Increase in plasma adenosine during brain ischemia in man: A study during transient ischemic attacks, and stroke

Adenosine is a "retaliatory metabolite" which accumulates during experiment al brain ischemia and has vasodilatory and putative neuroprotective effects . The aim of this study was to assess whether human cerebral ischemia and n ecrosis - evaluated in the clinical models of transient ischemic attack (TI A) and stroke, respectively-acutely raise plasma adenosine levers, We studi ed 20 patients: 10 with TIA and 10 with stroke. In all, blood was serially sampled for assessment of plasma adenosine by an high-performance liquid ch romatography method. Sampling occurred on peripheral blood during TIA and s troke upon admission, and serially thereafter every day up to 7 days and ev ery other day up to 20 days. We found that in TIA and stroke patients, peri pheral adenosine levels were increased to a similar extent upon admission ( TIA = 264 +/- 53 vs, stroke = 257 +/- 60 nM, p = ns), peaked on the day 2 f or TIA (300 +/- 60) and on day 3 for stroke (289 +/- 43) patients, and stea dily decreased towards the normal range, reached by all TIA patients by day 5 and by stroke patients by day 15, Stroke and TIA are associated with a r apid increase in circulating plasma adenosine concentration in man, detecta ble in peripheral vein. The adenosine surge likely mirrors an increased pro duction from the ischemic brain, and it lasts days (for TIA) and weeks (for stroke) after the acute event. (C) 2000 Elsevier Science Inc.