Lipoic Acid prevents the changes of intracellular lipid partitioning by free Fatty Acid

Antioxidants Supplementation Reduces Ceramide Synthesis Improving the Cardiac Insulin Transduction Pathway in a Rodent Model of Obesity

Obesity-related disruption in lipid metabolism contributes to cardiovascular dysfunction. Despite numerous studies on lipid metabolism in the left ventricle, there is no data describing the influence of n-acetylcysteine (NAC) and α-lipoic acid (ALA), as glutathione precursors, on sphingolipid metabolism, and insulin resistance (IR) occurrence. The aim of our experiment was to evaluate the influence of chronic antioxidants administration on myocardial sphingolipid state and intracellular insulin signaling as a potential therapeutic strategy for obesity-related cardiovascular IR. The experiment was conducted on male Wistar rats fed a standard rodent chow or a high-fat diet with intragastric administration of NAC or ALA for eight weeks. Cardiac and plasma sphingolipid species were assessed by high-performance liquid chromatography (HPLC). The proteins expressed from sphingolipid and insulin signaling pathways were determined by Western blot. Antioxidant supplementation markedly reduced ceramide accumulation by lowering the expression of selected proteins from the sphingolipid pathway and simultaneously increased the myocardial sphingosine-1-phosphate level. Moreover, NAC and ALA augmented the expression of GLUT4 and the phosphorylation state of Akt (Ser473) and GSK3β (Ser9), which improved the intracellular insulin transduction pathway. Based on our results, we may postulate that NAC and ALA have a beneficial influence on the cardiac ceramidose under IR conditions.

The protective effect of lipoic acid on selected cardiovascular diseases caused by age-related oxidative stress

Oxidative stress is considered to be the primary cause of many cardiovascular diseases, including endothelial dysfunction in atherosclerosis and ischemic heart disease, hypertension, and heart failure. Oxidative stress increases during the aging process, resulting in either increased reactive oxygen species (ROS) production or decreased antioxidant defense. The increase in the incidence of cardiovascular disease is directly related to age. Aging is also associated with oxidative stress, which in turn leads to accelerated cellular senescence and organ dysfunction. Antioxidants may help lower the incidence of some pathologies of cardiovascular diseases and have antiaging properties. Lipoic acid (LA) is a natural antioxidant which is believed to have a beneficial effect on oxidative stress parameters in relation to diseases of the cardiovascular system.

Scavenging of blood glutamate for enhancing brain-to-blood glutamate efflux

The presence of excess glutamate in the brain interstitial fluid characterizes several acute pathological conditions of the brain, including traumatic brain injury and stroke. It has been demonstrated that it is possible to eliminate excess glutamate in the brain by decreasing blood glutamate levels and, accordingly, accelerating the brain-to-blood glutamate efflux. It is feasible to accomplish this process by activating blood resident enzymes in the presence of the respective glutamate cosubstrates. In the present study, several glutamate cosubstrates and cofactors were studied in an attempt to identify the optimal conditions to reduce blood glutamate levels. The administration of a mixture of 1 mM pyruvate and oxaloacetate (Pyr/Oxa) for 1 h decreased blood glutamate levels by ≤50%. The addition of lipoamide to this mixture resulted in a further reduction in blood glutamate levels of >80%. In addition, in vivo experiments showed that lipoamide together with Pyr/Oxa is able to decrease blood glutamate levels to a greater extent than Pyr/Oxa alone, and accordingly, this enhances the glutamate efflux from the brain to the blood. These results may outline a novel neuroprotective strategy with increased effectiveness for the removal of excess brain glutamate in various neurodegenerative conditions.