FuturePundit provides more commentary on recent research into the consequences of age-related damage to cellular mitochondria. "Failures in mitochondria due to aging are suspected of causing atherosclerosis and heart disease ... Mentally I file this under 'Totally Unsurprising'. Mitochondria have their own DNA for some of their proteins. Some gerontologists (e.g. Aubrey de Grey) theorize that the mitochondrial DNA (mtDNA) acts as a sort of Achilles Heel in cellular metabolism and cellular aging. Very reactive chemical compounds get generated in mitochondria by breaking down sugar and some of those compounds occasionally break loose and fly into the mtDNA causing damage. So mtDNA might accumulate damage at a much faster rate than DNA in the nucleus."