Aberrant metabolism is a hallmark of malignancies including gliomas. Intracranial microdialysis enables the longitudinal collection of extracellular metabolites within CNS tissues including gliomas and can be leveraged to evaluate changes in the CNS microenvironment over a period of days. However, delayed metabolic impacts of CNS injury from catheter placement could represent an important covariate for interpreting the pharmacodynamic impacts of candidate therapies. Intracranial microdialysis was performed in patient-derived glioma xenografts of glioma before and 72 h after systemic treatment with either temozolomide (TMZ) or a vehicle. Microdialysate from GBM164, an IDH-mutant glioma patient-derived xenograft, revealed a distinct metabolic signature relative to the brain that recapitulated the metabolic features observed in human glioma microdialysate. Unexpectedly, catheter insertion into the brains of non-tumor-bearing animals triggered metabolic changes that were significantly enriched for the extracellular metabolome of glioma itself. TMZ administration attenuated this resemblance. The human glioma microdialysate was significantly enriched for both the PDX versus brain signature in mice and the induced metabolome of catheter placement within the murine control brain. These data illustrate the feasibility of microdialysis to identify and monitor the extracellular metabolome of diseased versus relatively normal brains while highlighting the similarity between the extracellular metabolome of human gliomas and that of CNS injury.

Neurosurgical oncology outcomes are influenced by histological factors not available before surgery, complicating preoperative counseling regarding surgical risks. Anatomically tailored outcome data have demonstrated potential predictive value. This study aims to compare the incidence of supplementary motor area (SMA) syndrome and other postoperative outcomes for tumors in the middle and superior frontal gyri undergoing resection. A retrospective single-center cohort study of patients undergoing resection of the middle frontal gyrus (MFG), superior frontal gyrus (SFG), or both (SMFG) from 2008 to 2020. The study followed STROBE guidelines. A total of 124 patients underwent 144 craniotomies. Seizures were the most common preoperative symptom, particularly in patients with MFG tumors, who also had higher rates of preoperative aphasia. Pathology varied significantly (P < 0.05) between groups, with glioblastoma multiforme more prevalent in SMFG tumors and metastases more common in MFG tumors. Supplementary motor area (SMA) syndrome occurred in 43%, more frequently in SFG tumors (47%) compared to MFG (40%) and SMFG (27%), although these differences were not statistically significant. SMA syndrome duration varied significantly (P < 0.05) across groups, with SMFG cases being the most persistent. Early postoperative aphasia was more common (P < 0.001) in MFG cases (55%), but there were no permanent deficits in the MFG group. The SMFG group had more permanent neurological deficits and higher rates of early complications (P < 0.05). Survival was significantly lower in SMFG tumors (P < 0.05) on univariate analysis but not on multivariate analysis. The study found no significant difference in SMA syndrome frequency by location, although the duration of SMA syndrome was significantly longer in SMFG cases. Postoperative aphasia was more common in MFG tumors but was temporary. Permanent deficits were rare across all regions. These anatomically tailored findings provide valuable information for surgical planning and patient counseling.