Background: Past failures in translating stroke cerebroprotection provoked calls for a more rigorous methodological approach, leading to the stroke preclinical assessment network SPAN (Stroke Preclinical Assessment Network), where uric acid (UA) treatment exceeded a prespecified efficacy boundary for the primary functional outcome. Still, successful translation to humans requires confirmation of the effect of UA across key biological variables relevant to patients with stroke.
Methods: We measured the effects of intravenous UA treatment (16 mg/kg) versus intravenous saline in groups of animals enrolled in the SPAN network with diverse comorbidities, sex, and age. The masked study drug or placebo was administered during reperfusion in rodents undergoing a transient middle cerebral artery filament occlusion. The primary outcome was the modified corner test index at day 30 poststroke, and numerous secondary outcomes were collected. A modified intention-to-treat population was used in the analysis. We tested for any interactions with sex, age, and comorbidities (obesity-induced hyperglycemia and hypertension).
Results: In total, 710 animals were randomized to receive either intravenous UA or saline. After accounting for procedural dropouts and exclusions from treatment, a total of 687 animals were qualified and analyzed, including 458 assigned to UA and 229 to intravenous saline control. UA-treated animals exhibited a better primary functional outcome at day 30 (probability, 0.56 [95% CI, 0.52-0.60]; P=0.006). UA-treated animals also had a better corner test index at day 7 (probability, 0.55 [95% CI, 0.5-0.59]; P=0.035) and a higher survival rate at day 30 (hazard ratio, 1.41 [95% CI, 1.08-1.83]; P=0.011). Brain morphometry at day 2 and 30 was comparable between the treatment groups. The improved functional outcome and survival in UA-treated animals were preserved across different species, sexes, ages, and comorbidities.
Conclusions: UA provides ischemic stroke cerebroprotection across key relevant biological variables, making it a promising intervention to be further tested in human clinical trials.
Keywords: intention to treat analysis; ischemic stroke; middle cerebral artery; sex; uric acid.