LIFE EXPECTANCY STUDIES IN SPACE: CORRECTION OF MAGNESIUM DEFICITS
It seems clear that we should take advantage of the microgravity of the International Space Station (ISS) to serve as a laboratory in the investigation of aging – both on Earth and in Space as this process is accelerated in Space. The unique environment of the ISS would facilitate experimental model systems that would otherwise not be possible and could be utilized in studying the aging process over an entire lifespan. Even life span studies of rats require a period of 3 years on Earth. How much shorter might these studies be in Space? One hypothesis proposes that the aging process is triggered by the shortening of telomeres, species specific, repetitive DNA sequences and associated proteins that cap and protect the ends of chromosomes from deteriorating. Telomeres function somewhat like the ends of shoe laces which slowly unravel with increasing age and also with stress. The preservation of natural chromosome ends and the rejoining of broken DNA ends rely on a set of proteins thought to decline with advancing age. Magnesium (Mg) levels have been shown to be significantly decreased with space flight which may be at least partially responsible for the accelerated aging process in Space. It has been postulated that reductions in Mg. levels might disrupt the DNA and/or the proteins associated with the telomere required for telomere capping and in turn accelerate erosion of the telomeres. The mechanism of telomere shortening may be enhanced by Mg. - deficient induction of oxidative stress and inflammation as well as insulin resistance. Furthermore recent studies have also demonstrated a direct molecular link between telomeres and that telomeres play a major role in regulating mitochondrial dysfunction providing another link to aging. Identification and characterizaton of the underlying processes involved may require decades of research on the ISS. Until we have such information we will not be ready to spend long periods of times beyond low earth orbit.