New studies
1. Astaxanthin has inhibitory effects on macrophage activation
Authors : Kishimoto et al Eur J Nutr 2009
In this study, they investigated the effects of astaxanthin on the expression of scavenger receptors, MMPs (essential link between mechanical stimulus), and pro-inflammatory cytokines (cellular communication) in macrophages. Macrophages were incubated with 5–10 lM astaxanthin for 24 h. We found that astaxanthin remarkably decreased the class A scavenger receptor (thought to be one of the main receptors involved in foam cell formation, mediating the influx of lipids into the macrophages) and CD36 expression (FAT) in the protein and mRNA levels. Astaxanthin also reduced MMP activity and expression. The mRNA expression of tumor necrosis factor-a, inducible nitric oxide synthase, and cyclooxygenase-2 were significantly suppressed by astaxanthin. Furthermore, astaxanthin inhibited the phosphorylation of nuclear factor-jB (activates or deactivates many protein enzymes, causing or preventing the mechanisms of diseases such as cancer and diabetes). These results indicate that astaxanthin has inhibitory effects on macrophage activation, such as scavenger receptors up-regulation, MMPs activation, and pro-inflammatory cytokines secretion.
2. Astaxanthin is effective in improving mitochondrial function
Authors: Wolf et al Astaxanthin and mitochondria J Nutr Biochem 2009 (2)
Mitochondria combine the production of energy with an efficient chain of reduction–oxidation (redox) reactions but also with the unavoidable production of reactive oxygen species. Oxidative stress leading to mitochondrial dysfunction is a critical factor in many diseases, such as cancer and neurodegenerative and lifestyle-related diseases. Effective antioxidants thus offer great therapeutic and preventive promise. Investigating the efficacy of antioxidants, we found that a carotenoid, astaxanthin (AX), decreased physiologically occurring oxidative stress and protected cultured cells against strong oxidative stress induced with a respiratory inhibitor. Moreover, AX improved maintenance of a high mitochondrial membrane potential and stimulated respiration. Investigating how AX stimulates and interacts with mitochondria, a redox-sensitive fluorescent protein (roGFP1) was stably expressed in the cytosol (intracellular fluid) and mitochondrial matrix to measure the redox state in the respective compartments. AX at nanomolar concentrations was effective in maintaining mitochondria in a reduced state. Additionally, AX improved the ability of mitochondria to remain in a reduced state under oxidative challenge. Taken together, these results suggest that AX is effective in improving mitochondrial function through retaining mitochondria in the reduced state.
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Published 10-03-03