Rapid and simple extraction of lipids from blood plasma and urine for liquid chromatography-tandem mass spectrometry

Addressing the untargeted lipidomics challenge in urine samples: Comparative study of extraction methods by UHPLC-ESI-QTOF-MS

Urine analysis has remained a fundamental and widely used method in clinical diagnostics for over a century. With its minimal invasive nature and comprehensive range of analytes, urine has established itself as a clinical diagnostic tool for various disorders, including renal, urological, metabolic, and endocrine diseases. Furthermore, urine's unique attributes make it an attractive matrix for biomarker discovery, as well as in assessing the metabolic and physiological states of patients and healthy individuals alike. However, limitations in our knowledge of average values and sources of urinary lipids decrease the wider clinical application of urinary lipidomics. In this context, untargeted lipidomics analysis relies heavily on the extraction and analysis of lipids in biological samples. Nevertheless, this type of analysis presents challenges in lipid identification due to the diverse nature of lipids. Therefore, proper sample treatment before analysis is crucial to obtain robust and reproducible lipidomic profiles. To address this gap, we conducted a comparative study of a urine pool sample collected from twenty healthy volunteers using four different lipid extraction methods: one biphasic and three monophasic protocols. The extracted lipids were then analyzed using UHPLC-MS and MS/MS, and the semi-quantification of all the accurately annotated lipid species was performed for each extraction method.

QuEChERS-assisted ion pair chromatography/fluorescence detection method for determination of antimigraine combination therapy in rabbit plasma samples: Application to a pharmacokinetic study

Antimigraine combination therapy has shown significant effectiveness in relieving pain, as well as reducing the frequency, duration, and severity of migraine attacks if compared to a single migraine medication. This work represents the first analytical investigation for emphasizing the synergistic effect of combining ophthalmic beta blockers with triptans in migraine treatment. The presented study was conducted to investigate the pharmacokinetic profile of almotriptan (ALM), a serotonin (5-HT1B/1D) receptor agonist used to treat migraine, when coadministered with timolol (TIM) or verapamil (VER) which are considered as an adjuvant therapy in migraine prevention. Ion pair chromatography (IPC) with online fluorescence detection was applied to simultaneously detect and quantify the binary mixtures of ALM/TIM and ALM/VER in rabbit plasma samples. The separation was achieved using a Platinum C18 analytical column with a mobile phase composed of methanol: 35 mmol L-1 phosphate buffer solution containing 10 mmol L-1 SDS at pH = 6.8 (60:40 v/v). Several parameters were evaluated during the optimization of separation conditions including mobile phase composition, buffer concentration, buffer pH and concentration of ion pair reagent. A thorough investigation of the retention mechanism was performed, and the results showed that Coulomb forces were the main contributors to the overall retention mechanism, which may be hydrophobically assisted. QuEChERS extraction technique was utilized to extract the investigated drugs from plasma samples and a detailed study was carried out to optimize partition/extraction solvents, pH, extraction salts, sample volume and clean-up step. The method had a limit of detection and quantitation of 5.6 and 16.9 ng mL-1 for ALM in ALM/TIM mixture and 2.5 and 7.6 ng mL-1 for ALM in ALM/VER mixture, with an overall recovery not less than 95.22%. This newly proposed method offers a faster alternative to existing chromatographic methods for extraction and determination of ALM in binary mixtures with TIM or VER in rabbit plasma and provides a platform for studying pharmacokinetic parameters. The coadministration of either TIM or VER with ALM resulted in a notable rise in Cmax (maximum plasma concentration) and AUC (area under the plasma concentration-time curve) of ALM, implying possible alterations in the absorption and overall exposure of ALM.

Optimisation of saliva volumes for lipidomic analysis by nanoflow ultrahigh performance liquid chromatography-tandem mass spectrometry

Saliva is a readily accessible and clinically useful biofluid that can be used to develop disease biomarkers because of a variety of biologically active molecules in it that are also found in blood. However, even though saliva sampling is simple and non-invasive, few studies have investigated the use of salivary lipids as biomarkers, and the extraction of lipids from saliva needs to be examined thoroughly. In the present study, methods (i.e., saliva sample volume, 0.1-1.0 mL) for the extraction and analysis of salivary lipids by nanoflow ultrahigh performance liquid chromatography-tandem mass spectrometry (nUHPLC-ESI-MS/MS) were evaluated according to the matrix effect, extraction recovery, and number of quantifiable lipids. A total of 780 lipids were identified in a pooled saliva sample from 20 healthy volunteers, and 372 lipids without differentiating acyl chain structures were quantified, along with comprehensive information on salivary lipid composition and individual lipid levels. Even though extraction recovery was maintained at saliva sample volumes as low as 0.2 mL, the matrix effect and limit of detection (LOD) were relatively large with 1.0 mL. Considering the matrix effect, LOD, and number of quantifiable lipids (>limit of quantitation), the minimum volume of saliva sufficient for lipidomic analysis using nUHPLC-ESI-MS/MS was determined to be 0.5 mL.

Recent advances in microscale separation techniques for lipidome analysis

This review paper highlights the recent research on liquid-phase microscale separation techniques for lipidome analysis over the last 10 years, mainly focusing on capillary liquid chromatography (LC) and capillary electrophoresis (CE) coupled with mass spectrometry (MS). Lipids are one of the most important classes of biomolecules which are involved in the cell membrane, energy storage, signal transduction, and so on. Since lipids include a variety of hydrophobic compounds including numerous structural isomers, lipidomes are a challenging target in bioanalytical chemistry. MS is the key technology that comprehensively identifies lipids; however, separation techniques like LC and CE are necessary prior to MS detection in order to avoid ionization suppression and resolve structural isomers. Separation techniques using μm-scale columns, such as a fused silica capillary and microfluidic device, are effective at realizing high-resolution separation. Microscale separation usually employs a nL-scale flow, which is also compatible with nanoelectrospray ionization-MS that achieves high sensitivity. Owing to such analytical advantages, microscale separation techniques like capillary/microchip LC and CE have been employed for more than 100 lipidome studies. Such techniques are still being evolved and achieving further higher resolution and wider coverage of lipidomes. Therefore, microscale separation techniques are promising as the fundamental technology in next-generation lipidome analysis.

Recent developments in sample preparation techniques combined with high-performance liquid chromatography: A critical review

This review article compares and contrasts sample preparation techniques coupled with high-performance liquid chromatography (HPLC) and describes applications developed in biomedical, forensics, and environmental/industrial hygiene in the last two decades. The proper sample preparation technique can offer valued data for a targeted application when coupled to HPLC and a suitable detector. Improvements in sample preparation techniques in the last two decades have resulted in efficient extraction, cleanup, and preconcentration in a single step, thus providing a pathway to tackle complex matrix applications. Applications such as biological therapeutics, proteomics, lipidomics, metabolomics, environmental/industrial hygiene, forensics, glycan cleanup, etc., have been significantly enhanced due to improved sample preparation techniques. This review looks at the early sample preparation techniques. Further, it describes eight sample preparation technique coupled to HPLC that has gained prominence in the last two decades. They are (1) solid-phase extraction (SPE), (2) liquid-liquid extraction (LLE), (3) gel permeation chromatography (GPC), (4) Quick Easy Cheap Effective Rugged, Safe (QuEChERS), (5) solid-phase microextraction (SPME), (6) ultrasonic-assisted solvent extraction (UASE), and (7) microwave-assisted solvent extraction (MWASE). SPE, LLE, GPC, QuEChERS, and SPME can be used offline and online with HPLC. UASE and MWASE can be used offline with HPLC but have also been combined with the online automated techniques of SPE, LLE, GPC, or QuEChERS for targeted analysis. Three application areas of biomedical, forensics, and environmental/industrial hygiene are reviewed for the eight sample preparation techniques. Three hundred and twenty references on the eight sample preparation techniques published over the last two decades (2001-2021) are provided. Other older references were included to illustrate the historical development of sample preparation techniques.

MG@PD@TiO2 nanocomposite based magnetic solid phase extraction coupled with LC-MS/MS for determination of lysophosphatidylcholines biomarkers of plasma in psoriasis patients

Lysophosphatidylcholine (LPC) was commonly known as a class of significant differential metabolites of high relevance with many diseases including psoriasis, of which the accurate determination is of great importance to diagnosis or prediction to many diseases. However, it is challenging and complicated because of the enormous biological sample complexity and impurities interference. In this study, we synthesized a magnetic nanocomposite MG@PD@TiO₂ and took advantage of the interactions of Lewis acid-base between the phosphate groups in LPCs and Ti ions on MG@PD@TiO₂ nanomaterials for selective separation and enrichment of LPCs from complex biological matrix. The solid-phase extraction sample pretreatment process by means of MG@PD@TiO₂ nanomaterials coupled with LC-MS/MS method was then applied to actual determination of six typical LPCs (LPC 10:0, 14:0, 16:0, 18:0, 18:1, 22:0) in human plasma. The extraction conditions were scientifically optimized by single-factor test (adsorbent amount, adsorption and desorption time, elution solvent type, eluant volume). Under the optimal conditions, the detection limits (LOD, S/N = 3) and quantification limits (LOQ, S/N = 10) were 1 and 5 ng/mL for LPC 10:0 and LPC 14:0, 0.02 and 0.1 ng/mL for LPC 16:0 and LPC 18:1, 0.05 and 0.2 ng/mL LPC 18:0 and LPC 22:0, respectively. The intra- and inter-day precisions were 3.82-12.60 % (n = 6) and 3.29-13.50 % (n = 6) respectively, the recoveries were in the range of 91.92-113.69 % and the stability of the analytes in the matrix performed well with RSDs≤15.51 %. Finally, the developed method was successfully applied to the accurate determination of six LPCs biomarkers of plasma in patients with psoriasis (n = 10) and control groups (n = 10).

Optimisation of high-speed lipidome analysis by nanoflow ultrahigh-performance liquid chromatography-tandem mass spectrometry: Application to identify candidate biomarkers for four different cancers

Lipid analysis is a powerful tool that can elucidate the pathogenic roles of lipids in metabolic diseases, and facilitate the development of potential biomarkers. Lipid analysis by large-scale lipidomics requires a high-speed and high-throughput analytical platform. In the present study, a high-speed analytical method for lipid analysis using nanoflow ultrahigh-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry (nUHPLC-ESI-MS/MS) was optimised by investigating the effects of column flow rate, pump flow rate, dwell time, initial binary mobile phase composition, and gradient duration on the separation efficiency of standard lipid mixtures. The minimum gradient time for high-speed lipid separation was determined by examining the time-based separation efficiency and spectral overlap of isobaric lipid species during selected reaction monitoring-based quantification of sphingomyelin and a second isotope of phosphatidylcholine, which differ in molecular weight by only 1 Da. Finally, the optimised nUHPLC-ESI-MS/MS method was applied to analyse 200 plasma samples from patients with liver, gastric, lung, and colorectal cancer to evaluate its performance by measuring previously identified candidate lipid biomarkers. About 73% of the reported marker candidates (6 out of 7 in liver, 5/9 in gastric, 4/6 in lung, and 6/7 in colorectal cancer) could be assigned using the optimised method, supporting its use for high-throughput lipid analysis.

A narrative review of urinary phospholipids: from biochemical aspect towards clinical application

As a newly emerged discipline, lipidomic studies have focused on the comprehensive characterization and quantification of lipids in a given biological system, which has remarkably advanced in recent years owing to the rapid development of analytical techniques, especially mass spectrometry. Among diverse lipid classes, phospholipids, which have fundamental roles in the formation of cellular membranes, signaling processes, and bioenergetics have gained momentum in several fields of research. The altered composition, concentration, spatial distribution, and metabolism of phospholipids in cells, tissues, and body fluids have been elucidated in various human diseases such as cancer, inflammation, as well as cardiovascular and metabolic disorders. Among the different kinds of phospholipid sources in the human body, urine has not been extensively investigated in recent years owing to the extremely low concentrations of phospholipids and high levels of salts and other contaminants, which can interfere with precise detection. However, with profound advances and rapid expansion in analytical methods, urinary phospholipids have attracted increasing attention in current biomedical research as urine is an easily available source for the discovery of noninvasive biomarkers. In this review, we provide an overview of urinary phospholipids, including their biochemical aspects and clinical applications, aimed at promoting this field of research.

Bifidobacterium bifidum strains synergize with immune checkpoint inhibitors to reduce tumour burden in mice

The gut microbiome can influence the development of tumours and the efficacy of cancer therapeutics^1-5; however, the multi-omics characteristics of antitumour bacterial strains have not been fully elucidated. In this study, we integrated metagenomics, genomics and transcriptomics of bacteria, and analyses of mouse intestinal transcriptome and serum metabolome data to reveal an additional mechanism by which bacteria determine the efficacy of cancer therapeutics. In gut microbiome analyses of 96 samples from patients with non-small-cell lung cancer, Bifidobacterium bifidum was abundant in patients responsive to therapy. However, when we treated syngeneic mouse tumours with commercial strains of B. bifidum to establish relevance for potential therapeutic uses, only specific B. bifidum strains reduced tumour burden synergistically with PD-1 blockade or oxaliplatin treatment by eliciting an antitumour host immune response. In mice, these strains induced tuning of the immunological background by potentiating the production of interferon-γ, probably through the enhanced biosynthesis of immune-stimulating molecules and metabolites.

Comprehensive Identification of Glycosphingolipids in Human Plasma Using Hydrophilic Interaction Liquid Chromatography-Electrospray Ionization Mass Spectrometry

Glycosphingolipids (GSL) represent a highly heterogeneous class of lipids with many cellular functions, implicated in a wide spectrum of human diseases. Their isolation, detection, and comprehensive structural analysis is a challenging task due to the structural diversity of GSL molecules. In this work, GSL subclasses are isolated from human plasma using an optimized monophasic ethanol–water solvent system capable to recover a broad range of GSL species. Obtained deproteinized plasma is subsequently purified and concentrated by C18-based solid-phase extraction (SPE). The hydrophilic interaction liquid chromatography coupled to electrospray ionization linear ion trap tandem mass spectrometry (HILIC-ESI-LIT-MS/MS) is used for GSL analysis in the human plasma extract. Our results provide an in-depth profiling and structural characterization of glycosphingolipid and some phospholipid subclasses identified in the human plasma based on their retention times and the interpretation of tandem mass spectra. The structural composition of particular lipid species is readily characterized based on the detailed interpretation of mass spectrometry (MS) and tandem mass spectrometry (MS/MS) spectra and further confirmed by specific fragmentation behavior following predictable patterns, which yields to the unambiguous identification of 154 GSL species within 7 lipid subclasses and 77 phospholipids representing the highest number of GSL species ever reported in the human plasma. The developed HILIC-ESI-MS/MS method can be used for further clinical and biological research of GSL in the human blood or other biological samples.

Effect of agricultural pesticide on precocious puberty in urban children: an exploratory study

BACKGROUND

The incidence of precocious puberty has increased throughout the 20th century. The association between precocious puberty and endocrine disrupting chemicals including agricultural pesticides has been a subject of global study, but human data are lacking.

PURPOSE

We investigated the relationship between agricultural pesticides and the development of precocious puberty.

METHODS

We enrolled 60 female subjects at Severance Children's Hospital from December 2015 to January 2017. Of them, 30 were diagnosed with precocious puberty, while the other 30 prepubertal girls were enrolled as normal controls. We investigated their clinical characteristics and analyzed the urinary levels of 320 different agricultural pesticides.

RESULTS

Agricultural pesticide was detected in one of 30 patients with precocious puberty (3.3%) versus 2 of 30 girls in the normal control group (3.3% vs. 6.7%, P=0.554). Dinotefuran, a neonicotinoid-class insecticide, was detected in the samples of all 3 positive subjects.

CONCLUSION

Our results showed no relationship between agricultural pesticides and the development of precocious puberty. Larger sample sizes and robustly controlled variables are necessary to further investigate this topic.

Searching for Potential Lipid Biomarkers of Parkinson's Disease in Parkin-Mutant Human Skin Fibroblasts by HILIC-ESI-MS/MS: Preliminary Findings

Early diagnosis of neural changes causing cerebral impairment is critical for proposing preventive therapies for Parkinson’s disease (PD). Biomarkers currently available cannot be informative of PD onset since they are characterized by analysing post-mortem tissues from patients with severe degeneration of the substantia nigra. Skin fibroblasts (SF) are now recognized as a useful model of primary human cells, capable of reflecting the chronological and biological aging of the subjects. Here a lipidomic study of easily accessible primary SF is presented, based on hydrophilic interaction liquid chromatography coupled to electrospray ionization and mass spectrometry (HILIC/ESI-MS). Phospholipids (PL) from dermal fibroblasts of five PD patients with different parkin mutations and healthy control SF were characterized by single and tandem MS measurements using a hybrid quadrupole-Orbitrap and a linear ion trap mass analysers. The proposed approach enabled the identification of more than 360 PL. Univariate statistical analyses highlight abnormality of PL metabolism in the PD group, suggesting down- or up-regulation of certain species according to the extent of disease progression. These findings, although preliminary, suggest that the phospholipidome of human SF represents a source of potential biomarkers for the early diagnosis of PD. The dysregulation of ethanolamine plasmalogens in the circulatory system, especially those containing polyunsaturated fatty acids (PUFA), might be likely associated with neurodegeneration.

Comparison of modified Matyash method to conventional solvent systems for polar metabolite and lipid extractions

In the last decade, metabolomics has experienced significant advances in the throughput and robustness of analytical methodologies. Yet the preparation of biofluids and low-mass tissue samples remains a laborious and potentially inconsistent manual process, and a significant bottleneck for high-throughput metabolomics. To address this, we have compared three different sample extraction solvent systems in three diverse sample types with the purpose of selecting an optimum protocol for subsequent automation of sample preparation. We have investigated and re-optimised the solvent ratios in the recently introduced methyl tert-butyl ether (MTBE)/methanol/water solvent system (here termed modified Matyash; 2.6/2.0/2.4, v/v/v) and compared it to the original Matyash method (10/3/2.5, v/v/v) and the conventional chloroform/methanol/water (stepwise Bligh and Dyer, 2.0/2.0/1.8, v/v/v) using two biofluids (human serum and urine) and one tissue (whole Daphnia magna). This is the first report of the use of the Matyash method for extracting metabolites from the US National Institutes of Health (NIH) model organism D. magna. Extracted samples were analysed by non-targeted direct infusion mass spectrometry metabolomics or LC-MS metabolomics. Overall, the modified Matyash method yielded a higher number of peaks and putatively annotated metabolites compared to the original Matyash method (1-29% more peaks and 1-30% more metabolites) and the Bligh and Dyer method (4-20% more peaks and 1-41% more metabolites). Additionally the modified Matyash method was superior when considering metabolite intensities. The reproducibility of the modified Matyash method was higher than other methods (in 10 out of 12 datasets, compared to the original Matyash method; and in 8 out of 12 datasets, compared to the Bligh and Dyer method), based upon the observation of a lower mRSD of peak intensities. In conclusion, the modified Matyash method tended to provide a higher yield and reproducibility for most sample types in this study compared to two widely used methods.

Glycosphingolipidomics of donkey milk by hydrophilic interaction liquid chromatography coupled to ESI and multistage MS

Hydrophilic interaction liquid chromatography coupled to negative-ion electrospray linear ion-trap multiple-stage MS (HILIC-ESI-MSⁿ , n = 2,3) was used to characterize polar lipids occurring in donkey milk. Besides the detection of abundant phospholipids, the structural characterization and content evaluation of minor glycosphingolipids (GSLs) were assessed. We report an unprecedented characterization of 11 hexosyl-ceramides (HexCer), 10 Hex₂ Cer, and 4 Hex₃ Cer. CID-MS/MS spectra in negative ion mode mainly afford information on the monosaccharide number and ceramide constitution (i.e., N-acyl residue and long-chain base), whereas MS/MS/MS spectra on the ceramide anions allow to recognize for each GSL the sphingoid base. The occurrence of sphingosine (S), sphinganine (DS), and phytosphingosine (P) was inferred from the fragmentation patterns. The milk samples exhibit a relatively high number of phytosphingosine substitutes, perhaps because of the feeding of donkeys, mainly based on pasture grass. However, the incidence of hydroxylated species on the α-carbon of the acyl chain was also revealed. The fatty acid composition of N-acyl chains showed high values of long-chain saturated fatty acids such as 20:0, 22:0, 23:0, and 24:0. An average content of GSL is also provided and three representative mono-, di-, and tri-HexCer in donkey milk are the following: HexCer 18:0/24:1 phytosphingosine nonhydroxylated [PN] at m/z 862.6 as chloride adduct [M+Cl]^- , and content 225.9 ± 2.8 μg 100 mL^-1 ; Hex₂ Cer 18:0/16:0 sphinganine nonhydroxylated [DSN] at m/z 862.7 as deprotonated adduct [M-H]^- , and content 70.8 ± 1.4 μg 100 mL^-1 ; and Hex₃ Cer 18:1/24:1 [SN] at m/z 1132.8 as [M-H]^- , and content 38.5 ± 0.7 μg 100 mL^-1 .

Natural phospholipids: Occurrence, biosynthesis, separation, identification, and beneficial health aspects

During the last years, phospholipids (PLs) have attracted great attention because of their crucial roles in providing nutritional values, technological and medical applications. There are considerable proofs that PLs have unique nutritional benefits on human health, such as reducing cholesterol absorption, improving liver functions, and decreasing the risk of cardiovascular diseases. PLs are the main structural lipid components of cell and organelle membranes in all living organisms, and therefore, they occur in all organisms and the derived food products. PLs are distinguished by the presence of a hydrophilic head and a hydrophobic tail, consequently they possess amphiphilic features. Due to their unique characteristics, the extraction, separation, and identification of PLs are critical issues to be concerned. This review is focused on the content of PLs classes in several sources (including milk, vegetable oils, egg yolk, and mitochondria). As well, it highlights PLs biosynthesis, and the methodologies applied for PLs extraction and separation, such as solvent extraction and solid-phase extraction. In addition, the determination and quantification of PLs classes by using thin layer chromatography, high-performance liquid chromatography coupled with different detectors, and nuclear magnetic resonance spectroscopy techniques.

Identification of phospholipids classes and molecular species in different types of egg yolk by using UPLC-Q-TOF-MS

Egg phospholipids (PLs) are currently the products of greatest commercial interest with major area of importance in various fields. Therefore, in this study, duck, hen and quail egg yolk PLs were isolated by solvent extraction with chilled acetone precipitation, and subsequently separated and identified by using ultra-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Egg PLs were separated on hydrophilic interaction liquid chromatography (HILIC) with ethylene bridged hybrid (BEH) column by gradient elution using acetonitrile/ammonium formate as a mobile phase, and detected by mass spectrometry (MS) under electrospray ionization in positive and negative ion mode. Structural characterizations of 57 molecular species of egg yolk PLs were identified based on MS/MS fragment ion information and elemental composition in MassLynx 4.1 software. The obtained results showed that phosphatidylcholine (16:0-18:1), phosphatidylethanolamine (18:0-20:4), phosphatidylinositol (18:0-18:2), phosphatidylserine (18:0-18:2), sphingomyelin (d18:1/16:0) and lysophosphatidylcholine (16:0) were the predominant species among the different classes of egg yolk phospholipids.

An HPLC-ECD method for monoamines and metabolites quantification in cuttlefish (cephalopod) brain tissue

The cuttlefish belongs to the mollusk class Cephalopoda, considered as the most advanced marine invertebrates and thus widely used as models to study the biology of complex behaviors and cognition, as well as their related neurochemical mechanisms. Surprisingly, methods to quantify the biogenic monoamines and their metabolites in cuttlefish brain remain sparse and measure a limited number of analytes. This work aims to validate an HPLC-ECD method for the simultaneous quantification of dopamine, serotonin, norepinephrine and their main metabolites in cuttlefish brain. In comparison and in order to develop a method suitable to answer both ecological and biomedical questions, the validation was also carried out on a phylogenetically remote species: mouse (mammals). The method was shown to be accurate, precise, selective, repeatable and sensitive over a wide range of concentrations for 5-hydroxyindole-3-acetic acid, serotonin, dopamine, 3,4-dihydroxyphenylacetic acid and norepinephrine in the both extracts of cuttlefish and mouse brain, though with low precision and recovery for 4-hydroxy-3-methoxyphenylethylene glycol. Homovanillic acid, accurately studied in rodents, was not detectable in the brain of cuttlefish. Overall, we described here the first fully validated HPLC method for the routine measurement of both monoamines and metabolites in cuttlefish brain. Copyright © 2016 John Wiley & Sons, Ltd.

Lipidomic profiling of plasma and urine from patients with Gaucher disease during enzyme replacement therapy by nanoflow liquid chromatography-tandem mass spectrometry

Gaucher disease (GD) is a rare genetic disorder that arises from lipid species, especially monohexosylceramide (MHC), accumulating in different organs. GD results from a β-glucocerebrosidase deficiency, causing metabolic or neurologic complications. This study comprehensively profiled lipids from patients and healthy controls to discover active lipid species related to GD. Most studies have evaluated lipids from one type of biological sample, such as plasma, urine, or spinal fluid, which are the main sources of lipids in human bodies. The purpose of this study, however, was to collect and assess both plasma and urine samples from a group of individuals, explore the lipids, and select characteristic species that show significant differences between controls and patients from the two sources. Also, the response of lipids to enzyme replacement therapy (ERT), which is targeted to reduce excessive lipid accumulation within lysosomes, was investigated by obtaining plasma and urine from patients after receiving the therapy. Most lipid species were found in both plasma and urine but their concentrations differed, and some species were found in either plasma or urine only. Out of 125 plasma and 105 urinary lipids that were identified by nLC-ESI-MS/MS, 20 plasma and 10 urinary lipids were selected as characteristic species for having average concentrations that were significantly increased or decreased in patients by greater than 2-fold. Moreover, the concentrations of most lipids that showed greater than 2-fold of difference in patients decreased after ERT indicating that these species were directly or indirectly affected by the therapy.

Mass Spectrometry-based Lipidomics and Its Application to Biomedical Research

Lipidomics, a branch of metabolomics, is the large-scale study of pathways and networks of all cellular lipids in biological systems such as cells, tissues or organisms. The recent advance in mass spectrometry technologies have enabled more comprehensive lipid profiling in the biological samples. In this review, we compared four representative lipid profiling technoligies including GC-MS, LC-MS, direct infusion-MS and imaging-MS. We also summarized representative lipid database, and further discussed the applications of lipidomics to the diagnostics of various diseases such as diabetes, obesity, hypertension, and Alzheimer diseases.