摘要:血管痙攣至今仍為造成腦動脈瘤破裂病人殘障最常見的原因。最近的研究顯示造成血管痙攣的主因來自血塊溶解後的代謝產物。endothelin-1 的釋放與NO synthase 受抑制為現在最被接受的兩個理論。膽色素過氧化物質雖較少被提及但已有相當實驗證實其也是造成血管痙攣的主因之一。證據顯示藉由持續性腰椎引流能減少血管痙攣,但原因仍無法完全解釋,一般認為可能腰椎引流可以盡快幫助身體將蜘蛛膜下腔之血塊排出體內。我們先前的研究於病人出血後第七天作腰椎穿刺,根據我們的結果顯示,腰椎穿刺所得的腦脊髓液,其ADMA,NO,endothelin 等皆有顯著大於腦室引流管中的腦脊髓液。因此我們進行臨床試驗,我們假設腰椎中的腦脊髓液才比較接近蜘蛛膜下腔的腦脊髓液,經由腰椎引流可以比腦室外引流更容易引流出蜘蛛膜下腔的積血。我們於病人出血後第三到五天置入腰椎引流管持續引流,藉由每日定量腦脊髓液中血塊與造成血管痙攣的物質的代謝速度來探討血管痙攣的機制以期能改善預後。但臨床上卻發現血管痙攣的程度或部位與腦部梗塞性中風病變不一定相關,因此我們將每日取得的腦脊髓液進行體內的動物模式實驗:我們將大鼠的顱骨與腦膜打開,將每日取得的新鮮的腦脊髓液浸潤在腦表面。我們發現有些昏迷指數較差、出血量較大的病人雖然臨床上無明顯血管痙攣,但在動物實驗上卻可造成很嚴重的血管栓塞,在一位嚴重血管痙攣的病患,我們發現在不同時期血管痙攣與血管栓塞並不成比例。因此我們大膽假設造成血管栓塞與血管痙攣為兩種不同物質,且血管栓塞比血管痙攣更嚴重的影響病人的預後。因此我們將進行下述實驗:我們將腦動脈瘤破裂病人分為三組,一為臨床上有血管痙攣、第二組為臨床上沒有血管痙攣但是昏迷指數8 分以下,第三組為臨床上沒有血管痙攣且昏迷指數9-15 分。我們將每日測量腦脊髓液中的膽色素過氧化物質與ADMA,並同時進行大鼠體內動物實驗,我們將觀察老鼠腦微血管循環(MOOR)與血管收縮的程度,並用laser doppler 測量血流的變化及血管管徑測量,最後在經由組織灌流後取下腦染色定量腦栓塞的嚴重度。在更進一步我們將進行神經細胞,血管內皮細胞及平滑肌細胞培養,來研究這些病人的腦脊髓液對腦部產生傷害的機制,初步研究以顯示神經細胞在與腦脊髓液培養18 小時後PARA 活性明顯被活化,神經細胞也有apoptosis 情形。最後腦脊髓液將再進行體外去除內皮細胞的老鼠胸主動脈體外生理收縮測試。至於是何種物質造成這些變化我們將再另一個計劃使用HPLC 加上MS 進行分析。
Abstract: Cerebral vasospasm remains a significant source of morbidity and mortality in patientswith subarachnoid hemorrhage (SAH) after an aneurysmal rupture. Despite being asignificant source of morbidity and mortality, death and disability from vasospasm havedeclined from approximately 35% in the early 1970's, to between 15% and 20% in the 1980'sto <10% in the 1990's(1,2,3,4). Extensive research has shown that the big event that leads tothe initiation of vasospasm is the release of oxyhemoglobin (blood breakdownproduct)(1,12,13). This mechanism appears to be a multifactorial process that involves thegeneration of free radicals, lipid peroxidation and activation of protein kinase C as well asphospholipase C and A2 with resultant accumulation of diacylglycerol and the release ofendothelin-1(14,15,16,17,18). On the other hand, depletion of NO synthase (19,20,21) wasalso noted after SAH.Previous reports showed that shunting of CSF through a lumbar drain after an SAHmarkedly reduces the risk of clinically evident vasospasm and its sequelae, shortens hospitalstay, and improves outcome. Its beneficial effects are probably mediated through the removalof spasmogens that exist in the CSF(22). In our previous data, we insert lumbar drain andkeep continuous drainage 3-5 day after operation. We have proofed that ADMA and BOXwas much higher in CSF from lumbar drain than EVD. CSF in lumbar drain was more closeto the CSF in subarachnoid space. However, we found that diffuse thromboembolismhappened in some cases without clinical vasospasm. There are also infarction areas beyondthe territory of vasospasm. So, we do the in vivo study of Rat by using fresh CSF taken dailyfrom patients. We do the craniotomy 0.5x0.5 cm, and then open the dura. Fresh CSF wasincubated on the brain surface. Microcirculation was recorded continuously and the diameterof vessels were recorded by laser Doppler. We have demonstrate that CSF from somepatients without clinical vasospasm can cause severe thrmboembolism in rat brain, especiallyin cases with poor-grade SAH(GCS < 8).Patients after aneurysmal SAH was divided into 3groups. Group 1 includes patients with clinical vasospasm. Group 2 includes patients withoutclinical vasospasm but presented with poor-grade SAH(GCS 3-8), The last group includespatients without vasospasm and good grade SAH.(GCS 9-15). We will check ADMA, BOXand endothelin daily, and in vivo animal model will be done immediately after CSF aspirated.We will correlate the clinical outcome of the patient with animal study and CSF bio-markers.Furthered, in order to verify the toxic effect of CSF, we will incubate the CSF with primaryneuron culture, endothelial cell and smooth muscle cell. In our preliminary data, obviousactivation of PARP can be shown after incubation 18 and 24 hours. Apoptosis of neuron alsocan be demonstrated by activation of caspase III. We will further identify the spasmogens byHPLC and MS in other study.