An untargeted metabolomic study using MALDI-mass spectrometry imaging reveals region-specific biomarkers associated with bowel inflammation.

Introduction: Inflammatory bowel diseases (IBDs) are chronic immune driven intestinal disorders with marked metabolic alteration. Mass spectrometry imaging (MSI) enables the direct visualization of biomolecules within tissues and facilitates the study of metabolic changes. Integrating multiple spatial information sources is a promising approach for discovering new biomarkers and understanding biochemical alteration within the context of the disease.

Penetration Profile of Terbinafine Compared to Amorolfine in Mycotic Human Toenails Quantified by Matrix-Assisted Laser Desorption Ionization-Fourier Transform Ion Cyclotron Resonance Imaging.

Introduction: Amorolfine 5% lacquer is an established topical treatment for fungal infection of the nails. The success of topical therapy for onychomycosis depends on whether the permeated drug concentration in the deep nail bed is retained above the effective antifungal minimum inhibitory concentration (MIC). We compared the penetration profile of amorolfine and a new topical formula of terbinafine in human mycotic toenails using matrix-assisted laser desorption ionization mass spectrometry imaging-Fourier transform ion cyclotron resonance (MALDI-FTICR) imaging.

Penetration Profiles of Four Topical Antifungals in Mycotic Human Toenails Quantified by Matrix-Assisted Laser Desorption Ionization-Fourier Transform Ion Cyclotron Resonance Imaging.

Introduction: Onychomycosis is a fungal infection of the nails that can be challenging to treat. Here, matrix-assisted laser desorption ionization-Fourier transform ion cyclotron resonance (MALDI-FTICR) imaging was applied to the quantitative analysis of the penetration profile of the antifungal compound, amorolfine, in human mycotic toenails. The amorolfine profile was compared with those of three other antifungals, ciclopirox, naftifine, and tioconazole.

MALDI Mass Spectrometry Imaging and Semi-Quantification of Topically Delivered Lactic Acid.

Background: Lactic acid is a common active ingredient in many topical skincare products; however, measuring its delivery into the skin is challenging due to the presence of a large level of endogenous lactic acid. In this study, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was used to quantitatively and qualitatively measure the delivery of lactic acid into the skin from a range of topical skincare products.

Materials And Methods: Porcine skin samples were treated with various skincare products containing lactic acid.

Early Life to Adult Brain Lipidome Dynamic: A Temporospatial Study Investigating Dietary Polar Lipid Supplementation Efficacy.

The lipid composition of the brain is well regulated during development, and the specific temporospatial distribution of various lipid species is essential for the development of optimal neural functions. Dietary lipids are the main source of brain lipids and thus contribute to the brain lipidome. Human milk is the only source of a dietary lipids for exclusively breastfed infant.

Hyaluronic acid detection and relative quantification by mass spectrometry imaging in human skin tissues.

Hyaluronic acid (HA) is a major component of the skin, contributing to tissue hydration and biomechanical properties. As HA content in the skin decreases with age, formulas containing HA are widely used in cosmetics and HA injections in aesthetic procedures to reduce the signs of aging. To prove the beneficial effects of these treatments, efficient quantification of HA levels in the skin is necessary, but remains difficult.

Neuronal Cholesterol Accumulation Induced by Cyp46a1 Down-Regulation in Mouse Hippocampus Disrupts Brain Lipid Homeostasis.

Impairment in cholesterol metabolism is associated with many neurodegenerative disorders including Alzheimer's disease (AD). However, the lipid alterations underlying neurodegeneration and the connection between altered cholesterol levels and AD remains not fully understood. We recently showed that cholesterol accumulation in hippocampal neurons, induced by silencing gene expression, leads to neurodegeneration with a progressive neuronal loss associated with AD-like phenotype in wild-type mice.

Longitudinal analysis of serum oxylipin profile as a novel descriptor of the inflammatory response to surgery.

Background: Oxylipins are potent lipid mediators demonstrated to initiate and regulate inflammation yet little is known regarding their involvement in the response to surgical trauma. As key modulators of the inflammatory response, oxylipins have the potential to provide novel insights into the physiological response to surgery and the pathophysiology of post-operative complications. We aimed to investigate the effects of major surgery on longitudinal oxylipin profile.

Development and Validation of a High-Throughput Ultrahigh-Performance Liquid Chromatography-Mass Spectrometry Approach for Screening of Oxylipins and Their Precursors.

Lipid mediators, highly bioactive compounds synthesized from polyunsaturated fatty acids (PUFAs), have a fundamental role in the initiation and signaling of the inflammatory response. Although extensively studied in isolation, only a limited number of analytical methods offer a comprehensive coverage of the oxylipin synthetic cascade applicable to a wide range of human biofluids. We report the development of an ultrahigh-performance liquid chromatography-electrospray ionization triple quadrupole mass spectrometry (UHPLC-MS) assay to quantify oxylipins and their PUFA precursors in 100 μL of human serum, plasma, urine, and cell culture supernatant.

Ultra performance liquid chromatography - mass spectrometry studies of formalin-induced alterations of human brain lipidome.

The development of 'omics' sciences offers new opportunities for the study of neurodegenerative diseases but increases at the same time the sample demand on brain banks that collect and store valuable human post-mortem tissue. Our study aims to evaluate in lipidomics the potential of formalin-fixed tissue compared with the cryopreservation method, considered as the gold standard for biochemical research. Two complementary liquid chromatography/mass spectrometry analytical platforms were used on the basis of hybrid quadrupole time-of-flight and triple quadrupole mass spectrometers.

Objective set of criteria for optimization of sample preparation procedures for ultra-high throughput untargeted blood plasma lipid profiling by ultra performance liquid chromatography-mass spectrometry.

Exploratory or untargeted ultra performance liquid chromatography-mass spectrometry (UPLC-MS) profiling offers an overview of the complex lipid species diversity present in blood plasma. Here, we evaluate and compare eight sample preparation protocols for optimized blood plasma lipid extraction and measurement by UPLC-MS lipid profiling, including four protein precipitation methods (i.e.

Lipidomics of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive brain disease that leads to an irreversible loss of neurons and cognition. It is the most common cause of dementia and can be considered as a major public health problem. At the histological level, AD is characterized by senile plaques and neurofibrillary tangles.

Ceramides and sphingomyelinases in senile plaques.

The senile plaque is a hallmark lesion of Alzheimer disease (AD). We compared, without a priori, the lipidome of the senile plaques and of the adjacent plaque-free neuropil. The analysis by liquid chromatography coupled with electrospray ionization mass spectrometry revealed that laser microdissected senile plaques were enriched in saturated ceramides Cer(d18:1/18:0) and Cer(d18:1/20:0) by 33 and 78% respectively with respect to the surrounding neuropil.

Choline-containing phospholipids in microdissected human Alzheimer's disease brain senile plaque versus neuropil.

Background: Lipidomic studies related to Alzheimer's disease have been reported on either biological fluids or large human brain samples. For a better understanding of the role of lipids, especially during the amyloid-β peptide aggregation, it is crucial to determine the composition of the senile plaque versus the surrounding tissue, that is, the neuropil.

Results: A laser microdissection step was added to the analysis by UPLC-MS/MS.

Development of a novel method for quantification of sterols and oxysterols by UPLC-ESI-HRMS: application to a neuroinflammation rat model.

Cholesterol and oxysterols are involved as key compounds in the development of severe neurodegenerative diseases and in neuroinflammation processes. Monitoring their concentration changes under pathological conditions is of interest to get insights into the role of lipids in diseases. For numerous years, liquid chromatography coupled to mass spectrometry has been the method of choice for metabolites identification and quantification in biological samples.

Comparison of electrospray ionization, atmospheric pressure chemical ionization and atmospheric pressure photoionization for a lipidomic analysis of Leishmania donovani.

A comparison of electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) for the analysis of a wide range of lipids has been performed on standard mixtures and extracts of Leishmania donovani promastigotes resistant to Amphotericin B (AmB). Calibration model, precision, limits of detection and quantification (LOD and LOQ) were assessed for each source. APPI provided the highest signal, signal-to-noise (S/N), and sensitivity for non-polar and low-polarity lipids, while ESI and APCI gave better results for the most polar ones.

The subgenomic promoter of brome mosaic virus folds into a stem-loop structure capped by a pseudo-triloop that is structurally similar to the triloop of the genomic promoter.

In brome mosaic virus, both the replication of the genomic (+)-RNA strands and the transcription of the subgenomic RNA are carried out by the viral replicase. The production of (-)-RNA strands is dependent on the formation of an AUA triloop in the stem-loop C (SLC) hairpin in the 3'-untranslated region of the (+)-RNA strands. Two alternate hypotheses have been put forward for the mechanism of subgenomic RNA transcription.

Atmospheric pressure photoionization as a powerful tool for large-scale lipidomic studies.

Lipidomic studies often use liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) for separation, identification, and quantification. However, due to the wide structural diversity of lipids, the most apolar part of the lipidome is often detected with low sensitivity in ESI. Atmospheric pressure (APPI) can be an alternative ionization source since normal-phase solvents are known to enhance photoionization of these classes.