Untargeted Lipidomic Analysis of Plasma from High-fat Diet-induced Obese Rats Using UHPLC–Linear Trap Quadrupole–Orbitrap MS

Liang

Rapid Comm Mass Spectrometry

et al. 2020

Self Cite

RationaleFatty acid esters of hydroxy fatty acids (FAHFAs) are recently discovered endogenous lipids with outstanding health benefits. FAHFAs are known to exhibit antioxidant, antidiabetic and anti‐inflammatory properties. The number of known long‐chain FAHFAs in mammalian tissues and dietary resources increased recently because of the latest developments in high‐resolution tandem mass spectrometry techniques. However, there are no reports on the identification of short‐chain fatty acid esterified hydroxy fatty acids (SFAHFAs).MethodsIntestinal contents, tissues, and plasma of rats fed with high‐fat diet (HFD) and normal diet (ND) were analyzed for fatty acids, hydroxy fatty acids, and FAHFAs using ultra‐high‐performance liquid chromatography (UHPLC) and linear trap quadrupole‐Orbitrap mass spectrometry (LTQ Orbitrap MS) with negative heated electrospray ionization.ResultsUntargeted analysis of total lipid extracts from murine samples (male 13‐week‐old WKAH/HKmSlc rats) led to the identification of several new SFAHFAs of acetic acid or propanoic acid esterified long‐chain (>C20)‐hydroxy fatty acids. Furthermore, MS3 analysis revealed the position of the hydroxyl group in the long‐chain fatty acid as C‐2. The relative amounts of SFAHFAs were quantified in intestinal contents and their tissues (Cecum, small intestine, and large intestine), liver, and plasma of rats fed with HFD and ND. The large intestine showed the highest abundance of SFAHFAs with a concentration range from 0.84 to 57 pmol/mg followed by the cecum with a range of 0.66 to 28.6 pmol/mg. The SFAHFAs were significantly altered between the HFD and ND groups, with a strong decreasing tendency under HFD conditions.ConclusionsIdentification of these novel SFAHFAs can contribute to a better understanding of the chemical and biological properties of individual SFAHFAs and their possible sources in the gut, which in turn helps us tackle the role of these lipids in various metabolic diseases.

Section: Animal Experimentsmentioning

confidence: 99%

Identification of short‐chain fatty acid esters of hydroxy fatty acids (SFAHFAs) in a murine model by nontargeted analysis using ultra‐high‐performance liquid chromatography/linear ion trap quadrupole‐Orbitrap mass spectrometry

Liang

Rapid Comm Mass Spectrometry

et al. 2020

Self Cite

“…The cecum and colon contents were collected (after exsanguination) from the two groups of 13-week-old WKAH/HkmSlc rats that were fed either a normal diet or high-fat diet fed. The details of animal experiments and diet compositions were provided in our previous report [ 12 , 28 ]. All the experiments were conducted by obtaining approval (No.…”

Section: Methodsmentioning

confidence: 99%

Chemical Labeling Assisted Detection and Identification of Short Chain Fatty Acid Esters of Hydroxy Fatty Acid in Rat Colon and Cecum Contents

Liang

et al. 2020

Metabolites

Self Cite

Branched fatty acid esters of hydroxy fatty acids (FAHFAs) are novel endogenous lipids with important physiological functions in mammals. We previously identified a new type of FAHFAs, named short-chain fatty acid esterified hydroxy fatty acids (SFAHFAs), with acetyl or propyl esters of hydroxy fatty acids of carbon chains, C ≥ 20. However, sensitive determination of SFAHFAs is still a challenge, due to their high structural similarity and low abundance in biological samples. This study employs one-step chemical derivatization following total lipid extraction using 2-dimethylaminoethylamine (DMED) for enhanced detection of SFAHFAs. The labeled extracts were subjected to ultrahigh performance liquid chromatography coupled to linear ion trap quadrupole-Orbitrap mass spectrometry (UHPLC/LTQ-Orbitrap MS). Our results demonstrated that the detection sensitivities of SFAHFAs increased after DMED labeling, and is highly helpful in discovering six additional novel SFAHFAs in the cecum and colon contents of WKAH/HKmSlc rats fed with normal and high-fat diet (HFD). The identified DMED labeled SFAHFAs were characterized by their detailed MS/MS analysis, and their plausible fragmentation patterns were proposed. The concentrations of SFAHFAs were significantly reduced in the cecum of HFD group compared to the control. Hence, the proposed method could be a promising tool to apply for the enhanced detection of SFAHFAs in various biological matrices, which in turn facilitate the understanding of their sources, and physiological functions of these novel lipids.

“…Metabolites maintain homeostasis in response to adverse biological responses. Previous studies have also shown that the use of untargeted metabolomics analysis provides a basis for metabolic syndrome in HFD fed rats [22,23]. Therefore, untargeted metabolomics is used to identify the phenotype-related metabolites and metabolic pathways, to explain the speci c functions of metabolites, and to understand the physiological effects.…”

Section: Introduction (Background)mentioning

confidence: 99%

Untargeted Metabolomics Analysis Revealed Lipometabolic Disorders in Perirenal Adipose Tissue of Rabbits Subject to a High-fat Diet

Xia

Shao

Elzo

et al. 2021

Preprint

Backgroud：High-fat diet (HFD) has been widely recognized as a significant modifiable risk for insulin resistance, inflammation, type 2-diabetes (T2D), atherosclerosis and other metabolic diseases. The biological mechanisms responsible for disturbances in perirenal adipose tissue (PAT) and other tissues in rodents fed a HFD are well understood. However, the biological mechanism responsible for key metabolic disorders in PAT of rabbits subject to HFD remains unclear. Methods: Here, untargeted metabolomics (LC-MS/MS) combined with liquid chromatography (LC) and high resolution mass spectrometry (MS) were used to evaluate PAT metabolic changes. Histological observations showed that the adipocytes cells and density of PAT was significantly increased in HFD rabbits. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) showed noticeable changes in PAT metabolites between the HFD and standard normal diet (SND) rabbit groups. Results: Our study revealed 206 differential metabolites (21 up-regulated and 185 down-regulated), and then the 47 differential metabolites (13 up-regulated and 34 down-regulated), mainly phospholipids, fatty acids, steroid hormones and amino acids, chosen as potential biomarkers to help explain metabolic disorders caused by HFD. These metabolites were mainly associated with biosynthesis of unsaturated fatty acids, the arachidonic acid metabolic pathway, the ovarian steroidogenesis pathway, and the platelet activation pathway. Our study revealed that a HFD caused significant metabolic disorders in rabbit PAT. Conclusion: High levels of phospholipids, fatty acids, steroid hormones and l-methionine may inhibit oxygen respiration by increasing the adipocytes cells and density cause mitochondrial and endoplasmic reticulum dysfunction, produce inflammation, and finally lead to insulin resistance, thus increasing the risk of T2D , atherosclerosis, and other metabolic syndromes.