Nutrition for health and sports performance
Nick Draper, Helen Marshall in Exercise Physiology, 2014
Phospholipids and glycolipids are involved in a variety of functions within the body including providing the insulating (myelin) sheath around nerve fibres, assisting in blood clotting and maintenance of each cell’s membrane and structure. Phospholipids and glycolipids, as their names suggest, are comprised of a lipid and a phosphate or glucose component respectively. Their structure is similar to that of a triglyceride with the exception that one of the fatty acids is replaced with a phosphate group and usually a nitrogen group in the case of a phospholipid, and a carbohydrate group in the case of glycolipids. A phospholipid bilayer, along with small amounts of glycolipids and cholesterol, forms the basic structure of the plasma membrane of cells. The phospholipid molecules have hydrophilic phosphate heads and hydrophobic fatty acid tails. The glycolipid structure is similar, with a glucose-based hydrophilic head. The structure of the plasma membrane is depicted in Figure 2.14. These unique properties enable phospholipids and glycolipids to create a sealed membrane that separates cells from their outside environment. The forces of attraction are strong enough that no covalent bond is needed between adjacent molecules to maintain the structural integrity of the cell membrane.
Lipid Raft Alteration and Functional Impairment in Aged Neuronal Membranes
Shamim I. Ahmad in Aging: Exploring a Complex Phenomenon, 2017
The rafts constitute preformed entities in the cell membrane and are present in different parts of the lipid bilayer [105]. These microdomains are asymmetric and contain 30%–50% cholesterol, 3–5 levels higher than other membrane regions [106–108], and up to 70% of cellular sphingomyelins (SM) [106,109]. Their external sheet is particularly rich in sphingoglycolipids. 10%–15% of the membrane sphingolipids and 10%–20% of the membrane glycolipids are concentrated in the rafts. Their cytoplasmic sheet is rich in glycerolipids. If the plasma membrane is very rich in PL, including phosphatidylethanolamine (PE) and phosphatidylcholine (PC), less than 30% of the lipids contained in the rafts are of this type [106–108,110]. The rafts are also very rich in gangliosides, in particular the GM1 which is almost exclusively located there [109]. Within these rafts, the hydrocarbon chains of the FAs are mainly saturated and in conformation stretched to form with the cholesterol a phase less fluid than the rest of the plasma membrane (Figure 24.1). The presence of raft-specific stabilizing proteins, such as flotillins or caveolins, is also necessary to maintain a stable conformation [105,110,111].
Neonatal enteral nutrition
Janet M Rennie, Giles S Kendall in A Manual of Neonatal Intensive Care, 2013
There are four major lipid types: glycerides, phospholipids, sterols and fatty acids. The fat globules in human milk consist mainly of triglyceride, with some cholesterol, phospholipid and fatty acids. Formula milks have only traces of cholesterol and few long-chain fatty acids. The amount of fat in breast milk changes with gestation and the phase of feeding. Fat in formula milk is constant and is derived from cow’s milk and/or vegetable oils such as corn oil. These fats are less well digested and absorbed than fat from breast milk. Artificially fed premature babies may lose up to 50% of ingested long-chain fat in their stools. Clinical trials in preterm infants fed formulas containing both arachidonic acid and docosahexaenoic acid have shown beneficial effects on the developing visual system and cognition in the first year of life. ESPGHAN has published recommended intakes of both these nutrients.
Noninvasive urine metabolomics of prostate cancer and its therapeutic approaches: a current scenario and future perspective
Published in Expert Review of Proteomics, 2021
Deepak Kumar, Kavindra Nath, Hira Lal, Ashish Gupta
As regards the subclasses of the metabolomics, other emerging areas such as lipidomics, volatilomics, etc., have also been progressing independently, with promising relevance in the study of characteristics biomarkers of the patho-physiological milieu. Lipidomics comprises the qualitative and quantitative analysis of the lipid species in the biological samples [15]. Lipid is a chief participant in the molecular cascade of cancer development [16]. The lipid plays a variety of roles; as essential building blocks in membrane development, as fuel to fulfill the cellular energy demand, as a central player as a signaling molecule and regulating a variety of cellular functions [16]. During malignant progression, several strategies are adopted in the tumor microenvironment to earn lipids and in parallel reprogramming the metabolism [16]. Altered lipidomic profiles associated in malignant milieu, have gained attention in connecting the dots to explore the cancer detection, pathogenesis, progression and therapeutic targets [16–18].
Serum metabolomics of end-stage renal disease patients with depression: potential biomarkers for diagnosis
Published in Renal Failure, 2021
Dezhi Yuan, Tian Kuan, Hu Ling, Hongkai Wang, Liping Feng, Qiuye Zhao, Jinfang Li, Jianhua Ran
In this study, we also found abnormalities in glycerolipid metabolism. Elevated levels of LysoPC(18:1), PG(36:1) and PA(34:2) are observed in ESRD patients with depression compared with ESRD patients without depression. Phospholipids that account for 60% of the brain weight, is critical for brain neuronal structures especially synaptic structures [54]. The three phospholipids of PA, PG, and LysoPC play important roles in signal transduction of dopamine, serotonin, glutamate, and acetylcholine [55,56]. The dysregulation of lipid metabolism has been demonstrated in patients and rats with CKD and ESRD [57–59]. It has been reported that PA, PG, and LysoPC are important signaling molecules with various biological functions involved in cell proliferation and inflammatory processes [60–62]. Therefore, our current demonstrated the dysregulation of lipid metabolism in ESRD patients with depression.
Toxicological profile of lipid-based nanostructures: are they considered as completely safe nanocarriers?
Published in Critical Reviews in Toxicology, 2020
Asaad Azarnezhad, Hadi Samadian, Mehdi Jaymand, Mahsa Sobhani, Amirhossein Ahmadi
SLNs were first introduced in the early 1990s as a substitute for conventional colloid carriers, such as emulsions and polymeric NPs (Ekambaram et al. 2012). SLNs are colloidal carriers with a size between 50 and 1000 nm, which are formed from biologic lipids dispersed in the liquid (oil) phase. To overcome the problems associated with the presence of lipid in the liquid phase, solid lipid particles are used instead of liquid oils. The active ingredient, such as the drug, is melt or mixed with the lipid phase during the manufacturing process and is added to the liquid phase. In this way, the APIs enter into the structure of the NPs (drug encapsulation) (Thassu et al. 2007; Ekambaram et al. 2012). The solid lipid can be selected from a variety of lipids including, monoglycerides to triglycerides, glyceride mixtures, and lipid acids.