Lipidomic analysis of serum samples from migraine patients

Metabolomics integrated with mass spectrometry imaging reveals novel action of tetramethylpyrazine in migraine

Migraine as a common neurological disorder still lacks effective therapies. Tetramethylpyrazine (TMP) is the main bioactive component from Ligusticum chuanxiong hort., a traditional edible-medicinal herb. This study aimed to investigate the action of TMP on migraine by metabolomics with mass spectrometry imaging (MSI) analysis and molecular exploring, including random forest model analysis, KEGG enrichment analysis and metabolite-metabolite interaction network analysis. The results indicated that 26 key representative metabolic biomarkers were identified, especially γ-glu-cys, which were highly related to glutathione (GSH) metabolism. MSI found the abundance of eleven endogenous metabolites were modulated by TMP, particularly glucose, the most important energy metabolism molecule, and GSH were increased that maintains intracellular redox balance, which was consistent with activation of Nrf2 signals by TMP. These findings provide insights into the effectiveness of metabolomics integrated with MSI in explaining the metabolic mechanisms of TMP, and afford valuable information for healthy development of TMP in migraine.

Study based on metabolomics and network pharmacology to explore the mechanism of Ginseng-Douch compound fermentation products in the treatment of hyperlipidemia

BACKGROUND

Ginseng-Douchi (GD) is a complex fermented product of ginseng and soybean, similar to natto, and is effective in the treatment of hyperlipidemia, but the mechanism of action involved needs to be further explored.

RESULTS

The present study combines a comprehensive strategy of network pharmacology and metabolomics to explore the lipid-lowering mechanism of GD. First, a hyperlipidemia rats model induced by a high-fat diet was established to evaluate the therapeutic effects of GD. Second, potential biomarkers were identified using serum metabolomics and metabolic pathway analysis was performed with MetaboAnalyst. Third, network pharmacology is used to find potential therapeutic targets based on the blood-influencing components of GD. Finally, core targets were obtained through a target-metabolite and the enrichment analysis of biomarkers-genes. Biochemistry analysis showed that GD exerted hypolipidemic effects on hyperlipidemic rats. Nineteen potential biomarkers for the GD treatment of hyperlipidemia were identified by metabolomics, which was mainly involved in linoleic acid metabolism, glycerophospholipid metabolism, ether lipid metabolism, alpha-linolenic acid metabolism and glycosylphosphatidylinositol-anchor biosynthesis. GD had a callback function for ether lipid metabolism and glycerophospholipid metabolism pathways. Eighteen blood components were identified in serum, associated with 85 potential therapeutic targets. The joint analysis showed that three core therapeutic targets were regulated by GD, including PIK3CA, AKT1 and EGFR.

CONCLUSION

This study combines serum medicinal chemistry of traditional Chinese medicine, network pharmacology and metabolomics to reveal the regulatory mechanism of GD on hyperlipidemia. © 2024 Society of Chemical Industry.

Determination of plasma lysophosphatidylethanolamines (lyso-PE) by LC-MS/MS revealed a possible relation between obesity and lyso-PE in Japanese preadolescent children: The Hokkaido study

BACKGROUND

Lysophosphatidylethanolamines (lyso-PEs) are the partial hydrolysis products of phosphatidylethanolamine. Although lyso-PEs are important biomarkers in various diseases, their determination is limited by the lack of simple and efficient quantification methods. This study aims to develop an improved quantitative method for the determination of lyso-PEs and its application to an epidemiological study.

METHODS

Single reaction monitoring channels by collision-induced dissociation for seven lyso-PEs were established using liquid chromatography-tandem mass spectrometry. Plasma lyso-PEs were extracted with a single-phase method using an isotopically labelled internal standard for quantification. The proposed method was adopted to define lyso-PEs in plasma samples of children aged 9-12 years living in Sapporo, Japan.

RESULTS

The limit of detection and limit of quantification for each lyso-PE ranged between 0.001-0.015 and 0.002-0.031 pmol/μL, respectively. Recoveries were found to be > 91% for all the species. The analysis results of children's plasma showed that the total lyso-PE concentrations in boys (n = 181) and girls (n = 161) were 11.53 and 11.00 pmol/μL (median), respectively. Participants were further classified by the percentage of overweight and subgrouped as underweight (n = 12), normal range (n = 292), or overweight (n = 38). Interestingly, the reduction of lyso-PE 16:0 and increased lyso-PE 22:6 were observed in overweight children compared with normal range (Fold change: 0.909 and 1.174, respectively).

CONCLUSIONS

This study successfully established a simple quantitative method to determine lyso-PE concentrations. Furthermore, our method revealed the possible relation between plasma lyso-PEs and overweight status.

The association between plasma trans-fatty acids level and migraine: A cross-sectional study from NHANES 1999-2000

OBJECTIVES

Trans-fatty acid (TFA) has been linked to an increased risk of a variety of diseases, such as cardiovascular disease (CVD), diabetes, and cancer. However, the relationship between plasma TFAs and migraine is little known. The current study aimed to determine the association between plasma TFAs and migraine in a large cross-sectional study among U.S. adults.

METHODS

The participants from the US National Health and Nutrition Examination Survey (NHANES) were included during the period 1999-2000. The plasma concentrations of four major TFAs, including palmitelaidic acid (C16:1n-7t), elaidic acid (C18:1n-9t), vaccenic acid (C18:1n-7t), and linolelaidic acid (C18:2n-6t, 9t) were measured by gas chromatography/mass spectrometry (GC/MS). The presence of migraine headache was determined by self-report questionnaire. Weighted multivariable logistic regressions and restricted cubic spline (RCS) regressions were explored to assess the relationship between plasma TFAs and migraine. Furthermore, stratified analysis and testing of interaction terms were used to evaluate the effect modification by sex, age, race/ethnicity, family income, and BMI.

RESULTS

A total of 1534 participants were included. The overall weighted prevalence of severe headache or migraine was 21.2 %. After adjusting for all potential covariates, plasma levels of elaidic acid and linolelaidic acid were positively associated with migraine. The adjusted OR values were 1.18 (95 %CI: 1.08-1.29, p=0.014, per 10 units increase) and 1.24 (95 %CI: 1.07-1.44, p=0.024). Then the included participants were divided into 2-quantiles by plasma TFA levels. Compared with participants with lower plasma levels of elaidic acid and linolelaidic acid (Q1 groups), those in the Q2 group had a higher prevalence of migraine when adjusted for all covariates in Model 2. The adjusted OR values were 2.43 (95 %CI: 1.14-5.18, p=0.037) for elaidic acid, and 2.18 (95 %CI: 1.14-4.20, p=0.036) for linolelaidic acid. Results were robust when analyses were stratified by sex, age, race/ethnicity, family income, and BMI, and no effect modification on the association was found.

CONCLUSIONS

Our results demonstrated a positive association between migraine prevalence and plasma levels of elaidic acid and linolelaidic acid in US adults. These results highlight the connection between circulating TFAs and migraine.

Transcriptomic and metabolomic profile changes in the liver of Sprague Dawley rat offspring after maternal PFOS exposure during gestation and lactation

Epidemiological and experimental research has indicated an association between perfluorooctane sulfonate (PFOS) exposure and liver disease. However, the potential hepatotoxic effects and mechanisms of low-level prenatal PFOS exposure in offspring remain ambiguous. The objective of this research was to examine the alterations in liver transcriptomic and metabolomic profiles in offspring rats at postnatal day (PND) 30 following gestational and lactational exposure to PFOS (from gestational day 1 to 20 and PND 1 to 21). Pregnant Sprague-Dawley rats were separated into a control group (3% starch gel solution, oral gavage) and a PFOS exposure group (0.03 mg/kg body weight per day, oral gavage). Histopathological changes in liver sections were observed by hematoxylin and eosin staining. Biochemical analysis was conducted to evaluate changes in glucose and lipid metabolism. Transcriptomic and metabolomic analyses were utilized to identify significant genes and metabolites associated with alterations of liver glucose and lipid metabolism through an integrated multi-omics analysis. No significant differences were found in the measured biochemical parameters. In total, 167 significant differentially expressed genes (DEGs) related to processes such as steroid biosynthesis, PPAR signaling pathway, and fat digestion and absorption were identified in offspring rats in the PFOS exposure group. Ninety-five altered metabolites were exhibited in the PFOS exposure group, such as heptaethylene glycol, lysoPE (0:0/18:0), lucidenic acid K, and p-Cresol sulfate. DEGs associated with steroid biosynthesis, PPAR signaling pathway, fat digestion and absorption were significantly upregulated in the PFOS exposure group (P < 0.05). The analysis of correlations indicated that there was a significant inverse correlation between all identified differential metabolites and the levels of fasting blood glucose, high-density lipoprotein, and triglycerides in the PFOS exposure group (P < 0.05). Our findings demystify that early-life PFOS exposure can lead to alterations in transcriptomic and metabolomic profiles in the offspring's liver, which provided mechanistic insights into the potential hepatotoxicity and developmental toxicity associated with environmentally relevant levels of PFOS exposure.

Microbiome in urological diseases: Axis crosstalk and bladder disorders

Since the identification of the human urinary microbiome, numerous studies have characterized this microbial community and improved our knowledge of its association with urinary diseases. This association between urinary diseases and microbiota is not confined to the urinary microbiota; it is interconnected with the microbiota of other organs. The gastrointestinal, vaginal, kidney, and bladder microbiota all affect urinary diseases because they work with their respective organs to control the growth and operation of the immune, metabolic, and nervous systems through dynamic bidirectional communication along the bladder-centered axis. Therefore, disturbances in the microbial communities may result in the emergence of urinary diseases. In this review, we describe the increasing and intriguing evidence of complicated and critical relationships that may contribute to the development and progression of urinary diseases through disruption of the microbiota in various organs.

Metabolomics combined with serum pharmacochemistry discovering the potential effective compounds of Fangji Huangqi Tang against nephrotic syndrome

Fangji Huangqi Tang (FHT) was first recorded in "Jin Gui Yao Lue," invented by the archaic Chinese medical doctor Zhongjing Zhang, and is a classic medicine that tonifies qi and expels wind, invigorates spleen for diuresis. A large number of literatures indicated that FHT showed a significant effect on Nephrotic Syndrome (NS). A comprehensive strategy was proposed to discover the potential effective compounds and therapeutic targets of FHT against NS as a case study. Serum metabolomics combined with multivariate statistical analysis was employed to analysis and screen the differential endogenous metabolites in serum samples of the control and model rats induced by Adriamycin. The correlation analysis between the efficacy biomarkers and different compounds absorbed in serum of FHT was conducted to explore the potential effective compounds of FHT against NS. With the help of network pharmacology, the therapeutic targets and the possible molecular mechanisms of FHT against NS were further investigated. Fifteen metabolites, including l-phenylalanine, 3-Hydroxybutyric acid and linolenic acid, were associated with renal damage based on the serum metabolomic results. Metabolic pathway analysis indicated that phenylalanine, tyrosine and tryptophan biosynthesis and linoleic acid metabolism were the key pathways associated with NS. Among them, 6 metabolites were defined as efficacy biomarkers such as uric acid, 2-methylbutyrylcarnitine and 10-HDA. The results of correlation analysis suggested that 14 constituents such as fanGhinoline, cycloastragenol, atractylenolide III, and glycyrrhetinic acid were recognized as potential effective compounds, whose potential protein targets participated in the MAPK signaling pathway, GnRH signaling pathway and aldoaterone-regulated sodium reabsorption. This study has clarified the potential effective compounds and therapeutic targets of FHT against NS. The results provided new evidence for the pharmacological mechanism of FHT on NS.

Lysophosphatidylcholine: Potential Target for the Treatment of Chronic Pain

The bioactive lipid lysophosphatidylcholine (LPC), a major phospholipid component of oxidized low-density lipoprotein (Ox-LDL), originates from the cleavage of phosphatidylcholine by phospholipase A2 (PLA2) and is catabolized to other substances by different enzymatic pathways. LPC exerts pleiotropic effects mediated by its receptors, G protein-coupled signaling receptors, Toll-like receptors, and ion channels to activate several second messengers. Lysophosphatidylcholine (LPC) is increasingly considered a key marker/factor positively in pathological states, especially inflammation and atherosclerosis development. Current studies have indicated that the injury of nervous tissues promotes oxidative stress and lipid peroxidation, as well as excessive accumulation of LPC, enhancing the membrane hyperexcitability to induce chronic pain, which may be recognized as one of the hallmarks of chronic pain. However, findings from lipidomic studies of LPC have been lacking in the context of chronic pain. In this review, we focus in some detail on LPC sources, biochemical pathways, and the signal-transduction system. Moreover, we outline the detection methods of LPC for accurate analysis of each individual LPC species and reveal the pathophysiological implication of LPC in chronic pain, which makes it an interesting target for biomarkers and the development of medicine regarding chronic pain.

Changes in Plasma Lipid Levels Following Cortical Spreading Depolarization in a Transgenic Mouse Model of Familial Hemiplegic Migraine

Metabolite levels in peripheral body fluids can correlate with attack features in migraine patients, which underscores the potential of plasma metabolites as possible disease biomarkers. Migraine headache can be preceded by an aura that is caused by cortical spreading depolarization (CSD), a transient wave of neuroglial depolarization. We previously identified plasma amino acid changes after CSD in familial hemiplegic migraine type 1 (FHM1) mutant mice that exhibit increased neuronal excitability and various migraine-related features. Here, we aimed to uncover lipid metabolic pathways affected by CSD, guided by findings on the involvement of lipids in hemiplegic migraine pathophysiology. Using targeted lipidomic analysis, we studied plasma lipid metabolite levels at different time points after CSD in wild-type and FHM1 mutant mice. Following CSD, the most prominent plasma lipid change concerned a transient increase in PGD₂, which lasted longer in mutant mice. In wild-type mice only, levels of anti-inflammatory lipid mediators DPAn-3, EPA, ALA, and DHA were elevated 24 h following CSD compared to Sham-treated animals. Given the role of PGs and neuroinflammation in migraine pathophysiology, our findings underscore the potential of monitoring peripheral changes in lipids to gain insight in central brain mechanisms.

Alterations in the Plasma Lipidome of Adult Women With Bipolar Disorder: A Mass Spectrometry-Based Lipidomics Research

Lipidomics has become a pivotal tool in biomarker discovery for the diagnosis of psychiatric illnesses. However, the composition and quantitative analysis of peripheral lipids in female patients with bipolar disorder (BD) have been poorly addressed. In this study, plasma samples from 24 female patients with BD and 30 healthy controls (HCs) were analyzed by comprehensive lipid profiling and quantitative validation based on liquid chromatography-mass spectrometry. Clinical characteristics and a correlation between the level of lipid molecules and clinical symptoms were also observed. We found that the quantitative alterations in several lipid classes, including acylcarnitine, lysophosphatidylethanolamine, GM2, sphingomyelin, GD2, triglyceride, monogalactosyldiacylglycerol, phosphatidylinositol phosphate, phosphatidylinositol 4,5-bisphosphate, phosphatidylethanolamine, phosphatidylserine, and lysophosphatidylinositol, were remarkably upregulated or downregulated in patients with BD and were positively or negatively correlated with the severity of psychotic, affective, or mania symptoms. Meanwhile, the composition of different carbon chain lengths and degrees of fatty acid saturation for these lipid classes in BD were also different from those of HCs. Moreover, 55 lipid molecules with significant differences and correlations with the clinical parameters were observed. Finally, a plasma biomarker set comprising nine lipids was identified, and an area under the curve of 0.994 was obtained between patients with BD and the HCs. In conclusion, this study provides a further understanding of abnormal lipid metabolism in the plasma and suggests that specific lipid species can be used as complementary biomarkers for the diagnosis of BD in women.

Phenotypic and Genotypic Associations Between Migraine and Lipoprotein Subfractions

BACKGROUND AND OBJECTIVE

To evaluate phenotypic and genetic relationships between migraine and lipoprotein subfractions.

METHODS

We evaluated phenotypic associations between migraine and 19 lipoprotein subfraction measures in the Women's Genome Health Study (n = 22,788). We then investigated genetic relationships between these traits using summary statistics from the International Headache Genetics Consortium for migraine (n_case = 54,552, n_control = 297,970) and combined summary data for lipoprotein subfractions (n up to 47,713).

RESULTS

There was a significant phenotypic association (odds ratio 1.27 [95% confidence interval 1.12-1.44]) and a significant genetic correlation at 0.18 (p = 0.001) between migraine and triglyceride-rich lipoproteins (TRLPs) concentration but not for low-density lipoprotein or high-density lipoprotein subfractions. Mendelian randomization (MR) estimates were largely null, implying that pleiotropy rather than causality underlies the genetic correlation between migraine and lipoprotein subfractions. Pleiotropy was further supported in cross-trait meta-analysis, revealing significant shared signals at 4 loci (chr2p21 harboring THADA, chr5q13.3 harboring HMGCR, chr6q22.31 harboring HEY2, and chr7q11.23 harboring MLXIPL) between migraine and lipoprotein subfractions. Three of these loci were replicated for migraine (p < 0.05) in a smaller sample from the UK Biobank. The shared signal at chr5q13.3 colocalized with expression of HMGCR, ANKDD1B, and COL4A3BP in multiple tissues.

CONCLUSIONS

The study supports the association between certain lipoprotein subfractions, especially for TRLP, and migraine in populations of European ancestry. The corresponding shared genetic components may help identify potential targets for future migraine therapeutics.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that migraine is significantly associated with some lipoprotein subfractions.

Genetic overlap and causality between blood metabolites and migraine

The availability of genome-wide association studies (GWASs) for human blood metabolome provides an excellent opportunity for studying metabolism in a heritable disease such as migraine. Utilizing GWAS summary statistics, we conduct comprehensive pairwise genetic analyses to estimate polygenic genetic overlap and causality between 316 unique blood metabolite levels and migraine risk. We find significant genome-wide genetic overlap between migraine and 44 metabolites, mostly lipid and organic acid metabolic traits (FDR < 0.05). We also identify 36 metabolites, mostly related to lipoproteins, that have shared genetic influences with migraine at eight independent genomic loci (posterior probability > 0.9) across chromosomes 3, 5, 6, 9, and 16. The observed relationships between genetic factors influencing blood metabolite levels and genetic risk for migraine suggest an alteration of metabolite levels in individuals with migraine. Our analyses suggest higher levels of fatty acids, except docosahexaenoic acid (DHA), a very long-chain omega-3, in individuals with migraine. Consistently, we found a causally protective role for a longer length of fatty acids against migraine. We also identified a causal effect for a higher level of a lysophosphatidylethanolamine, LPE(20:4), on migraine, thus introducing LPE(20:4) as a potential therapeutic target for migraine.

Combined Signature of the Urinary Microbiome and Metabolome in Patients With Interstitial Cystitis

Interstitial cystitis (IC) is a clinical syndrome characterized by frequency, urgency, and bladder pain or pelvic pain; however, the underlying pathophysiological mechanisms and diagnostic markers are unknown. In this study, microbiome and metabolome analysis were used to explain the urine signatures of IC patients. Urine samples from 20 IC patients and 22 control groups were analyzed by using 16S rRNA sequence and liquid chromatography coupled with mass spectrometry. Four opportunistic pathogen genera, including Serratia, Brevibacterium, Porphyromonas, and Citrobacter, were significantly upregulated in IC group. The altered metabolite signatures of the metabolome may be related to sphingosine metabolism, amino acid metabolism, and fatty acid biosynthesis. Meanwhile, the associations were observed between different metabolites and microbiomes of IC. The present study suggests that the combined signatures of IC in urine microbiome and metabolome may become its prospective diagnostic markers.

Transient receptor potential canonical 5 mediates inflammatory mechanical and spontaneous pain in mice

Tactile and spontaneous pains are poorly managed symptoms of inflammatory and neuropathic injury. Here, we found that transient receptor potential canonical 5 (TRPC5) is a chief contributor to both of these sensations in multiple rodent pain models. Use of TRPC5 knockout mice and inhibitors revealed that TRPC5 selectively contributes to the mechanical hypersensitivity associated with CFA injection, skin incision, chemotherapy induced peripheral neuropathy, sickle cell disease, and migraine, all of which were characterized by elevated concentrations of lysophosphatidylcholine (LPC). Accordingly, exogenous application of LPC induced TRPC5-dependent behavioral mechanical allodynia, neuronal mechanical hypersensitivity, and spontaneous pain in naïve mice. Lastly, we found that 75% of human sensory neurons express TRPC5, the activity of which is directly modulated by LPC. On the basis of these results, TRPC5 inhibitors might effectively treat spontaneous and tactile pain in conditions characterized by elevated LPC.

The Mystery of Red Blood Cells Extracellular Vesicles in Sleep Apnea with Metabolic Dysfunction

Sleep is very important for overall health and quality of life, while sleep disorder has been associated with several human diseases, namely cardiovascular, metabolic, cognitive, and cancer-related alterations. Obstructive sleep apnea (OSA) is the most common respiratory sleep-disordered breathing, which is caused by the recurrent collapse of the upper airway during sleep. OSA has emerged as a major public health problem and increasing evidence suggests that untreated OSA can lead to the development of various diseases including neurodegenerative diseases. In addition, OSA may lead to decreased blood oxygenation and fragmentation of the sleep cycle. The formation of free radicals or reactive oxygen species (ROS) can emerge and react with nitric oxide (NO) to produce peroxynitrite, thereby diminishing the bioavailability of NO. Hypoxia, the hallmark of OSA, refers to a decline of tissue oxygen saturation and affects several types of cells, playing cell-to-cell communication a vital role in the outcome of this interplay. Red blood cells (RBCs) are considered transporters of oxygen and nutrients to the tissues, and these RBCs are important interorgan communication systems with additional functions, including participation in the control of systemic NO metabolism, redox regulation, blood rheology, and viscosity. RBCs have been shown to induce endothelial dysfunction and increase cardiac injury. The mechanistic links between changes of RBC functional properties and cardiovascular are largely unknown. Extracellular vesicles (EVs) are secreted by most cell types and released in biological fluids both under physiological and pathological conditions. EVs are involved in intercellular communication by transferring complex cargoes including proteins, lipids, and nucleic acids from donor cells to recipient cells. Advancing our knowledge about mechanisms of RBC-EVs formation and their pathophysiological relevance may help to shed light on circulating EVs and to translate their application to clinical practice. We will focus on the potential use of RBC-EVs as valuable diagnostic and prognostic biomarkers and state-specific cargoes, and possibilities as therapeutic vehicles for drug and gene delivery. The use of RBC-EVs as a precision medicine for the diagnosis and treatment of the patient with sleep disorder will improve the prognosis and the quality of life in patients with cardiovascular disease (CVD).

Analysis of serum lysophosphatidylethanolamine levels in patients with non-alcoholic fatty liver disease by liquid chromatography-tandem mass spectrometry

Lysophosphatidylethanolamines (LysoPEs) are the partial hydrolysis products of phosphatidylethanolamine. Despite the unique in vitro bioactivities of LysoPEs, there are limited reports on the pathophysiological role of LysoPEs in the serum, due to the lack of sensitive analytical methods for determination of each molecular species in clinical samples. Herein, we developed a highly sensitive quantitative method to profile the serum LysoPE species by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with selected reaction monitoring (SRM). The internal standard (IS), chemically synthesized in-house, and the lineup of seven major LysoPE species were used in this study. The limits of detection and quantification for each LysoPE species ranged within 0.5-3.3 pmol/mL and 1.0-5.0 pmol/mL, respectively. The combined concentrations of LysoPEs in the serum from healthy subjects (n = 8) and the patients with non-alcoholic fatty liver diseases (NAFLD) including simple steatosis (SS, n = 9) and non-alcoholic steatohepatitis (NASH, n = 27) were 18.030 ± 3.832, 4.867 ± 1.852, and 5.497 ± 2.495 nmol/mL, respectively. The combined and individual concentrations of LysoPEs, except for LysoPE 18:0, significantly decreased in the patients with NAFLD compared with those for the healthy subjects. However, no significant difference was observed between the SS and NASH groups. Our proposed LC-MS/MS method is valid and has advantages of small sample volume, high sensitivity, and simultaneous absolute quantitation for multiple molecular species. This method may enable diagnostic evaluation and elucidation of the as-yet uncovered pathophysiological role of LysoPEs.

Evaluation of Injury Degree of Adriamycin-Induced Nephropathy in Rats Based on Serum Metabolomics Combined with Proline Marker

Nephrotic syndrome (NS) is one of the leading causes of end-stage renal failure. Unfortunately, reliable surrogate markers for early diagnosing and monitoring the entire progression of NS are as yet absent. A method using UPLC-Q exactive HR-MS was established for the serum metabolomic study of adriamycin-induced nephropathy in rats. Two rat nephropathy models induced by adriamycin were adopted to reflect different degrees of renal damage of early and advanced stages. Then two MPC5 cell models were used to verify the role of proline in the progression of kidney injury. The results showed that seven metabolites such as 14S-HDHA, DPA, and DHA were associated with early renal injury, while 12 metabolites such as tryptophan, linoleyl carnitine, and LysoPC (18:3) reflected the advanced renal disease. At the same time, metabolites including LPE (22:6), LysoPC (22:5), and proline that changed during the whole process of NS were defined as progressive markers. Pathway analysis results showed that fatty acid metabolism, glycerophospholipid metabolism, and amino acids metabolism participated in the occurrence and development of NS. In addition, the change trend of intracellular proline content was consistent with that in serum, and the results were further supported by the detection of the crucial gene PYCRL. This study provides an important basis for searching for diagnostic markers of NS and also provides a methodological reference for early diagnosing and monitoring the pathogenesis of other progressive diseases.

The Differences of Serum Metabolites Between Patients With Early-Stage Alzheimer's Disease and Mild Cognitive Impairment

Background: Mild cognitive impairment (MCI) is regarded as a transition phase between normal aging and Alzheimer's disease (AD). Identification of novel and non-invasive biomarkers that can distinguish AD at an early stage from MCI is warranted for therapeutic and support planning. The goal of this study was to identify the differences of serum metabolomic profiles between MCI and early-stage AD, which could be potential non-invasive biomarkers for early diagnosis of AD.

Methods: The subjects enrolled in the study were classified into two diagnostic groups: MCI (n = 40) and early-stage AD (n = 40). Targeted metabolomics analysis of serum samples was performed using the Biocrates Absolute-IDQ P180 kit. Targeted metabolic data were analyzed by TargetLynx, and MetIDQ software was applied to integrate the metabolites by automated calculation of metabolite concentrations.

Results: The datasets of targeted metabolite analysis were analyzed by the orthogonal-projection-to-latent-structure–discriminant-analysis (OPLS-DA) model. The OPLS-DA score plots demonstrated considerable separation between the MCI and early-stage AD patients. The levels of pimelylcarnitine, putrescine, SM (OH) C24:1, and SM C24:0 were significantly lower, whereas the levels of acetylornithine, methionine sulfoxide, and PC ae C44:3 were significantly higher in early-stage AD patients as compared with MCI patients. Receiver operating characteristic curve analysis of a combination of three lipid metabolites [SM (OH) C24:1, SM C24:0, and PC ae C44:3] showed an acceptable discrimination between the early-stage AD and MCI patients (area under the curve = 0.788).

Conclusions: Our results characterized the differences of serum metabolic profiles between MCI and early-stage AD patients. The positive findings from this study indicate that the minimally invasive method of blood sampling may help to identify patients with AD at an early stage from those with MCI.

Untargeted Metabolomics Study of the In Vitro Anti-Hepatoma Effect of Saikosaponin d in Combination with NRP-1 Knockdown

Saikosaponin d (SSd) is one of the main active ingredients in Radix Bupleuri. In our study, network pharmacology databases and metabolomics were used in combination to explore the new targets and reveal the in-depth mechanism of SSd. A total of 35 potential targets were chosen through database searching (HIT and TCMID), literature mining, or chemical similarity predicting (Pubchem). Out of these obtained targets, Neuropilin-1 (NRP-1) was selected for further research based on the degree of molecular docking scores and novelty. Cell viability and wound healing assays demonstrated that SSd combined with NRP-1 knockdown could significantly enhance the damage of HepG2. Metabolomics analysis was then performed to explore the underlying mechanism. The overall difference between groups was quantitatively evaluated by the metabolite deregulation score (MDS). Results showed that NRP-1 knockdown exhibited the lowest MDS, which demonstrated that the metabolic profile experienced the slightest interference. However, SSd alone, or NRP-1 knockdown in combination with SSd, were both significantly influenced. Differential metabolites mainly involved short- or long-chain carnitines and phospholipids. Further metabolic pathway analysis revealed that disturbed lipid transportation and phospholipid metabolism probably contributed to the enhanced anti-hepatoma effect by NRP-1 knockdown in combination with SSd. Taken together, in this study, we provided possible interaction mechanisms between SSd and its predicted target NRP-1.

Metabolomics and Biomarker Discovery

Recently, metabolomics-the study of metabolite profiles within biological samples-has found a wide range of applications. This chapter describes the different techniques available for metabolomic analysis, the various samples that can be utilised for analysis and applications of both global and targeted metabolomic analysis to biomarker discovery in medicine.

What Are We Missing in the Diagnostic Criteria for Migraine?

PURPOSE OF REVIEW

This review is intended to examine how the diagnostic criteria for migraine have evolved over the past 45 years and to evaluate the strengths and weaknesses of the current diagnostic criteria promulgated by the International Classification of Headache Disorders (ICHD).

RECENT FINDINGS

The ICHD is a comprehensive and systematic classification system for headache disorders. As the pathophysiology of migraine is more fully elucidated and more sophisticated diagnostic technologies are developed (e.g., the identification of biomarkers), the current diagnostic criteria for migraine will likely be further refined. The ICHD has allowed for more precise research study design in the field of headache medicine. The current diagnostic criteria for migraine outlined in the 3rd version of the ICHD are far more sensitive and specific than the clinical criteria proposed in 1962. In future iterations, dividing episodic and chronic migraine into subtypes based on frequency (i.e., low frequency vs high frequency; near-daily vs daily) potentially could assist in guiding clinical management. In addition, a better understanding of aura, vestibular migraine, migrainous infarction, and hemiplegic migraine likely will lead to more refined diagnostic criteria for those entities.

Lipidomic profiling of plasma samples from patients with mitochondrial disease

Mitochondrial disease (MD) is a rare mitochondrial respiratory chain disorder with a high mortality and extremely challenging to treat. Although genomic, transcriptomic, and proteomic analyses have been performed to investigate the pathogenesis of MD, the role of metabolomics in MD, particularly of lipidomics remains unclear. This study was undertaken to identify potential lipid biomarkers of MD. An untargeted lipidomic approach was used to compare the plasma lipid metabolites in 20 MD patients and 20 controls through Liquid Chromatography coupled to Mass Spectrometry. Volcano plot analysis was performed to identify the different metabolites. Receiver operating characteristic (ROC) curves were constructed and the area under the ROC curves (AUC) was calculated to determine the potentially sensitive and specific biomarkers. A total of 41 lipids were significantly different in MD patients and controls. ROC curve analysis showed the top 5 AUC values of lipids (phosphatidylinositols 38:6, lysoPC 20:0, 19:0, 18:0, 17:0) are more than 0.99. Multivariate ROC curve based exploratory analysis showed the AUC of combination of top 5 lipids is 1, indicating they may be potentially sensitive and specific biomarkers for MD. We propose combination of these lipid species may be more valuable in predicting the development and progression of MD, and this will have important implications for the diagnosis and treatment of MD.