Determination of Tyrosine and Its Metabolites in Human Serum with Application to Cancer Diagnosis

Analysis of 4-Hydroxyphenyllactic Acid and Other Diagnostically Important Metabolites of α-Amino Acids in Human Blood Serum Using a Validated and Sensitive Ultra-High-Pressure Liquid Chromatography-Tandem Mass Spectrometry Method

The profile of and dynamic concentration changes in tyrosine, phenylalanine, and tryptophan metabolites in blood are of great interest since they could be considered potential biomarkers of different disorders. Some aromatic metabolites, such as 4-hydroxyphenyllactic, 4-hydroxyphenylacetic, phenyllactic, and 4-hydroxybenzoic acids have previously demonstrated their diagnostic significance in critically ill patients and patients with post-COVID-19 syndrome. In this study, a sensitive method, including serum protein precipitation with methanol and ultra-high-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection, was developed and validated for six phenyl- and five indole-containing acids in human serum. The liquid-liquid extraction was also examined, but it demonstrated unsatisfactory results based on analyte recoveries and the matrix effect. However, the recoveries for all analytes reached 100% and matrix effects were not observed using protein precipitation. This made it possible to use deionized water as a blank matrix. The lower limits of quantitation (LLOQs) were from 0.02 to 0.25 μmol/L. The validated method was used for the analysis of serum samples of healthy volunteers (n = 48) to reveal the reference values of the target analytes. The concentrations of the most clinically significant metabolite 4-hydroxyphenyllactic acid, which were revealed using UPLC-MS/MS and a previously developed gas chromatography-mass spectrometry method, were completely comparable. The proposed UPLC-MS/MS protocol can be used in the routine clinical practice of medical centers.

The discovery of combined toxicity effects and mechanisms of hexaconazole and arsenic to mice based on untargeted metabolomics

The high detected frequencies of hexaconazole (Hex) and arsenic (As) increased the probabilities of their co-existence in agricultural products. However, the combined toxicity effect and mechanism of action for these two pollutants were still unclear. In this study, an untargeted metabolomics method with ultra high performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS) was developed to monitor the changes of endogenous metabolites and metabolism pathways in mice liver. Our study revealed that significant differences in metabolomics profiles were observed after Hex, As, and Hex+As exposure for 90 d. Hex exposure altered 54 metabolites and 11 pathways significantly which were mainly lipid-related. For As exposure, 63 metabolites and 9 pathways were affected most of which were amino acid-related. Hex+As induced 93 metabolites changes with 34% was lipids and lipid-like molecules and 22% was organic acids and derivatives. Hex+As exposure shared the pathways that altered by Hex and As indicated that the interaction of Hex and As might be independent action. The results of this study could provide an important insight for understanding the mechanism of combined toxicity for Hex and As and be helpful for evaluating their health risk to human.

Modulation of broiler plasma metabolic spectrum by the addition of lysine residue to the diet

Flavour is an important factor in evaluating meat quality, and amino acids and fats are important components affecting meat flavour. In this study, we evaluated the relationship between the variation of lysine residue addition and the slaughter performance and meat quality of broilers, which decreased with the addition of lysine residues but improved the meat quality of the broilers. 10% lysine residue addition was the most beneficial for reducing feed cost and improving meat quality. Meanwhile, the plasma metabolites of broilers fed increasing concentrations of lysine residue supplemented feeds were analysed using liquid chromatography-mass spectrometry (LC-MS). Principal component analysis (PCA) and partial least square discriminant analysis (OPLS-DA) were used screen, the differential metabolites induced by lysine residue. In the broilers 29, 37, 63, 87, 80 and 111 differential metabolites were detected (p < 0.05). Amongst them, 3-iodotyrosine, N-methyl-L-glutamic acid, coumaraldehyde, 2-dimethylphenol, N-methylnicotinamide and L-erythrone were the common differential metabolites between group A and groups B, C, D, E, F and G. The addition of lysine residue was positively correlated with alanine aminotransferase (p < 0.05, r = 0.942) and high-density lipoprotein cholesterol (p < 0.05, r = 0.798) and negatively correlated with aspartate aminotransferase (p < 0.05, r = 0.822). According to the classification of differential metabolites and their enriched pathway analysis, differential metabolites mainly caused changes in amino acid and lipid metabolism. Our study shows that a certain proportion of lysine residue in diet affects the specific metabolic pathway of broilers, which may affect amino acid and fat metabolism by regulating alanine aminotransferase, aspartate aminotransferase and high-density lipoprotein cholesterol, ultimately affecting the flavour.

A potential prognostic marker in primitive lung neuroendocrine tumor: A case report

BACKGROUND

The diagnosis and monitoring of primitive lung neuroendocrine tumors (lung pNETs) are usually performed by the measurement of serum chromogranin A (CgA) and urinary 5-hydroxyindolacetic acid (5-HIAA) levels. However, imaging techniques are necessary due to the poor diagnostic efficiency of the laboratory tests.

METHODS

A total-body computed tomography and bone scintigraphy scans showed multiple hepatic and bone metastases of a 55-year-old man affected by well-differentiated lung pNETs without severe initial symptoms. After diagnosis, he started therapy and was monitored with serum, urinary markers, and imaging techniques.

RESULTS

During follow-up, the urinary 5-HIAA levels did not significantly increase, while serum CgA and urinary para-hydroxyphenylacetic acid (pHPAA) levels (urinary organic acid physiologically present in the urines of healthy subjects) showed significant increases related to worsening clinical condition.

CONCLUSIONS

The early increase in urinary pHPAA levels-usually not dosed in pNET patient monitoring-could be a promising prognostic marker.

Metabolite Profiling of Naringin in Rat Urine and Feces Using Stable Isotope-Labeling-Based Liquid Chromatography-Mass Spectrometry

Naringin has been documented to possess various bioactivities. Due to thorny endogenous interferences, the metabolism pathways of naringin and exact amounts of derived phenolic catabolites have not been definitely assigned. In this work, stable isotope-labeling-based liquid chromatography-mass spectrometry methods were developed to eliminate the endogenous interferences. [2',3',5',6'-D₄]-naringin was orally administrated to rats. Urine and feces samples were collected and then analyzed with ultrahigh-performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS/MS). A total of 21 flavonoid metabolites and 11 phenolic catabolites were screened. The metabolism and catabolism pathways were proposed. Furthermore, deuterated naringin and its main metabolites were determined with rapid resolution liquid chromatography tandem triple quadrupole mass spectrometry (RRLC-QqQ-MS/MS). The overall recovery of ingested deuterated naringin was calculated as 56.9% without endogenous interferences. The obtained results provide essential information for further pharmacological studies of naringin.

Pharmacokinetics, Tissue Distribution, Metabolism, and Excretion of Naringin in Aged Rats

Aging is an inevitable biological process characterized by the loss of functional capacity and associated with changes in all phases of pharmacokinetic processes. Naringin, a dietary flavanone glycoside, has been proved to be beneficial for the treatment of multiple age-associated chronic diseases. To date, the pharmacokinetic processes of naringin in aged individuals are still unknown. Thus, a rapid resolution liquid chromatography tandem triple quadrupole mass spectrometry (RRLC-QQQ-MS/MS) method was established for the determination of naringin and its metabolite naringenin in rat plasma, urine, feces, and tissue homogenate. The pharmacokinetic parameters were calculated and a higher exposure of naringin and naringenin were observed in aged rats. Naringin and naringenin were mostly distributed in gastrointestinal tract, liver, kidney, lung, and trachea. Furthermore, a total of 39 flavonoid metabolites (mainly glucuronides and sulfates) and 46 microbial-derived phenolic catabolites were screened with ultra-fast liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS). Naringenin, hippuric acid, and 3-(4'-hydroxyphenyl)propionic acid were predominated metabolites. This study systemically investigated the pharmacokinetics, tissue distribution, metabolism, and excretion of naringin in aged rats, revealing age- and gender-related changes in the in vivo behavior of naringin. These results would be helpful for the interpretation of pharmacokinetics and pharmacodynamics of naringin in aged population.

UFLC-Q-TOF-MS/MS-Based Screening and Identification of Flavonoids and Derived Metabolites in Human Urine after Oral Administration of Exocarpium Citri Grandis Extract

Exocarpium Citri grandis (ECG) is an important Traditional Chinese Medicine (TCM) for the treatment of cough and phlegm, and the flavonoids contained were considered the main effective components. To date, the systematic chemical profiling of these flavonoids and derived in vivo metabolites in human have not been well investigated. ECG was extracted using boiling water and then provided to volunteers for oral administration. Following the ingestion, urine samples were collected from volunteers over 48 h. The extract and urine samples were analyzed using ultra-fast liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS) system to screen and identify flavonoids and derived in vivo metabolites. A total of 18 flavonoids were identified in the ECG extract, and 20 metabolites, mainly glucuronide and sulfate conjugates, were screened in urine samples collected post consumption. The overall excretion of naringenin metabolites corresponded to 5.45% of intake and occurred mainly within 4–12 h after the ingestion. Meanwhile, another 29 phenolic catabolites were detected in urine. Obtained data revealed that flavonoids were abundant in the ECG extract, and these components underwent extensive phase II metabolism in humans. These results provided valuable information for further study of the pharmacology and mechanism of action of ECG.