Analysis of free, mono- and diacetylated polyamines from human urine by LC–MS/MS

Wheat germ, a byproduct of the wheat milling industry, as a beneficial source of anti-aging polyamines: A quantitative comparison of various forms

Polyamines have received a lot of attention since the 1990s because of their anti-aging, anti-chronic disease, and proliferative effects. Wheat germ was reported as one of the natural sources of high polyamine, especially spermidine. The current study used three types of wheat germ: group A was industrially separated germ from whole grain, group B was the commercially available germinated wheat germ, and group C was manually separated wheat germ from germinated grain. The polyamine content of putrescine, spermidine, and spermine has been determined using a simplified isocratic LC-MS/MS method. An optimized extraction procedure was performed on all seven samples for obtaining a polyamine-enriched extract. The three dominant carbomylated polyamines were identified by analyzing the extracted samples in order to determine their relative abundance. Wheat germ powders contain the highest amount of polyamines (220-337 μg/g) of which spermidine is one of the most important. Germinated wheat grains, on the other hand, contain the least amount of this polyamine. The commercially available separated wheat germs are suggested as a good nutrition source of these polyamines.

Determination of polyamines in urine via electrospun nanofibers-based solid-phase extraction coupled with GC-MS and application to gastric cancer patients

The simultaneous determination of polyamines and their metabolites in urine samples was achieved by gas chromatography-mass spectrometry in the selected ion monitoring mode. After conjugating with the ion-pair reagent bis-2-ethylhexylphosphate in the aqueous phase, the polyamines in the samples were extracted with polystyrene nanofiber-based packed-fiber solid-phase extraction followed by a derivatization step using pentafluoropropionyl anhydride. With optimal conditions, all analytes were separated well. For analytes of putrescine, cadaverine, N-acetylputrescine, and N-acetylcadaverine, the linearity was good in the range of 0.05-500 μmol/L (R²  ≥ 0.993). While for spermidine, spermine, acetylspermidine, N⁸ -acetylspermidine, and N-acetylspermine, the linearity was good in the range of 0.5-500 μmol/L (R²  ≥ 0.990). The recoveries of three spiked concentrations (0.5, 5, 300 μmol/L) were 85.6%-108.4%, and relative standard deviations for intra- and interday were in the range of 2.9%-13.4% and 4.5%-15.1%, respectively. The method was successfully applied to the analysis of urine samples of gastric cancer patients. The results showed that the levels of most polyamines and N-acetylated polyamines from the patient group were significantly higher than those from the control group. The altered concentrations of the above-mentioned metabolites suggest their role in the pathogenesis of gastric cancer, and they should be further evaluated as potential markers of gastric cancer.

Bile-volatile organic compounds in the diagnostics of pancreatic cancer and biliary obstruction: A prospective proof-of-concept study

OBJECTIVES

Detection of volatile organic compounds (VOCs) from bodily fluids with field asymmetric waveform ion mobility spectrometry (FAIMS) and related methods has been studied in various settings. Preliminary results suggest that it is possible to detect prostate, colorectal, ovarian and pancreatic cancer from urine samples. In this study, our primary aim was to differentiate pancreatic cancer from pancreatitis and benign tumours of the pancreas by using bile samples obtained during endoscopic retrograde cholangiopancreatography (ERCP). Secondarily, we aimed to differentiate all pancreatic region malignancies from all other kinds of benign causes of biliary obstruction.

METHODS

A bile sample was successfully aspirated from 94 patients during ERCP in Tampere University Hospital. Hospital and patient records were prospectively followed up for at least two years after ERCP. Bile samples were analysed using a Lonestar chemical analyser (Owlstone, UK) using an ATLAS sampling system and a split-flow box. Diagnoses and corresponding data from the analyses were matched and divided into two subcategories for comparison. Statistical analysis was performed using linear discriminant analysis, support vector machines, and 5-fold cross-validation.

RESULTS

Pancreatic cancers (n=8) were differentiated from benign pancreatic lesions (n=9) with a sensitivity of 100%, specificity of 77.8%, and correct rate of 88%. All pancreatic region cancers (n=19) were differentiated from all other kinds of benign causes of biliary obstruction (n=75) with corresponding values of 21.1%, 94.7%, and 80.7%. The sample size was too small to try to differentiate pancreatic cancers from adjacent cancers.

CONCLUSION

Analysing bile VOCs using FAIMS shows promising capability in detecting pancreatic cancer and other cancers in the pancreatic area.

Discrimination between Pancreatic Cancer, Pancreatitis and Healthy Controls Using Urinary Polyamine Panel

BACKROUND

Polyamines play an important role in cellular proliferation, and the change in polyamine metabolism is reported in various cancers. We searched for urinary polyamine signature for distinguishing between pancreatic cancer, premalignant lesions of the pancreas (PLP), acute and chronic pancreatitis, and controls.

METHODS

Patients and controls were prospectively recruited in three Finnish hospitals between October 2013 and June 2016. The patients provided a urine sample at the time of the diagnosis. The panel of 14 polyamines was obtained in a single run with mass spectrometry. The polyamine concentrations were analysed with quadratic discriminant analysis and cross-validated with leave-one-out cross-validation.

RESULTS

Sixty-eight patients with pancreatic cancer, 36 with acute pancreatitis, 18 with chronic pancreatitis and 7 with PLP were recruited, as were 53 controls. The combination of 4 polyamines - acetylputrescine, diacetylspermidine, N⁸-acetylspermidine and diacetylputrescine - distinguished pancreatic cancer and PLP from controls (sensitivity = 94%, specificity = 68% and AUC = 0.88). The combination of diacetylspermidine, N8-acetylspermidine and diacetylspermine distinguished acute pancreatitis from controls (sensitivity = 94%, specificity = 92%, AUC = 0.98). The combination of acetylputrescine, diacetylspermidine and diacetylputrescine distinguished chronic pancreatitis from controls (sensitivity = 98%, specificity = 71%, AUC = 0.93).

CONCLUSIONS

Optimally selected urinary polyamine panels discriminate between pancreatic cancer and controls, as well as between acute and chronic pancreatitis and controls.

N1-acetylspermidine is a determinant of hair follicle stem cell fate

Stem cell differentiation is accompanied by increased mRNA translation. The rate of protein biosynthesis is influenced by the polyamines putrescine, spermidine and spermine, which are essential for cell growth and stem cell maintenance. However, the role of polyamines as endogenous effectors of stem cell fate and whether they act through translational control remains obscure. Here, we investigate the function of polyamines in stem cell fate decisions using hair follicle stem cell (HFSC) organoids. Compared to progenitor cells, HFSCs showed lower translation rates, correlating with reduced polyamine levels. Surprisingly, overall polyamine depletion decreased translation but did not affect cell fate. In contrast, specific depletion of natural polyamines mediated by spermidine/spermine N1-acetyltransferase (SSAT; also known as SAT1) activation did not reduce translation but enhanced stemness. These results suggest a translation-independent role of polyamines in cell fate regulation. Indeed, we identified N1-acetylspermidine as a determinant of cell fate that acted through increasing self-renewal, and observed elevated N1-acetylspermidine levels upon depilation-mediated HFSC proliferation and differentiation in vivo. Overall, this study delineates the diverse routes of polyamine metabolism-mediated regulation of stem cell fate decisions.

This article has an associated First Person interview with the first author of the paper.

Summary: Reduced protein synthesis is required for stem cell functions. Here, we delineate a complex interplay of polyamines and mRNA translation that determines hair follicle stem cell fate decisions.

The intracellular metabolome of starving cells

Fasting induces vast metabolic adaptations on the cellular level and leads to an organism-wide induction of autophagy. Autophagic degradation subserves resource recycling and facilitates the maintenance of energetic homeostasis. Mass spectrometry offers the possibility to assess changes in the metabolome that occur in conditions of nutrient deprivation and to profile such adaptations. Here we describe a detailed workflow for the targeted quantitation and untargeted profiling of metabolites that can be used to assess the intracellular metabolome of starving cells. Moreover, we outline a workflow for the use of non-radioactive isotope labeled metabolites. Altogether, we show that mass spectrometry is a powerful tool for monitoring metabolic changes in conditions of fasting.

Simultaneous determination of methionine cycle metabolites, urea cycle intermediates and polyamines in serum, urine and intestinal tissue by using UHPLC-MS/MS

Metabolites of methionine cycle, urea cycle and polyamine metabolism play important roles in regulating the metabolic processes and the development of diseases. It is rewarding and interesting to monitor the levels of the above metabolites in biological matrices to investigate pathological mechanisms. However, their quantitation is still unsatisfactory due to the poor retention behavior of the analytes on the traditional reversed-phase column. And never a single analytical method simultaneously quantify these three classes of metabolites. Besides, the concentrations of some metabolites are too low to be detected in the biological samples. In this study, we developed a UHPLC-ESI-MS/MS method to simultaneously determine the levels of 14 metabolites, including 4 methionine metabolism metabolites (methionine, homocysteine, S-adenosylmethionine and S-adenosylhomocysteine), 3 urea cycle intermediates (arginine, citrulline and ornithine) and 7 polyamines (putrescine, spermidine, spermine, N¹-acetylputrescine, N¹-acetylspermidine, N¹-acetylspermine and N¹,N¹²-diacetylspermine). The chromatographic separation was performed on the BEH amide column within 14 min using water and acetonitrile (both with 0.1% formic acid) as the mobile phases. The results of method validation showed good selectivity, linearity (r² > 0.99), recovery (93.1%-112.1%), inter-day and intra-day precision (RSD < 13.6% and RSD < 11.0%, respectively), stability (RSD < 15.1%) and matrix effect (76.0%-113.2%). The method is simple, quick and sensitive without derivatization processes and the use of ion-pairing reagents. This approach was successfully applied in urine, serum and tissue matrices, as well as in identifying potential biomarkers for hyperthyroidism and hypothyroidism. The method is promising to provide more information on pathophysiological mechanisms in metabolomics study.

Investigating the Association of the Biogenic Amine Profile in Urine with Therapeutic Response to Neoadjuvant Chemotherapy in Breast Cancer Patients

Neoadjuvant treatment (NAT) can downstage breast cancer and can be utilized for different clinical applications. However, the response to NAT varies among individuals. Having effective biomarkers is important to optimize the treatment of breast cancer. Concentrations of biogenic amines have been found to show an association with cancer cell proliferation, but their clinical utility remains unclear. This study developed a postcolumn-infused internal standard (PCI-IS)-assisted liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) method for profiling biogenic amines in human urine. Putrescine-d₈ was selected as the PCI-IS to calibrate the errors caused by matrix effects in the urine sample. The optimized method was applied to investigate the association between changes in 14 amines and the therapeutic response to NAT in breast cancer patients. Urine samples were collected before initiation of chemotherapy (n = 60). Our results indicated that the levels of N¹-acetylspermine, spermidine, norepinephrine, and dopamine were significantly higher in the responder group than the nonresponder group. These metabolites were incorporated with clinical factors to identify NAT responders, and the prediction model showed an area under the curve value of 0.949. These observations provide remarkable insights for future studies in elucidating the roles of biogenic amines in breast cancer. Additionally, the PCI-IS-assisted amine profiling method can facilitate these studies.

Skyline for Small Molecules: A Unifying Software Package for Quantitative Metabolomics

Vendor-independent software tools for quantification of small molecules and metabolites are lacking, especially for targeted analysis workflows. Skyline is a freely available, open-source software tool for targeted quantitative mass spectrometry method development and data processing with a 10 year history supporting six major instrument vendors. Designed initially for proteomics analysis, we describe the expansion of Skyline to data for small molecule analysis, including selected reaction monitoring, high-resolution mass spectrometry, and calibrated quantification. This fundamental expansion of Skyline from a peptide-sequence-centric tool to a molecule-centric tool makes it agnostic to the source of the molecule while retaining Skyline features critical for workflows in both peptide and more general biomolecular research. The data visualization and interrogation features already available in Skyline, such as peak picking, chromatographic alignment, and transition selection, have been adapted to support small molecule data, including metabolomics. Herein, we explain the conceptual workflow for small molecule analysis using Skyline, demonstrate Skyline performance benchmarked against a comparable instrument vendor software tool, and present additional real-world applications. Further, we include step-by-step instructions on using Skyline for small molecule quantitative method development and data analysis on data acquired with a variety of mass spectrometers from multiple instrument vendors.

Development of a new chromogenic method for putrescine quantification using coupling reactions involving putrescine oxidase

Quantification of polyamines, including putrescine, is generally performed using high-performance liquid chromatography (HPLC) or gas chromatography. However, these methods are time-consuming because of sample derivatization and analytical reagent preparation. In this study, we developed a simple and high-throughput putrescine quantification method on a 96-well microtiter plate using putrescine oxidase from Rhodococcus erythropolis NCIMB 11540, peroxidase, 4-aminoantipyrine, and N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt. The developed method (named as PuO-POD-4AA-TOPS method) was applicable to bacterial culture supernatants. Furthermore, putrescine concentrations determined by the developed method roughly corresponded to the concentrations determined by HPLC.

Gender-Related Differences on Polyamine Metabolome in Liquid Biopsies by a Simple and Sensitive Two-Step Liquid-Liquid Extraction and LC-MS/MS

Polyamines are involved in the regulation of many cellular functions and are promising biomarkers of numerous physiological conditions. Since the concentrations of these compounds in biological fluids are low, sample extraction is one of the most critical steps of their analysis. Here, we developed a comprehensive, sensitive, robust, and high-throughput LC-MS/MS stable-isotope dilution method for the simultaneous determination of 19 metabolites related to polyamine metabolism, including polyamines, acetylated and diacetylated polyamines, precursors, and catabolites from liquid biopsies. The sample extraction was optimized to remove interfering compounds and to reduce matrix effects, thus being useful for large clinical studies. The method consists of two-step liquid-liquid extraction with a Folch extraction and ethyl acetate partitioning combined with dansyl chloride derivatization. The developed method was applied to a small gender-related trial concerning human serum and urine samples from 40 obese subjects. Sex differences were found for cadaverine, putrescine, 1,3-diaminopropane, γ-aminobutyric acid, N8-acetylspermidine, and N-acetylcadaverine in urine; N1-acetylspermine in serum; and spermine in both serum and urine. The results demonstrate that the developed method can be used to analyze biological samples for the study of polyamine metabolism and its association with human diseases.

Detection of biogenic polyamines in blood of patients with breast cancer

The main threat of cancer diseases is their spreading throughout the population of many countries of the world and the complexity of their diagnostics at the early stages. Because of that, search and development of the latest diagnostic methods for oncological diseases which would allow them to be diagnosed more precisely and rapidly is going on. The objective of the study was developing a method for qualitative and quantitative analysis of polyamines as potential tumour markers in blood serum of patients with breast cancer using a newly created immune biosensor based on the effect of surface plasmon resonance (SPR). In the process of the study we used basics of immune analysis, methods of biosensor analysis with preliminary modification of biosensor analytical surface with certain reagents, such as protein A and BSA, for better orientation of the sensitive layer made from antibodies. During the study 30 samples of blood serum were analyzed, 21 of which were obtained from the patients with breast cancer and 9 samples were normal, taken from healthy people and used as controls. Analysis of blood serum samples was made, using previously created calibration curve, based on polyamine solutions in concentrations from 5 ng/mL to 1 µg/mL. It allowed determination of the presence of polyamines in blood samples and approximate concentration of polyamines comparing resonance angle shift in calibration curve and blood samples. According to the obtained results, the concentration of polyamines exceeded their physiological levels and was in the range of 21.3–125.1 ng/mL. The proposed approach allows one to determine the presence and approximate concentrations of polyamines in range from 5 ng/mL to 1 µg/mL in samples of blood serum of patients with breast cancer which correlates with tumour size and the age of the patients.

Urinary Polyamines as Biomarkers for Ovarian Cancer

OBJECTIVES

Elevated concentrations of polyamines have been found in urine of patients with malignant tumors, including ovarian cancer. Previous research has suffered from poorly standardized detection methods. Our liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is capable of simultaneous standardized analysis of most known polyamines. Liquid chromatography-tandem mass spectrometry has not previously been used in the differential diagnostics of ovarian tumors in postmenopausal women.

MATERIALS AND METHODS

In this prospective study, postmenopausal women (n = 71) presenting with an adnexal mass and, as controls, women with genital prolapse or urinary incontinence scheduled for surgery (n = 22) were recruited in the study. For analysis of the polyamines, a morning urine sample was obtained before surgery. Preoperative serum CA125 concentrations were determined in the study group.

RESULTS

Twenty-three women with benign and 37 with malignant ovarian tumors were eligible. Of all analyzed polyamines, only urinary N,N-diacetylspermine showed statistically significant differences between all groups except controls versus benign tumors. N,N-diacetylspermine was elevated in malignant versus benign tumors (P < 0.001), in high-grade versus low malignant potential tumors (P < 0.001), in stage III to IV versus stage I to II cancers (P < 0.001), and even in early-stage cancer (stage I-II) versus benign tumors (P = 0.017). N,N-diacetylspermine had better sensitivity (86.5%) but lower specificity (65.2%) for distinguishing benign and malignant ovarian tumors than CA125 with a cut-off value of 35 kU/L (sensitivity, 75.7%; specificity, 69.6%).

CONCLUSIONS

Urinary N,N-diacetylspermine seems to be able to distinguish benign and malignant ovarian tumors as well as early and advanced stage, and low malignant potential and high-grade ovarian cancers from each other, respectively.

Urinary Polyamines: A Pilot Study on Their Roles as Prostate Cancer Detection Biomarkers

Current screening methods towards prostate cancer (PCa) are not without limitations. Research work has been on-going to assess if there are other better tests suitable for primary or secondary screening of PCa to supplement the serum prostate specific antigen (PSA) test, which fails to work accurately in a grey zone of 4-10ng/ml. In this pilot study, the potential roles of urinary polyamines as prostate cancer biomarkers were evaluated. PCa, benign prostatic hyperplasia (BPH) patients and healthy controls (HC) showing PSA>4.0ng/ml were enrolled in the study. Their urine samples were obtained, and the urinary levels of putrescine (Put), spermidine (Spd) and spermine (Spm) were determined by ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometer (UPLC-MS/MS). Receiver operating characteristics (ROC) curve and Student’s t-test were used to evaluate their diagnostic accuracies. Among the three biogenic polyamines, Spm had demonstrated a good diagnostic performance when comparing their levels in PCa patients with BPH patients (1.47 in PCa vs 5.87 in BPH; p<0.0001). Results are in accordance with transrectal ultrasound prostatic biopsy (TRUSPB) results, with an area under curve (AUC) value of 0.83±0.03. Therefore urinary Spm shows potential to serve as a novel PCa diagnostic biomarker, which in turn can help to address the limited sensitivity and specificity problem of serum PSA test.

Use of microextraction by packed sorbents and gas chromatography-mass spectrometry for the determination of polyamines and related compounds in urine

A novel methodology for the determination of ornithine, putrescine, cadaverine, spermidine and gamma-amino butyric acid in urine samples has been developed. The method uses in situ aqueous derivatization followed by automated microextraction by packed sorbent coupled to a gas chromatography-mass spectrometry system equipped with a programmed temperature vaporizer. This instrumental configuration minimizes sample manipulation due to from the mixing of the reagents, the process is completely automated. The analytes were derivatized using ethyl chloroformate as derivatization reagent. The reaction occurred in aqueous medium and was carried out in 1min in the vial of an autosampler used to perform microextraction by packed sorbent. The parameters affecting derivatization, extraction and separation were optimized in order to obtain maximum sensitivity. Calibration curves were obtained for five calibration levels in three different matrices. All the calibration models displayed good linearity, with R(2) values higher than 0.95. The validity of the models was checked using ANOVA, and it was observed that they did not exhibit any lack of fit. Repeatability and reproducibility was evaluated, with values below 15% in both cases. LOD and LOQ values were found to be in the low μg/L level. Influence of the matrix was confirmed, thus quantification was performed using the standard additions method and normalization to IS. The method developed was applied to the analysis of these compounds in urine samples from healthy individuals and cancer diagnosed patients (Internal Medicine Unit of the Virgen de la Vega Hospital, Salamanca, Spain). Significant differences (Mann-Whitney U test) were observed for putrescine and ornithine concentrations.

Quantification of free polyamines and their metabolites in biofluids and liver tissue by UHPLC-MS/MS: application to identify the potential biomarkers of hepatocellular carcinoma

Polyamines and their N-acetylated metabolites are potential biomarkers in the diagnosis and therapeutic evaluation of cancer. Thus, we present here an ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of 6 free, 3 monoacetylated, and 2 diacetylated polyamines without derivatization. The major improvement of this method is the use of 0.2 % perfluoroheptanoic acid methanol in the pretreatment step to achieve protein precipitation and 0.0125 % perfluoroheptanoic acid in the mobile phase to achieve analyte separation within 9 min. The established analytical method was validated with plasma, urine, and liver tissue and applied to determine plasma, urine, and liver tissue samples from healthy rats, hepatocellular carcinoma rats, and administrated rats successfully. Results indicated free polyamines such as putrescine mainly existed in liver tissue but more polar N-acetylated metabolites such as N (1),N (12)-diacetylspermine seemed to exist in biological fluid. After carcinogenesis, the levels of polyamines were increased, but the elevated levels of polyamines and their metabolites tended to decrease when administrated with anticancer drug. The method provided a more versatile manner for clinical application in the diagnosis and therapeutic evaluation of hepatocellular carcinoma.