1) Chronic hyperuricemia causes oxidative stress-related disease. Definitive examples are the Lesch-Nyhan syndrome and hyperuricemic syndrome in Dalmatian dogs. The latter is even associated with classic symptoms of oxidative stress such as "bronzing". Likewise, this syndrome responds to treatment with "orgotein" the pharmaceutical formulation of superoxide dysmutase. See Proctor,1989 for more details.
Further, hyperuricemia in Dalmatians is produced by a lesion in liver uptake of urate and not by increased urate production. Ergo, it is urate and hyperuricemia per se and not xanthine oxidase that produces the oxidative stress.
2) Urate is likely acutely neuroprotective thru its antioxidant properties. This is because the increased local flux of oxidant species such as peroxinitrite under conditions of acute brain ischemia render the lessor pro-oxidant properties of uric acid moot.
3) Unique high levels of putative antioxidant neuroprotectants in humans may account for the recurrent difficulty in translating positive animal studies with neuroprotectants to clinical treatment of stroke.