Untargeted lipidomics uncovers lipid signatures distinguishing severe versus moderate forms of acutely decompensated cirrhosis

BACKGROUND AND AIM: Acutely decompensated of cirrhosis is a heterogeneous clinical entity associated with moderate mortality. In some patients, this condition develops quickly into a more often deadly acute-on-chronic liver failure (ACLF), in which other organs such as the kidneys or brain fail. The aim of this study was to characterize the blood lipidome in a large series of patients with cirrhosis and identify specific signatures associated with acute decompensation and ACLF development. METHODS: Serum untargeted lipidomics was performed in 561 patients with acutely decompensated (AD) cirrhosis (518 without and 43 with ACLF) (discovery cohort) and in 265 AD patients (128 without and 137 with ACLF) in whom serum samples were available to perform repeated measurements during the 28-day follow-up (validation cohort). Analyses were also performed in 78 AD patients included in a therapeutic albumin trial, 43 patients with compensated cirrhosis and 29 healthy subjects. RESULTS: The circulating lipid landscape associated with cirrhosis was characterized by a generalized suppression, which was more manifest during acute decompensation and in non-surviving patients. By computing discriminating accuracy and the variable importance projection score for each of the 223 annotated lipids, we identified a sphingomyelin fingerprint specific for AD cirrhosis and a distinct cholesteryl ester and lysophosphatidylcholine fingerprint for ACLF. Liver dysfunction, mainly, and infections were the principal net contributors to these fingerprints, which were dynamic and interchangeable between AD patients whose condition worsened to ACLF and those who improved. Notably, blood lysophosphatidylcholine levels increased in these patients after albumin therapy. CONCLUSIONS: Our findings provide insights into the lipid landscape associated with decompensation of cirrhosis and ACLF progression and identify unique noninvasive diagnostic biomarkers of advanced cirrhosis. LAY SUMMARY: Analysis of lipids in blood from patients with advanced cirrhosis reveals a general suppression of their levels in the circulation of these patients. A specific group of lipids known as sphingomyelins are useful to distinguish compensated from decompensated patients with cirrhosis. Another group of lipids designated cholesteryl esters further distinguish patients with decompensated patients who are at risk of developing organ failures

Low-Density Lipoprotein Has an Enormous Capacity To Bind (E)-4-Hydroxynon-2-enal (HNE): Detection and Characterization of Lysyl and Histidyl Adducts Containing Multiple Molecules of HNE

(E)-4-Hydroxynon-2-enal (HNE), an electrophilic bifunctional cytotoxic lipid peroxidation product, forms covalent adducts with nucleophilic side chains of amino acid residues. HNE-derived adducts have been implicated in many pathophysiological processes including atherosclerosis, diabetes, and Alzheimer’s disease. Tritium- and deuterium-labeled HNE (d4-HNE) were used orthogonally to study adduction with proteins and individual nucleophilic groups of histidyl, lysyl, and cysteine residues. Using tritium-labeled HNE, we detected the binding of 486 molecules of HNE per low-density lipoprotein (LDL) particle, significantly more than the total number of all reactive nucleophiles in the LDL particle. This suggests the formation of adducts that incorporate multiple molecules of HNE with some nucleophilic amino acid side chains. We also found that the reaction of a 1:1 mixture of d4-HNE and d0-HNE with N-acetylhistidine, N-acetyl-Gly-Lys-OMe, or N-acetyl cysteine generates 1:1, 2:1, and 3:1 adducts, which exhibit unique mass spectral signatures that aid in structural characterization. A domino-like reaction of initial 1:1 HNE Michael adducts of histidyl or lysyl nucleophiles with multiple additional HNE molecules forms 2:1 and 3:1 adducts that were structurally characterized by tandem mass spectrometry

Blood metabolomics uncovers inflammation-associated mitochondrial dysfunction as a potential mechanism underlying ACLF (vol 72, pg 688, 2020)

Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Analysis of protein carbonylation - pitfalls and promise in commonly used methods

Abstract Oxidation of proteins has received a lot of attention in the last decades due to the fact that they have been shown to accumulate and to be implicated in the progression and the patho-physiology of several diseases such as Alzheimer, coronary heart diseases, etc. This has also resulted in the fact that research scientist became more eager to be able to measure accurately the level of oxidized protein in biological materials, and to determine the precise site of the oxidative attack on the protein, in order to get insights into the molecular mechanisms involved in the progression of diseases. Several methods for measuring protein carbonylation have been implemented in different laboratories around the world. However, to date no methods prevail as the most accurate, reliable and robust. The present paper aims at giving an overview of the common methods used to determine protein carbonylation in biological material as well as to highlight the limitations and the potential. The ultimate goal is to give quick tips for a rapid decision making when a method has to be selected and taking into consideration the advantage and drawback of the methods

Développement de matériaux poreux hybrides innovants pour l'analyse glycomique

International audienceL'analyse glycomique consiste à établir le profil des oligosaccharides présents sur l'ensemble des glycoprotéines d'un fluide biologique d'intérêt (ex : plasma) . Cependant, la préparation des échantillons implique de nombreuses étapes souvent manuelles, très chronophages et peu compatibles avec l'analyse à haut débit des échantillons. Les matériaux préparés selon le procédé sol-gel, par leur grande adaptabilité en terme de porosité et de propriétés physico-chimiques, ont montré qu'ils pouvaient être utilisés pour une grande variété d'applications tels que la détection (capteurs) ou la capture de molécules d'intérêt , notamment dans le domaine biomédical. Dans cette optique, nous développons des matériaux à porosité bimodale pour faciliter et accélérer la préparation des échantillons dédiés à l'analyse glycomique. Les premiers résultats obtenus seront présentés, en particulier le procédé de synthèse, les modulations possibles des matériaux (microstructure et porosité) ainsi que la caractérisation de leurs propriétés texturales et microstructurales. Enfin, quelques résultats prometteurs obtenus à l'aide de ces matériaux sur des échantillons biologiquement pertinents seront également présentés

Innovative porous materials for enhanced glycomic analysis

International audienceHierarchical porosity sol-gel monoliths (HPMs) are of increasing interest for a wide variety of applications due to their outstanding microstructural (homogenous) and textural properties (high porosity and specific surface area) [1]. The high flow rate and low-pressure resultant compared to conventional materials, makes them suited for extraction and enrichment of analytes of interest in analytical techniques (HPLC, SPE, etc.) [2–4]. However, pure inorganic materials have rarely been considered for relevant applications in various omics fields such as metabolomics or proteomics [5].In the context, we report on: (i) a pure silica HPM based on a finely tuned bimodal porosity thoroughly controlled, (ii) coupled to a new way to a miniaturize shaping (iii) and its use as an innovative tool for sample preparation prior to glycan analysis by mass spectrometry, as a new source of disease biomarkers (glycomics analysis). The monolith synthesis will be presented with a special emphasize on its robustness and on the modulations of the bimodal porosity obtained ([0.1–5] μm and [1-25] nm). Beside microstructural and textural properties measurements (SEM, Hg porosimetry, etc.), the transport of small molecules through mesoporous network were evaluated by TEM tomography. Finally, the material was processed in different shapes and size (50 μm – 4 mm in diameter) demonstrating a high flexibility of our approach to produce devices dedicated to a biological analysis. The use of HPM for the analysis of both free and protein-bound oligosaccharides present in precious samples (human blood and milk) and their detection by MALDI-TOF mass spectrometry will be presented as a proof of concept. Optimized experimental conditions, as well as material textures and shapes, enabled straightforward and time-efficient purification and MS- based glycomics analysis using minute quantities (few μl) of solvents but above all of complex human biofluids, thus outperforming common laboratory protocols