Simultaneous Determination of Polyamines and Steroids in Human Serum from Breast Cancer Patients Using Liquid Chromatography-Tandem Mass Spectrometry

A simultaneous quantitative profiling method for polyamines and steroids using liquid chromatography-tandem mass spectrometry was developed and validated. We applied this method to human serum samples to simultaneously evaluate polyamine and steroid levels. Chemical derivatization was performed using isobutyl chloroformate to increase the sensitivity of polyamines. The method was validated, and the matrix effects were in the range of 78.7-126.3% and recoveries were in the range of 87.8-123.6%. Moreover, the intra-day accuracy and precision were in the ranges of 86.5-116.2% and 0.6-21.8%, respectively, whereas the inter-day accuracy and precision were in the ranges of 82.0-119.3% and 0.3-20.2%, respectively. The linearity was greater than 0.99. The validated method was used to investigate the differences in polyamine and steroid levels between treated breast cancer patients and normal controls. In our results, N-acetyl putrescine, N-acetyl spermidine, cadaverine, 1,3-diaminopropane, and epitestosterone were significantly higher in the breast cancer patient group. Through receiver operating characteristic curve analysis, all metabolites that were significantly increased in patient groups with areas under the curve >0.8 were shown. This mass spectrometry-based quantitative profiling method, used for the investigation of breast cancer, is also applicable to androgen-dependent diseases and polyamine-related diseases.

Profiling of Steroid Metabolic Pathways in Human Plasma by GC-MS/MS Combined with Microwave-Assisted Derivatization for Diagnosis of Gastric Disorders

Steroid hormones are associated in depth to cellular signaling, inflammatory immune responses, and reproductive functions, and their metabolism alterations incur various diseases. In particular, quantitative profiling of steroids in plasma of patients with gastric cancer can provide a vast information to understand development of gastric cancer, since both sex hormones and glucocorticoids might be correlated with the pathological mechanisms of gastric cancer. Here, we developed a gas chromatography-tandem mass spectrometry-dynamic multiple reaction monitoring (GC-MS/MS-dMRM) method combined with solid-phase extraction (SPE) and microwave-assisted derivatization (MAD) to determine 20 endogenous steroids in human plasma. In this study, MAD conditions were optimized with respect to irradiation power and time. The SPE enabled effective cleanup and extraction for profiling of steroid hormones in human plasma samples. The MAD could improve laborious and time-consuming derivatization procedure, since dielectric heating using microwave directly increase molecular energy of reactants by penetrating through medium. Furthermore, dMRM method provided more sensitive determination of 20 steroids, compared to traditional MRM detection. The limits of quantification of steroids were below 1.125 ng/mL and determination coefficients of calibration curves were higher than 0.9925. Overall precision and accuracy results were below 19.93% and within ±17.04%, respectively. The developed method provided sufficient detection sensitivities and reliable quantification results. The established method was successfully applied to profile steroid metabolism pathways in plasma of patients with chronic superficial gastritis (CSG), intestinal metaplasia (IM), and gastric cancer. Statistical significances of steroid plasma levels between gastric disorder groups were investigated. In conclusion, this method provided comprehensive profiling of 20 steroids in human plasma samples and will be helpful to discover potential biomarkers for the development of gastric cancer and to further understand metabolic syndrome.

UHPLC-MS/MS profiling of histidine and bile acid metabolism in human gastric fluid for diagnosis of gastric diseases

Bile acids (BAs) are synthesized in the liver and can mediate homeostasis and various metabolism processes in the human body. Their levels in the gastrointestinal tract are closely related to various gastrointestinal diseases. In particular, farnesoid X receptor activated by free BAs is associated with overexpression of histidine decarboxylase in tumorigenesis. Therefore, comprehensive profiling of histamine (HIST), histidine (His), and BAs in biological samples can provide insight into the pathological mechanisms of gastrointestinal diseases. However, development of an analytical platform to profile HIST, His, and BAs in biological samples has several challenges such as highly different polarities between acidic and basic targets, low physiological concentrations of analytes, and high matrix interference of biological samples. In this study, an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method combined with serial derivatization was developed to simultaneously determine HIST, His, and 5 BAs (cholic acid, deoxycholic acid, chenodeoxycholic acid, ursodeoxycholic acid, and lithocholic acid) in human gastric fluid. In serial derivatization, benzoyl chloride (BzCl) and N,N-dimethylethylenediamine (DMED) were used to selectively derivatize amino and carboxyl groups of analytes, respectively. After serial derivatization, all target derivatives were determined using a reverse-phase C18 LC column and positive multiple reaction monitoring (MRM) mode, with reasonable chromatographic separation and sensitive MS detection. To accurately quantify target metabolites, 7 stable isotope-labeled internal standards were used. The MS/MS spectra of DMED and Bz derivatives exhibited specific fragments via loss of a neutral molecule (dimethylamine; 45 Da) and inductive cleavage (benzoyl; m/z 105) from protonated molecules, enabling selection of appropriate MRM transition ions for selective and sensitive detection. The developed method was validated with respect to limits of detection and quantification, linearity, precision, accuracy, stability, and matrix effect. The established method was successfully applied to human gastric fluid samples. This method provides reliable quantification of HIST, His, and BAs in human gastric fluid and will be helpful to understand pathophysiological mechanisms of gastric diseases.

Untargeted Metabolomics and Polyamine Profiling in Serum before and after Surgery in Colorectal Cancer Patients

Colorectal cancer is one of the most prevalent cancers in Korea and globally. In this study, we aimed to characterize the differential serum metabolomic profiles between pre-operative and post-operative patients with colorectal cancer. To investigate the significant metabolites and metabolic pathways associated with colorectal cancer, we analyzed serum samples from 68 patients (aged 20–71, mean 57.57 years). Untargeted and targeted metabolomics profiling in patients with colorectal cancer were performed using liquid chromatography-mass spectrometry. Untargeted analysis identified differences in sphingolipid metabolism, steroid biosynthesis, and arginine and proline metabolism in pre- and post-operative patients with colorectal cancer. We then performed quantitative target profiling of polyamines, synthesized from arginine and proline metabolism, to identify potential polyamines that may serve as effective biomarkers for colorectal cancer. Results indicate a significantly reduced serum concentration of putrescine in post-operative patients compared to pre-operative patients. Our metabolomics approach provided insights into the physiological alterations in patients with colorectal cancer after surgery.

Assessing the progression of gastric cancer via profiling of histamine, histidine, and bile acids in gastric juice using LC-MS/MS

Bile acid (BA) imbalance may be directly associated with gastric cancer and indirectly influence stomach carcinogenesis via overexpression of histidine decarboxylase (HDC), which converts histidine (His) into histamine (HIST). Moreover, the progression of gastric cancer, could change the gut microbiome, including bacteria spp. that produce secondary BAs. Gastric juice has various metabolites that could indicate gastric cancer-related stomach conditions. Therefore, profiling of HIST, His, and BAs in gastric juice is crucial for understanding the etiological mechanisms of gastric cancer. We used a profiling method to simultaneously determine targeted metabolites in gastric juice using liquid chromatography-tandem mass spectrometry (LC-MS/MS). We successfully analyzed 70 human gastric juice samples from patients with chronic superficial gastritis (CSG, n = 20), intestinal metaplasia (IM, n = 12), and gastric cancer (n = 38). Furthermore, we investigated the relevance between BA metabolism and gastric cancer. There were statistical differences in the metabolism of cholic acid (CA) into deoxycholic acid (DCA) based on the progression of CSG into IM and gastric cancer. Hence, the progression of gastric cancer might be related to the alterations in gut microbiome composition. We provide insight into the etiological mechanisms of the progression of gastric cancer and biomarkers to diagnose and treat gastric cancer.

Sex-related differences in urinary immune-related metabolic profiling of alopecia areata patients

INTRODUCTION

Alopecia areata is a well-known autoimmune disease affecting humans. Polyamines are closely associated with proliferation and inflammation, and steroid hormones are involved in immune responses. Additionally, bile acids play roles in immune homeostasis by activating various signaling pathways; however, the roles of these substances and their metabolites in alopecia areata remain unclear.

OBJECTIVES

In this study, we aimed to identify differences in metabolite levels in urine samples from patients with alopecia areata and healthy controls.

METHODS

To assess polyamine, androgen, and bile acid concentrations, we performed high-performance liquid chromatography-tandem mass spectrometry.

RESULTS

Our results showed that spermine and dehydroepiandrosterone levels differed significantly between male patients and controls, whereas ursodeoxycholic acid levels were significantly higher in female patients with alopecia areata than in controls.

CONCLUSION

Our findings suggested different urinary polyamine, androgen, and bile acid concentrations between alopecia areata patients and normal controls. Additionally, levels of endogenous substances varied according to sex, and this should be considered when developing appropriate treatments and diagnostic techniques. Our findings improve our understanding of polyamine, androgen, and bile acid profiles in patients with alopecia areata and highlight the need to consider sex-related differences.

Altered polyamine profiling in the hair of patients with androgenic alopecia and alopecia areata

Hair follicles are among the most highly proliferative tissues. Polyamines are associated with proliferation, and several polyamines including spermidine and spermine play anti-inflammatory roles. Androgenic alopecia results from increased dihydrotestosterone metabolism, and alopecia areata is an autoimmune disease. This study aimed to investigate differences in polyamine profiles in hair samples between patients with androgenic alopecia and alopecia areata. Polyamine concentrations were determined through high-performance liquid chromatography-mass spectrometry. Hair samples were derivatized with isobutyl chloroformate. Differences in polyamine levels were observed between androgenic alopecia and alopecia areata compared with normal controls. In particular, polyamine levels were higher in alopecia areata patients than in normal controls. Certain polyamines displayed different concentrations between the androgenic alopecia and alopecia areata groups, suggesting that some polyamines, particularly N-acetyl putrescine (P = 0.007) and N-acetyl cadaverine (P = 0.0021), are significantly different in androgenic alopecia. Furthermore, spermidine (P = 0.021) was significantly different in alopecia areata. Our findings suggest that non-invasive quantification of hair polyamines may help distinguish between androgenic alopecia and alopecia areata. Our study provides novel insights into physiological alterations in patients with androgenic alopecia and those with alopecia areata and reveals some differences in polyamine levels in hair loss diseases with two different modes of action.

Distribution of polyamines may be altered in different scalp regions of patients with hair loss

Hair loss, from the vertex or front of the head, generally occurs due to increased androgenic steroid levels. Androgenic steroids, particularly testosterone and dihydrotestosterone, are distributed differently across the vertex and occipital regions and are involved in inducing ornithine decarboxylase expression. Therefore, we hypothesized that the distribution of polyamines may be altered in different scalp regions. For the overall metabolic profiling of polyamines in patients with hair loss, a liquid chromatography-mass spectrometry was used. We investigated the differential polyamine levels in different regions of the hair of patients with male pattern baldness and those with female pattern hair loss. The levels of most polyamines were higher in the vertex region than in the occipital region, and N-acetyl polyamine levels differed significantly. We proposed to test our hypothesis by profiling polyamines in human hair fibre to evaluate the distribution of metabolites in various regions of the scalp.

Metabolomic Analysis Identifies Alterations of Amino Acid Metabolome Signatures in the Postmortem Brain of Alzheimer's Disease

Despite significant advances in neuroscience research over the past several decades, the exact cause of AD has not yet fully understood. The metabolic hypothesis as well as the amyloid and tau hypotheses have been proposed to be associated with AD pathogenesis. In order to identify metabolome signatures from the postmortem brains of sporadic AD patients and control subjects, we performed ultra performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometer (UPLC-LTQ-Orbitrap-MS). Not only our study identified new metabolome signatures but also verified previously known metabolome profiles in the brain. Statistical modeling of the analytical data and validation of the structural assignments discovered metabolic biomarkers associated with the AD pathogenesis. Interestingly, hypotaurin, myo-inositol and oxo-proline levels were markedly elevated in AD while lutamate and N-acetyl-aspartate were decreased in the postmortem brain tissue of AD patients. In addition, neurosteroid level such as cortisol was significantly increased in AD. Together, our data indicate that impaired amino acid metabolism is associated with AD pathogenesis and the altered amino acid signatures can be useful diagnostic biomarkers of AD. Thus, modulation of amino acid metabolism may be a possible therapeutic approach to treat AD.

Simultaneous determination of androgens and prostaglandins in human urine using ultra-high-performance liquid chromatography-tandem mass spectrometry

A simultaneous quantitative profiling method for androgens and prostaglandins using ultra-high-performance liquid chromatography-tandem mass spectrometry was developed and validated to evaluate urinary androgen and prostaglandin levels. Solid-phase extraction and liquid-liquid extraction steps were combined during the sample preparation. β-Glucuronidase/arylsulfatase was also used in the enzyme hydrolysis step. Chemical derivatization was performed using 2-hydrazinopyridine for simultaneous determination of androgen and prostaglandin in the same ionization mode. The analytes were all separated and measured using multiple reaction monitoring in the positive ion mode within a run time of 22 min. The method was validated, achieving overall recoveries ranging from 81.0 to 102.9% with limits of quantification ranging from 0.01 to 2 ng/mL. The intra-day accuracy and precision ranged from 6.5 to 14.3% and from 77.1 to 106.8%, respectively. The inter-day accuracy and precision ranged from 8.9 to 18.2% and 89.9 to 101.4%, respectively. The linearity was expressed using the correlation coefficient, which was >0.99. The method developed herein was used to investigate the effects of a one-year finasteride treatment through differences in urinary androgen and prostaglandin levels between treated male pattern baldness patients and normal controls. The urinary androgen and prostaglandin levels were not significantly different between the two groups because of the administration of finasteride. The results confirmed that finasteride affects androgens and PGs related to hair regrowth and growth length, and a one-year finasteride treatment is effective for MPB. The mass spectrometry-based quantitative profiling method used herein for the investigation of male pattern baldness also holds great potential for the evaluation of androgens and prostaglandins associated with the metabolism of various inflammatory diseases.

Improved detectability of sex steroids from frozen sections of breast cancer tissue using GC-triple quadrupole-MS

Sex steroids in clinical endocrinology have been mainly investigated with peripheral blood and urine samples, while there is limited information regarding the local levels within tissues. To improve analytical properties of sex steroids from trace amounts of tissue samples, two-phase extractive ethoxycarbonlyation and subsequent pentafluoropropionyl derivatization coupled to gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. The optimized analytical conditions led to excellent chromatographic separation of 15 estrogens, 6 androgens, and 2 progestins. The quantitative results were calculated based on in-house control samples as the steroid-free tissues, and the precision and accuracy were 4.2%-26.8% and 90.8%-116.4%, respectively. The on-column limit of quantification was from 180 fg to 0.5 pg for androgens and estrogens, and 1.25 pg for progestins, which were found to be linear (r²> 0.990). The validated method was then applied to quantify 7 sex steroids from three 100-μm-thick frozen breast tissue slices from postmenopausal patients with breast cancer. This is the first report on the improved GC-MS/MS method for the detection of androgens and pregnenolone from breast cancer tissues, and it can be a useful technique to measure the local levels of sex steroids, thus, enhancing our understanding of the pathophysiological significances of steroidogenesis.

Profiling of a wide range of neurochemicals in human urine by very-high-performance liquid chromatography-tandem mass spectrometry combined with in situ selective derivatization

Development of a reliable analytical method of neurochemicals in biological fluids is important to discover potential biomarkers for the diagnosis, treatment and prognosis of neurological disorders. However, neurochemical profiling of biological samples is challenging because of highly different polarities between basic and acidic neurochemicals, low physiological levels, and high matrix interference in biological samples. In this study, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method combined with in situ selective derivatization for comprehensive profiling of 20 neurochemicals in urine was developed for a wide range of neurochemicals. In situ selective derivatization greatly improved the peak capacity on a reversed-phase C18 column and sensitive mass detection in LC-ESI-MS/MS-positive ion mode due to reduction of the distinct physicochemical properties between acidic and basic neurochemicals. The MS/MS spectra of neurochemicals exhibited specific ions, such as losses of amine, methanol, or methyl formate molecules from protonated molecules, enabling selection of appropriate multiple reaction monitoring (MRM) ions for selective and sensitive detection. The developed method was validated in terms of linearity, limit of detection (LOD) and limit of quantification (LOQ), precision, accuracy, and recovery. The correlation coefficients (R²) of calibration curves were above 0.9961. The ranges of LODs and LOQs were 0.1-3.6ng/mL and 0.3-12.0ng/mL, respectively. The overall precision and accuracy were 0.52-16.74% and 82.26-118.17%, respectively. The method was successfully applied to simultaneously profile the metabolic pathways of tyrosine, tryptophan, and glutamate in Parkinson's disease patient urine (PD, n=21) and control urine (n=10). Significant differences (P≤0.01) between two groups in the activity of phenylethanolamine N-methyltransferase (PNMT) and alcohol dehydrogenase (ADH) were observed. In conclusion, this method provides reliable quantification of a wide range of neurochemicals in human urine and would be helpful for finding biomarkers related to specific neuronal diseases.

Urinary profiling of tryptophan and its related metabolites in patients with metabolic syndrome by liquid chromatography-electrospray ionization/mass spectrometry

Tryptophan (Trp) is an essential amino acid that plays an important role in protein synthesis and is a precursor of various substances related to diverse biological functions. An imbalance in Trp metabolites is associated with inflammatory diseases. The accurate and precise measurement of these compounds in biological specimens would provide meaningful information for understanding the biochemical states of various metabolic syndrome-related diseases, such as hyperlipidemia, hypertension, diabetes, and obesity. In this study, we developed a rapid, accurate, and sensitive liquid chromatography-tandem mass spectrometry-based method for the simultaneous targeted analysis of Trp and its related metabolites of the kynurenine (Kyn), serotonin, and tryptamine pathways in urine. The application of the developed method was tested using urine samples after protein precipitation. The detection limits of Trp and its metabolites were in the range of 0.01 to 0.1 μg/mL. The method was successfully validated and applied to urine samples from controls and patients with metabolic syndrome. Our results revealed high concentrations of Kyn, kynurenic acid, xanthurenic acid, and quinolinic acid as well as a high Kyn-to-Trp ratio (KTR) in patients with metabolic syndromes. The levels of urine Kyn and KTR were significantly increased in patients under 60 years old. The profiling of urinary Trp metabolites could be a useful indicator for age-related diseases including metabolic syndrome. ᅟ.

Metabolic profiling of tyrosine, tryptophan, and glutamate in human urine using gas chromatography-tandem mass spectrometry combined with single SPE cleanup

The tyrosine, tryptophan, and glutamate metabolic pathways play key roles on pathological state of neuronal functions and the change of their levels in biological systems reflects the progress degree of neuronal diseases. Comprehensive profiling of these metabolites is important to find new biomarkers for diagnosis or prognosis of various neuronal diseases. However, the overall profiling analysis of various neurochemicals in biological sample is confronted with several limitations due to their low concentration and physicochemical properties and the coexistence of matrices. We developed an efficient and feasible method using gas chromatography-tandem mass spectrometry (GC-MS/MS). Wide-bore mixed cation exchange (MCX) SPE process enables a rapid and effective cleanup of 20 neurochemicals even including acidic and basic neurochemicals in a single SPE cartridge by using different composition of eluents. Selective derivatization of various types of metabolites was applied to achieve highly chromatographic separation and sensitive mass detection. Appropriate selection of precursor and product transition ions used in multiple reaction-monitoring (MRM) mode based on the MS/MS fragmentations of the derivatized neurochemicals could be significantly minimized the matrix effects and enhanced the reliability of quantification results. The developed method was validated in terms of linearity, limits of detection, precision, accuracy, and matrix effects. The intra- and inter-assay analytical variations were less than 10%. The overall linearity for all of the targets was excellent (R²≥0.996). The detection limits ranged between 0.38 and 8.13ng/mL for the acidic neurochemicals and between 0.02 and 11.1ng/mL for the basic neurochemicals. The developed protocol will be expected to be a promising tool for the understanding of the pathological state and diagnosis of various neuronal diseases.

Simultaneous Analysis of Free and Sulfated Steroids by Liquid Chromatography/Mass Spectrometry with Selective Mass Spectrometric Scan Modes and Polarity Switching

Sulfated steroids can act as a latent form of active free steroids, coexisting with them in biological specimens. To evaluate the metabolic significance of free and sulfated steroid species, a simultaneous analysis of eight free steroids [cholesterol, pregnenolone, 17α-hydroxypregnenolone, progesterone, 17α-hydroxyprogesterone, dehydroepiandrosterone (DHEA), testosterone, and 17β-estradiol] and four biologically relevant sulfated steroids was developed and validated, using selected-ion and multiple-reaction monitoring modes coupled to polarity-switching liquid chromatography/mass spectrometry (LC/MS). All steroids were separated on a reversed-phase phenyl column (50 mm × 2 mm, 3 μm) at a flow rate of 0.5 mL/min. The limits of quantification ranged from 0.1 to 50 ng/mL at extraction recoveries of 94.1-105.5%, while the precision and accuracy were 2.5-9.3% and 92.4-105.9%, respectively. Quantitative results obtained for samples from obese girls showed that the serum levels of DHEA sulfate were significantly increased (P = 0.004), along with the metabolic ratio representing DHEA sulfotransferase (P < 0.02). The developed novel LC/MS method can quantitatively profile both free and sulfated steroids in a single analytical run.

Metabolite profiling of sex developmental steroid conjugates reveals an association between decreased levels of steroid sulfates and adiposity in obese girls

Free and conjugated steroids coexist in a dynamic equilibrium due to complex biosynthetic and metabolic processes. This may have clinical significance related to various physiological conditions, including sex development involving the reproductive system. Therefore, we performed quantitative profiling of 16 serum steroids conjugated with glucuronic and sulfuric acids using liquid chromatography-mass spectrometry (LC-MS). All steroid conjugates were purified by solid-phase extraction and then separated through a 3-μm particle size C18 column (150mm×2.1mm) at a flow rate of 0.3 mL/min in the negative ionization mode. The LC-MS-based analysis was found to be linear (r(2)>0.99), and all steroid conjugates had a limit-of-quantification (LOQ) of 10ng/mL, except for cholesterol sulfate and 17β-estradiol-3,17-disulfate (20ng/mL). The extraction recoveries of all steroid conjugates ranged from 97.9% to 110.7%, while the overall precision (% CV) and accuracy (% bias) ranged from 4.8% to 10.9% and from 94.4% to 112.9% at four different concentrations, respectively. Profiling of steroid conjugates corrected by adiposity revealed decreased levels of steroid sulfates (P<0.01) in overweight and obese girls compared to normal girls. The suggested technique can be used for evaluating metabolic changes in steroid conjugates and for understanding the pathophysiology and relative contributions of adiposity in childhood obesity.

Liquid Chromatography-Mass Spectrometry-Based In Vitro Metabolic Profiling Reveals Altered Enzyme Expressions in Eicosanoid Metabolism

Background

Eicosanoids are metabolites of arachidonic acid that are rapidly biosynthesized and degraded during inflammation, and their metabolic changes reveal altered enzyme expression following drug treatment. We developed an eicosanoid profiling method and evaluated their changes on drug treatment.

Methods

Simultaneous quantitative profiling of 32 eicosanoids in liver S9 fractions obtained from rabbits with carrageenan-induced inflammation was performed and validated by liquid chromatography-mass spectrometry coupled to anion-exchange solid-phase purification.

Results

The limit of quantification for the devised method ranged from 0.5 to 20.0 ng/mg protein, and calibration linearity was achieved (R²>0.99). The precision (% CV) and accuracy (% bias) ranged from 4.7 to 10.3% and 88.4 to 110.9%, respectively, and overall recoveries ranged from 58.0 to 105.3%. Our method was then applied and showed that epitestosterone treatment reduced the levels of all eicosanoids that were generated by cyclooxygenases and lipoxygenases.

Conclusions

Quantitative eicosanoid profiling combined with in vitro metabolic assays may be useful for evaluating metabolic changes affected by drugs during eicosanoid metabolism.

Hair sterol signatures coupled to multivariate data analysis reveal an increased 7β-hydroxycholesterol production in cognitive impairment

Altered cholesterol metabolism could be associated with cognitive impairment. The quantitative profiling of 19 hair sterols was developed using gas chromatography-mass spectrometry coupled to multivariate data analysis. The limit of quantification of all sterols ranged from 5 to 20 ng/g, while the calibration linearity was higher than 0.98. The precision (% CV) and accuracy (% bias) ranged from 3.2% to 9.8% and from 83.2% to 119.4%, respectively. Among the sterols examined, 8 were quantitatively detected from two strands of 3-cm-long scalp hair samples of female participants, including mild cognitive impairment (MCI, n=15), Alzheimer's disease (AD, n=31), and healthy controls (HC, n=36). The cognitive impairment (MCI or AD) was correlated with a higher metabolic rate than that of HCs based on 7β-hydroxycholesterol (P<0.005). Significant negative correlations (r=-0.822) were detected between Mini-Mental State Examination (MMSE) scores and hair sample metabolic ratios of 7β-hydroxycholesterol to cholesterol, which is an accepted, sensitive, and specific tool for discriminating HCs from individuals with MCI or AD. In conclusion, improved diagnostic values can be obtained using hair sterol signatures coupled with MMSE scores. This method may prove useful for predictive diagnosis in population screening of cognitive impairment.

Top-down and bottom-up lipidomic analysis of rabbit lipoproteins under different metabolic conditions using flow field-flow fractionation, nanoflow liquid chromatography and mass spectrometry

This study demonstrated the performances of top-down and bottom-up approaches in lipidomic analysis of lipoproteins from rabbits raised under different metabolic conditions: healthy controls, carrageenan-induced inflammation, dehydration, high cholesterol (HC) diet, and highest cholesterol diet with inflammation (HCI). In the bottom-up approach, the high density lipoproteins (HDL) and the low density lipoproteins (LDL) were size-sorted and collected on a semi-preparative scale using a multiplexed hollow fiber flow field-flow fractionation (MxHF5), followed by nanoflow liquid chromatography-ESI-MS/MS (nLC-ESI-MS/MS) analysis of the lipids extracted from each lipoprotein fraction. In the top-down method, size-fractionated lipoproteins were directly infused to MS for quantitative analysis of targeted lipids using chip-type asymmetrical flow field-flow fractionation-electrospray ionization-tandem mass spectrometry (cAF4-ESI-MS/MS) in selected reaction monitoring (SRM) mode. The comprehensive bottom-up analysis yielded 122 and 104 lipids from HDL and LDL, respectively. Rabbits within the HC and HCI groups had lipid patterns that contrasted most substantially from those of controls, suggesting that HC diet significantly alters the lipid composition of lipoproteins. Among the identified lipids, 20 lipid species that exhibited large differences (>10-fold) were selected as targets for the top-down quantitative analysis in order to compare the results with those from the bottom-up method. Statistical comparison of the results from the two methods revealed that the results were not significantly different for most of the selected species, except for those species with only small differences in concentration between groups. The current study demonstrated that top-down lipid analysis using cAF4-ESI-MS/MS is a powerful high-speed analytical platform for targeted lipidomic analysis that does not require the extraction of lipids from blood samples.

Serum sterol profiling reveals increased cholesterol biosynthesis in childhood obesity

Quantitative sterol profiling in obese children and their clinical implications have not been fully investigated. The aim of study was to evaluate the metabolic changes in serum cholesterol and its precursors and metabolites, and their associations with clinical characteristics of childhood obesity. A total of 253 children aged 6-14 years (72 obese, 39 overweight, and 72 normal controls; 147 girls and 106 boys) were recruited. Anthropometric indices, body composition, and fasting total lipid profiles were determined. Serum concentrations of 20 sterols, as their free fraction, were analyzed through gas chromatography-mass spectrometry-based metabolite profiling. There were no significant differences in total- and LDL-cholesterols between groups. Serum levels of the main cholesterol precursors, lanosterol (P<0.02) and lathosterol (P<0.0001), were significantly higher in obese children. In addition, they showed positive correlations with waist to hip ratio, body fat percent, and body fat mass. The metabolic ratios of lanosterol and lathosterol to cholesterol were also elevated (P<0.01 both), indicating the up-regulation of cholesterol biosynthesis with childhood obesity. In contrast, the absorption of plant sterols tended to show a compensatory decrease in obese children. Strong correlations between free cholesterol and total- and LDL-cholesterols were observed (r>0.760, P<0.001), while there was no correlation with HDL-cholesterols. The levels of total cholesteryl ester were closely associated with triglyceride (r=0.763, P<0.001). Quantitative results indicate that childhood obesity may increase cholesterol synthesis while maintaining overall cholesterol homeostasis.

Bringing GC-MS profiling of steroids into clinical applications

Abnormalities of steroid biosynthesis and excretion are responsible for the development and prevention of endocrine disorders, such as metabolic syndromes, cancers, and neurodegenerative diseases. Due to their biochemical roles in endocrine system, qualitative and quantitative analysis of steroid hormones in various biological specimens is needed to elucidate their altered expression. Mass spectrometry (MS)-based steroid profiling can reveal the states of metabolites in biological systems and provide comprehensive insights by allowing comparisons between metabolites present in cells, tissues, or organisms. In addition, the activities of many enzymes related to steroid metabolism often lead to hormonal imbalances that have serious consequences, and which are responsible for the progress of hormone-dependent diseases. In contrast to immunoaffinity-based enzyme assays, MS-based methods are more reproducible in quantification. In particular, high-resolution gas chromatographic (GC) separation of steroids with similar chemical structures can be achieved to provide rapid and reproducible results with excellent purification. GC-MS profiling therefore has been widely used for steroid analysis, and offers the basis for techniques that can be applied to large-scale clinical studies. Recent advances in analytical technologies combined with inter-disciplinary strategies, such as physiology and bioinformatics, will help in understanding the biochemical roles of steroid hormones. Therefore, comprehensive analytical protocols in steroid analysis for different research purposes may contribute to the elucidation of complex metabolic processes relevant to steroid function in many endocrine disorders, and in the identification of diagnostic biomarkers.

Metabolic changes in serum steroids induced by total-body irradiation of female C57B/6 mice

The short- and long-term effects of a single exposure to gamma radiation on steroid metabolism were investigated in mice. Gas chromatography-mass spectrometry was used to generate quantitative profiles of serum steroid levels in mice that had undergone total-body irradiation (TBI) at doses of 0Gy, 1Gy, and 4Gy. Following TBI, serum samples were collected at the pre-dose time point and 1, 3, 6, and 9 months after TBI. Serum levels of progestins, progesterone, 5β-DHP, 5α-DHP, and 20α-DHP showed a significant down-regulation following short-term exposure to 4Gy, with the exception of 20α-DHP, which was significantly decreased at each of the time points measured. The corticosteroids 5α-THDOC and 5α-DHB were significantly elevated at each of the time points measured after exposure to either 1 or 4Gy. Among the sterols, 24S-OH-cholestoerol showed a dose-related elevation after irradiation that reached significance in the high dose group at the 6- and 9-month time points.

Reference ranges for urinary levels of testosterone and epitestosterone, which may reveal gonadal function, in a Korean male population

Cannabis, or marijuana, the most commonly used illicit drug in the world, has been shown to be responsible for suppressing the production and secretion of androgens, particularly testosterone. However, despite such findings in animals, the chronic effects of marijuana use on human endocrine systems have proved to be inconsistent. Here, we investigated the reference ranges of urinary levels of testosterone (T) and epitestosterone (E) as well as their metabolic ratio of T/E in a Korean male population (n=337), which would enable an evaluation of abnormal changes in steroid metabolism induced by habitually administered cannabis. The T/E ratio was significantly decreased in the marijuana group (n=18), while the urinary testosterone concentrations were also tended to decrease. This study is the first to provide data for the reference values of two urinary androgens and T/E values among control Korean males, and, furthermore, suggests that the T/E ratio, though not testosterone levels, might be used to understand the suppression of human male gonadal function affected by smoking marijuana.

Association between urinary levels of bisphenol-A and estrogen metabolism in Korean adults

Bisphenol-A (BPA) possesses estrogenic properties both in vitro and in vivo as an endocrine disrupting chemical. Humans experience a long-term and cumulative exposure to BPA. BPA was detectable in 97.3% of 1904 urine specimens from Korean adults. We investigated urinary estrogen concentrations in subjects with low and high BPA concentrations and its possible association with estrogen metabolism. Urine samples were collected from a high BPA concentration group (BPA-H; n=100, 11.05 ± 20.47 μg/g creatinine) and a low BPA concentration group (BPA-L; n=100, 0.70 ± 0.22 μg/g creatinine) from Korea Biomonitoring Program of Hazardous Materials Survey 2009-2010. Urinary estrogens were enzymatically hydrolyzed, extracted, and then derivatized for quantitative analysis by gas chromatography-mass spectrometry. Estrogen levels were higher in the BPA-H group than in the BPA-L group. Concentrations of estrone, 17β-estradiol, and their hydroxylated metabolites in both men and women were significantly higher in the BPA-H group than in the BPA-L group (p<0.04). Furthermore, in the BPA-H group, estrogen metabolism to 4-hydroxy-estrone and 4-hydroxy-17β-estradiol was more active than that to 2-hydroxy-estrone and 2-hydroxy-17β-estradiol. Although single measurement and/or single spot urine samples limit the measurement of long-term exposure to BPA, we found significant differences of estrogen metabolism in the BPA-H and the BPA-L groups. The increase of hydroxyestrogens, especially 4-hydroxyestrogens, can be an important factor resulting negative effects of prolonged exposure to BPA.

Cytochrome P450-mediated metabolic alterations in preeclampsia evaluated by quantitative steroid signatures

Although preeclampsia has been suggested potential risk factors including placental and systemic inflammation, oxidative stress, and abnormal steroid metabolism during pregnancy, the pathogenesis of preeclampsia has not fully been elucidated, particularly in steroid metabolism. The association between various cytochrome P450 (CYP)-mediated steroid metabolic markers and preeclampsia risk was therefore investigated. The serum levels of 54 CYP-mediated regioselective hydroxysteroids and their substrates were quantitatively evaluated from both pregnant women with preeclampsia (n=30; age, 30.8±4.5 years) and normotensive controls (n=30; age, 31.0±3.5 years), who were similar with respect to maternal age, gestational age, and body mass index. The levels of 6ß-, 7a-, and 11ß-hydroxymetabolites of androgens and corticoids were significantly increased in women with preeclampsia. In addition, the levels of oxysterols, including 7a-, 7ß-, 4ß-, 20a-, 24S-, and 27-hydroxycholesterol, were markedly higher, while the levels of 16a-OH-DHEA, 16a-OH-androstenedione, and cholesterol were significantly decreased in patients. The 6ß-hydroxylation of androgens and corticoids by CYP3A4 (P<0.01), the activation of 20,22-desmolase (a cholesterol side-chain cleavage enzyme) by CYP11A1 (P<0.00001), and the multi-hydroxylation of cholesterol at C-4ß, C-7a, C-7ß, C-24S, C-27, and C-20a (P<0.0001) by catalytic or enzymatic reaction (e.g. CYP3A4, CYP7A1, CYP27A1, and CYP46A1) were differed between preeclamptic women and control subjects. In particular, an increased oxysterols (induction>2.0-fold) were positively correlated with the conditions of preeclampsia. Our metabolic profiling suggests the CYP-mediated alterations in steroid metabolism and hydroxylation in pregnancy-induced hypertension. These multiple markers could serve as background information for improved clinical diagnosis and management during pregnancy. This article is part of a Special Issue entitled "Pregnancy and Steroids".

High-temperature GC-MS-based serum cholesterol signatures may reveal sex differences in vasospastic angina

Alterations of cholesterol metabolism are responsible for vasospastic angina and atherosclerosis. To comprehensively evaluate cholesterol metabolism, 18 sterols, including cholesterol, 6 cholesteryl esters (CEs), 3 cholesterol precursors, and 8 hydroxycholesterols (OHCs), were simultaneously analyzed using hybrid solid-phase extraction (SPE) purification coupled to high-temperature gas chromatography-mass spectrometry (HTGC-MS). Methanol-based hybrid SPE increased the selective extraction, and HTGC resulted in a good chromatographic resolution for the separation of lipophilic compounds. The limits of quantification of cholesterol and CEs ranged from 0.2 to 10.0 μg/ml, while OHCs and cholesterol precursors ranged from 0.01 to 0.10 μg/ml. Linearity as the correlation coefficient was higher than 0.99 with the exception of cholesteryl laurate, myristate, oleate, and linoleate (r² > 0.98). The precision (% coefficient of variation) and accuracy (% bias) ranged from 1.1 to 9.8% and from 75.9 to 125.1%, respectively. The overall recoveries of CEs ranged from 26.1 to 64.0%, and the recoveries of other sterols ranged from 83.8 to 129.3%. The cholesterol signatures showed sex differences in patients with vasospastic angina and may associate with 24-reductases. This technique can be useful for making clinical diagnoses and for an increased understanding of the pathophysiology of vasospastic angina.

Comparison of metabolic ratios of urinary estrogens between benign and malignant thyroid tumors in postmenopausal women

Background

Estrogen metabolism may be associated with the pathophysiological development of papillary thyroid carcinoma (PTC).

Methods

To evaluate the differential estrogen metabolism between benign and malignant PTCs, estrogen profiling by gas chromatography–mass spectrometry was applied to urine samples from postmenopausal patients with 9 benign tumors and 18 malignant stage I and III/IV PTCs.

Results

The urinary concentration of 2-methoxyestradiol was significantly lower in the stage I malignant patients (3.5-fold; P < 0.025) than in the benign group. The metabolic ratios of 16α-OH-estrone/estrone and estriol/estradiol, which are responsible for 16α-hydroxylase activity, were increased more than 2.5-fold in the advanced-stage malignant PTC (P < 0.02 each). The more than 6.2-fold decrease in the urinary 2-/16α-hydroxylase ratio in stage III/IV malignant PTC was consistent with the ratio in postmenopausal patients with endocrine gland cancers. In addition, reductive 17β-hydroxysteroid dehydrogenase (17β-HSD; estradiol/estrone or estriol/16α-OH-estrone) was present at significantly higher levels in subjects with stage III/IV malignant PTCs than in benign subjects (>3.5-fold difference; P < 0.002). In particular, the estriol/16α-OH-estrone ratio differentiated between the benign and early-stage malignant patients (P < 0.01).

Conclusions

Increased 16α-hydroxylation and/or a decreased 2-/16α-ratio, as well increased reductive 17β-HSD, with regard to estrogen metabolism could provide potential biomarkers. The devised profiles could be useful for differentiating malignant thyroid carcinomas from benign adenomas in postmenopausal women.

Differential estimation of isomeric 2- and 4-methoxylated estrogens in serum by matrix-assisted laser desorption ionization-tandem mass spectrometry

As a simple and rapid method for small-molecule analysis, matrix-assisted laser desorption ionization coupled with linear ion-trap tandem mass spectrometry (MALDI-LTQ-MS/MS) was used to differentially quantify 2- and 4-methoxyestrogens in spiked serum samples. Both 2- and 4-methoxyestrogens were consistently identified using distinct analyte-matrix adduct [M+H+CHCA](+) precursor ions when a mixture of 10 mg mL(-1) α-cyano-4-hydroxycinnamic acid (CHCA) in 0.2% trifluoroacetic acid/70% acetonitrile was used as the MALDI matrix. Especially, unusual isomeric product ions from each precursor ion were characterized during MALDI-MS/MS analysis, which permitted differential estimations of isomeric 2- and 4-methoxylated estrone and 17β-estradiol. The calibration linearity was higher than 0.99 in the dynamic range, while the inter-day precision and accuracy ranged from 6.8 to 30.6%, and from 91.4 to 108.5%, respectively. The present technique could be used as a screening assay for 2- and 4-methoxyestrogens without the need for prior chromatographic separation, opening up possible applications in large-scale pharmacokinetic studies.

Urinary metabolites before and after cleanup and subjective symptoms in volunteer participants in cleanup of the Hebei Spirit oil spill

BACKGROUND

On December 7th, 2007, the Hong Kong tanker Hebei Spirit (HS) (146,848 tons) was crushed by a crane ship near the shore of Taean, Korea. More than 12,547 kl of crude oil spilled into the sea and contaminated the western coastline of the Korean peninsula. For a period of six months after the accident, approximately 1,000,000 volunteers participated in the cleanup. Our goal in this study was to examine the exposure status and acute health effects on volunteers that participated in the oil spill cleanup.

METHODS

A survey questionnaire was filled out by 565 volunteers, requesting information regarding physical symptoms. Out of the total number of participants, urine samples from 105 university student volunteers were collected before and after the cleanup work, and metabolite levels of volatile organic compounds and polycyclic aromatic hydrocarbons were analyzed.

RESULTS

Volunteers that participated for longer cleanup work reported an increase in physical symptoms including visual disturbance, nasal and bronchus irritation, headaches, heart palpitations, fatigue and fever, memory and cognitive disturbance, and abdominal pain. The levels of t,t-muconic acid, mandelic acid, and 1-hydroxypyrene were significantly higher in samples after cleanup than those measured before participation (p<0.05). Other than the associated risk of dermal irritation with the difference in the t,t-muconic acid level between the post- to pre-cleanup levels, no other physical symptoms demonstrated a significant association with changes observed in the levels of urinary metabolites.

CONCLUSIONS

Based on the significant increase of subjective symptoms in volunteers participating in the study, monitoring of the long term health effects, focusing on those with longer exposure, is warranted.

Discovery of common urinary biomarkers for hepatotoxicity induced by carbon tetrachloride, acetaminophen and methotrexate by mass spectrometry-based metabolomics

Liver toxicity represents an important healthcare issue because it causes significant morbidity and mortality and can be difficult to predict before symptoms appear owing to drug therapy or exposure to toxicants. Using metabolomic techniques, we discovered common biomarkers for the prediction of hepatotoxicity in rat urine using mass spectrometry. For this purpose, liver toxicity was induced by 5 days of oral administration of carbon tetrachloride (1 ml kg(-1) per day), acetaminophen (1000 mg kg(-1) per day) and methotrexate (50 mg kg(-1) per day). Serum levels of alkaline phosphatase aspartate aminotransferase, alanine aminotransferase and histopathology in liver tissue were then checked to demonstrate liver toxicity. Global metabolic profiling with UPLC-TOF-MS (ultraperformance liquid chromatography-mass spectrometry), multivariate analysis (partial least square-discriminant analysis, hierarchical analysis) and database searching were performed to discover common biomarkers for liver toxicity induced by these three compounds. Urinary concentrations of the newly discovered biomarkers were then quantified to confirm them as biomarkers of hepatotoxicity with targeted metabolic profiling using GC (gas chromatography)-MS and CE (capillary electrophoresis)-MS. In the results, steroids, amino acids and bile acids were metabolically changed between the control and drug-treated groups in global metabolic profiling; 11β-hydroxyandrosterone, epiandrosterone, estrone, 11-dehydrocorticosterone, glycine, alanine, valine, leucine, dl-ornithine, 3-methylhistidine, cholic acid and lithocholic acid were selected as liver toxicity biomarkers after performing targeted metabolic profiling. In conclusion, we discovered metabolite biomarkers belonging to three different metabolic pathways to check for liver toxicity with mass spectrometry from a metabolomics study that could be used to evaluate hepatotoxicity induced by drugs or other toxic compounds.

Metabolic alteration of urinary steroids in pre- and post-menopausal women, and men with papillary thyroid carcinoma

BACKGROUND

To evaluate the metabolic changes in urinary steroids in pre- and post-menopausal women and men with papillary thyroid carcinoma (PTC).

METHODS

Quantitative steroid profiling combined with gas chromatography-mass spectrometry was used to measure the urinary concentrations of 84 steroids in both pre- (n = 21, age: 36.95 ± 7.19 yr) and post-menopausal female (n = 19, age: 52.79 ± 7.66 yr), and male (n = 16, age: 41.88 ± 8.48 yr) patients with PTC. After comparing the quantitative data of the patients with their corresponding controls (pre-menopause women: n = 24, age: 33.21 ± 10.48 yr, post-menopause women: n = 16, age: 49.67 ± 8.94 yr, male: n = 20, age: 42.75 ± 4.22 yr), the levels of steroids in the patients were normalized to the mean concentration of the controls to exclude gender and menopausal variations.

RESULTS

Many urinary steroids were up-regulated in all PTC patients compared to the controls. Among them, the levels of three active androgens, androstenedione, androstenediol and 16α-hydroxy DHEA, were significantly higher in the pre-menopausal women and men with PTC. The corticoid levels were increased slightly in the PTC men, while progestins were not altered in the post-menopausal PTC women. Estrogens were up-regulated in all PTC patients but 2-hydroxyestrone and 2-hydroxy-17β-estradiol were remarkably changed in both pre-menopausal women and men with PTC. For both menopausal and gender differences, the 2-hydroxylation, 4-hydroxylation, 2-methoxylation, and 4-methoxylation of estrogens and 16α-hydroxylation of DHEA were differentiated between pre- and post-menopausal PTC women (P < 0.001). In particular, the metabolic ratio of 2-hydroxyestrone to 2-hydroxy-17β-estradiol, which could reveal the enzyme activity of 17β-hydroxysteroid dehydrogenase, showed gender differences in PTC patients (P < 1 × 10-7).

CONCLUSIONS

These results are expected be helpful for better understanding the pathogenic differences in PTC according to gender and menopausal conditions.

Up-regulation of BLT2 is critical for the survival of bladder cancer cells

The incidence rates of urinary bladder cancer continue to rise yearly, and thus new therapeutic approaches and early diagnostic markers for bladder cancer are urgently needed. Thus, identifying the key mediators and molecular mechanisms responsible for the survival of bladder cancer has valuable implications for the development of therapy. In this study, the role of BLT2, a receptor for leukotriene B((4)) (LTB((4))) and 12(S)-hydroxyeicosatetraenoic acid (HETE), in the survival of bladder cancer 253J-BV cells was investigated. We found that the expression of BLT2 is highly elevated in bladder cancer cells. Also, we observed that blockade of BLT2 with an antagonist or BLT2 siRNA resulted in cell cycle arrest and apoptotic cell death, suggesting a role of BLT2 in the survival of human bladder cancer 253J-BV cells. Further experiments aimed at elucidating the mechanism by which BLT2 mediates survival revealed that enhanced level of reactive oxygen species (ROS) are generated via a BLT2-dependent up-regulation of NADPH oxidase members NOX1 and NOX4. Additionally, we observed that inhibition of ROS generation by either NOX1/4 siRNAs or treatment with an ROS-scavenging agent results in apoptotic cell death in 253J-BV bladder cancer cells. These results demonstrated that a 'BLT2-NOX1/4-ROS' cascade plays a role in the survival of this aggressive bladder cancer cells, thus pointing to BLT2 as a potential target for anti-bladder cancer therapy.

A novel GC-MS method in urinary estrogen analysis from postmenopausal women with osteoporosis

Estrogen metabolites play important roles in the development of female-related disorders and homeostasis of the bone. To improve detectability, a validated gas chromatography-mass spectrometry (GC-MS) method was conducted with two-phase extractive ethoxycarbonlyation (EOC) and subsequent pentafluoropropionyl (PFP) derivatization was introduced. The resulting samples were separated through a high-temperature MXT-1 column within an 8 min run and were detected in the selected ion monitoring (SIM) mode. The optimized analytical conditions led to good separation with a symmetric peak shape for 19 estrogens as their EOC-PFP derivatives. The limit of quantification (LOQ) was from 0.02 to ∼0.1 ng/ml for most estrogens analyzed, except for 2-hydroxyestriol (0.5 ng/ml). The devised method was found to be linear (r² > 0.995) in the range from the LOQ to 40 ng/ml, whereas the precision (% CV) and accuracy (% bias) ranged from 1.4 to 10.5% and from 91.4 to 108.5%, respectively. The good sensitivity and selectivity of this method even allowed quantification of the estrogen metabolites in urine samples obtained from the postmenopausal female patients with osteoporosis. The present technique can be useful for clinical diagnosis as well as to better understand the pathogenesis of estrogen-related disorders in low-level quantification.

Gas chromatography/mass spectrometry based hair steroid profiling may reveal pathogenesis in hair follicles of the scalp

A method of steroid profiling, including androgens, progestins, corticoids and sterols, was developed to evaluate the concentrations of steroids as well as the activities of the enzymes responsible for steroidogenesis in hair by gas chromatography/mass spectrometry. The extraction efficiencies of steroids from the hair matrix were improved by ultrasonication for 1 h at 50 °C. The overall recoveries ranged from 71 to 132%, with a limit of quantification for all analytes ranging from 1 to 50 ng/g. The devised method was used to identify the metabolic changes for both male-pattern baldness (MPB) and the drug efficiency of dutasteride, which inhibits 5α-reductase. Increased dihydrotestosterone levels and the dihydrotestosterone/testosterone (DHT/T) ratio, which is responsible for the 5α-reductase activity, were observed in the MPB patients. A dutasteride treatment resulted in decreases in the DHT and 5α-androstanedione concentrations and DHT/T ratio in the hair samples. Hair steroid profiling reflects the sebaceous status in the scalp and may be useful for monitoring the metabolic responses to both the disease and drug actions.

Cellular uptake of ginsenosides in Korean white ginseng and red ginseng and their apoptotic activities in human breast cancer cells

Panax ginseng has been reported to have cancer-preventive properties and, through anti-inflammatory, antioxidant, and pro-apoptotic mechanisms, to influence gene expression. However, the comparison of Korean white ginseng (WG) and red ginseng (RG) in their apoptotic effects and the identification of the selective cellular uptake of the ginsenosides in human breast cancer cells have not yet been fully understood. In the present study, the relative nonpolar and protopanaxadiol (PPD) class ginsenosides exhibited more cytotoxic and efficient cellular uptake on MCF-7 cells compared with the relative polar and protopanaxatriol (PPT) class compounds. PPD class ginsenosides were present in RG in a 2.5 times higher concentration as compared to WG, while PPT class ginsenosides were only present in WG. Thus, RG exerted more potent cytotoxicity than WG against MCF-7 and MDA-MB231 cells. RG also increased the sub-G1 DNA contents of the cell cycle and Annexin V-positive apoptotic bodies undergoing apoptosis through the caspase-3 activation in MCF-7 cells. In addition, RG downregulated the proliferative and anti-apoptotic gene products and potentiated paclitaxel-induced apoptosis in MCF-7 cells. Overall, RG contained a higher concentration of PPD class ginsenosides as compared to WG; the greater cellular uptake of PPD resulted in more substantial antiproliferative activity in human breast cancer cells.

Shotgun lipidomics for candidate biomarkers of urinary phospholipids in prostate cancer

Qualitative and quantitative profiling of six different categories of urinary phospholipids (PLs) from patients with prostate cancer was performed to develop an analytical method for the discovery of candidate biomarkers by shotgun lipidomics method. Using nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry, we identified the molecular structures of a total of 70 PL molecules (21 phosphatidylcholines (PCs), 11 phosphatidylethanolamines (PEs), 17 phosphatidylserines (PSs), 11 phosphatidylinositols (PIs), seven phosphatidic acids, and three phosphatidylglycerols) from urine samples of healthy controls and prostate cancer patients by data-dependent collision-induced dissociation. Identified molecules were quantitatively examined by comparing the MS peak areas. From statistical analyses, one PC, one PE, six PSs, and two PIs among the PL species showed significant differences between controls and cancer patients (p < 0.05, Student's t test), with concentration changes of more than threefold. Cluster analysis of both control and patient groups showed that 18:0/18:1-PS and 16:0/22:6-PS were 99% similar in upregulation and that the two PSs (18:1/18:0, 18:0/20:5) with two PIs (18:0/18:1 and 16:1/20:2) showed similar (>95%) downregulation. The total amount of each PL group was compared among prostate cancer patients according to the Gleason scale as larger or smaller than 6. It proposes that the current study can be utilized to sort out possible diagnostic biomarkers of prostate cancer.

Expression and activation of matrix metalloproteinase-9 and NADPH oxidase in tissues and plasma of experimental autoimmune encephalomyelitis in mice

Experimental autoimmune encephalomyelitis (EAE) is a widely used animal model for multiple sclerosis (MS) that can be induced by immunization with myelin antigens such as myelin oligodendrocyte glycoprotein (MOG). The objective of this study was (i) to investigate how matrix metalloproteinase-9 (MMP-9) and NADPH oxidase enzymes are affected in the EAE mouse model and (ii) to know whether peripheral organs also express these enzymes in the EAE model. MOG(33-55) was administered subcutaneously on two sites over the back. Pertussis toxin was administered intraperitoneally immediately after MOG and again two days later. A significant difference was observed in body weights and clinical signs of EAE-induced mice. MMP-9 and NADPH oxidase enzymes were measured in central nervous system (CNS) tissues, peripheral tissues and plasma of EAE-induced mice. The primary findings include the distribution pattern of MMP-9 in CNS and peripheral tissues, and alterations in the enzymatic expression of MMP-9 and NADPH oxidase in the CNS tissues, spleen and plasma of EAE-induced mice. From these results, it can be considered that the spleen as well as the CNS can act as target organs in EAE disease, and plasma MMP-9 and NADPH oxidase may contribute to the pathogenesis of the disease.

Multivariate classification of urine metabolome profiles for breast cancer diagnosis

Background

Diagnosis techniques using urine are non-invasive, inexpensive, and easy to perform in clinical settings. The metabolites in urine, as the end products of cellular processes, are closely linked to phenotypes. Therefore, urine metabolome is very useful in marker discoveries and clinical applications. However, only univariate methods have been used in classification studies using urine metabolome. Since multiple genes or proteins would be involved in developments of complex diseases such as breast cancer, multiple compounds including metabolites would be related with the complex diseases, and multivariate methods would be needed to identify those multiple metabolite markers. Moreover, because combinatorial effects among the markers can seriously affect disease developments and there also exist individual differences in genetic makeup or heterogeneity in cancer progressions, single marker is not enough to identify cancers.

Results

We proposed classification models using multivariate classification techniques and developed an analysis procedure for classification studies using metabolome data. Through this strategy, we identified five potential urinary biomarkers for breast cancer with high accuracy, among which the four biomarker candidates were not identifiable by only univariate methods. We also proposed potential diagnosis rules to help in clinical decision making. Besides, we showed that combinatorial effects among multiple biomarkers can enhance discriminative power for breast cancer.

Conclusions

In this study, we successfully showed that multivariate classifications are needed to precisely diagnose breast cancer. After further validation with independent cohorts and experimental confirmation, these marker candidates will likely lead to clinically applicable assays for earlier diagnoses of breast cancer.

Database-dependent metabolite profiling focused on steroid and fatty acid derivatives using high-temperature gas chromatography-mass spectrometry

BACKGROUND

A database-dependent gas chromatography-mass spectrometry (GC-MS) based approach was developed for non-targeted metabolite profiling, focusing on 232 steroids, 24 fatty acids, 10 eicosanoids, 10 cannabinoids and 22 steroid-fatty acid esters in biological specimens.

METHODS

This method, used to search for potent biomarkers in lipid metabolism, included MS based analysis combined with high-temperature gas chromatographic (HTGC) separation of biological metabolites, statistical clustering and an in-house database (DB) searching.

RESULTS

The HTGC technique showed better detectability of high lipophilic compounds, particularly steroid-fatty acid esters, which generally have poor chromatographic properties on a conventional GC column. The in-house DB search consisted of the retention index and mass spectrum corresponding to each compound selected. The method was applied to tissue samples obtained from cardiac hypertrophy-induced mice. Increased levels of palmitic, linoleic, oleic, and stearic acids and cholesterol were detected and identified.

CONCLUSIONS

This data-dependent non-targeted metabolite profiling technique could be more effective in biomarker studies associated with the steroid and lipid metabolism than commercially available DBs.

Validated quantification for selective cellular uptake of ginsenosides on MCF-7 human breast cancer cells by liquid chromatography-mass spectrometry

The cellular behavior of ginsenosides on cancer cells has not been measured directly despite their potent anticancer activities and biological actions. A liquid chromatography-mass spectrometry (LC-MS) method was developed to measure the selective cellular uptake of ginsenosides in both cell lysates and culture media. Fifteen ginsenosides were separated within 17 min with good peak shapes using a 2-microm sub-particle size C18 column. Quantification was performed by triple-quadrupole MS with electrospray ionization in negative ion mode. The sample preparation containing the solid-phase extraction was linear (correlation coefficient, r(2) > 0.992) for all analytes, while the limit of quantification ranged from 0.5 to 2.0 ng/mL in both matrices. The assay precision (%CV) and accuracy (%bias) at three different concentrations (5, 20, and 100 ng/mL) were 1.4% to 11.6% and 94.9% to 106.4%, respectively. When this method was used to examine the selective cellular uptake of ginsenosides, the relative non-polar and protopanaxadiol class ginsenosides, such as Rg3, Rk1, Rg5, Rh2, compound-K, and protopanaxadiol (PPD), showed cellular uptake in the MCF-7 cells, but the relative polar and protopanaxatriol class of ginsenosides did not accumulate in the cells. The most non-polar ginsenoside PPD, which is an aglycone of the protopanaxadiol type, resulted in the highest uptake rate. These results show that the different anticancer activities are due to the selective uptake of ginsenosides based on their chemical structures. This LC-MS-based method can be used to estimate the biological activity of ginsenosides on cells from their structural diversity.