Biomolecular diagnosis of human glioblastoma multiforme using Synchrotron mid-infrared spectromicroscopy

Abstract

Abstract. Glioblastoma multiforme (GBM) is one of the most malignant human tumors, with a uniformly poor outcome. One obstacle in curing malignant brain tumors is the limitation of conventional light microscopy in detecting microscopic residual tumor in biopsy samples from the perimeter of the surgically resected tumor. We further refined the identification of GBM tumor tissue at the sub-cellular level, utilising the technique of Synchrotron, sourced mid-infrared (mid-IR) spectromicroscopy. Paired, thin (5 μm) cryosections of snap-frozen human GBM tumor samples removed at elective surgery were mounted on glass slides (hematoxylin and eosin-stained tissue section) and calcium fluoride (CaF 2 ) windows (unstained tissue section for transmission spectromicroscopy), respectively. Concordance of tumor bearing areas identified in the stained section with the unstained IR tissue section was confirmed by the pathologist of the study. Compared with molecular signatures obtained from normal control brain tissue, unique spectroscopic patterns were detected in GBM tumor samples from 6 patients. The identifying features of GBM were: i) high protein-to-lipid ratios (amide I+II/CH 2 symmetric stretch; amide I+II/CH 2 +CH 3 symmetric and asymmetric stretch), and ii) considerable enhancement of the intensities of characteristic peaks at 2,957 and 2,871 cm -1 representing CH 3 asymmetric and symmetric stretch, respectively. Spectral data sets were subjected to Ward's algorithm for assignment to similar groups, and then subjected to hierarchical cluster analysis (HCA) by means of false color digital maps. False color images of 5 clusters obtained by HCA identified dominant clusters corresponding to tumor tissue. Corroboration of these findings in a larger number of GBM may allow for more precise identification of these and other types of brain tumors.

The biochemical changes in hippocampal formation occurring in normal and seizure experiencing rats as a result of a ketogenic diet

“…Such biochemical data including the distributions of main organic compounds ( proteins, lipids, nucleic acids) as well as their conformational changes may be obtained using synchrotron Fourier transform infrared (SRFTIR) microspectroscopy. [23][24][25][26] In this paper the influence of a ketogenic diet on the biochemical composition of hippocampal formations in normal and seizure experiencing rats is analyzed. With the first method we are able to localize microscopic details in the analyzed samples, while the second provides information concerning its chemical composition.…”

Differences in the hippocampal frequency of creatine inclusions between the acute and latent phases of pilocarpine model defined using synchrotron radiation-based FTIR microspectroscopy

“…The high brightness of the synchrotron source of infrared radiation allows achieving diffraction-limited spot sizes. Because in biomedical research micrometer spatial resolution is often of great importance, SRFTIR microspectroscopy is becoming a more and more desired analytical tool in the case of investigation of different biological systems [15–19]. It concerns also the following study in frame of which creatine inclusions with the typical sizes varying from a few to dozens of micrometers were analyzed.…”

Automation of an algorithm based on fuzzy clustering for analyzing tumoral heterogeneity in human skin carcinoma tissue sections

“…As a consequence, IR hyperspectral images need to be processed by powerful digital signal processing and pattern recognition methods in order to highlight these changes. To date, unsupervised 'hard' clustering techniques including K-means (KM) 3,[16][17][18][19][20] or agglomerative hierarchical (AH) 11,16,[21][22][23] clustering have been usually applied to create color-coded images allowing to localize tumoral tissue surrounded by other tissue structures (normal, inflammatory, fibrotic).…”