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Lipidomic Insight into Membrane Remodeling in Aging and Neurodegenerative Diseases
Published in Abhai Kumar, Debasis Bagchi, Antioxidants and Functional Foods for Neurodegenerative Disorders, 2021
In a healthy state, the adult human brain lipidome is under strict homeostatic control. Lipidome adapts to the structural and functional needs of the neural cells in a region-specific manner. Some basic characteristics are shared between regions such as the average chain length (18 carbon atoms) and the SFA:UFAs ratio (40:60, respectively), but there are differences in other lipid traits such as the particular content of DHA which is strictly maintained in a range between 8% and 13% depending on the specific region. This DHA content ensures the specific and special structural and functional properties of the neural cells (and particularly neurons), covers the generation of lipid mediators that signal cells for specific functions and survival mechanisms and, additionally, functions as a target of oxidative damage based on the high susceptibility derived from the number of double bonds. Curiously, DHA synthesis requires oxidative conditions, and, in turn, DHA is a target of oxidative stress. To maintain this dynamic pool of DHA constant, cells offer several mechanisms including biosynthesis pathways (for DHA, lipid mediators, antioxidants), as well as lipid remodeling and repair mechanisms which are under homeostatic control.
Lipidomics in Human Cancer and Malnutrition
Published in Qiu-Xing Jiang, New Techniques for Studying Biomembranes, 2020
Iqbal Mahmud, Timothy J. Garrett
The entire spectrum of lipid molecular species in any biological system, tissue, cell or fluid is called the lipidome, and the profiling/mapping of the lipidome is called lipidomics.1,2 Lipidomics not only involves the full characterization of lipid molecular species, but also explains biological roles with respect to expression/regulation of genes/proteins involved in lipid metabolism and function.3 Lipidomics can be either untargeted, in which case global lipid profiling is usually performed on complex biological mixtures, or targeted, in which lipids of interest are already known and the instrument is set to analyze only those of interest.4,5 Lipids are a collection of an extremely heterogeneous group of molecules and have been divided into eight categories (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterol lipids, prenol lipids, saccharolipids, and polyketides) where ketoacyl or isoprene subunits are the two common building blocks6–9 (Figure 2.1).
Functional Omics and Big Data Analysis in Microalgae
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
Chetan Paliwal, Tonmoy Ghosh, Asha A. Nesamma, Pavan P. Jutur
Lipidomics can be used to quantify different lipid classes along with their molecular species (Brügger 2014). A lipidome gives insights into lipid remodeling during altered environmental conditions such as nitrogen starvation. A study on Chlorella sp. (Trebouxiophyceae) and Nannochloropsis sp. (Eustigmatophyceae) has shown that in nitrogen depletion, phosphoglycerolipids tend to increase while long-chain fatty acids in TAGs were broken down (Martin et al. 2014). Another study to assess the variation in lipidomes due to heat stress on C. reinhardtii found that at 42°C, cells produce higher polyunsaturated TAGs and diacylglycerols (DAGs), while major chloroplastic monogalactosyldiacyl glycerol sn1-18:3/sn2-16:4 was decreased, triggering an increase in accumulation of DAG sn1-18:3/sn2-16:4 and TAG sn1-18:3/sn2-16:4/sn3-18:3 (Légeret et al. 2016). The study also revealed that TAGs are converted from DAGs via direct conversion from monogalactosyldiacylglycerols (MGDG). The study also finds that the third fatty acid of a TAG is generally originated from a phosphatidyl ethanolamine or a diacylglyceryl-O-4′- (N, N, N, -trimethyl)-homoserine betaine.
What can we learn from the platelet lipidome?
Published in Platelets, 2023
Gaëtan Chicanne, Jean Darcourt, Justine Bertrand-Michel, Cédric Garcia, Agnès Ribes, Bernard Payrastre
The application of lipidomic approaches to measure large-scale lipid species is now extending into the clinical field, as illustrated by the term “clinical lipidomics” which aims to quantify the lipidome of cells, biopsies or body fluids from patients and link it to clinical data, genomics and proteomics [25]. This discipline is expected to allow identification of diagnostic/prognostic biomarkers and to help the monitoring of therapy. The clinical importance of platelets is well-recognized in cardiovascular diseases and in bleeding diathesis. It is also strongly emerging in immune, inflammatory and likely malignant diseases. Clinical lipidomics of platelets is therefore expected to provide new insights in various pathologies. However, it is important to keep in mind that there is a certain degree of heterogeneity of the platelet lipidome in healthy individuals [10,11]. The platelet lipid profile is in part dynamic and variables like age, gender and diet may contribute to this interindividual heterogeneity. Nevertheless, the platelet lipidome has been reported to vary in different diseases such as liver disease [26], hyperlipoproteinemia and dyslipoproteinemias [27,28], arterial hypertension [29], cancer [30], and following dietary supplement of n-3 polyunsaturated fat [31].
Bio-chemical markers of chronic, non-infectious disease in the human tear film
Published in Clinical and Experimental Optometry, 2022
Sultan Alotaibi, Maria Markoulli, Jerome Ozkan, Eric Papas
With the caveat that sampling meibum involves different techniques to those used for the tear film as a whole40 and in general, the profile of lipids in the two substrates is not identical,41 high-pressure liquid chromatography–mass spectrometry has been used to study meibum taken from healthy individuals, as well as in patients with diabetes and dry eye disease.30 This work reported that reduced triglyceride and OAHFA levels were associated with diabetes, as were increases in cholesterol esters, the phospholipids—phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol, as well as in sphingomyelin and glucosylceramide. The significance of these findings is difficult to understand due to the coexistence of diabetes and dry-eye disease among the study groups. Further work is needed to establish if changes in the lipidome can be firmly linked to specific disease processes.
Liposomes as vehicles for topical ophthalmic drug delivery and ocular surface protection
Published in Expert Opinion on Drug Delivery, 2021
José Javier López-Cano, Miriam Ana González-Cela-Casamayor, Vanessa Andrés-Guerrero, Rocío Herrero-Vanrell, Irene Teresa Molina-Martínez
The lipid layer is the outermost layer of the preocular tear film and has been widely associated to the reduction of the surface tension favoring the spread of the tear film over the entire surface and the protection against tear evaporation [22,27]. Its production occurs in the Meibomian glands [24,28] and include a complex variety of lipids. The tear lipidome contains amphiphilic and nonpolar lipids which have different function. The group of amphiphilic lipids is composed of phospholipids including phosphatidylcholine, lysophosphatidylcholine and phosphatidylethanolamine and others such as sphingolipids [28–30]. Amphiphilic lipids appear to form a sublayer capable of interacting with polar and nonpolar tear compounds. The polar heads are oriented toward the aqueous layer and the apolar ones interact with the nonpolar lipids. In this way, the amphiphilic sublayer allows the formation of a stable nonpolar lipid sublayer on the surface and its spreading [30,31]. Nonpolar lipid sublayer comprehends mainly wax esters, cholesteryl esters, and triglycerides. This sublayer is directly in contact with the air and when it is in proper amounts prevents the evaporation of aqueous layer. If the lipid layer is destabilized, aqueous evaporation increases, causing pathologies such as dry eye disease (DED) [31,32].