Mitochondrial Senescence and Oxidative Stress

The intracellular mitochondria, organelles involved in energy metabolism, are central to the process of cell senescence. They are also involved in regulating thermogenesis, calcium buffering, and integrating apoptosis. With aging, mitochondria become less efficient, in part due to mutations in the cell nucleus, derepressing the expression of proteins that compete with mitochondrial function. This disrupts energy metabolism for the cell and makes the mitochondria more porous, releasing reactive oxygen species into the rest of the cell. The mitochondrial production of reactive oxygen species is inversely proportional to longevity in animals. The oxidative activity also damages the mitochondria themselves. Mitochondria have their own DNA strands, and these accumulate mutations with age. In tissues dependent on progenitor (stem) cells, mitochondrial DNA mutations can disrupt replication.

Free radicals and reactive oxidative species can produce mutations in nuclear material and oxidize proteins and lipids throughout the cells. Aging involves an accumulation of oxidative damage at the cellular level, if not an increase in its intensity as well. The thiol-containing antioxidant mechanisms, typified by glutathione but represented by a number of sulfur-containing species, represent an important buffer against intracellular free radicals, but decline with age due to downregulation of their synthetic enzymes. Confirming the cellular trend to oxidative stress in aging cells, clinical biomarkers of oxidation and antioxidant mechanisms reveal that systemic oxi-dative stress increases with aging characterized by lower concentrations of vitamins E and C and carotenes as well as lower activities of Cu-Zn-superoxide dismutase, catalase, and glutathione peroxidase.

How To Add Ten Years To Your Life

How To Add Ten Years To Your Life

When over eighty years of age, the poet Bryant said that he had added more than ten years to his life by taking a simple exercise while dressing in the morning. Those who knew Bryant and the facts of his life never doubted the truth of this statement.

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