RESULTS
The samples returned from space were analyzed
by specialized mass spectrometry equipment to
determine the amount of drug metabolites
formed by the liver cells from the drug
substances added. Overall this analysis showed
the rate of metabolism by the liver cells in space
was lower than that of the liver cells maintained
under similar conditions on Earth. This was true
for all of the drug substances tested as well as
for cells from 3 different liver donors. These
results indicate that microgravity may well
retard the rate of drug metabolism in the
human liver, although the mechanism for this
effect is yet unknown.Returned samples were also analyzed by gene
array to determine whether genetic expression
differed for cells in microgravity. Differences
were found, including 9,200 of 13,000 genes
that had at least 2-fold greater expression in space as compared to Earth and 9,800 genes that
had decreased expression in space. This large body of data is being analyzed for clues as to how
liver cell function changes in specific ways in the microgravity environment of space.
This investigation is complete and all results are published.
A 3-D aggregate composed of thousands of liver
cells. This aggregate has been grown in the
investigator's laboratory for 8 days in the NASA
Rotating Bioreactor. StelSys image.