Editorial Comment—“Malignant” or Not: Is There a Role for In Vivo Neurochemistry?

Abstract

Background and Purpose-Space-occupying brain edema is a life-threatening complication in patients with large middle cerebral artery (MCA) infarction. To determine predictors of this detrimental process, we investigated alterations of extracellular non-transmitter amino acid concentrations in peri-infarct tissue. Methods-Thirty-one patients with infarctions covering Ͼ50% of the MCA territory in early cranial CT scans were included in the study. Probes for microdialysis, intracranial pressure, and tissue oxygen pressure were placed into the noninfarcted ipsilateral frontal lobe. Positron emission tomography imaging was performed in 16 of these patients to measure cerebral blood flow in the tissue around the neuromonitoring probes. Results-Fourteen of the 31 patients developed a malignant MCA infarction, and 17 did not. The patients in the malignant group had significantly lower extracellular concentrations of non-transmitter amino acids than those in the benign group in the first 12 hours of neuromonitoring. At this time, CBF values determined in regions of interest around the probes by positron emission tomography and tissue oxygen pressure showed that the monitored tissues were not yet infarcted, and no differences in transmitter amino acids concentrations were found between the 2 groups. Furthermore, extracellular concentrations of non-transmitter amino acids were negatively correlated with size of infarction. Conclusions-We

The proteome of human brain microdialysate

“…However, monitoring the efficacy of these measures is often difficult, especially with regard to early prognostic detection of severe neuronal damage. Microdialysis was developed for neurochemical monitoring and allows measurement of the extracellular concentrations of various endogenous substances, such as excitotoxic amino acids or metabolic end products in short sampling periods of time [2,17,18]. …”