Proton High-resolution Magic Angle Spinning Research Articles

Investigations of Serum Metabolomic Relationships between Lung Cancer and Alzheimer’s Disease using Nuclear Magnetic Resonance Spectroscopy

AbstractBackgroundAlzheimer’s Disease (AD) and Lung cancer (LuCa) are among the leading causes of mortality in the United States. Remarkably, several studies demonstrated a potential inverse co‐morbidity of AD with LuCa. Possible explanations related to the cell cycle (dys)regulation include presence of specific neuropathological features, immune checkpoint functions and increased circular RNA levels. Metabolomic profiles for LuCa or AD alone have been proposed. Here, using high‐resolution magic angle spinning (HRMAS) MRS, we aim to study metabolomic relationship between the two diseases with serum metabolomic profiles for matched LuCa patients, with and without AD, by comparing serum profiles measured from matched healthy controls.MethodsLuCa sera from of patients with (LCAD, n = 10, 3M, 7F, 77.3±7.7yrs) and without (LCnonAD, n = 10, 3M, 7F, 77.4±5.2yrs) clinically defined AD were obtained from Harvard/MGH Lung Cancer Susceptibility Study (a.k.a. BLCS) Repository, with individually age‐ and gender‐matched healthy controls (Ctrl‐LCAD and Ctrl‐LCnonAD, n = 10/each) obtained from the MGB BioBank. HRMAS proton NMR for these 40 samples were measured on 10 µl, at 4°C with a spin rate of 5000 Hz using a Bruker Avance 600 MHz spectrometer. Spectra were analyzed with Bruker Topspin 3.6.2. Statistical analysis was performed using JMP Pro on 18 spectral regions identified from HRMAS proton NMR.ResultsAs a survey of the entire data ensemble of 18 spectral regions measured from 40 samples, the hierarchical clustering analysis (Fig. 1) seems to associate different groups into different clusters. Unsupervised principal component analysis (PCA) conducted on all spectral regions generate PCs (PC1 and PC2) that can differentiate among groups (Fig. 2). Further noticed that, four out of 18 regions can significantly differentiate LCAD from LCnonAD. Calculations of PCA using these four regions result in PC1_4regions that can significantly differentiate LCAD from LCnonAD (Fig. 3). Collectively evaluating potential contributing metabolites towards PC1_4regions indicate increases in myo‐inositol suggesting towards LCAD, which increases in creatine, phosphocreatine, serine, aspartate, tyrosine, proline, glutamine, and 2‐oxoglutarate suggesting towards LCnonAD.ConclusionOur findings, whilst preliminary, seem promising in guiding further investigations into serum NMR metabolomics for better understanding LuCa‐AD metabolic relationships.

Characterization of the metabolomic profile of renal cell carcinoma by high resolution magic angle spinning proton magnetic resonance spectroscopy

BackgroundRenal cell carcinoma (RCC) is a metabolic disease, with subtypes exhibiting aberrations in different metabolic pathways. Metabolomics may offer greater sensitivity for revealing disease biology. We investigated the metabolomic profile of RCC using high-resolution magic angle spinning (HRMAS) proton magnetic resonance spectroscopy (1HMRS). MethodsSurgical tissue samples were obtained from our frozen tissue bank, collected from radical or partial nephrectomy. Specimens were fresh-frozen, then stored at −80 °C until analysis. Tissue HRMAS-1HMRS was performed. A MatLab-based curve fitting program was used to process the spectra to produce relative intensities for 59 spectral regions of interest (ROIs). Comparisons of the metabolomic profiles of various RCC histologies and benign tumors, angiomyolipoma, and oncocytoma, were performed. False discovery rates (FDR) were used from the response screening to account for multiple testing; ROIs with FDR p < 0.05 were considered potential predictors of RCC. Wilcoxon rank sum test was used to compare median 1HMRS relative intensities for those metabolites that may differentiate between RCC and benign tumor. Logistic regression determined odds ratios for risk of malignancy based on the abundance of each metabolite. ResultsThirty-eight RCC (16 clear cell, 11 papillary, 11 chromophobe), 10 oncocytomas, 7 angiomyolipomas, and 13 adjacent normal tissue specimens (matched pairs) were analyzed. Candidate metabolites for predictors of malignancy based on FDR p-values include histidine, phenylalanine, phosphocholine, serine, phosphocreatine, creatine, glycerophosphocholine, valine, glycine, myo-inositol, scyllo-inositol, taurine, glutamine, spermine, acetoacetate, and lactate. Higher levels of spermine, histidine, and phenylalanine at 3.15 to 3.13 parts per million (ppm) were associated with decreased risk of RCC (OR 4 × 10−5, 95% CI 7.42 × 10−8, 0.02), while 2.84 to 2.82 ppm increased the risk of malignant pathology (OR 7158.67, 95% CI 6.3, 8.3 × 106). The specific metabolites characterizing this region remain to be identified. Tumor stage did not affect metabolomic profile of malignant tumors, suggesting that metabolites are dependent on histologic subtype. ConclusionsHRMAS-1HMRS identified metabolites that may predict RCC. We demonstrated that those in the 3.14 to 3.13 ppm ROI were present in lower levels in RCC, while higher levels of metabolites in the 2.84 to 2.82 ppm ROI were associated with substantially increased risk of RCC. Further research in a larger population is required to validate these findings.

Association between altered metabolism and genetic mutations in human glioma.

Molecular markers for classification of gliomas include isocitrate dehydrogenase (IDH) mutations and codeletion of chromosomal arms 1p and 19q (1p/19q). While mutations in IDH enzymes result in the well-characterized production of oncometabolite 2-hydroxyglutarate, dysregulation of other metabolites in IDH tumors is less characterized. Similarly, the effects of 1p/19q codeletion on cellular metabolism are also unclear. This study aimed to quantify changes in tumor metabolites in human glioma tissue as a function of both IDH mutation and 1p/19q codeletion. Deidentified human glioma tissue and associated clinical data were obtained from the Emory University Winship Cancer Institute tissue biobank from 14 patients (WHO grades II, III, and IV; seven female and seven male). Proton (1 H) high-resolution magic angle spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy data were acquired using a 600 MHz Bruker AVANCE III NMR spectrometer. Metabolite concentrations were calculated using LCModel. Differences in metabolite concentrations as a function of IDH mutation, 1p/19q codeletion, and survival status were determined using Mann-Whitney U tests. Concentrations of alanine, glutamine, and glutamate were significantly lower in glioma tissue with IDH mutations compared to tissue with IDH wildtype. Additionally, glutamate concentration was significantly lower in glioma tissue with 1p/19q codeletion compared to intact 1p/19q. Exploratory analysis revealed alanine concentration varied significantly as a function of survival status. Given the emerging landscape of glioma treatments that target metabolic dysregulation, an improved understanding of altered metabolism in molecular sub-types of gliomas, including those with IDH mutation and 1p/19q codeletion, is an important consideration for treatment stratification and personalized medicine.

Leaf tissue metabolomics fingerprinting of Citronella gongonha Mart. by 1H HR-MAS NMR

This research characterizes key metabolites in the leaf from Citronella gongonha Martius (Mart.) Howard (Cardiopteridaceae). All metabolites were assessed in intact leaf tissue by proton (1H) high-resolution magic angle spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy integrated with the principal component analysis (PCA) to depict molecular association with the seasonal change. The major ‘known unknown’ metabolites detected in 1H HR-MAS NMR were derivatives of flavonoid, polyphenolic and monoterpenoid compounds such as kaempferol-3-O-dihexoside, caffeoyl glucoside (2), 3-O-caffeoylquinic acid (3), 5-O-caffeoylquinic acid (4), kingiside (5), 8-epi-kingisidic acid (6), (7α)-7-O-methylmorroniside (7), (7β)-7-O-methylmorroniside (8) and alpigenoside (9) together with the universally occurring sucrose (10), α-glucoses (11, 12), alanine (13), and fatty (linolenic) acid (14). Several of the major metabolites (1, 2–9) were additionally confirmed by liquid chromatography tandem mass spectrometry (LC–MS/MS). In regard with the PCA results, metabolites 1, 2–9 and 14 were influenced by seasonal variation and/or from further (a) biotic environmental conditions. The findings in this work indicate that C. gongonha Mart. is an effective medicinal plant by preserving particularly compounds 2, 3–9 in abundant amounts. Because of close susceptibility with seasonal shift and ecological trends, further longitudinal studies are needed to realize the physiology and mechanism involved in the production of these and new metabolites in this plant under controlled conditions. Also, future studies are recommended to classify different epimers, especially of the phenolics and monoterpenoids in the given plant.

SPION nanoparticles for delivery of dopaminergic isoquinoline and benzazepine derivatives

Superparamagnetic iron nanoparticles (SPIONs) have become one of the most useful colloidal systems in nanomedicine. We report here the preparation of new hybrid core@shell systems based on SPION nanoparticles coated with a SiO2 shell (SPION@SiO2) and functionalized with carboxyl groups (SPION@SiO2-COOH). A series of new N-alkylamino- and N-alkylamido-terminated 1-phenyl- tetrahydroisoquinolines (THIQs) and 3-tetrahydrobenzazepines (THBs) derivatives presenting -SMe and -Cl groups, respectively, with potential dopaminergic activity, are synthesized and incorporated to the hybrid system. We include the synthetic details for THIQs and THBs derivatives preparation and investigate the influence of the terminal-functional group as well as the number of carbon atoms linked to THIQ and THB molecules during the coupling to the SPION@SiO2-COOH. Nuclear magnetic resonance (NMR) and electron ionization mass spectrometry (EI-MS) are used to characterize the synthesized THIQs and THBs. High-angle annular dark-field transmission electron microscopy (HAADF-TEM), energy dispersive X-ray transmission electron microscopy (EDX-TEM), and proton high-resolution magic angle spinning NMR spectroscopy1H HRMAS-NMR) are used to confirm the presence of THB and THIQ molecules onto the surface of the nanoparticles. The hybrid SPION@SiO2-THIQ and THB systems show significant activity toward the D2 receptor, reaching Ki values of about 20 nM, thus having potential application in the treatment of central nervous system (CNS) diseases.

Metabolites response to onion yellow dwarf virus (OYDV) infection in 'Rossa di Tropea' onion during storage: a 1 H HR-MAS NMR study.

Plant viral infections induce changes in metabolic components in the host plant, with potential effects on compositional, organoleptic and storability features of agricultural products. Identification of modulated metabolites may provide clues concerning pathways implementing responses in plant-pathogen interactions. A time course study of metabolic fingerprinting of onion yellow dwarf virus (OYDV)-infected versus healthy 'Rossa di Tropea' onion bulbs was performed using proton high-resolution magic angle spinning nuclear magnetic resonance (1 H HR-MAS NMR) and ultra-performance liquid chromatography (UPLC), providing an overview of the metabolic state of the bulb in response to OYDV infection during storage. Metabolites accumulated/depleted upon infection were identified, belonging to flavonoid, saccharide, amino acid and organic acid classes. A decrease in quercetin glucosides content and antioxidant activity was observed in infected bulbs; some amino acids (Arg, Asn, Phe, Val) accumulated, while others were depleted (Leu); for some metabolites, a bimodal time-course was observed during storage (Glc, Lys). Virus interference on metabolic pathways, and the effects of the metabolic shift on edible product storability, organoleptic and nutritional quality were discussed. OYDV infection induces a metabolic shift in 'Rossa di Tropea' onion during bulb storage, involving several pathways and affecting storability and organoleptic and nutritional quality of bulbs at marketable stage. © 2020 Society of Chemical Industry.

Supplemental Shimming for HR-μMAS NMR Spectroscopy

Occasionally in proton high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (1H HR-MAS NMR), the standard field shimming across the region-of-interest with the active shims is not sufficient in the presence of substantial magnetic susceptibility gradients. This can be ascribed to the presence of large air pocket within the sample, the proximity between sample and probehead (especially with micro-sized probes), or data acquisition at high magnetic fields. Herein, the study demonstrates a simple approach to enhance the capacity of the shim fields—by supplementing a specific passive ferro-shim—for unifying the field distributions across the sample. Qualitative field numerical analyses were carried out to illustrate the effectiveness of the applied passive shims together with the active shims.

Effects of a small, volatile bacterial molecule on Pseudomonas aeruginosa bacteria using whole cell high-resolution magic angle spinning nuclear magnetic resonance spectroscopy and genomics.

In the present study, high-resolution magic-angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy was applied to live Pseudomonas aeruginosa (PA) bacterial cells to determine the metabolome of this opportunistic Gram-negative human pathogen, and in particular, its response to the volatile aromatic low molecular weight signaling molecule, 2-aminoacetophenone (2-AA). Multi-dimensional HRMAS NMR is a promising method which may be used to determine the in vivo metabolome of live intact bacterial cells; 2-AA is produced by PA and triggers the emergence of phenotypes that promote chronic infection phenotypes in in vitro and in vivo (animal) models. In the present study, we applied one-dimensional and two-dimensional proton (1H) HRMAS NMR to PA cells which were grown with or without 2-AA in order to examine the associations between metabolites and cellular processes in response to 2-AA. We also compared whole-genome transcriptome profiles of PA cells grown with or without 2-AA and found that 2-AA promoted profound metabolic changes in the PA cells. By comparing the whole-genome transcriptome profiles and metabolomic analysis, we demonstrated that 2-AA profoundly reprogramed the gene expression and metabolic profiles of the cells. Our in vivo 1H HRMAS NMR spectroscopy may prove to be a helpful tool in the validation of gene functions, the study of pathogenic mechanisms, the classification of microbial strains into functional/clinical groups and the testing of anti-bacterial agents.

1H HR-MAS NMR-based metabolomics analysis for dry-fermented sausage characterization

Proton high-resolution magic angle spinning (1H HR-MAS) nuclear magnetic resonance (NMR) spectroscopy in combination with principal component analysis (PCA) was employed to characterize dry-fermented sausages salchichón type throughout the manufacturing process. 1H HR-MAS NMR metabolite profiling was achieved from a small sample of intact sausage after 0, 2, 4, 7, 11 and 14days of drying. Intriguingly, the obtained results enabled the identification of the three main stages in the traditional production of salchichón. Formulation, fermentation and drying-ripening periods showed distinct and characteristic metabolomic profiles. Compositional changes related to microbial activity, as well as proteolytic and lipolytic phenomena, decisive steps in such a ripening process, could be monitored through the NMR spectra. This study shows the potential of 1H HR-MAS as a rapid method for probing metabolomic profiles and compositional changes during sausages processing.

Differential metabonomic profiles of primary hepatocellular carcinoma tumors from alcoholic liver disease, HBV-infected, and HCV-infected cirrhotic patients.

Our objective was to comparatively profile the metabolite composition of primary hepatocellular carcinoma (HCC) tumors from alcoholic liver disease (ALD), hepatitis B virus (HBV)-infected, and hepatitis C virus (HCV)-infected cirrhotic patients. Primary HCC tumors were collected from ALD, HBV-infected, and HCV-infected cirrhotic patients (n=20 each). High-resolution magic-angle spinning proton nuclear magnetic resonance spectroscopy and metabonomic data analysis were performed to compare HCC tumors from the three groups. Sensitivity analyses were performed to determine the effects of diabetes, high body mass index, and smoking status. Metabonomic pathway analyses were conducted to identify dysregulated pathways. Three metabolites were significantly differentiated between ALD and HBV-infected patients, which were distinguishable by changes in ketone body, glycerolipid, and phenylalanine metabolism. Five metabolites were significantly differentiated between ALD and HCV-infected patients, which were distinguishable by changes in ketone body, alanine/aspartate/glutamate, and phenylalanine metabolism. Six metabolites were significantly differentiated between HBV-infected and HCV-infected patients, which were distinguishable by changes in ketone body, tyrosine, and alanine/aspartate/glutamate metabolism. In conclusion, this is the first study to demonstrate that the metabolic phenotypes of primary HCC tumors vary significantly across ALD, HBV-infected, and HCV-infected cirrhotic patients.

Metabolic Portraits of Breast Cancer by HR MAS MR Spectroscopy of Intact Tissue Samples.

Despite progress in early detection and therapeutic strategies, breast cancer remains the second leading cause of cancer-related death among women globally. Due to the heterogeneity and complexity of tumor biology, breast cancer patients with similar diagnosis might have different prognosis and response to treatment. Thus, deeper understanding of individual tumor properties is necessary. Cancer cells must be able to convert nutrients to biomass while maintaining energy production, which requires reprogramming of central metabolic processes in the cells. This phenomenon is increasingly recognized as a potential target for treatment, but also as a source for biomarkers that can be used for prognosis, risk stratification and therapy monitoring. Magnetic resonance (MR) metabolomics is a widely used approach in translational research, aiming to identify clinically relevant metabolic biomarkers or generate novel understanding of the molecular biology in tumors. Ex vivo proton high-resolution magic angle spinning (HR MAS) MR spectroscopy is widely used to study central metabolic processes in a non-destructive manner. Here we review the current status for HR MAS MR spectroscopy findings in breast cancer in relation to glucose, amino acid and choline metabolism.

Metabolic Profiling of IDH Mutation and Malignant Progression in Infiltrating Glioma

Infiltrating low grade gliomas (LGGs) are heterogeneous in their behavior and the strategies used for clinical management are highly variable. A key factor in clinical decision-making is that patients with mutations in the isocitrate dehydrogenase 1 and 2 (IDH1/2) oncogenes are more likely to have a favorable outcome and be sensitive to treatment. Because of their relatively long overall median survival, more aggressive treatments are typically reserved for patients that have undergone malignant progression (MP) to an anaplastic glioma or secondary glioblastoma (GBM). In the current study, ex vivo metabolic profiles of image-guided tissue samples obtained from patients with newly diagnosed and recurrent LGG were investigated using proton high-resolution magic angle spinning spectroscopy (1H HR-MAS). Distinct spectral profiles were observed for lesions with IDH-mutated genotypes, between astrocytoma and oligodendroglioma histologies, as well as for tumors that had undergone MP. Levels of 2-hydroxyglutarate (2HG) were correlated with increased mitotic activity, axonal disruption, vascular neoplasia, and with several brain metabolites including the choline species, glutamate, glutathione, and GABA. The information obtained in this study may be used to develop strategies for in vivo characterization of infiltrative glioma, in order to improve disease stratification and to assist in monitoring response to therapy.

Applications of Solid-State NMR Spectroscopy for the Study of Lipid Membranes with Polyphilic Guest (Macro)Molecules.

The incorporation of polymers or smaller complex molecules into lipid membranes allows for property modifications or the introduction of new functional elements. The corresponding molecular-scale details, such as changes in dynamics or features of potential supramolecular structures, can be studied by a variety of solid-state NMR techniques. Here, we review various approaches to characterizing the structure and dynamics of the guest molecules as well as the lipid phase structure and dynamics by different high-resolution magic-angle spinning proton and 13C NMR experiments as well as static 31P NMR experiments. Special emphasis is placed upon the incorporation of novel synthetic polyphilic molecules such as shape-persistent T- and X-shaped molecules as well as di- and tri-block copolymers. Most of the systems studied feature dynamic heterogeneities, for instance those arising from the coexistence of different phases; possibilities for a quantitative assessment are of particular concern.

Staging research of human lung cancer tissues by high‐resolution magic angle spinning proton nuclear magnetic resonance spectroscopy (HRMAS 1H NMR) and multivariate data analysis

High-resolution magic-angle spinning proton nuclear magnetic resonance (HRMAS 1 H NMR) spectroscopy technique was employed to analyze the metabonomic characterizations of lung cancer tissues in hope to identify potential diagnostic biomarkers for malignancy detection and staging research of lung tissues. HRMAS 1 H NMR spectroscopy technique can rapidly provide important information for accurate diagnosis and staging of cancer tissues owing to its noninvasive nature and limited requirement for the samples, and thus has been acknowledged as an excellent tool to investigate tissue metabolism and provide a more realistic insight into the metabonomics of tissues when combined with multivariate data analysis (MVDA) such as component analysis and orthogonal partial least squares-discriminant analysis in particular. HRMAS 1 H NMR spectra displayed the metabonomic differences of 32 lung cancer tissues at the different stages from 32 patients. The significant changes (P < 0.05) of some important metabolites such as lipids, aspartate and choline-containing compounds in cancer tissues at the different stages had been identified. Furthermore, the combination of HRMAS 1 H NMR spectroscopy and MVDA might potentially and precisely provided for a high sensitivity, specificity, prediction accuracy in the positive identification of the staging for the cancer tissues in contrast with the pathological data in clinic. This study highlighted the potential of metabonomics in clinical settings so that the techniques might be further exploited for the diagnosis and staging prediction of lung cancer in future.

Testicular lactate content is compromised in men with Klinefelter Syndrome

Klinefelter syndrome (KS) is the most common genetic cause of human infertility, but the mechanism(s) responsible for its phenotype remain largely unknown. KS is associated with alterations in body composition and with a higher risk of developing metabolic diseases. We therefore hypothesized that KS men seeking fertility treatment possess an altered testicular metabolism profile that may hamper the nutritional support of spermatogenesis. Testicular biopsies from control (46, XY) (n = 6) and KS (47, XXY) (n = 6) individuals were collected and analyzed by proton high-resolution magic-angle spinning nuclear magnetic resonance spectroscopy. The mRNA and protein expression of crucial glycolysis-associated enzymes and transporters were evaluated in parallel by quantitative PCR and Western blot, respectively. Our data revealed altered regulation of glucose transporters (GLUT1 and GLUT3); phosphofructokinase 1, liver isoform (PFKL); and lactate dehydrogenase A (LDHA) expression in the testis of KS patients. Moreover, we detected a severe reduction in lactate and creatine accumulation within testicular tissue from KS men. The aberrant levels of the biomarkers detected in testicular biopsies of KS men may therefore be associated with the infertility phenotypes presented by these men. Mol. Reprod. Dev. 83: 208-216, 2016. © 2015 Wiley Periodicals, Inc.

(1)H HR-MAS NMR Spectroscopy and the Metabolite Determination of Typical Foods in Mediterranean Diet.

NMR spectroscopy has become an experimental technique widely used in food science. The experimental procedures that allow precise and quantitative analysis on different foods are relatively simple. For a better sensitivity and resolution, NMR spectroscopy is usually applied to liquid sample by means of extraction procedures that can be addressed to the observation of particular compounds. For the study of semisolid systems such as intact tissues, High-Resolution Magic Angle Spinning (HR-MAS) has received great attention within the biomedical area and beyond. Metabolic profiling and metabolism changes can be investigated both in animal organs and in foods. In this work we present a proton HR-MAS NMR study on the typical vegetable foods of Mediterranean diet such as the Protected Geographical Indication (PGI) cherry tomato of Pachino, the PGI Interdonato lemon of Messina, several Protected Designation of Origin (PDO) extra virgin olive oils from Sicily, and the Traditional Italian Food Product (PAT) red garlic of Nubia. We were able to identify and quantify the main metabolites within the studied systems that can be used for their characterization and authentication.

Characterization of metabolites in infiltrating gliomas using ex vivo 1 H high‐resolution magic angle spinning spectroscopy

Gliomas are routinely graded according to histopathological criteria established by the World Health Organization. Although this classification can be used to understand some of the variance in the clinical outcome of patients, there is still substantial heterogeneity within and between lesions of the same grade. This study evaluated image-guided tissue samples acquired from a large cohort of patients presenting with either new or recurrent gliomas of grades II–IV using ex vivo proton high-resolution magic angle spinning spectroscopy. The quantification of metabolite levels revealed several discrete profiles associated with primary glioma subtypes, as well as secondary subtypes that had undergone transformation to a higher grade at the time of recurrence. Statistical modeling further demonstrated that these metabolomic profiles could be differentially classified with respect to pathological grading and inter-grade conversions. Importantly, the myo-inositol to total choline index allowed for a separation of recurrent low-grade gliomas on different pathological trajectories, the heightened ratio of phosphocholine to glycerophosphocholine uniformly characterized several forms of glioblastoma multiforme, and the onco-metabolite D-2-hydroxyglutarate was shown to help distinguish secondary from primary grade IV glioma, as well as grade II and III from grade IV glioma. These data provide evidence that metabolite levels are of interest in the assessment of both intra-grade and intra-lesional malignancy. Such information could be used to enhance the diagnostic specificity of in vivo spectroscopy and to aid in the selection of the most appropriate therapy for individual patients.

Metabolic profiling of cervical tubercular lymphadenitis tissues by proton HR-MAS NMR spectroscopy

Proton metabolic profiling of incisional biopsied cervical lymph node tissue specimens of 109 patients suffering from tubercular (CTBL) and non-specific (NSCLA) lymphadenitis were analyzed by high resolution magic angle spinning (HR-MAS) NMR spectroscopy. In the present study, 40 endogenous metabolites namely, myo-inositol (m-Ins), branched chain amino acids (BCAA), glutamate, serine, taurine (Tau) aromatic amino acids, choline (Cho) containing compounds and glucose were characterized. To the best of our knowledge, this is the first report on metabolic profiling of cervical tubercular lymph node tissues using HR-MAS NMR spectroscopy. The principal component analysis revealed a clear discrimination between CTBL and NSCLA tissues. Increase in the concentration of mobile poly unsaturated fatty acids, BCAA, Cho, Tau, glycine and a decrease in the concentration of lactate, phosphocholine and m-Ins was observed in CTBL cases. The partial least square discriminant analysis (PLS-DA) with R 2 = 0.95 and Q 2 = 0.92 provided >98 % of correct classification between the two groups. A PLS-DA training set model of 75 % (CTBL = 54, NSCLA = 27) of the subjects when subjected for prediction of 25 % cases (CTBL = 18, NSCLA = 10) as an unknown dataset provided more than 98 % of diagnostic accuracy in their respective histological categories. The receiver operator characteristic curve was generated from PLS-DA factor-1 projected an area under the curve of 0.962. The metabolic profile obtained from HR-MAS NMR spectroscopy may be used as surrogate markers in vivo MRS for differentiating between CTBL and NSCLA cases non-invasively.

Differentiating Diffuse World Health Organization Grade II and IV Astrocytomas With Ex Vivo Magnetic Resonance Spectroscopy

The prognosis and treatment of astrocytomas, which are primary brain tumors, vary depending on the grade of the tumor, necessitating a precise preoperative classification. Magnetic resonance spectroscopy (MRS) provides information about metabolites in tissues and is an emerging noninvasive tool to improve diagnostic accuracy in patients with intracranial neoplasia. To investigate whether ex vivo MRS could differentiate World Health Organization grade II (A-II) and IV astrocytomas (glioblastomas; GBM) and to correlate MR spectral profiles with clinical parameters. Patients with A-II and GBM (n = 58) scheduled for surgical resection were enrolled. Tumor specimens were collected during surgery and stored in liquid nitrogen before being analyzed with high-resolution magic angle spinning MRS. The tumors were histopathologically classified according to World Health Organization criteria as GBM (n = 48) and A-II (n = 10). Multivariate analysis of ex vivo proton high-resolution magic angle spinning spectra MRS showed differences in the metabolic profiles of different grades of astrocytomas. A-II had higher levels of glycerophosphocholine and myo-inositol than GBM. The latter had more phosphocholine, glycine, and lipids. We observed a significant metabolic difference between recurrent and nonrecurrent GBM (P < .001). Primary GBM had more phosphocholine than recurrent GBM. A significant correlation (P < .001) between lipid and lactate signals and histologically estimated percentage of necrosis was observed in GBM. Spectral profiles were not correlated with age, survival, or magnetic resonance imaging-defined tumor volume. Ex vivo MRS can differentiate astrocytomas based on their metabolic profiles.

Magnetic Resonance of 2-Hydroxyglutarate in IDH1 -Mutated Low-Grade Gliomas

Recent studies have indicated that a significant survival advantage is conferred to patients with gliomas whose lesions harbor mutations in the genes isocitrate dehydrogenase 1 and 2 (IDH1/2). IDH1/2 mutations result in aberrant enzymatic production of the potential oncometabolite D-2-hydroxyglutarate (2HG). Here, we report on the ex vivo detection of 2HG in IDH1-mutated tissue samples from patients with recurrent low-grade gliomas using the nuclear magnetic resonance technique of proton high-resolution magic angle spinning spectroscopy. Relative 2HG levels from pathologically confirmed mutant IDH1 tissues correlated with levels of other ex vivo metabolites and histopathology parameters associated with increases in mitotic activity, relative tumor content, and cellularity. Ex vivo spectroscopic measurements of choline-containing species and in vivo magnetic resonance measurements of diffusion parameters were also correlated with 2HG levels. These data provide extensive characterization of mutant IDH1 lesions while confirming the potential diagnostic value of 2HG as a surrogate marker of patient survival. Such information may augment the ability of clinicians to monitor therapeutic response and provide criteria for stratifying patients to specific treatment regimens.