Bone Formation and Skeletal Aging - The effects of oxygen tension and DNA repair

Aging is a process that affects everybody and importantly, affects all cells and therefore all the tissues in our body. In the worst cases, tissue aging leads to organ failure and death; in other cases, the effects of aging are more subtle and less dramatic. In our tissue of choice – bone and the skeletal system - aging manifests in the form of osteoporosis, low bone mineral density and a higher risk of fractures, all contributors to a higher morbidity [1]. There are several theories applicable to the process of aging, of which the free radical theory of aging is one of the oldest and well-studied. This theory, first proposed by Denham Harman in the 1950’s, states that organisms age because cells accumulate free radical damage over time [2]. Free radicals are atoms or molecules that have a single unpaired electron in their outer shell. Many biologically relevant free radicals are highly reactive and can be produced by the cell’s metabolic mechanisms. Free radicals can cause intracellular damage to DNA and proteins.