Modeling and Quantifying Biochemical Changes in C6 Tumor Gliomas by Fourier Transform Infrared Imaging

Abstract

The purpose of the study was to investigate molecular changes associated with glioma tissues using FT-IR microspectroscopic imaging (FT-IRM). A multivariate statistical analysis allowed one to successfully discriminate between normal, tumoral, peri-tumoral, and necrotic tissue structures. Structural changes were mainly related to qualitative and quantitative changes in lipid content, proteins, and nucleic acids that can be used as spectroscopic markers for this pathology. We have developed a spectroscopic model of glioma to quantify these chemical changes. The model constructed includes individual FT-IR spectra of normal and glioma brain constituents such as lipids, DNA, and proteins (measured on delipidized tissue). Modeling of FT-IR spectra yielded fit coefficients reflecting the chemical changes associated with a tumor. Our results demonstrate the ability of FT-IRM to assess the importance and distribution of each individual constituent and its variation in normal brain structures as well as in the different pathological states of glioma. We demonstrated that (i) cholesterol and phosphatidylethanolamine contributions are highest in corpus callosum and anterior commissure but decrease gradually towards the cortex surface as well as in the tumor, (ii) phosphatidylcholine contribution is highest in the cortex and decreases in the tumor, (iii) galactocerebroside is localized only in white, but not in gray matter, and decreases in the vital tumor region while the necrosis area shows a higher concentration of this cerebroside, (iv) DNA and oleic acid increase in the tumor as compared to gray matter. This approach could, in the future, contribute to enhance diagnostic accuracy, improve the grading, prognosis, and play a vital role in therapeutic strategy and monitoring.

Synchrotron-based FTIR spectra of stained single cells. Towards a clinical application in pathology

“…[22][23][24] The use of ethanol in both H&E and Pap staining procedures would explain the decrease in the intensity of these two peaks. 15,16,25 This is further confirmed by the fact that physical removal of membrane and cytoplasmic lipids caused a reduction in the intensity of these two peaks. 6 On the other hand, we did not see any differences in the bands around 2870 and 2960 cm À1 , which originate from the CH 3 groups not only of lipids and proteins, but also of nucleic acids.…”

Diagnosis of Periodontal Disease from Saliva Samples Using Fourier Transform Infrared Microscopy Coupled with Partial Least Squares Discriminant Analysis

“…The IR spectrum of a biological sample is formed by superposition of all infrared-active vibrational modes of all the molecules present in the sample. Therefore, FT-IR has been recently applied to analyze biological samples for the following purposes: classification of bacteria, 4-11 discrimination of cancer cells, [12][13][14][15][16][17][18][19][20] detection of scrapie, 18,[21][22][23] and histopathologic recognition. 24,25 Importantly, Xiang et al used mid-infrared spectroscopy to analyze the gingival crevicular fluid (GCF) in order to determine differences between periodontitis, gingivitis, and normal sites.…”

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).…”