Effect of age on the breath methylated alkane contour, a display of apparent new markers of oxidative stress

Reactive oxygen species (ROS) are toxic byproducts of mitochondrial energy production that inflict oxidative stress, a constant barrage of damage to D NA, proteins, lipids, and other biologically important molecules. Oxidative stress has been implicated as a pathologic mechanism in aging and in sever al diseases. We developed a display of apparent new markers of oxidative st ress in human beings, the breath methylated alkane contour (BMAC). The BMAC is a three-dimensional display of C4 to C20 alkanes and monomethylated alk anes in breath, with x-axis = carbon chain length, z-axis = methylation sit e, and y-axis = alveolar gradient (relative abundance in breath minus relat ive abundance in room air). In 102 normal human subjects of 9 to 89 years o f age, alveolar gradients of components of the BMAC increased significantly with age. The mean alveolar gradient of all components of the BMAC varied from negative in the youngest quartile (ages 9 to 31 years) to positive in the oldest quartile (ages 74 to 89 years)(P < 2.10(-9)). These findings wer e consistent with an increase in oxidative stress with advancing age, altho ugh an age-related decline in clearance by cytochrome p450 may have contrib uted. The BMAC provides a display of apparent new markers of oxidative stre ss with potential applications in aging research, clinical diagnosis, pharm acology, and toxicology.