Study of the biodistribution of fluorescein in glioma-infiltrated mouse brain and histopathological correlation of intraoperative findings in high-grade gliomas resected under fluorescein fluorescence guidance
Intravenous fluorescein sodium has been used during resection of high-grade gliomas to help the surgeon visualize tumor margins. Several studies have reported improved rates of gross-total resection (GTR) using high doses of fluorescein sodium under white light. The recent introduction of a fluorescein-specific camera that allows for high-quality intraoperative imaging and use of very low dose fluorescein has drawn new attention to this fluorophore. However, the ability of fluorescein to specifically stain glioma cells is not yet well understood.
The authors designed an in vitro model to assess fluorescein uptake in normal human astrocytes and U251 malignant glioma cells. An in vivo experiment was also subsequently designed to study fluorescein uptake by intracranial U87 malignant glioma xenografts in male nonobese diabetic/severe combined immunodeficient mice. A genetically induced mouse glioma model was used to adjust for the possible confounding effect of an inflammatory response in the xenograft model. To assess the intraoperative application of this technology, the authors prospectively enrolled 12 patients who underwent fluorescein-guided resection of their high-grade gliomas using low-dose intravenous fluorescein and a microscope-integrated fluorescence module. Intraoperative fluorescent and nonfluorescent specimens at the tumor margins were randomly analyzed for histopathological correlation.
The in vitro and in vivo models suggest that fluorescein demarcation of glioma-invaded brain is the result of distribution of fluorescein into the extracellular space, most likely as a result of an abnormal blood-brain barrier. Glioblastoma tumor cell–specific uptake of fluorescein was not observed, and tumor cells appeared to mostly exclude fluorescein. For the 12 patients who underwent resection of their high-grade gliomas, the histopathological analysis of the resected specimens at the tumor margin confirmed the intraoperative fluorescent findings. Fluorescein fluorescence was highly specific (up to 90.9%) while its sensitivity was 82.2%. False negatives occurred due to lack of fluorescence in areas of diffuse, low-density cellular infiltration. Margins of contrast enhancement based on intraoperative MRI–guided StealthStation neuronavigation correlated well with fluorescent tumor margins. GTR of the contrast-enhancing area as guided by the fluorescent signal was achieved in 100% of cases based on postoperative MRI.
Fluorescein sodium does not appear to selectively accumulate in astrocytoma cells but in extracellular tumor cell-rich locations, suggesting that fluorescein is a marker for areas of compromised blood-brain barrier within high-grade astrocytoma. Fluorescein fluorescence appears to correlate intraoperatively with the areas of MR enhancement, thus representing a practical tool to help the surgeon achieve GTR of the enhancing tumor regions.
Correspondence Aaron A. Cohen-Gadol, Goodman Campbell Brain and Spine, Department of Neurological Surgery, Indiana University, 355 W. 16th St., Ste. 5100, Indianapolis, IN 46202. email: email@example.com.
INCLUDE WHEN CITING Published online April 3, 2015; DOI: 10.3171/2015.2.JNS132507.
DISCLOSURE Aaron A. Cohen-Gadol has a consulting agreement with Carl Zeiss Meditec AG. The compensation from this arrangement is donated to a not-for-profit educational organization, The Neurosurgical Atlas.
ÁbrahámCSDeliMAJoóFMegyeriPTorpierG: Intracarotid tumor necrosis factor-alpha administration increases the blood-brain barrier permeability in cerebral cortex of the newborn pig: quantitative aspects of double-labelling studies and confocal laser scanning analysis. Neurosci Lett208:85–881996
BecherOJHambardzumyanDWalkerTRHelmyKNazarianJAlbrechtS: Preclinical evaluation of radiation and perifosine in a genetically and histologically accurate model of brainstem glioma. Cancer Res70:2548–25572010
KabutoMKubotaTKobayashiHNakagawaTIshiiHTakeuchiH: Experimental and clinical study of detection of glioma at surgery using fluorescent imaging by a surgical microscope after fluorescein administration. Neurol Res19:9–161997
KunesMKvetinaJMalakovaJBuresJKopacovaMRejchrtS: Pharmacokinetics and organ distribution of fluorescein in experimental pigs: an input study for confocal laser endomicroscopy of the gastrointestinal tract. Neuroendocrinol Lett31 :Suppl 257–612010