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.