Untargeted metabolomics of blood plasma samples of patients with hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths in the world. HCC is often diagnosed late because patients with early-stage cancer have no apparent symptoms. Therefore, it is desirable to find a reliable method for an early diagnosis based on the detection of metabolites - biomarkers, that can be detected in the early stages of the disease. Untargeted metabolomics is often used as a tool to find a suitable biomarker for several diseases. In this work, untargeted metabolomics was performed on blood plasma samples of HCC patients and compared with healthy individuals and patients with liver cirrhosis. A combination of liquid chromatography and high-resolution mass spectrometry was used as an analytical method. More than a thousand peaks were detected in the blood plasma samples, from which mainly amino acids, carboxylic acids, lipids, and their derivatives were evaluated as potential biomarkers. The data obtained were statistically processed using the analysis of variance, correlation analysis, and principal component analysis.

Monitoring of kynurenine pathway metabolites, neurotransmitters and their metabolites in blood plasma and brain tissue of individuals with latent toxoplasmosis.

The aim of the presented work was to develop a highly sensitive, accurate and rapid analytical method for the determination of concentration levels of tryptophan and its metabolites of kynurenine catabolic pathway, as well as neurotransmitters and their metabolites in complex biological matrices (brain tissue and blood plasma). The developed analytical method consists of analytes separation from the biological matrices by protein precipitation (blood plasma) or solvent extraction (brain tissue), derivatization of the analytes and their detection by high-performance liquid chromatography combined with mass spectrometry. Individual steps of the whole process were optimized and the method was validated in the terms of selectivity, linearity (R2≥0.980), precision (RSD ≤ 13.3%), recovery (≥82.0%), limit of detection (1.8 ng/mL of blood plasma, 2.2 pg/mg of brain tissue) and limit of quantification (2.5 ng/mL of blood plasma, 2.8 pg/mg of brain tissue). The method was subsequently verified by an animal study, where the concentration levels of the analytes in biological matrices (blood plasma and brain tissue) of T. gondii - infected rats and control animals were compared. All the data obtained from the animal study were statistically evaluated. Increased concentration levels of kynurenine catabolic pathway metabolites (e.g. kynurenine, 3-hydroxykynurenine, quinolinic acid) were observed in the case of T. gondii - infected rats in contrast to the control group. The opposite effect was determined in the case of serotonin and its metabolite 5-hydroxyindoleacetic acid, where higher concentration levels were found in blood plasma of healthy subjects. Finally, Principal Component Analysis (PCA) was utilized for a score plot formation. PCA score plots have demonstrated the similarities of individuals within each group and the differences among the groups.

Multimarker screening of oxidative stress in aging.

Aging is a complex process of organism decline in physiological functions. There is no clear theory explaining this phenomenon, but the most accepted one is the oxidative stress theory of aging. Biomarkers of oxidative stress, substances, which are formed during oxidative damage of phospholipids, proteins, and nucleic acids, are present in body fluids of diseased people as well as the healthy ones (in a physiological concentration). 8-iso prostaglandin F2α is the most prominent biomarker of phospholipid oxidative damage, o-tyrosine, 3-chlorotyrosine, and 3-nitrotyrosine are biomarkers of protein oxidative damage, and 8-hydroxy-2(')-deoxyguanosine and 8-hydroxyguanosine are biomarkers of oxidative damage of nucleic acids. It is thought that the concentration of biomarkers increases as the age of people increases. However, the concentration of biomarkers in body fluids is very low and, therefore, it is necessary to use a sensitive analytical method. A combination of HPLC and MS was chosen to determine biomarker concentration in three groups of healthy people of a different age (twenty, forty, and sixty years) in order to find a difference among the groups.

Immunomagnetic molecular probe with UHPLC-MS/MS: a promising way for reliable bronchial asthma diagnostics based on quantification of cysteinyl leukotrienes.

A sensitive and precise method for simultaneous quantification of cysteinyl leukotrienes (=cys LTs) - leukotriene C4 (=LTC4), leukotriene D4 (=LTD4) and leukotriene E4 (=LTE4) - essential biomarkers of bronchial asthma present in exhaled breath condensate (=EBC) was developed. An immunomagnetic molecular probe was prepared by anchoring cysteinyl leukotrienes antibody on the surface of functionalized monodispersed magnetic particles and used to selectively isolate cys LTs from biological matrices - EBC, plasma and urine. Immobilization and the immunoaffinity capture procedures were optimized to maximize the amount of separated cys LTs, which were detected "off-beads" after acidic elution by UHPLC-ESI-MS/MS operated in a multiple reaction monitoring mode. The developed method was characterized with high precision ≤13.6% (intra-day precision determined as RSD) and ≤14.5% (inter-day precision determined as RSD), acceptable accuracy ≤18.5% (determined as RE), and high recovery of immunoseparation (≥93.1%) in aforementioned biological matrices. The applicability of the method was demonstrated on EBC, plasma and urine clinical samples of patients with various subtypes of bronchial asthma (occupational, steroid-resistant, moderate with and without corticosteroids therapy) and healthy subjects where reasonable differences in cys LTs concentration levels were found. Combining extremely selective immunomagnetic separation with highly sensitive and precise detection step, the developed method was used to aid diagnosis, predict the most effective therapy, and monitor the response to treatment. The detection of elevated inflammatory mediators (cys LTs) in EBC of subjects with relatively asymptomatic asthma and normal pulmonary function tests could offer a novel way for monitoring the lung inflammation and perhaps initiating treatment in an earlier stage.