BACKGROUND: Urate is a natural antioxidant and may prevent CNS tissue damage and the clinical manifestations of experimental autoimmune encephalitis (EAE; the animal model of MS). Results from clinical studies are conflicting and the contribution of urate to the pathogenesis of MS remains uncertain.
|The chemical structure of uric acid|
METHODS: Levels of non-fasting serum uric acid (the form or urate in the blood) and creatinine (a breakdown product from muscle) were determined by an automated enzymatic assay and glomerular filtration rate (an index of renal function that could affect uric acid levels) was assessed in 245 MSers, in 252 age/sex-matched neurological controls (NC) and in 59 healthy controls (HC).
RESULTS: Median serum urate levels did not differ between MSers (3.8 mg/dL), HC (4.0 mg/dl) and NC (4.0 mg/dL). Serum urate levels were lower in females than in males in all groups (p = <0.0001). In female-MS, serum urate levels (3.2 mg/dL) were lower compared to those in female HC (3.8; p = 0.01) and NC (3.5 mg/dL; p = 0.02), whereas in male-MS they (4.8 mg/dL) did not differ from those in male HC (4.5 mg/dl) and NC (4.8 mg/dL). Urate concentrations trended to be lower in Clinically Isolated Syndromes suggestive of MS (3.7 mg/dL) and in relapsing MS (3.7 mg/dL), compared to MSers with progressive MS (4.4 mg/dL; p = 0.06), and in MSers with an annual relapse rate (ARR) >2 (3.3 mg/dL) than in those with an ARR ≤2: 3.9 mg/dL; p = 0.05). Significant lower serum urate levels were found in females than in males in all clinical MS subtypes (p<0.01), separately evaluated. Female sex (beta: -0.53; p<0.00001) was the most significant determinant of serum urate concentrations in MSers on multivariate regression analysis.
CONCLUSIONS: These findings suggest that low urate levels could be of significance in predominantly inflammatory phases of MS even at the early stage and mainly in females.
|Uric acid crystals|