Department of Neurology, University Hospital Essen, Hufelandstrasse 55, D-45122 Essen, Germany.
Stroke. 2010 May;41(5):1008-12. doi: 10.1161/STROKEAHA.109.574418. Epub 2010 Apr 1.
After 1 clinical study in which recombinant erythropoietin (EPO) protected against ischemic stroke and improved clinical outcome, the German multicenter EPO trial recently reported increased mortality in stroke patients receiving EPO after tissue-plasminogen activator (t-PA)-induced thrombolysis. The reasons for the adverse effects of EPO in t-PA-treated patients are unknown.
Mice were submitted to 90 minutes of middle cerebral artery occlusion. Immediately after reperfusion, animals were treated with normal saline or t-PA (10 mg/kg). Animals subsequently received injections of normal saline or EPO that were administered after reperfusion and 12 hours later (2500 IU/kg each). Ischemic injury and brain edema were analyzed at 24 hours after reperfusion by cresyl violet staining and terminal transferase biotinylated-dUTP nick end labeling. Blood-brain barrier integrity was assessed by histochemistry for extravasated serum IgG. Matrix metalloproteinase activity was evaluated by gelatinase zymography.
EPO did not influence ischemic infarct size but reduced brain swelling. This effect was abolished by t-PA, which exacerbated serum IgG extravasation in ischemic tissue. Gelatinase zymographies revealed that EPO promoted matrix metalloproteinase-9 activity that was markedly elevated by t-PA. Add-on treatment with t-PA increased the density of DNA-fragmented cells in ischemic tissue of EPO-treated, but not vehicle-treated, mice.
Our data demonstrate a hitherto unknown interaction of t-PA with EPO at the blood-brain interface, ie, promotion of vascular permeability and extracellular matrix breakdown, which may account for the unfavorable actions of EPO in t-PA-treated patients. After t-PA-induced thrombolysis, EPO may not be suitable as stroke treatment.
在一项重组促红细胞生成素（EPO）可预防缺血性中风并改善临床预后的临床研究之后，德国多中心 EPO 试验最近报告称，接受组织型纤溶酶原激活剂（t-PA）溶栓后接受 EPO 治疗的中风患者死亡率增加。EPO 在接受 t-PA 治疗的患者中产生不良反应的原因尚不清楚。
将小鼠置于大脑中动脉闭塞 90 分钟。再灌注后立即用生理盐水或 t-PA（10mg/kg）处理动物。动物随后接受生理盐水或 EPO 注射，再灌注后和 12 小时后各注射一次（每次 2500IU/kg）。再灌注后 24 小时通过结晶紫染色和末端转移酶生物素化-dUTP 缺口末端标记法分析缺血性损伤和脑水肿。通过组织化学评估血清 IgG 外渗来评估血脑屏障完整性。通过明胶酶酶谱法评估基质金属蛋白酶活性。
EPO 不影响缺血性梗死面积，但可减轻脑水肿。这种作用被 t-PA 所消除，t-PA 加剧了缺血组织中血清 IgG 的外渗。明胶酶酶谱显示 EPO 促进了基质金属蛋白酶-9 的活性，而 t-PA 可显著增加其活性。与 t-PA 联合治疗可增加 EPO 治疗、而非载体治疗的小鼠缺血组织中 DNA 片段化细胞的密度。
我们的数据表明，t-PA 与 EPO 在血脑界面上存在一种迄今为止未知的相互作用，即促进血管通透性和细胞外基质降解，这可能是 EPO 在接受 t-PA 治疗的患者中产生不良作用的原因。在 t-PA 诱导的溶栓后，EPO 可能不适合作为中风的治疗方法。
