Inhibition of lipoprotein lipid oxidation

Cholesteryl hemiazelate identified in CVD patients causes in vitro and in vivo inflammation

Oxidation of PUFAs in LDLs trapped in the arterial intima plays a critical role in atherosclerosis. Though there have been many studies on the atherogenicity of oxidized derivatives of PUFA-esters of cholesterol, the effects of cholesteryl hemiesters (ChEs), the oxidation end products of these esters, have not been studied. Through lipidomics analyses, we identified and quantified two ChE types in the plasma of CVD patients and identified four ChE types in human endarterectomy specimens. Cholesteryl hemiazelate (ChA), the ChE of azelaic acid (n-nonane-1,9-dioic acid), was the most prevalent ChE identified in both cases. Importantly, human monocytes, monocyte-derived macrophages, and neutrophils exhibit inflammatory features when exposed to subtoxic concentrations of ChA in vitro. ChA increases the secretion of proinflammatory cytokines such as interleukin-1β and interleukin-6 and modulates the surface-marker profile of monocytes and monocyte-derived macrophage. In vivo, when zebrafish larvae were fed with a ChA-enriched diet, they exhibited neutrophil and macrophage accumulation in the vasculature in a caspase 1- and cathepsin B-dependent manner. ChA also triggered lipid accumulation at the bifurcation sites of the vasculature of the zebrafish larvae and negatively impacted their life expectancy. We conclude that ChA behaves as an endogenous damage-associated molecular pattern with inflammatory and proatherogenic properties.

Fundamentals of Membrane Lipid Replacement: A Natural Medicine Approach to Repairing Cellular Membranes and Reducing Fatigue, Pain, and Other Symptoms While Restoring Function in Chronic Illnesses and Aging

Membrane Lipid Replacement (MLR) uses natural membrane lipid supplements to safely replace damaged, oxidized lipids in membranes in order to restore membrane function, decrease symptoms and improve health. Oral MLR supplements contain mixtures of cell membrane glycerolphospholipids, fatty acids, and other lipids, and can be used to replace and remove damaged cellular and intracellular membrane lipids. Membrane injury, caused mainly by oxidative damage, occurs in essentially all chronic and acute medical conditions, including cancer and degenerative diseases, and in normal processes, such as aging and development. After ingestion, the protected MLR glycerolphospholipids and other lipids are dispersed, absorbed, and internalized in the small intestines, where they can be partitioned into circulating lipoproteins, globules, liposomes, micelles, membranes, and other carriers and transported in the lymphatics and blood circulation to tissues and cellular sites where they are taken in by cells and partitioned into various cellular membranes. Once inside cells, the glycerolphospholipids and other lipids are transferred to various intracellular membranes by lipid carriers, globules, liposomes, chylomicrons, or by direct membrane-membrane interactions. The entire process appears to be driven by 'bulk flow' or mass action principles, where surplus concentrations of replacement lipids can stimulate the natural exchange and removal of damaged membrane lipids while the replacement lipids undergo further enzymatic alterations. Clinical studies have demonstrated the advantages of MLR in restoring membrane and organelle function and reducing fatigue, pain, and other symptoms in chronic illness and aging patients.

Membrane Lipid Replacement for chronic illnesses, aging and cancer using oral glycerolphospholipid formulations with fructooligosaccharides to restore phospholipid function in cellular membranes, organelles, cells and tissues

Membrane Lipid Replacement is the use of functional, oral supplements containing mixtures of cell membrane glycerolphospholipids, plus fructooligosaccharides (for protection against oxidative, bile acid and enzymatic damage) and antioxidants, in order to safely replace damaged, oxidized, membrane phospholipids and restore membrane, organelle, cellular and organ function. Defects in cellular and intracellular membranes are characteristic of all chronic medical conditions, including cancer, and normal processes, such as aging. Once the replacement glycerolphospholipids have been ingested, dispersed, complexed and transported, while being protected by fructooligosaccharides and several natural mechanisms, they can be inserted into cell membranes, lipoproteins, lipid globules, lipid droplets, liposomes and other carriers. They are conveyed by the lymphatics and blood circulation to cellular sites where they are endocytosed or incorporated into or transported by cell membranes. Inside cells the glycerolphospholipids can be transferred to various intracellular membranes by lipid globules, liposomes, membrane-membrane contact or by lipid carrier transfer. Eventually they arrive at their membrane destinations due to 'bulk flow' principles, and there they can stimulate the natural removal and replacement of damaged membrane lipids while undergoing further enzymatic alterations. Clinical trials have shown the benefits of Membrane Lipid Replacement in restoring mitochondrial function and reducing fatigue in aged subjects and chronically ill patients. Recently Membrane Lipid Replacement has been used to reduce pain and other symptoms as well as removing hydrophobic chemical contaminants, suggesting that there are additional new uses for this safe, natural medicine supplement. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.

Chlorinated Phospholipids and Fatty Acids: (Patho)physiological Relevance, Potential Toxicity, and Analysis of Lipid Chlorohydrins

Chlorinated phospholipids are formed by the reaction of hypochlorous acid (HOCl), generated by the enzyme myeloperoxidase under inflammatory conditions, and the unsaturated fatty acyl residues or the head group. In the first case the generated chlorohydrins are both proinflammatory and cytotoxic, thus having a significant impact on the structures of biomembranes. The latter case leads to chloramines, the properties of which are by far less well understood. Since HOCl is also widely used as a disinfecting and antibacterial agent in medicinal, industrial, and domestic applications, it may represent an additional source of danger in the case of abuse or mishandling. This review discusses the reaction behavior of in vivo generated HOCl and biomolecules like DNA, proteins, and carbohydrates but will focus on phospholipids. Not only the beneficial and pathological (toxic) effects of chlorinated lipids but also the importance of these chlorinated species is discussed. Some selected cleavage products of (chlorinated) phospholipids and plasmalogens such as lysophospholipids, (chlorinated) free fatty acids and α-chloro fatty aldehydes, which are all well known to massively contribute to inflammatory diseases associated with oxidative stress, will be also discussed. Finally, common analytical methods to study these compounds will be reviewed with focus on mass spectrometric techniques.

Lipid Replacement Therapy: a natural medicine approach to replacing damaged lipids in cellular membranes and organelles and restoring function

Lipid Replacement Therapy, the use of functional oral supplements containing cell membrane phospholipids and antioxidants, has been used to replace damaged, usually oxidized, membrane glycerophospholipids that accumulate during aging and in various clinical conditions in order to restore cellular function. This approach differs from other dietary and intravenous phospholipid interventions in the composition of phospholipids and their defense against oxidation during storage, ingestion, digestion and uptake as well as the use of protective molecules that noncovalently complex with phospholipid micelles and prevent their enzymatic and bile disruption. Once the phospholipids have been taken in by transport processes, they are protected by several natural mechanisms involving lipid receptors, transport and carrier molecules and circulating cells and lipoproteins until their delivery to tissues and cells where they can again be transferred to intracellular membranes by specific and nonspecific transport systems. Once delivered to membrane sites, they naturally replace and stimulate removal of damaged membrane lipids. Various chronic clinical conditions are characterized by membrane damage, mainly oxidative but also enzymatic, resulting in loss of cellular function. This is readily apparent in mitochondrial inner membranes where oxidative damage to phospholipids like cardiolipin and other molecules results in loss of trans-membrane potential, electron transport function and generation of high-energy molecules. Recent clinical trials have shown the benefits of Lipid Replacement Therapy in restoring mitochondrial function and reducing fatigue in aged subjects and patients with a variety of clinical diagnoses that are characterized by loss of mitochondrial function and include fatigue as a major symptom. This Article is Part of a Special Issue Entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.

Design, synthesis, and action of antiatherogenic antioxidants

Ample evidence supports the critical role of oxidized low-density lipoprotein (ox-LDL) in initiation and progression of atherosclerosis. Oxidation of LDL is a complex process involving several steps (processes) of reactions such as initiation and propagation. Both proteins and lipids in LDL undergo free radical-mediated oxidations leading to the formation of ox-LDL that plays a pivotal role in atherosclerosis. Antioxidants of various types (both aqueous and lipophilic) either arrest or retard the oxidation of LDL at various steps of the oxidation process (e.g., initiation or propagation). Certain lipophilic antioxidants act as the chain-terminating antioxidants leading to the inhibition of LDL oxidation. The current chapter describes the designing and efficacy of two novel lipophilic antioxidants (benzofuranol, BO-653 and aniline, BO-313) in inhibiting the LDL oxidation and atherogenesis in experimental animal model. Furthermore, the characteristics of an effective antioxidant to inhibit LDL oxidation and atherogenesis which dictates the designing of the antioxidant drug and its mechanism(s) of antiatherogenic action are discussed.

Antioxidative effect and active components from leaves of Lotus ( Nelumbo nucifera )

The DPPH scavenging effect, the inhibition of human low-density lipoprotein oxidation, and antioxidative contents were employed for the activity-guided purification to identify the antioxidant components of lotus leaves (leaves of Nelumbo nucifera Gaertn.). The methanolic extract of lotus leaves (LLM) was separated into ethyl acetate (LLME), n-butanol (LLMB), and water (LLMW) fractions. LLME and LLMB exhibited greater capacity to scavenge DPPH radical, delayed LDL oxidation, and had higher antioxidative contents than LLMW. Seven flavonoids were isolated from both fractions by column chromatography. On the basis of 1D- and 2D-NMR experiments and MS data analyses, these compounds were identified as catechin (1), quercetin (2), quercetin-3-O-glucopyranoside (3), quercetin-3-O-glucuronide (4), quercetin-3-O-galactopyranoside (5), kaempferol-3-O-glucopyranoside (6), and myricetin-3-O-glucopyranoside (7). Quercetin and its glycosides (compounds 2-5) exerted potent inhibition of LDL oxidation, whereas myricetin-3-O-glucopyranoside (7) showed stronger DPPH scavenging activity. These results indicate that the antioxidant capacity of lotus leaves is partially relevant to its flavonoids.

Schisanhenol attenuated ox-LDL-induced apoptosis and reactive oxygen species generation in bovine aorta endothelial cells in vitro

The aim of this paper was to investigate the protective effect of schisanhenol (Sal) isolated from Schisandra rubriflora Rhed, on human ox-LDL-induced bovine aorta endothelial cells (BAECs) apoptosis and intracellular reactive oxygen species (ROS) production in vitro. The BAECs were cultured with ox-LDL (200 microg/ml) in the presence and absence of Sal (10 and 50 micromol L(- 1)) for 24 h. The cytotoxicity of ox-LDL was evaluated by LDH leakage, cell viability and morphological change. Cell apoptosis was estimated by DNA ladder, chromatin condensation, and flow cytometry assay. The intracellular ROS production was detected by using DCF, a ROS probe, with laser confocal microscopy and flow cytometry. Sal was shown to reduce LDH leakage and increase cell viability. Sal also attenuated ox-LDL-induced BAECs apoptosis as indicated in typical internucleosomal DNA degradation (DNA ladder), condensed chromatin, and the sub-G1 peak appearance in flow cytometry assay. Furthermore, Sal was shown to inhibit ROS generation in BAECs with stimulation of ox-LDL. The results indicated that the anti-apoptosis effect of Sal on BACSs might be related to its inhibition of ROS generation.

The effect of an endogenous antioxidant glabridin on oxidized LDL

Oxidative stress is thought to play a central role in low-density lipoprotein (LDL) oxidation, and the oxidative modification of LDL is thought to be a key factor during early atherogenesis. Therefore, the prevention of LDL oxidation by antioxidants might arrest the progression of atherosclerosis. This study was conducted to determine the effect of glabridin, a natural polyphenolic isoflavone antioxidant isolated from licorice root, on LDL oxidation. The determination of the extent of LDL oxidation was accomplished by measuring the formation of thiobarbituric acid reactive substances (TBARS). The oxidative stress level was assessed using a FORM system/CR 3000 instrument. After the oral administration of a glycyrrhizin-free licorice-root methanol extract (containing glabridin 60 mg) to healthy subjects for 6 months, the subjects' oxidative stress level as well as plasma LDL oxidation decreased by 20%. We conclude that the dietary consumption of glabridin can partially protect LDL from oxidation.

Biochemical Assessments of Total Antioxidant Status in Active and Nonactive Female Adults with Intellectual Disability

Long-term physical activity is known to increase the antioxidant defense (AOD) system, whereas sedentary lifestyle is associated with oxidative stress (OS). The underlying molecular mechanisms are incompletely understood. The aim of this prospective, nonrandomized study was to evaluate and compare the relationship between long-term physical activity and inactivity and plasma antioxidant status in female adults with intellectual disability (ID) that were diagnosed after birth. A total of 21 adults with ID were examined. The following AOD was examined: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), vitamin E, and vitamin A. Inactive persons with ID had significantly lower SOD (p<0.05), CAT (p<0.05), and GPX (p<0.05). All plasma vitamin levels were significantly higher in physically active subjects (vitamin A: 1.42 +/- 0.05 mmol/l, vitamin E: 31.32 +/- 2.62 mmol/l) than in sedentary control subjects (vitamin A: 1.02 +/- 0.03 mmol/l, vitamin E: 18.88 +/- 2.23 mmol/l) p<0.01. These results suggest that regular physical activity is associated with preserved AODs in adults with ID. As opposed to a physically active lifestyle, an inactive results in low levels of antioxidants.

Protective effect of vitamin E supplements on experimental atherosclerosis is modest and depends on preexisting vitamin E deficiency

Vitamin E has failed to protect humans from cardiovascular disease outcome, yet its role in experimental atherosclerosis remains less clear. A previous study (Proc. Natl. Acad. Sci. USA 97:13830-13834; 2000) showed that vitamin E deficiency caused by disruption of the alpha-tocopherol transfer protein gene (Ttpa) is associated with a modest increase in atherosclerosis in apolipoprotein E gene deficient (Apoe(-/-)) mice. Here we confirm this finding and report that in Apoe(-/-)Ttpa(-/-) mice dietary alpha-tocopherol (alphaT) supplements restored circulating and aortic levels of alphaT, and decreased atherosclerosis in the aortic root to a level comparable to that seen in Apoe(-/-) mice. However, such dietary supplements did not decrease disease in Apoe(-/-) mice, whereas dietary supplements with a synthetic vitamin E analog (BO-653), either alone or in combination with alphaT, decreased atherosclerosis in Apoe(-/-) and in Apoe(-/-)Ttpa(-/-) mice. Differences in atherosclerosis were not associated with changes in the arterial concentrations of F(2)-isoprostanes and cholesterylester hydro(pero)xides, nor were they reflected in the resistance of plasma lipids to ex vivo oxidation. These results show that vitamin E at best has a modest effect on experimental atherosclerosis in hyperlipidemic mice, and only in situations of severe vitamin E deficiency and independent of lipid oxidation in the vessel wall.