De Micheli E, Pinna G, Alfieri A, Caramia G, Bianchi L, Colivicchi M A, Della Corte L, Bricolo A
Dipartimento di Neurochirurgia, Università ed Ospedale di Verona, Italia.
Adv Exp Med Biol. 2000;483:595-603. doi: 10.1007/0-306-46838-7_64.
Intracerebral MD enables the retrieval of endogenous substances from the extracellular fluid (ECF) of the brain and has been demonstrated to be a sensitive technique for early detection of subtle vasospasm-induced neurometabolic abnormalities in patients with subarachnoid hemorrhage (SAH). The aim of this study was to monitor cortical extracellular concentrations of energy metabolism markers, such as glucose and lactate, neurotransmitter amino acids, such as glutamate, aspartate, GABA and taurine to identify any neurochemical patterns of cerebral ischemia. A prospective clinical study was conducted on a group of 16 patients with non-severe SAH operated on within 72 hours after initial bleeding. Following aneurysm clipping, an MD catheter was inserted in the cortical region where vasospasm could be expected to develop, and perfused with artificial CSF at 0.3 microl/min flow rate. Dialysate was collected every 6 hours and then analyzed on High Performance Liquid Cromatography (HPLC) for glucose, lactate, pyruvate, glutamate, aspartate, GABA and taurine. Mean ECF taurine concentrations ranged from 1.4 + 0.7 to 12.3 + 7.8 micromol/l in single patients: global mean value was 5.8 + 3.8 micromol/l. In this series, the highest absolute taurine value was 25.7 micromol/l, observed in a patient who developed clinical and radiological signs of cerebral ischemia. Nine patients presented clinical disturbances related to cerebral vasospasm. In this setting, representing a mild-to-moderate hypoxic condition, MD data demonstrated that lactate is the most sensitive marker of cellular energy imbalance. Increased lactate levels positively correlated with glutamate (P<0.0001), aspartate (P<0.0001), GABA (P<0.0001) and taurine (P<0.0001) concentrations. These results suggest that also in humans increased taurine levels reflect a condition of cellular stress. This study confirms that MD is a sensitive technique to reveal subtle metabolic abnormalities possibly resulting in cell damage.
脑内微透析技术能够从脑的细胞外液（ECF）中提取内源性物质，并且已被证明是一种用于早期检测蛛网膜下腔出血（SAH）患者细微血管痉挛诱导的神经代谢异常的敏感技术。本研究的目的是监测能量代谢标志物（如葡萄糖和乳酸）、神经递质氨基酸（如谷氨酸、天冬氨酸、γ-氨基丁酸和牛磺酸）的皮质细胞外浓度，以识别任何脑缺血的神经化学模式。对一组16例非重度SAH患者进行了前瞻性临床研究，这些患者在初次出血后72小时内接受手术。动脉瘤夹闭后，将微透析导管插入预计会发生血管痉挛的皮质区域，并以0.3微升/分钟的流速用人工脑脊液灌注。每6小时收集一次透析液，然后用高效液相色谱法（HPLC）分析葡萄糖、乳酸、丙酮酸、谷氨酸、天冬氨酸、γ-氨基丁酸和牛磺酸。单例患者的平均细胞外液牛磺酸浓度范围为1.4 + 0.7至12.3 + 7.8微摩尔/升：总体平均值为5.8 + 3.8微摩尔/升。在该系列中，在一名出现脑缺血临床和放射学体征的患者中观察到最高的绝对牛磺酸值为25.7微摩尔/升。9例患者出现与脑血管痉挛相关的临床障碍。在这种代表轻度至中度缺氧状态的情况下，微透析数据表明乳酸是细胞能量失衡最敏感的标志物。乳酸水平升高与谷氨酸（P<0.0001）、天冬氨酸（P<0.0001）、γ-氨基丁酸（P<0.0001）和牛磺酸（P<0.0001）浓度呈正相关。这些结果表明，在人类中牛磺酸水平升高也反映了细胞应激状态。本研究证实微透析是一种揭示可能导致细胞损伤的细微代谢异常的敏感技术。
