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Sima, the 47 months-old Sprague Dawley rat — interview with Dr. Harold Katcher

Talks about Sima - the longest lived Sprague Dawley rat ever - and his E5 plasma-based therapeutic

Key points from the interview:

  • Sprague Dawley rats usually live 24-36 months
  • previous recorded maximum lifespan of 45.5 months
  • Sima has now lived 47 months
  • average lifespan in treated cohort increased, but Sima is outlier
  • difference may be due to variation of original biological age, or success of each application - lots of variables
  • healthspan was also extended - measured cognitive function and organ function
  • aiming to double or triple maximum lifespan
  • plasma treatments seem to be temporary, E5 treatment is semi-permanent
  • seems to be a different mechanism that determines maximum lifespan
  • ovary plays an import part if female ageing
  • Cold Spring Harbor hid us in a corner - ageing community would prefer to overlook us
  • 1 rat month is equivalent to 2.5 years - so equivalent of human living an extra 20 years
  • think we will do better than that
  • wants to do a dog study
  • looking at different methods of administration, e.g. patches
  • could generate more activity per milligram
  • competitors all believe ageing happens at the cellular level - but has been shown that's not the case
  • if you put a young cell in and old body, then it becomes old, and vice versa
  • may be able to synthesize E5 in future (currently from pigs)
  • original intention was to use plasma exchange - but now thinks that effect would be temporary
  • skin test looking good 7 months later (single application) which might suggest no pro-ageing factors in blood
  • final question... when might we be able to increase maximum lifespan of humans
  • Harold thinks maybe about a year... and will be one of the first volunteers!

See more details about the experiment in the blog: Harold Katcher’s E5/Elixir (Young Plasma) Rat Trial Results

Visit website:

See also: Company Yuvan Research - US arm of Harold Katcher's young plasma research

Details last updated 10-Feb-2023

Mentioned in this Resource

Cold Spring Harbor Laboratory (CSH)

Biomedical research and education lab with programs in cancer, neuroscience, plant biology and quantitative biology

Harold Katcher

Professor at University of Maryland - working on rejuvenation blood factors

Topics mentioned on this page:
Young Blood, Rejuvenation
Sima, the 47 months-old Sprague Dawley rat — interview with Dr. Harold Katcher