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In metabolomics, mass spectrometry is used to detect a large number of low-molecular substances in a single analysis. Such a capacity could have direct application in disease diagnostics. However, it is challenging because of the analysis complexity, and the search for a way to simplify it while maintaining the diagnostic capability is an urgent task. It has been proposed to use the metabolomic signature without complex data processing (mass peak detection, alignment, normalization, and identification of substances, as well as any complex statistical analysis) to make the analysis more simple and rapid. Methods: A label-free approach was implemented in the metabolomic signature, which makes the measurement of the actual or conditional concentrations unnecessary, uses only mass peak relations, and minimizes mass spectra processing. The approach was tested on the diagnosis of impaired glucose tolerance (IGT). Results: The label-free metabolic signature demonstrated a diagnostic accuracy for IGT equal to 88% (specificity 85%, sensitivity 90%, and area under receiver operating characteristic curve (AUC) of 0.91), which is considered to be a good quality for diagnostics. Conclusions: It is possible to compile label-free signatures for diseases that allow for diagnosing the disease in situ, i.e., right at the mass spectrometer without complex data processing. This achievement makes all mass spectrometers potentially versatile diagnostic devices and accelerates the introduction of metabolomics into medicine.

In the frame of the work, data on the implementation of metabolomics tests in medicine have been systematized. Based on the obtained data, a set of protocols was proposed, the sequential realization of which makes it possible to conduct a blood metabolome analysis for medical purposes. Using this analysis and the number of blood samples from healthy volunteers, a prototype of a healthy person's metabolomic image has been developed; it allows visually and digitally to assess the compliance of the human blood metabolome with the norm. At the same time, 99% of the metabolic processes reflected in the blood plasma are estimated. If abnormalities are detected, the metabolomic image allows to get the value of these deviations of metabolic processes in digital terms.Sistematizirovany dannye po vnedreniiu metabolomnykh testov v meditsinu. Osnovyvaias' na poluchennykh dannykh, predlozhena sovokupnost' protokolov, posledovatel'naia realizatsiia kotorykh pozvoliaet provesti metabolomnyĭ analiz krovi dlia meditsinskikh tseleĭ. Ispol'zuia dannyĭ analiz i vyborku obraztsov krovi zdorovykh dobrovol'tsev, razrabotan prototip metabolomnogo obraza zdorovogo cheloveka, pozvoliaiushchiĭ nagliadno i v tsifrovom vyrazhenii otsenit' sootvetstvie metaboloma krovi cheloveka norme. Pri étom otsenivaetsia 99% metabolicheskikh protsessov, otrazhennykh v plazme krovi. V sluchae vyiavleniia otkloneniĭ metabolomnyĭ obraz pozvoliaet poluchit' v tsifrovom vyrazhenii velichinu étikh otkloneniĭ metabolicheskikh protsessov.

There are a number of different animals that belong to long- and short-lived species and show a various rate of ageing, providing an ideal model to investigate mechanisms of longevity. In this work, a metabolome profiling of blood plasma from fishes with various ageing rates—negligible (Pike Esox Lucius and Sterlet Acipenser ruthenus), gradual (Zander Sander lucioperca and Perch Perca fluviatilis) and rapid (Chum Salmon Oncorhynchus keta and Pink Salmon Oncorhynchus gorbuscha)—was assessed by means of direct infusion to quadrupole time-of-flight mass spectrometry. Of the 2056 distinct m/z features detected by a mass spectrometry metabolic profiling of blood plasma samples, fifteen metabolites in the classes of dipeptides, fatty acids, glycerolipids, phosphoethanolamines and phosphatidylcholines were significantly associated with ageing rate, independent of species differences. This is the first study of the metabolome of fishes with various ageing rate, and this untargeted approach highlighted the metabolic conditions that may serve to assess the ageing process.

In metabolomics, a large number of small molecules can be detected in a single run. However, metabolomic data do not include the absolute concentrations of each metabolite. Generally, mass spectrometry analyses provide metabolite concentrations that are derived from mass peak intensities, and the peak intensities are strictly dependent on the type of mass spectrometer used, as well as the technical characteristics, options and protocols applied. To convert mass peak intensities to actual concentrations, calibration curves have to be generated for each metabolite, and this represents a significant challenge depending on the number of metabolites that are detected and involved in metabolome-based diagnostics. To overcome this limitation, and to facilitate the development of diagnostic tests based on metabolomics, mass peak intensities may be expressed in quintiles. The present study demonstrates the advantage of this approach. The examples of diagnostic signatures, which were designed in accordance to this approach, are provided for lung and prostate cancer (leading causes of mortality due to cancer in developed countries) and impaired glucose tolerance (which precedes type 2 diabetes, the most common endocrinology disease worldwide).

Recent decades have been marked by advances in omics sciences based on high-throughput technologies, which have enabled the measurement of enormous numbers of molecules in biosamples. This study investigated the capacity of blood plasma metabolome to be used for diagnostics. Blood plasma samples ( n = 120) were methanol-treated to remove proteins. The remaining metabolite fractions were directly analyzed by mass spectrometry. Various diagnostic substances with different molecular weights, chemical classes, and plasma abundances were directly estimated from mass spectra or predicted from mass spectra by neural networking. Predicted levels of these substances were correlated ( r = 0.51–0.78) with their actual values. Blood plasma metabolomics may be considered as a diagnostic tool capable of substituting for several clinical laboratory tests.

The goal of this study was to evaluate the capacity for mass spectrometry of blood plasma to diagnose impaired glucose tolerance (IGT). For this study, blood plasma samples from control subjects (n = 30) and patients with IGT (n = 20) were treated with methanol and low molecular weight fraction were then analyzed by direct infusion mass spectrometry. A total of 51 metabolite ions strongly associated with IGT were detected. The area under a receiver operating characteristic (ROC) curve (AUC) for diagnosing IGT that was based on an analysis of all these metabolites was 0.93 (accuracy 90%, specificity 90%, and sensitivity 90%). The associated reproducibility was 85%. The metabolites identified were also consistent with risk factors previously associated with the development of diabetes. Thus, direct infusion mass spectrometry of blood plasma metabolites represents a rapid, single-step, and reproducible method for the analysis of metabolites. Moreover, this method has the potential to serve as a prototype for clinical analyses that could replace the currently used glucose tolerance test with a more patient-friendly assay.

Lung cancer is one of the most common types of cancer in men, and is a leading cause of cancer-related deaths. Therefore, the identification of specific markers associated with a risk of lung cancer development, particularly metabolites that are more easily assayed, would be very valuable. To this end, а comparative metabolomics study of blood plasma samples collected from patients with lung cancer (n=100) and controls (n=100) recruited in Moscow was carried out. After the extraction of blood plasma proteins with methanol, the remaining plasma metabolite fractions were analyzed directly using mass spectrometry. Hundreds of cancer-associated metabolites were detected, and at least 70 metabolite ions with odds ratio values of 10-288 were found to be associated with the presence of cancer. Although these metabolites were present at higher levels in cancer patients, particularly in the early stages of disease, they did not correlate positively with cancer progression. On the basis of these findings, this metabolomics study of blood plasma samples from cancer patients shows that numerous cancer-associated metabolites were present in the studied population, and these could be used as factors for calculating the risk of lung cancer development in addition to currently used risk factors.

A new method for the analysis of blood lipid based on direct mass spectrometry of lipophilic low molecular weight fraction of blood plasma has been considered. Such technique allows quantification of hundreds of various types of lipids and this changes existing concepts on diagnostics of lipid disorders and related diseases. The versatility and quickness of the method significantly simplify its wide use. This method is applicable for diagnostics of atherosclerosis, diabetes, cancer and other diseases. Detalization of plasma lipid composition at the molecular level by means of mass spectrometry allows to assess the effectiveness of therapy and to optimize the drug treatment of cardiovascular diseases by phospholipid preparations.Rassmotren novyĭ metod analiza lipidnogo sostava krovi, osnovannyĭ na priamoĭ mass-spektrometrii lipofil'noĭ nizkomolekuliarnoĭ fraktsii plazmy krovi. Dannaia metodika pozvoliaet kolichestvenno opredeliat' sotni razlichnykh vidov lipidov, chto meniaet sushchestvuiushchee predstavlenie o diagnostike lipidnykh narusheniĭ i sviazannykh s nimi zabolevaniĭ. Pokazany universal'nost' i bystrota vypolneniia metoda, sushchestvenno uproshchaiushchie ego povsemestnoe primenenie. Obosnovana vozmozhnost' primeneniia metoda dlia diagnostiki ateroskleroza, sakharnogo diabeta, onkologicheskikh i drugikh zabolevaniĭ. Detalizatsiia lipidnogo sostava plazmy krovi na molekuliarnom urovne s pomoshch'iu mass-spektrometrii pozvoliaet otsenit' éffektivnost' lecheniia zabolevaniĭ i optimizirovat' lekarstvennuiu terapiiu serdechno-sosudistykh zabolevaniĭ fosfolipidnymi preparatami.