Lipid Analysis Research Articles

Relationship Between the Lipidome Profile and Disease Activity in Patients with Rheumatoid Arthritis.

Lipid mediators have been suggested to play important roles in the pathogenesis of rheumatoid arthritis (RA). Lipidomics has recently allowed for the comprehensive analysis of lipids and has revealed the potential of lipids as biomarkers for the early diagnosis of RA and prediction of therapeutic responses. However, the relationship between disease activity and the lipid profile in RA remains unclear. In the present study, we performed a plasma lipidomic analysis of 278 patients with RA during treatment and examined relationships with disease activity using the Disease Activity Score in 28 joints (DAS28)-erythrocyte sedimentation rate (ESR). In all patients, five lipids positively correlated and seven lipids negatively correlated with DAS28-ESR. Stearic acid [FA(18:0)] (r = -0.45) and palmitic acid [FA(16:0)] (r = -0.38) showed strong negative correlations. After adjustments for age, body mass index (BMI), and medications, stearic acid, palmitic acid, bilirubin, and lysophosphatidylcholines negatively correlated with disease activity. Stearic acid inhibited osteoclast differentiation from peripheral blood monocytes in in vitro experiments, suggesting its contribution to RA disease activity by affecting bone metabolism. These results indicate that the lipid profile correlates with the disease activity of RA and also that some lipids may be involved in the pathogenesis of RA.

Lipid-based paleoecological and biogeochemical reconstruction of Store Saltsø, an extreme lacustrine system in SW Greenland

Polar lakes harbour a unique biogeochemistry that reflects the implications of climatic fluctuations against a susceptible yet extreme environment. In addition to polar, Store Saltsø (Kangerlussuaq, southwestern Greenland) is an endorheic lake with alkaline and oligotrophic waters that host a distinctive ecology adapted to live in such particular physico-chemical and environmental conditions. By exploring the sedimentary record of Store Saltsø at a molecular and compound-specific isotopic level, we were able to understand its ecology and biogeochemical evolution upon climate change. We employed lipid biomarkers to identify biological sources and metabolic traits in different environmental samples (shore terrace, sediment core, and white precipitates at the shore), and their succession over time to reconstruct the lake paleobiology. Different molecular ratios and geochemical proxies provided further insights toward the evolution of environmental conditions in the frame of the deglaciation history of Kangerlussuaq. The relative abundance of terrestrial (i.e., plant derived) biomarkers (odd long-chain n-alkanes, even long-chain n-alkanols, and phytosterols) in the upper half of the shore terrace versus the relatively more present aquatic biomarkers (botryococcenes and long-chain alkenones) in its lower half revealed higher lake water levels in the past. Moreover, the virtual absence of organics in the deepest section of the sediment core (32–29 cm depth) suggested that the lake did not yet exist at the northwestern shore of Store Saltsø ∼5100 years ago. According to the relative abundance of lipid biomarkers detected in the adjacent section above (29–25 cm depth), we hypothesize that the northwestern shore of Store Saltsø formed ∼4900 years ago. By combining the molecular and compound-specific isotopic analysis of lipids in a ∼360 cm sedimentary sequence, we recreated the paleobiology and evolution of an extreme lacustrine environment suitable for the study of the limits of life and the effects of climate warming.

Tetraether archaeal lipids promote long-term survival in extreme conditions.

The sole unifying feature of the incredibly diverse Archaea is their isoprenoid-based ether-linked lipid membranes. Unique lipid membrane composition, including an abundance of membrane-spanning tetraether lipids, impart resistance to extreme conditions. Many questions remain, however, regarding the synthesis and modification of tetraether lipids and how dynamic changes to archaeal lipid membrane composition support hyperthermophily. Tetraether membranes, termed glycerol dibiphytanyl glycerol tetraethers (GDGTs), are generated by tetraether synthase (Tes) by joining the tails of two bilayer lipids known as archaeol. GDGTs are often further specialized through the addition of cyclopentane rings by GDGT ring synthase (Grs). A positive correlation between relative GDGT abundance and entry into stationary phase growth has been observed, but the physiological impact of inhibiting GDGT synthesis has not previously been reported. Here, we demonstrate that the model hyperthermophile Thermococcus kodakarensis remains viable when Tes (TK2145) or Grs (TK0167) are deleted, permitting phenotypic and lipid analyses at different temperatures. The absence of cyclopentane rings in GDGTs does not impact growth in T. kodakarensis, but an overabundance of rings due to ectopic Grs expression is highly fitness negative at supra-optimal temperatures. In contrast, deletion of Tes resulted in the loss of all GDGTs, cyclization of archaeol, and loss of viability upon transition to the stationary phase in this model archaea. These results demonstrate the critical roles of highly specialized, dynamic, isoprenoid-based lipid membranes for archaeal survival at high temperatures.

Studies of Labware Contamination during Lipid Extraction in Mass Spectrometry-Based Lipidome Analysis.

In lipidomic analysis, plasticware is increasingly being used for lipid extraction and other sample processing procedures over glassware. However, a systematic investigation of the consequences of plasticware use on mass spectrometry (MS)-based lipidome analysis is lacking. In this work, we present an analytical approach for detecting and comparing solvent and labware contaminants encountered in lipidomic workflows. It is shown that the contaminant profiles varied widely between microcentrifuge tubes from different manufacturers. The most suitable polypropylene tubes tested introduced 847 labware-originating contaminant m/z's when three different manufacturing batches were tested for Folch lipid extractions. Of particular concern is that 21 primary amide and fatty acid surfactants were introduced that were identical to biological endogenous lipids, 16 of which had not been previously reported as leachables from polypropylene materials. Alternatively, the use of borosilicate glassware and PTFE-lined screw caps introduced 98 different contaminant m/z's across three manufacturing batches tested for Folch extractions. Despite the overwhelming number of labware contaminants introduced, current databases and literature only facilitated the identification of 32 contaminants. To address the dearth of publicly available contaminant information, we provide a comprehensive labware contamination repository containing high-resolution m/z values, adductation information, retention times, and MS/MS spectra. This resource should prove to be valuable for researchers in detecting and distinguishing contaminants from analytes of interest. A companion paper presents a detailed study of how labware contamination can lead to ion-suppression effects on coeluting lipids and interference in the analysis of endogenous lipids, such as those from human sera.

Sleep, Diet Quality, and Lipid Profile Assessment in NCAA Division I Acrobatics and Tumbling Student-Athletes: A Cross-Sectional Study

Objective Acrobatics and Tumbling (A&T), an emerging National Collegiate Athletics Association (NCAA) sport, involves athletes with rigorous training backgrounds, usually extending from youth through early adulthood. This study examines the sleep health, diet quality, and lipid profile of A&T athletes clustered by their performance position. Methods Forty-two A&T athletes, clustered as tops (n = 19; age = 19.6 ± 1.0 years; body mass index [BMI] = 22.3 ± 1.7 kg/m2) and bases (n = 23; age = 19.6 ± 1.3 years; BMI = 25.7 ± 2.5 kg/m2), completed preseason sleep and diet quality (Rapid Eating Assessment for Participants–Shortened [REAP-S]) surveys. Fasting blood samples were collected for lipid analysis. Body composition was assessed via dual-energy X-ray absorptiometry. Results Most athletes (71.4%; base n = 14, top n = 16) reported insufficient sleep (≤7 hours) and “good” sleep quality (90.4%, n = 38; base n = 18, top n = 20). Average REAP-S score was 29.24 ± 3.74. Approximately 31% (n = 13) displayed at least one undesirable lipid concentration according to medical guidelines for normal levels (total cholesterol [TC] < 200 mg/dL, triglycerides [TG] < 150 mg/dL, high-density lipoprotein cholesterol [HDL-C] > 40 mg/dL, low-density lipoprotein cholesterol [LDL-C] < 130 mg/dL). Approximately 20% exhibited elevated TC (top n = 4, base n = 4), 12.5% had elevated TG (base n = 5), 2.5% showed low HDL-C (base n = 1), and 10% presented elevated LDL-C (top n = 2, base n = 2). Conclusions Most athletes experienced suboptimal sleep (≤7 hours/night) and 31% displayed at least one undesirable lipid concentration (elevated TC, TG, or LDL-C or reduced HDL-C). Tailoring interventions with sports dietitians is recommended, focused on increasing monounsaturated and polyunsaturated fat intake while reducing saturated fat consumption. These interventions could mitigate cardiovascular risks, improve recovery, and possibly enhance athletic performance.

Recent Analytical Methodologies in Lipid Analysis.

Lipids represent a large group of biomolecules that are responsible for various functions in organisms. Diseases such as diabetes, chronic inflammation, neurological disorders, or neurodegenerative and cardiovascular diseases can be caused by lipid imbalance. Due to the different stereochemical properties and composition of fatty acyl groups of molecules in most lipid classes, quantification of lipids and development of lipidomic analytical techniques are problematic. Identification of different lipid species from complex matrices is difficult, and therefore individual analytical steps, which include extraction, separation, and detection of lipids, must be chosen properly. This review critically documents recent strategies for lipid analysis from sample pretreatment to instrumental analysis and data interpretation published in the last five years (2019 to 2023). The advantages and disadvantages of various extraction methods are covered. The instrumental analysis step comprises methods for lipid identification and quantification. Mass spectrometry (MS) is the most used technique in lipid analysis, which can be performed by direct infusion MS approach or in combination with suitable separation techniques such as liquid chromatography or gas chromatography. Special attention is also given to the correct evaluation and interpretation of the data obtained from the lipid analyses. Only accurate, precise, robust and reliable analytical strategies are able to bring complex and useful lipidomic information, which may contribute to clarification of some diseases at the molecular level, and may be used as putative biomarkers and/or therapeutic targets.

Effect of kilning on the macronutrient composition profile of three Swedish oat varieties

AbstractBackground and ObjectivesKilning is crucial in oat processing, to prevent rancidity and extend shelf‐life. This study examines kilning effects on the macronutrient composition in Swedish oat varieties Galant, Fatima, and Belinda. We compared two kilning methods: one mimicking industrial practice and a simplified version. We analyzed dietary fibers (arabinoxylan, β‐glucan), protein and amino acids, lipid profile, lipase activity, and antioxidant capacity in these oat samples.FindingsDistinct compositional differences were found: Galant had low lipid content, Fatima had elevated lipid and protein levels with fewer carbohydrates, and Belinda was rich in β‐glucan and dietary fibers. Both kilning procedures had similar impacts on all varieties, causing no major changes in dietary fiber or total protein content, but resulting in a 20% decrease in soluble proteins. Kilning decreased levels of several amino acids in Belinda, while the l‐glutamate/glutamine ratio increased across all varieties. Lipid analysis showed minimal kilning‐induced changes; yet, antioxidative capacity diminished. Both kilning methods effectively inactivated lipases.ConclusionsThese findings emphasize macronutrient variations among oat varieties and the effect of kilning on soluble proteins, amino acids, and antioxidative capacity.Significance and NoveltyThis study underscores the need for precise control in oat processing, crucial in plant‐based protein and novel food development for optimal quality and yield.

Longitudinal analysis of blood pressure and lipids in childhood nephrotic syndrome.

In the current study, longitudinal BP and lipid measurements were examined in a NEPTUNE cohort of children with newly diagnosed nephrotic syndrome (cNEPTUNE). We hypothesized that hypertensive BP and dyslipidemia would persist in children with nephrotic syndrome, regardless of steroid treatment response. A multi-center longitudinal observational analysis of data obtained from children < 19years of age with new onset nephrotic syndrome enrolled in the Nephrotic Syndrome Study Network (cNEPTUNE) was conducted. BP and lipid data were examined over time stratified by disease activity and steroid exposure. Generalized estimating equation regressions were used to find determinants of hypertensive BP and dyslipidemia. Among 122 children, the prevalence of hypertensive BP at any visit ranged from 17.4% to 57.4%, while dyslipidemia prevalence ranged from 40.0% to 96.2% over a median of 30months of follow-up. Hypertensive BP was found in 46.2% (116/251) of study visits during active disease compared with 31.0% (84/271) of visits while in remission. Dyslipidemia was present in 88.2% (120/136) of study visits during active disease and in 66.0% (101/153) while in remission. Neither dyslipidemia nor hypertensive BP were significantly different with/without medication exposure (steroids and/or CNI). In regression analysis, male sex and urine protein:creatinine ratio (UPC) were significant determinants of hypertensive BP over time, while eGFR was found to be a determinant of dyslipidemia over time. Results demonstrate persistent hypertensive BPs and unfavorable lipid profiles in the cNEPTUNE cohort regardless of remission status or concurrent steroid or calcineurin inhibitor treatment.

Spatio-temporal transcriptome and storage compound profiles of developing faba bean (Vicia faba) seed tissues.

Faba bean (Vicia faba) is a legume grown in diverse climate zones with a high potential for increased cultivation and use in food due to its nutritional seeds. In this study, we characterized seed tissue development in faba bean to identify key developmental processes; from embryo expansion at the expense of the endosperm to the maturing storage stages of the bean seed. A spatio-temporal transcriptome profiling analysis, combined with chemical nutrient analysis of protein, starch, and lipid, of endosperm and embryo tissues at different developmental stages, revealed gene expression patterns, transcriptional networks, and biochemical pathways in faba bean. We identified key players in the LAFL (LEC1, ABI3, FUS3, and LEC2) transcription factor network as well as their major repressors VAL1 and ASIL1. Our results showed that proteins accumulated not only in the embryo but also in the endosperm. Starch accumulated throughout seed development and oil content increased during seed development but at very low levels. The patterns of differentially expressed transcripts encoding proteins with functions in the corresponding metabolic pathways for the synthesis of these storage compounds, to a high extent, aligned with these findings. However, the early expression of transcripts encoding WRI1 combined with the late expression of oil body proteins indicated a not manifested high potential for lipid biosynthesis and oil storage. Altogether, this study contributes to increased knowledge regarding seed developmental processes applicable to future breeding methods and seed quality improvement for faba bean.

Effect of laser power on Raman analyses of lipids and amino acids: Implications for extraterrestrial life exploration

One of the primary objectives of Mars exploration missions is to search for traces of past or present life. The search for bioorganic molecules is highly desirable because they have diagnostic features to indicate the presence of life. Lipids and amino acids are particularly favored because of their high preservation potential in the geological record. Raman spectroscopy has emerged as a promising tool for detecting and identifying organic molecules on extraterrestrial planets. However, cautions should be exercised in operating Raman instruments to detect organic samples, especially concerning laser power. Excessive laser power can potentially alter spectral characteristics and even damage samples, while low power levels suffer from attenuation of the measured Raman signal, making it challenging to interpret. Therefore, it is crucial to determine the optimal Raman laser power for organic detection and build a laser power-based spectral library to increase our capability to interpret the Martian spectroscopic data. As such, we performed a comprehensive Raman analysis of several lipids (decanol, hexadecane, and palmitic acid) and amino acids (alanine, aspartic acid, glycine, histidine, and tyrosine). The Raman laser power varies in two modes, i.e., increasing from 1% (0.63 ± 0.01 mW) to 100% (66.40 ± 1.85 mW) and vice versa, within the operational range of Raman payloads of Mars rovers. The results show that different spectra can be obtained for the organic samples when using different excitation powers. Using high-power lasers could cause damage to lipid samples, whereas amino acids exhibit stability even under the strong irradiation of 100% laser power. In addition, low-power lasers significantly reduce the Raman signal of lipids, while amino acids remain detectable at low laser powers even as low as 1%. Therefore, the most effective and secure operation is to gradually increase the laser power in the Raman analyses for detecting various organic compounds. Our study serves as a reference for operating Raman instruments and contributes to the accurate interpretation of spectral data returned from spacecraft. The supplementary material provides all the spectral data, facilitating further comparisons with future in situ and orbital measurements on Mars.

Non-HDL-C in Conjunction to LDL-C is associated with Incidence of Chronic Coronary Syndrome in Clinical Settings

Background: The biggest cause of death and a major contributor to disability globally is coroner's artery disease (CAD). Chronic coronary syndrome (CCS) is a term that can be used to describe a wide variety of CAD clinical manifestations in clinical settings. Non-HDL-C is advised as a routine component of lipid analysis for risk assessment in patients with elevated plasma TGs. Conflicting results have been yielded as Non-HDL-C is a better marker comparing LDL-C.Objective: The purpose of this study is to find out the relationship of Non-HDL-C levels with the incidence of CCS in conjunction with LDL-C testing in a clinical setting. Methods: Observational analytical research with a cross-sectional design was conducted in Muhammadiyah Palembang Hospital from October to December 2019. Simple random sampling techniques were used to select 89 patients who met the study's inclusion and exclusion criteria. Non-HDL-C and LDL-C calculations based on routine lipid testing. The Chi-Square test with a significant p-value &lt;0,005 was used for bivariate analysis.Results: There is a statistically significant association between non-HDL-C levels and the incidence of CCS (p=0,001), as well as a significant association between LDL-C and CCS incidents (p=0,009). Conclusion: Non-HDL-C provide additional benefits in identifying CAD risk factors in outpatients with CCS patient as well as LDL-C

Lipidomics based on UHPLC/Q-TOF-MS to characterize lipid metabolic profiling in patients with newly diagnosed type 2 diabetes mellitus with dyslipidemia

Dyslipidemia often accompanies type 2 diabetes mellitus (T2DM). Elevated blood glucose in patients commonly leads to high levels of lipids. Lipid molecules can play a crucial role in early detection, treatment, and prognosis of T2DM with dyslipidemia. Previous lipid studies on T2DM mainly focused on Western diabetic populations with elevated blood glucose. In this research, we investigate both high blood sugar and high lipid levels to better understand changes in plasma lipid metabolism in newly diagnosed Chinese T2DM patients with dyslipidemia (NDDD). We used a plasma lipid analysis method based on ultra-high performance liquid chromatography coupled with mass spectrometry technology (UHPLC-MS) and statistical analysis to characterize lipid profiles and identify potential biomarkers in NDDD patients compared to healthy control (HC) subjects. Additionally, we examined the differences in lipid profiles between hyperlipidemia (HL) patients and HC subjects. We found significant changes in 15 and 23 lipid molecules, including lysophosphatidylcholine (LysoPC), phosphatidylcholine (PC), phosphatidylethanolamine (PE), sphingomyelin (SM), and ceramide (Cer), in the NDDD and HL groups compared to the HC group. These altered lipid molecules are associated with five metabolic pathways, with sphingolipid metabolism and glycerophospholipid metabolism being the most relevant to glucose and lipid metabolism changes. These lipid biomarkers are strongly correlated with traditional markers of glucose and lipid metabolism. Notably, Cer(d18:1/24:0), SM(d18:1/24:0), SM(d18:1/16:1), SM(d18:1/24:1), and SM(d18:2/24:1) were identified as essential potential biomarkers closely linked to clinical parameters through synthetic analysis of receiver operating characteristic curves, random forest analysis, and Pearson matrix correlation. These lipid biomarkers can enhance the risk prediction for the development of T2DM in individuals with dyslipidemia but no clinical signs of high blood sugar. Furthermore, they offer insights into the pathological mechanisms of T2DM with dyslipidemia.

Acetic acid stress response of the acidophilic sulfate reducer Acididesulfobacillus acetoxydans.

Acid mine drainage (AMD) waters are a severe environmental threat, due to their high metal content and low pH (pH <3). Current technologies treating AMD utilize neutrophilic sulfate-reducing microorganisms (SRMs), but acidophilic SRM could offer advantages. As AMDs are low in organics these processes require electron donor addition, which is often incompletely oxidized into organic acids (e.g., acetic acid). At low pH, acetic acid is undissociated and toxic to microorganisms. We investigated the stress response of the acetotrophic Acididesulfobacillus acetoxydans to acetic acid. A. acetoxydans was cultivated in bioreactors at pH 5.0 (optimum). For stress experiments, triplicate reactors were spiked until 7.5 mM of acetic acid and compared with (non-spiked) triplicate reactors for physiological, transcriptomic, and membrane lipid changes. After acetic acid spiking, the optical density initially dropped, followed by an adaptation phase during which growth resumed at a lower growth rate. Transcriptome analysis revealed a downregulation of genes involved in glutamate and aspartate synthesis following spiking. Membrane lipid analysis revealed a decrease in iso and anteiso fatty acid relative abundance; and an increase of acetyl-CoA as a fatty acid precursor. These adaptations allow A. acetoxydans to detoxify acetic acid, creating milder conditions for other microorganisms in AMD environments.

Acacia auriculiformis leaves’ powder as an alternative for antibiotics uses in broilers organic farming

The experiment tested Acacia auriculiformis leaves’ powder actions on broilers’ growing performance and their blood plasma lipid profile. So, an experiment with 150-day-old broiler chicks was set. At the end of week 3, all the broilers were weighed, and 10 homogenous groups of 12 chicks each were constituted, within whose 5 groups per gender. Also, Acacia auriculiformis (Aa) leaves were collected, dried during 2 weeks in laboratory rooms, and were powdered with a blender. Then, in addition to a control diet, 4 diets were made by incorporating 0.75%, 1.5%, 2.25% and 3%Aa leaves’ powder. So, the diets were 0%Aa, 0.75%Aa, 1.5%Aa, 2.25%Aa, and 3%Aa, respectively. Randomly, each broilers’ group was fed on a diet for 7 weeks and the birds were weekly weighed. At the end of week 10, 3 broilers of similar weights were slaughtered per group. Their blood was collected in 2 types of tubes, for blood cells count, and blood plasma lipid analysis. As a result, white blood cell (WBC) counts were 22.80, 21.52, 20.28 and 18.11*103/µL, with diets 0%Aa, 2.25%Aa, 1.5%Aa, and 3%Aa, respectively. Thus, this WBC count decrease confers an antibiotic action to Aa leaves powder. Following, HDL cholesterol content increased from 31.62 for diet 0%Aa to 37.80 mg/dL for diet 1.5%Aa (+6.18 mg/dL, p&lt;0.001). Simultaneously, with 1.5%Aa, triglyceride content was the smallest for 21.03 mg/dL (p&lt;0.001), and protein content was the highest for 4.01 g/dL. In conclusion, at 1.5% in the diet, Acacia auriculiformis leaves’ powder may be very beneficial to broilers’ organic rearing.

Classifying patients with psoriatic arthritis according to their disease activity status using serum metabolites and machine learning

IntroductionPsoriatic arthritis (PsA) is a heterogeneous inflammatory arthritis, affecting approximately a quarter of patients with psoriasis. Accurate assessment of disease activity is difficult. There are currently no clinically validated biomarkers to stratify PsA patients based on their disease activity, which is important for improving clinical management.ObjectivesTo identify metabolites capable of classifying patients with PsA according to their disease activity.MethodsAn in-house solid-phase microextraction (SPME)—liquid chromatography-high resolution mass spectrometry (LC-HRMS) method for lipid analysis was used to analyze serum samples obtained from patients classified as having low (n = 134), moderate (n = 134) or high (n = 104) disease activity, based on psoriatic arthritis disease activity scores (PASDAS). Metabolite data were analyzed using eight machine learning methods to predict disease activity levels. Top performing methods were selected based on area under the curve (AUC) and significance.ResultsThe best model for predicting high disease activity from low disease activity achieved AUC 0.818. The best model for predicting high disease activity from moderate disease activity achieved AUC 0.74. The best model for classifying low disease activity from moderate and high disease activity achieved AUC 0.765. Compounds confirmed by MS/MS validation included metabolites from diverse compound classes such as sphingolipids, phosphatidylcholines and carboxylic acids.ConclusionSeveral lipids and other metabolites when combined in classifying models predict high disease activity from both low and moderate disease activity. Lipids of key interest included lysophosphatidylcholine and sphingomyelin. Quantitative MS assays based on selected reaction monitoring, are required to quantify the candidate biomarkers identified.

Structural determination of Rickettsia lipid A without chemical extraction confirms shorter acyl chains in later-evolving spotted fever group pathogens.

Rickettsiae are Gram-negative obligate intracellular parasites of numerous eukaryotes. Human pathogens of the transitional group (TRG), typhus group (TG), and spotted fever group (SFG) rickettsiae infect blood-feeding arthropods, have dissimilar clinical manifestations, and possess unique genomic and morphological attributes. Lacking glycolysis, rickettsiae pilfer numerous metabolites from the host cytosol to synthesize peptidoglycan and lipopolysaccharide (LPS). For LPS, O-antigen immunogenicity varies between SFG and TG pathogens; however, lipid A proinflammatory potential is unknown. We previously demonstrated that Rickettsia akari (TRG), Rickettsia typhi (TG), and Rickettsia montanensis (SFG) produce lipid A with long 2' secondary acyl chains (C16 or C18) compared to short 2' secondary acyl chains (C12) in Rickettsia rickettsii (SFG) lipid A. To further probe this structural heterogeneity and estimate a time point when shorter 2' secondary acyl chains originated, we generated lipid A structures for two additional SFG rickettsiae (Rickettsia rhipicephali and Rickettsia parkeri) utilizing fast lipid analysis technique adopted for use with tandem mass spectrometry (FLATn). FLATn allowed analysis of lipid A structure directly from host cell-purified bacteria, providing a substantial improvement over lipid A chemical extraction. FLATn-derived structures indicate SFG rickettsiae diverging after R. rhipicephali evolved shorter 2' secondary acyl chains. While 2' secondary acyl chain lengths do not distinguish Rickettsia pathogens from non-pathogens, in silico analyses of Rickettsia LpxL late acyltransferases revealed discrete active sites and hydrocarbon rulers for long versus short 2' secondary acyl chain addition. Our collective data warrant determining Rickettsia lipid A inflammatory potential and how structural heterogeneity impacts lipid A-host receptor interactions.IMPORTANCEDeforestation, urbanization, and homelessness lead to spikes in Rickettsioses. Vector-borne human pathogens of transitional group (TRG), typhus group (TG), and spotted fever group (SFG) rickettsiae differ by clinical manifestations, immunopathology, genome composition, and morphology. We previously showed that lipid A (or endotoxin), the membrane anchor of Gram-negative bacterial lipopolysaccharide (LPS), structurally differs in Rickettsia rickettsii (later-evolving SFG) relative to Rickettsia montanensis (basal SFG), Rickettsia typhi (TG), and Rickettsia akari (TRG). As lipid A structure influences recognition potential in vertebrate LPS sensors, further assessment of Rickettsia lipid A structural heterogeneity is needed. Here, we sidestepped the difficulty of ex vivo lipid A chemical extraction by utilizing fast lipid analysis technique adopted for use with tandem mass spectrometry, a new procedure for generating lipid A structures directly from host cell-purified bacteria. These data confirm that later-evolving SFG pathogens synthesize structurally distinct lipid A. Our findings impact interpreting immune responses to different Rickettsia pathogens and utilizing lipid A adjuvant or anti-inflammatory properties in vaccinology.

Comparative analysis of the skin surface lipids between acne patients and controls using UFLC method

Comparative analysis of the skin surface lipids between acne patients and controls using UFLC method

LCMS: An R package for automated semitargeted analysis in lipidomics

AbstractWhile nontargeted analysis aims to profile and report the relative distributions of a wide range of molecules from different lipid classes/subclasses, its major challenge is the annotation and identification of the molecules. Semitargeted analysis circumvents the problem by establishing a (potentially large) list of molecules to be targeted in the samples that are identified before the analysis. This approach is particularly adapted for lipid analysis to help with the automation of lipid annotation and identification. However, the manual extraction of peaks for many molecules and many samples is time consuming. Consequently, an automation of these extractions is deeply required. This paper presents a free R package for the automation of semitargeted analysis for lipid analysis. From raw files collected with LC‐MS device and a list of molecules to target (containing their class), it automatically returns Excel files containing the intensities for each targeted molecule and each sample. This package allows a fast computation of the intensities. Furthermore, it guarantees the reproducibility of the results and is freely available and user‐friendly.Practical Applications: With the help of the R package presented in this paper, the use of semitargeted lipidomics as an alternative to untargeted analysis should be investigated by more labs. Work on the comparisons between the approaches could be conducted. While untargeted methods are mostly used, they require long pretreatments and identification of molecules of interest. On the contrary, in semitargeted analysis, once the integration table and retention time are obtained, the results are fast and directly interpretable. An idea for lipidomics would be to use untargeted lipidomics to compute the integration table and retention table, then use semitargeted analysis for a fast computation of well identified molecules.

Comparison of three rapid diagnostic tests for bloodstream infections using Benefit-risk Evaluation Framework (BED-FRAME).

Rapid diagnostic tests (RDTs) for bloodstream infections have the potential to reduce time to appropriate antimicrobial therapy and improve patient outcomes. Previously, an in-house, lipid-based, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) method, Fast Lipid Analysis Technique (FLAT MS), has shown promise as a rapid pathogen identification method. In this study, FLAT MS for direct from blood culture identification was evaluated and compared to FDA-cleared identification methods using the Benefit-risk Evaluation Framework (BED-FRAME) analysis. FLAT MS was evaluated and compared to Bruker Sepsityper and bioMérieux BioFire FilmArray BCID2 using results from a previous study. For this study, 301 positive blood cultures were collected from the University of Maryland Medical Center. The RDTs were compared by their sensitivities, time-to-results, hands-on time, and BED-FRAME analysis. The overall sensitivity of all platforms compared to culture results from monomicrobial-positive blood cultures was 88.3%. However, the three RDTs differed in their accuracy for identifying Gram-positive bacteria, Gram-negative bacteria, and yeast. Time-to-results for FLAT MS, Sepsityper, and BioFire BCID2 were all approximately one hour. Hands-on times for FLAT MS, Sepsityper, and BioFire BCID2 were 10 (±1.3), 40 (±2.8), and 5 (±0.25) minutes, respectively. BED-FRAME demonstrated that each RDT had utility at different pathogen prevalence and relative importance. BED-FRAME is a useful tool that can used to determine which RDT is best for a healthcare center.

Lipidomic analysis of facial skin surface lipids in acne in young women.

Alterations in the secretion and composition of skin surface lipids (SSL) are closely associated with the development of acne. Lipidomics is a useful tool to analyse the SSL of different types of acne. Our previous study found that phosphatidylserine and triacylglycerols dominate SSL changes in male acne and infantile acne, respectively. However, skin surface lipids as well as specific lipids in female acne patients remain to be investigated. To analyse and compare the SSL profile of acne women and healthy women and to discuss the involvement of differential lipids in acne development. Systematic lipidomics approach (high-throughput UPLC-QTOF-MS technology in combination with multivariate data analysis methods) was used to analyse the variations of SSL between acne and healthy groups. Analysis revealed significant differences in lipid content and composition between the two groups. Further analysis showed that levels of 13 individual lipids were significantly different and followed the same trend as the main class and subclasses. The largest individual contributor to the subgroup was triglycerides (TG) and phosphatidylinositol (PI). In addition, female acne patients exhibited reduced ceramide chain length (CCL) and increased levels of unsaturated fatty acids (UFAs), The changes of CCL in female acne are identical to male acne. There was a significantly higher level of TG and PI in the SSL of female acne patients. A reduction in CCL and an increase in UFAs content might contribute to the reduced skin barrier function in acne patients. The results suggest that female acne may have different pathogenesis than male acne.