovered. Furthermore, there were no statistically significant changes in the levels of IL-1β and TNFα in tears between the groups with asymptomatic hyperuricemia and gout. Conclusions: Patients who had gout and asymptomatic hyperuricemia had higher tear urate levels than controls. Tear uric acid levels had a substantial positive connection with IL-1β levels, suggesting an interaction between hyperuricemia and ocular inflammation.